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Showing 1 - 200 of 3043 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 22, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 21, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 84, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 30, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 351, SJR: 0.726, h-index: 43)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 3)
Acta Biomaterialia     Hybrid Journal   (Followers: 25, SJR: 2.02, h-index: 104)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 1)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 8, SJR: 0.172, h-index: 29)
Acta Haematologica Polonica     Free   (SJR: 0.123, h-index: 8)
Acta Histochemica     Hybrid Journal   (Followers: 3, SJR: 0.604, h-index: 38)
Acta Materialia     Hybrid Journal   (Followers: 238, SJR: 3.683, h-index: 202)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.615, h-index: 21)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.442, h-index: 21)
Acta Oecologica     Hybrid Journal   (Followers: 10, SJR: 0.915, h-index: 53)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription   (Followers: 1)
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 3, SJR: 0.311, h-index: 16)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2)
Acta Poética     Open Access   (Followers: 4)
Acta Psychologica     Hybrid Journal   (Followers: 23, SJR: 1.365, h-index: 73)
Acta Sociológica     Open Access  
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.059, h-index: 77)
Acta Urológica Portuguesa     Open Access  
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 4)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 3)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 2)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 4)
Acute Pain     Full-text available via subscription   (Followers: 13)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 5)
Additive Manufacturing     Hybrid Journal   (Followers: 7, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 21)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 135, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 25, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 11, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 26, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 9, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 29, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Dermatology     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 6)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 41, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 25, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 41, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 50, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 61)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 353, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 43, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 325, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 405, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 15, SJR: 2.18, h-index: 116)
Agricultural Systems     Hybrid Journal   (Followers: 30, SJR: 1.275, h-index: 74)
Agricultural Water Management     Hybrid Journal   (Followers: 39, SJR: 1.546, h-index: 79)
Agriculture and Agricultural Science Procedia     Open Access  
Agriculture and Natural Resources     Open Access   (Followers: 1)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 54, SJR: 1.879, h-index: 120)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.434, h-index: 14)
Air Medical J.     Hybrid Journal   (Followers: 5, SJR: 0.234, h-index: 18)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.285, h-index: 3)
Alcohol     Hybrid Journal   (Followers: 10, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 8)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
Alpha Omegan     Full-text available via subscription   (SJR: 0.121, h-index: 9)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 8, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 49, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 47, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 39, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 8, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 15, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 25, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 32, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 45, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 235, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 57, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 26, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 22, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 34, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 57, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 11)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 4, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 37, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 167, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 161, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 1, SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Agriculture, Ecosystems & Environment
  [SJR: 1.879]   [H-I: 120]   [54 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0167-8809 - ISSN (Online) 1873-2305
   Published by Elsevier Homepage  [3043 journals]
  • Are traditional home gardens in southern Ethiopia heading for
           extinction' Implications for productivity, plant species richness and
           food security
    • Authors: Beyene Teklu Mellisse; Katrien Descheemaeker; Ken E. Giller; Tesfaye Abebe; Gerrie W.J. van de Ven
      Pages: 1 - 13
      Abstract: Publication date: 15 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 252
      Author(s): Beyene Teklu Mellisse, Katrien Descheemaeker, Ken E. Giller, Tesfaye Abebe, Gerrie W.J. van de Ven
      While home garden systems are acknowledged for their capacity of supporting a very dense population, the productivity of these systems and their contribution to food security and dietary diversity are poorly quantified. Although several articles document the decrease in species richness in home gardens due to processes of modernization, relatively little attention has been given to how the change in diversity impacted productivity. Five predominant home garden systems identified in a previous study were intensively monitored during 12 months within four districts of Sidama and Gedeo zones of southern Ethiopia. Data from 24 farms were collected on plant species, soil characteristics, crop inputs, field sizes and crop yields and livestock production. The productivity of enset for both food and feed was lowest in Enset-coffee home gardens. Barley and khat yielded significantly more per ha in Khat-based systems than in other ones. Maize and coffee productivity did not differ significantly between home garden types. Overall crop productivity was lowest in the traditional Enset-coffee systems (1820kgDMha−1) and highest in the newly evolved Enset-cereal-vegetable systems (3020DMkgha−1). Energy productivity from food crops was higher in Enset-based systems (43GJha−1) than in other systems whereas revenue was lowest in Enset-based systems (719US$ha−1) and highest in newly evolved Khat-based systems (6817US$ha−1). The rate of N application through compost explained 30% of the variability in kocho standing biomass. The rate of N application in inorganic fertilizer explained 43% and 25% of the variability in khat and barley yield respectively. There was no positive effect of plant species richness on total crop and energy productivity except for the revenue in enset-oriented systems. Khat-based and Enset-cereal-vegetable systems were more food secure than the traditional home gardens, and these newly evolved systems also did not lead to a loss in plant species richness. The modification of traditional home garden systems by introducing the high value cash crop khat and annual cereals in response to farmland constraints and market opportunities enabled smallholders to maintain food security and dietary diversity without jeopardizing plant species richness. With population density expected to continually increase in the region, improvement options tailored to the specific systems are required for sustainable development.

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.09.026
      Issue No: Vol. 252 (2017)
  • Transport mechanisms for veterinary pharmaceuticals from beef cattle
           feedyards to wetlands: Is aerial deposition a contributing source'
    • Authors: Melissa A. Sandoz; Kimberly J. Wooten; Sheree L. Clendening; Loren L. Hensley; Lucas R. Smith; Philip N. Smith
      Pages: 14 - 21
      Abstract: Publication date: 15 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 252
      Author(s): Melissa A. Sandoz, Kimberly J. Wooten, Sheree L. Clendening, Loren L. Hensley, Lucas R. Smith, Philip N. Smith
      Veterinary pharmaceuticals from beef cattle feedyards have, with increasing frequency, been identified as contaminants in aquatic systems. Transport of these pharmaceuticals has generally been assumed to be via manure land application, surface runoff, or groundwater percolation. However, veterinary pharmaceuticals in airborne particulate matter downwind of beef cattle feedyards have recently been documented, indicating that aerial transport and deposition are a potential transport mechanism in arid and semi-arid environments. In this study, 35 hydrologically discrete playa wetlands within 15km of beef cattle feedyards were examined for occurrence of six steroid hormones and eight antibiotics. 17α-trenbolone, estrone, estradiol, tetracycline, chlortetracycline, oxytetracycline, tylosin, and monensin were all detected in either water or sediment samples. Concentrations for the majority of analytes were <15ng/g in sediment and <70ng/L in water. Tylosin and monensin were detected at highest concentrations in water, at 3 and 84μg/L, respectively. A correlation between distance from the nearest beef cattle feedyard and concentration of monensin in playa water was observed, similar to correlations observed between pharmaceutical concentrations and distance from feedyard among air samples collected downwind of feedyards. This study suggests that airborne transport and deposition of pharmaceutical-laden particulate matter are a possible contributor to pharmaceutical concentrations in aquatic systems. Aerial deposition of pharmaceutical-laden particulate matter, not typically included in risk assessments, is of yet poorly characterized but may play a significant role in pharmaceutical transport in arid and semi-arid locations and deserves further investigation.
      Graphical abstract image

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.09.016
      Issue No: Vol. 252 (2017)
  • Assessing changes in structural vegetation and soil properties following
           riparian restoration
    • Authors: Robin Hale; Paul Reich; Tom Daniel; Philip S. Lake; Timothy R. Cavagnaro
      Pages: 22 - 29
      Abstract: Publication date: 15 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 252
      Author(s): Robin Hale, Paul Reich, Tom Daniel, Philip S. Lake, Timothy R. Cavagnaro
      Efforts are underway in many areas to restore riparian zones to arrest and/or reverse their degradation and the subsequent loss of the ecosystem services they provide. Despite strong links between edaphic conditions and riparian zone function, limited research has tested how soil properties respond to restoration, especially in an experimental context. With this important knowledge gap in mind, we established a field experiment to asssess structural vegetation and soil responses in the eight years following livestock exclusion and replanting in lowland streams in south-eastern Australia. On three streams, paired restored and control sites were experimentally established and we monitored vegetation (stem density, cover of bare ground and tree canopy, and loadings of organic matter), once beforehand, and then biennually after restoration. Selected soil properties (total carbon, total nitrogen, plant-available phosphorus) were sampled once shortly after restoration, then after another five years. Significant changes in structural vegetation occurred (e.g. decreased bare ground, increased plant stem density, organic matter, and canopy cover). In contrast, those soil properties did not respond. A mega-drought occurred throughout much of the study which was immediately followed by severe flooding. The floods redistributed organic matter at our study sites, with this effect mediated by vegetation structure: the probability of organic matter retention was positively correlated with groundcover and stem density of plants. The timing of flooding was also correlated with increased soil carbon and nitrogen, which could be due to increased productivity in these systems (for the former), or potentially due to increased fertiliser inputs or increased fixation (for the latter). Our study is the first to comprehensively and experimentally test how vegetation, litter layer and surface soil properties respond following riparian restoration, and will help guide the development and implementation of other monitoring programmes.
      Graphical abstract image

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.09.036
      Issue No: Vol. 252 (2017)
  • Effectiveness of field isolation distance, tillage practice, cultivar type
           and crop rotations in controlling phoma stem canker on oilseed rape
    • Authors: L. Hossard; V. Souchere; M.H. Jeuffroy
      Pages: 30 - 41
      Abstract: Publication date: 15 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 252
      Author(s): L. Hossard, V. Souchere, M.H. Jeuffroy
      Modern agriculture has led to simpler agricultural landscapes that favour the spread of pathogens and increase pressure from pests and diseases. Landscape-dependent interactions between crops and pathogens, including disease related dispersal patterns, and the benefits of reducing pathogen significance call for the design of disease-suppressive landscapes. Model-based assessment is the most efficient method of choosing among management strategies. Based on a case study in France, we ranked the effectiveness of different crop mosaics for control of phoma stem canker on winter oilseed rape (WOSR). Assessed crop mosaics were developed from strategies defined by local stakeholders: (1) isolating target from source fields (all WOSR or only WOSR harbouring RlmX specific resistance), and (2) specifying tillage on WOSR stubble according to cultivar type (with or without RlmX). Model simulations highlighted the effectiveness of WOSR-isolation as compared to RlmX-isolation. Our analyses suggest that tillage (mouldboard ploughing) was the most important factor in explaining the size and genetic structure of the pathogen population (determinant in explaining the breakdown of resistance), and yield loss. While the pathogen population and yield loss decreased with intensive management of non-RlmX-cultivars (85% of WOSR), the same management with RlmX-cultivars modified the genetic structure of the pathogen population. Increasing isolation distances led to reductions in pathogen population and yield loss only in the strategy of WOSR-isolation. Isolating source and target RlmX-cultivar had no effect on the evolution of the population's genetic structure. Although effective in phoma stem canker control, changing tillage can require significant changes for farms. Isolation distance would require extensive information on the landscape, and imply an aggregation of crops that might or might not be possible depending on a farm's spatial organization. This study could lead to the design of a Decision Support System targeting high risk (diseased) WOSR fields to be ploughed or isolated from the following year's cultivation.

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.10.001
      Issue No: Vol. 252 (2017)
  • Carbon dynamics of a warm season turfgrass using the eddy-covariance
    • Authors: Roshani Pahari; Monique Y. Leclerc; Gengsheng Zhang; Hafsah Nahrawi; Paul Raymer
      Pages: 11 - 25
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Roshani Pahari, Monique Y. Leclerc, Gengsheng Zhang, Hafsah Nahrawi, Paul Raymer
      Despite their ubiquitous presence in the urban landscape throughout the United States, scant attention has been given to evaluate the magnitude of net carbon balance from turfgrasses. Warm season turfgrasses, in particular, have largely been understudied for their carbon sequestration potential. With questions being frequently raised on the environment friendliness of warm season turfgrasses, detailed and robust studies focusing on the carbon behavior of such systems are warranted. This study delves into the carbon balance of ‘Tifway’ bermudagrass, the extensively used warm-season turfgrass in Georgia and other subtropical and warm temperate areas. Using the eddy-covariance method, the amount of CO2 captured by a highly managed turfgrass system was measured by deploying two eddy-covariance systems for the study period of 31 months. The results show that ‘Tifway’ bermudagrass is a net sink of carbon, sequestering it at the rate of 4.51–5.15MgCha−1 yr−1. The turf canopy as well as management activities carried out in the farm appear to have a powerful influence on the carbon behavior of the turf. Seasonal and monthly fluxes suggest that turf is an efficient assimilator of carbon during its active growth period of summer and fall months. The results show that the turf sequestered higher amounts of carbon than many agricultural crop systems, supporting the assertion that it is an efficient assimilator of atmospheric carbon.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.09.015
      Issue No: Vol. 251 (2017)
  • The dynamic mechanism of landscape structure change of arable landscape
           system in China
    • Authors: Penghui Jiang; Qianwen Cheng; Zhuzhou Zhuang; Haoqing Tang; Manchun Li; Liang Cheng; Xiaolong Jin
      Pages: 26 - 36
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Penghui Jiang, Qianwen Cheng, Zhuzhou Zhuang, Haoqing Tang, Manchun Li, Liang Cheng, Xiaolong Jin
      The healthy functioning of arable landscape ecosystems depends on their functional structure and productivity. In view of current global climate change and constant population mobility, the global agricultural industry has to address the effects of such factors on the functional structure of arable lands. In our research on these issues, we combined information on land use/cover changes with several other datasets. These include meteorological data from 1 823 national and local meteorological stations, agrometeorological disasters from 430 national monitoring stations, and population surveys covering 9 856 townships. Our findings indicate that the arable landscape system in China shows an overall trend of fragmentation, with the extent of the core arable land decreasing by 10 336.06km2. This trend is affected minimally by climate differences and population changes in traditional agricultural regions. However, in eastern and western China, the trend is affected significantly by the rate of population aging, the population migration rate, and the agricultural labor scale. Urban land expansion plays a key role in changing the arable landscape system. Rapid urbanization in the form of an integral transition from arable land to construction, which is represented by large-scale increase in construction land area, is the core dynamic mechanism of landscape structure change of arable landscape systems in China.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.09.006
      Issue No: Vol. 251 (2017)
  • Impacts of management intensification on ground-dwelling beetles and
           spiders in semi-natural mountain grasslands
    • Authors: Malie Lessard-Therrien; Jean-Yves Humbert; Izabela Hajdamowicz; Marzena Stańska; Roel van Klink; Lukas Lischer; Raphaël Arlettaz
      Pages: 59 - 66
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Malie Lessard-Therrien, Jean-Yves Humbert, Izabela Hajdamowicz, Marzena Stańska, Roel van Klink, Lukas Lischer, Raphaël Arlettaz
      Agricultural intensification is one of the major threats to the biodiversity of montane and subalpine grasslands. This calls for regional agriculture policies that efficiently protect their flora and fauna without jeopardizing agricultural viability. We experimentally sought a sustainable management, testing the effects of fertilisation (slurry) and aerial irrigation (sprinklers) – separately and in combination (at different levels of intensity) – on the arthropod communities occurring in extensively-managed montane and subalpine meadows in the SW Swiss Alps. Four years after the start of the intensification experiment, we measured the abundance, species richness, community composition and variability (β-diversity) of ground-dwelling beetles and spiders. The abundance of both taxa showed a curvilinear relationship with management intensity. Spider abundance peaked at a moderate level of intensification while ground beetle abundance appeared to be more resilient to intensification, peaking at a high level of intensification. These responses were mainly driven by fertilisation, while irrigation played a minor role. For both taxa, we found no impact of irrigation or fertilisation, either when applied separately or in combination on species richness. Community composition was altered by management intensification in both taxa, but community variability was not. Given these taxon-specific patterns for abundance, applying organic fertiliser and water at levels corresponding to two-thirds of the quantity necessary to achieve local maximum hay yield appears to be compatible with the maintenance of rich ground-dwelling arthropod communities in mountain grasslands.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.08.025
      Issue No: Vol. 251 (2017)
  • Conservation agriculture based on crop rotation and tillage in the
           semi-arid Loess Plateau, China: Effects on crop yield and soil water use
    • Authors: Lei Sun; Shulan Wang; Yujiao Zhang; Jun Li; Xiaoli Wang; Rui Wang; Wei Lyu; Ningning Chen; Qian Wang
      Pages: 67 - 77
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Lei Sun, Shulan Wang, Yujiao Zhang, Jun Li, Xiaoli Wang, Rui Wang, Wei Lyu, Ningning Chen, Qian Wang
      In the semi-arid Loess Plateau region, water stress is the main limiting factor for rainfed agriculture; thus, conservation agriculture has been proposed to address this problem in these areas. Since 2007, a middle- to long-term experiment was established in Heyang County, Shaanxi, a region typical of the Loess Plateau, to evaluate the impact of no-tillage (NT), subsoiling tillage (ST) and conventional tillage (CT) on crop yield, water use, and soil water dynamics for winter wheat (Triticum aestivum L.) continuous cropping (WWC), spring maize (Zea mays L.) continuous cropping (SMC), and spring maize-winter wheat rotation cropping (MWR) systems. The highest four-year average wheat yield amounting to 5958kgha−1 was attained in MWR-ST, while the highest maize yield advantage averaging 772kgha−1 was obtained in SMC-NT. There were no significant differences in evapotranspiration (ET) and soil water storage (SWS) at the sowing/harvest stage among all treatments, but the relative greater average SWS before sowing was maintained under conservation tillage practices. The highest water use efficiency (WUE) reaching 10.0kgha−1 mm−1 for wheat in MWR and 20.3kgha−1 mm−1 for maize in SMC was obtained under ST treatment, while the significant WUE advantage of NT compared with CT was only obtained in SMC. At key growth stages, the higher soil water content (SWC) in the 0–200cm soil profile was maintained in the conservation tillage and MWR system for wheat but in the conservation tillage and SMC system for maize. The longer-duration fallows did not produce a better effect on SWS at the sowing stage, while the reduction of soil disturbance enhanced SWS compared with CT. In summary, tillage, cropping system, and their interaction effect produced significant effects on crop production and soil water status, and the above findings might be helpful to draft appropriate management strategies to realize optimal crop yield based on water use.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.09.011
      Issue No: Vol. 251 (2017)
  • Nitrogen losses, use efficiency, and productivity of early rice under
           controlled-release urea
    • Authors: Pengfei Li; Jianwei Lu; Yang Wang; Sen Wang; Saddam Hussain; Tao Ren; Rihuan Cong; Xiaokun Li
      Pages: 78 - 87
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Pengfei Li, Jianwei Lu, Yang Wang, Sen Wang, Saddam Hussain, Tao Ren, Rihuan Cong, Xiaokun Li
      Ammonia (NH3) volatilization and nitrogen (N) surface runoff from rice (Oryza sativa L.) paddies contribute to air and water pollution in China and everywhere else. The purposes of this study were to assess N losses through NH3 volatilization and surface runoff and to determine the grain yield and N use efficiency (NUE) of early rice in double rice cropping system in southern China. We implemented six treatments viz., control with 0kgNha−1 (CK), basal application and split application (1/2 at transplanting, 1/4 at tillering, and 1/4 at panicle stages) of urea (U), and basal applications of three controlled-release urea (CRU) sources (polyurethane-coated urea [CRU-1], degradable polymer-coated urea [CRU-2], and water-based polymer-coated urea [CRU-3]) all applied at 165kgNha−1. Results showed that CRU-1 and CRU-2 significantly reduced NH3 volatilization (23 to 62%) and N surface runoff losses (8 to 58%) compared with U. Precipitation and ammonium-nitrogen (NH4-N) concentration in surface water from rice paddy were predominant factors defining N losses through NH3 volatilization and surface runoff. Application of CRU reduced NH4-N concentration and pH of surface water and N losses through surface runoff. The CRU produced similar (−3 to 4%) or higher (5–16%) rice grain yields and increased NUE (3 to 34%) and N uptake (3–55%) compared with U. Polymer-coated urea can reduce environmental risks of N losses through volatilization and surface runoff while maintaining rice yield and N uptake, it also enhances NUE compared with urea in double rice cropping system in southern China.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.09.020
      Issue No: Vol. 251 (2017)
  • Can our global food system meet food demand within planetary
    • Authors: J.G. Conijn; P.S. Bindraban; J.J. Schröder; R.E.E. Jongschaap
      Pages: 244 - 256
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): J.G. Conijn, P.S. Bindraban, J.J. Schröder, R.E.E. Jongschaap
      Global food demand is expected to increase, affecting required land, nitrogen (N) and phosphorus (P) inputs along with unintended emissions of greenhouse gasses (GHG) and losses of N and P. To quantify these input requirements and associated emissions/losses as a function of food demand, we built a comprehensive model of the food system and investigated the effects of multiple interventions in the food system on multiple environmental goals. Model outcomes are compared to planetary boundaries for land system change, climate change and the global N and P cycles to identify interventions that direct us towards a safe operating space for humanity. Results show a transgression of most boundaries already for 2010 and a drastic deterioration in the reference scenario for 2050 in which no improvements relative to 2010 were implemented. We defined the following improvements for 2050: reduction of waste, less consumption of animal products, higher feed conversion efficiency, higher crop and grassland yields, reduction of N and P losses from agricultural land and reduction of ammonia (NH3) volatilization. The effects of these measures were quantified individually and in combination. Significant trade-offs and synergies in our results underline the importance of a comprehensive analysis with respect to the entire food system, including multiple measures and environmental goals. The combination of all measures was able to partly prevent transgression of the boundaries for: agricultural area requirement, GHG emission and P flow into the ocean. However, global mineral N and P fertilizer inputs and total N loss to air and water still exceeded their boundaries in our study. The planetary boundary concept is discussed in relation to the selected variables and boundary values, including the additional necessity of eliminating the dependency of our food production on finite P reserves. We argue that total N loss is a better indicator of the environmental impacts of the global N cycle than fertilizer N input. Most measures studied in this paper are also on the agenda of the United Nations for Sustainable Development, which gives added support to their implementation.

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.06.001
      Issue No: Vol. 251 (2017)
  • Drivers of forage provision and erosion control in West African
           savannas—A macroecological perspective
    • Authors: Reginald T. Guuroh; Jan C. Ruppert; Jessica Ferner; Kristijan Čanak; Sebastian Schmidtlein; Anja Linstädter
      Pages: 257 - 267
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Reginald T. Guuroh, Jan C. Ruppert, Jessica Ferner, Kristijan Čanak, Sebastian Schmidtlein, Anja Linstädter
      Rangelands’ ability to provide ecosystem services (ESs) depends on ecosystem properties and functions, which are interactively driven by biophysical and land-use drivers. In West Africa’s savanna rangelands, the relative importance of these drivers for ES supply is still poorly understood, hampering the identification of appropriate management strategies. In this context, trade-offs between the ES of forage provision and the regulating ES of erosion control are of particular importance. Taking a macroecological perspective, we aimed at detecting consistent patterns in ES drivers and identifying good predictors. The study area comprises a steep gradient of climatic aridity across West Africa’s Sudanian savannas from northern Ghana to central Burkina Faso, in combination with local gradients of land-use intensity and topo-edaphic conditions. We used aboveground biomass, metabolisable energy and metabolisable energy yield as proxies for forage provision, and the cover of perennials in the grass layer as a proxy for erosion control. Linear mixed-effect models and model selection were used to test relationships between multiple environmental variables and ES proxies. We found differential responses of ES proxies to environmental drivers. Vegetation properties were important for all ESs. Antecedent rainfall was the most important predictor of aboveground biomass, while plants’ phenology and land-use were most important for metabolisable energy. Environmental variables (such as aridity, soil properties and grazing intensity) mediated via vegetation properties were the most important predictors of erosion control followed by the direct effect of climatic aridity. Our finding that antecedent rainfall was more important for forage provision than climatic aridity implies that the effects of long-term climatic aridity may in a given year be overridden by current season’s precipitation particularly in case of a good rain year. The observed importance of land-use and vegetation properties implies that well-conceived adaptation strategies could mitigate potential negative effects of climate change.

      PubDate: 2017-10-14T13:55:41Z
      DOI: 10.1016/j.agee.2017.09.017
      Issue No: Vol. 251 (2017)
  • Modelling spatial and inter-annual variations of nitrous oxide emissions
           from UK cropland and grasslands using DailyDayCent
    • Authors: N. Fitton; A. Datta; J.M. Cloy; R.M. Rees; C.F.E. Topp; M.J. Bell; L.M. Cardenas; J. Williams; K. Smith; R. Thorman; C.J. Watson; K.L. McGeough; M. Kuhnert; A. Hastings; S. Anthony; D. Chadwick; P. Smith
      Pages: 1 - 11
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): N. Fitton, A. Datta, J.M. Cloy, R.M. Rees, C.F.E. Topp, M.J. Bell, L.M. Cardenas, J. Williams, K. Smith, R. Thorman, C.J. Watson, K.L. McGeough, M. Kuhnert, A. Hastings, S. Anthony, D. Chadwick, P. Smith
      Agricultural soils are the primary source of nitrous oxide emissions due to management practices including fertiliser application. While fertiliser rates are one of the main drivers of nitrous oxide emissions, emissions are also dependent on other variables such as climate and soil properties. To understand the spatial and inter-annual variations in emission rate, simulations of N2O emissions were made from 2000 to 2010 for UK grass and croplands. In addition, the sensitivity of these emissions to soil and climate inputs was also tested. Emissions of between 0.3 to 3.5kgNha−1 yr−1 and 0.7–7kgNha−1 yr−1 were simulated across UK croplands and grasslands, respectively. While inter-annual variations can be attributed to climate influences, the primary driver of spatial variations in emissions was soil clay content. However, when the sensitivity of nitrous oxide emissions to soil clay content alone was tested, it was not always the best predictor of emissions, when soil texture is altered outside of the normal range used as inputs to the model from different databases.

      PubDate: 2017-09-11T20:12:45Z
      DOI: 10.1016/j.agee.2017.08.032
      Issue No: Vol. 250 (2017)
  • How scattered trees matter for biodiversity conservation in active
    • Authors: Flávia Freire Siqueira; Lucas Voellger Calasans; Renato Queiroz Furtado; Vilany Matilla Colares Carneiro; Eduardo van den Berg
      Pages: 12 - 19
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Flávia Freire Siqueira, Lucas Voellger Calasans, Renato Queiroz Furtado, Vilany Matilla Colares Carneiro, Eduardo van den Berg
      Large areas of Tropical Forest have been cleared and deeply modified aiming at growing crops and producing livestock. Many of these areas are transformed in pastures with scattered trees. We investigated an area of 618.59ha in Southeastern Brazil composed of active pastures of an African grass, Urochloa decumbens, with scattered trees and forest patches. We surveyed all the scattered trees in the active pastures and in 60 plots of 200m2 within eight forest patches. To identify the ecosystem services and the history of scattered trees we applied a semi-structured survey to the landowners. We assessed regeneration, distance of propagules source, grass cover, microclimate, seed rain, and soil compaction under scattered tree crowns and in samples in the pasture without scattered trees. We found the scattered tree community highly diverse and associated this to apparent lack of preference for species showed by farmers during the clearing process for pasture, choosing the trees only by their shading capability (size). We also found that the scattered trees strongly affect seed rain and sapling regeneration in the pastures, improving microclimate and attracting dispersers, although this last effect is strongly dependent of the forest proximity. We found that the major difference between the scattered tree community and forest patches is associated with small trees lost during forest clearing and not to the largest trees left in the pastures. We see the scattered trees as key factors for promoting forest recovery, as well as an important biodiversity pool per si in highly fragmented landscapes.

      PubDate: 2017-09-11T20:12:45Z
      DOI: 10.1016/j.agee.2017.08.002
      Issue No: Vol. 250 (2017)
  • The way forward: An agroecological perspective for Climate-Smart
    • Authors: Stéphane Saj; Emmanuel Torquebiau; Etienne Hainzelin; Jacques Pages; Florent Maraux
      Pages: 20 - 24
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Stéphane Saj, Emmanuel Torquebiau, Etienne Hainzelin, Jacques Pages, Florent Maraux
      The concept of Climate-Smart Agriculture (CSA) has consistently been positioned between science and policy. CSA has given rise to a lively debate in both the scientific community and civil society although it addresses the pressing need for an efficient strategy to manage agriculture and food systems facing climate change (CC). CSA formally targets the simultaneous fulfilment of three criteria: (i) CC mitigation, (ii) adaptation to CC and (iii) food security. Yet, the review of scientific literature on CSA displays a clear discrepancy between these three objectives, underlining the fact that CSA is regularly perceived as addressing only adaptation, and not mitigation and food security. On the other hand, research on agroecology (AE) reveals an extensive knowledge about food security and adaptation, often at scales which can be considered complementary to those of CSA. A better use by CSA of AE research results may help CSA focus on two currently overlooked dimensions, i.e. (i) mitigation and (ii) trade-offs and synergies between the three criteria. CSA does not have a specific blueprint for climate-smart practices and has rather a strong focus on policies, institutions and financing. Hence AE actually responds to the needs of CSA in terms of site-specificity and potential for adoption by farmers because it is strongly based on local practices. We argue that an eco- and socio-logical approach to CSA represents a sine qua non condition if CSA is to promote inclusive development and participate to collective efforts to manage agriculture and food systems under climate change.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.09.003
      Issue No: Vol. 250 (2017)
  • Organic amendment practices as possible drivers of biogenic Volatile
           Organic Compounds emitted by soils in agrosystems
    • Authors: Kevin Potard; Cécile Monard; Jean-Luc Le Garrec; Jean-Pierre Caudal; Nathalie Le Bris; Françoise Binet
      Pages: 25 - 36
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Kevin Potard, Cécile Monard, Jean-Luc Le Garrec, Jean-Pierre Caudal, Nathalie Le Bris, Françoise Binet
      We investigated whether perennial soil organic amendments of pig slurry (PS) and methanized pig slurry (MPS) affect active bacterial communities and change the diversity and the C-flux of Volatile Organic Compounds (VOCs) emitted by soils compared to control plots without any fertilization (C). The long term effects of the fertilization history of the amendments and the short term impact of the organic inputs were both investigated by measuring VOCs emissions using a Proton Transfer Reaction-Mass Spectrometer (PTR-MS) and by analyzing active bacterial diversity by MiSeq Illumina sequencing just before and up to 64days following the inputs. Soil VOCs emissions (diversity and fluxes) naturally varied with temperature and rainfall variations, irrespective of manure inputs. No effect of the 5-yr fertilization history was observed on bacterial communities’ composition and on soil VOCs emissions. However, both manure inputs (PS and MPS) were associated with an inoculation of γ-Proteobacteria (Pseudomonas sp. and/or Marinospirillum sp.) to the soil on top of which PS inputs activated native soil Bacillus sp. (Firmicutes). VOCs spectra was mainly dominated by methanol and acetonitrile, the acetonitrile emissions not depending on the organic practices. C-VOCs fluxes from the soil to the atmosphere varied from 12 to 76μg of C-VOCs h−1 m−2 in the control plots. Pig slurry and methanized pig slurry differentially impacted soil VOCs emissions: PS inputs doubled the C-VOC fluxes due to high emission of methanol while MPS inputs reduced VOCs fluxes even less than the control unamended plots, which is of great interest in the context of mitigating greenhouse gases in agriculture. Our results suggest that soil fluxes could, under certain conditions, not be marginal compared to plant fluxes and be potentially driven by new land-uses in agriculture.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.09.007
      Issue No: Vol. 250 (2017)
  • Interactive effects of straw incorporation and tillage on crop yield and
           greenhouse gas emissions in double rice cropping system
    • Authors: Jun Zhang; Xiaoning Hang; Samoura Mohamed Lamine; Yu Jiang; Daniel Afreh; Haoyu Qian; Xiaomin Feng; Chengyan Zheng; Aixing Deng; Zhenwei Song; Weijian Zhang
      Pages: 37 - 43
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Jun Zhang, Xiaoning Hang, Samoura Mohamed Lamine, Yu Jiang, Daniel Afreh, Haoyu Qian, Xiaomin Feng, Chengyan Zheng, Aixing Deng, Zhenwei Song, Weijian Zhang
      Great efforts have been made on the assessment of the effects of straw managements or tillage practices on rice yield and greenhouse gas (GHG) emissions. However, their interactive effects were not well documented. Based on a seven-year field experiment under a double rice system, we tested the effects of rotary tillage (RT) vs. plough tillage (PT) on rice yield, methane (CH4) and nitrous oxide (N2O) emissions with or without straw incorporation. As compared to straw removal, straw incorporation increased rice yield by 12.7% and 1.3% under the PT and the RT, respectively. Straw incorporation significantly stimulated CH4 emissions under both tillage regimes in the late rice season, while no significant effect occurred in the early rice season. Compared to the RT, PT significantly decreased DOC concentrations and methanogen abundances, resulting in a reduction in CH4 emission. The PT decreased yield-scaled global warming potential (GWP) with or without straw incorporation by 31.0% and 15.5%, respectively, as compared to the RT. Together, our results indicate that straw incorporation with plough tillage benefits rice production for higher-yield with less GHG emissions in double rice cropping areas.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.07.034
      Issue No: Vol. 250 (2017)
  • Carbon quality mediates the temperature sensitivity of soil organic carbon
           decomposition in managed ecosystems
    • Authors: Jinquan Li; Junmin Pei; Jun Cui; Xueping Chen; Bo Li; Ming Nie; Changming Fang
      Pages: 44 - 50
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Jinquan Li, Junmin Pei, Jun Cui, Xueping Chen, Bo Li, Ming Nie, Changming Fang
      The carbon quality-temperature (CQT) hypothesis suggests that the temperature sensitivity (Q 10) of soil organic carbon (SOC) decomposition is negatively related to soil C quality. This hypothesis was widely tested in various natural ecosystems, but the effect of soil C quality on the temperature response of SOC decomposition has not been well addressed in managed ecosystems. In this study, Q 10 values of SOC decomposition were estimated in three adjacent managed ecosystems (planted forest (PF), paddy (PA), and upland (UL)) within the topsoil (0–5cm) and subsoil (30–35cm) layers of six sites across different climate zones in northeast China. The results suggested that the soil C quality differed significantly among the managed ecosystems (PF>PA>UL; P< 0.05) or soil types (P< 0.05), and decreased with soil depth (P< 0.001). Overall, Q 10 values differed significantly across the ecosystems (PF<PA<UL) and soil types (P< 0.05), but were significantly greater in the subsoil than those in the topsoil (P< 0.001). The negative relationship between Q 10 value and soil C quality suggested that the CQT hypothesis was applicable to ecosystem types, soil types, and soil profiles of the managed ecosystems. In addition, the Q 10 value had a positive correlation with soil pH (P< 0.001). The results suggested that incorporating soil C quality and soil pH into models would help us to predict the feedbacks between soil C dynamics and global warming in managed ecosystems.
      Graphical abstract image

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.09.001
      Issue No: Vol. 250 (2017)
  • Effects of diet and manure storage method on carbon and nitrogen dynamics
           during storage and plant nitrogen uptake
    • Authors: Mutian Niu; Jayasooriya A.D.R.N. Appuhamy; Robert S. Dungan; Ermias Kebreab; April B. Leytem
      Pages: 51 - 58
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Mutian Niu, Jayasooriya A.D.R.N. Appuhamy, Robert S. Dungan, Ermias Kebreab, April B. Leytem
      Altering dairy cattle diets to reduce both enteric methane (CH4) production and nitrogen (N) excretion are valuable tools for mitigating the environmental impact of dairy production. We examined the impact of altering diets on changes in physicochemical properties of manure during storage and short term plant N availability. Manure collected from cattle fed diets with differing forage and crude protein (CP) content were stored via two methods (slurry and static pile) for 29 weeks and sampled at week 0, 1, 2, 3, 4, 9, 14, 19, 24, and 29. There was no effect of diet on C and N dynamics during storage for either storage treatment. Mass losses of total carbon (C) were 10% greater for the static pile manure treatment than the slurry (P< 0.01). Total N losses ranged from were approximately 46% with no treatment differences. The soil 2-week plant available N was 67% less in the static pile than the slurry treatment, while the short-term plant N use efficiency was similar for both the static pile and slurry treatments (22–24%). Due to the high inorganic N content of slurry following storage, greater care may be needed to ensure that environmental losses do not occur.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.08.034
      Issue No: Vol. 250 (2017)
  • Can cattle grazing substitute fire for maintaining appreciated pine
           savannas at the frontier of a montane forest biosphere-reserve'
    • Authors: Marco Braasch; Luis García-Barrios; Neptalí Ramírez-Marcial; Elisabeth Huber-Sannwald; Sergio Cortina-Villar
      Pages: 59 - 71
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Marco Braasch, Luis García-Barrios, Neptalí Ramírez-Marcial, Elisabeth Huber-Sannwald, Sergio Cortina-Villar
      Human induced savannas in subtropical regions are often favored by small-holder farmers for livestock production and extraction of wood or non-wood products. Frequent burning and grazing are required to maintain the savanna vegetation structure. However, in conservation areas, fire suppression is promoted to avoid wildfires; whereas domestic livestock grazing is considered a strong interfering factor for tree establishment, due to trampling and browsing. In tropical forests which were converted to savannas, competitive exotic grasses have often replaced the native grasses. Where exotic grasses are present, aboveground biomass accumulation and thus man-induced fire risk are high and potentially undermine tree recruitment. On the long-term, the savanna state may shift into a grass-dominated state with little tree cover, generating unfavorable conditions from a livelihood perspective. We examined this problem in a human-induced pine savanna in the La Sepultura Biosphere Reserve in Chiapas, Mexico. Smallholder farmers highly valued this savanna for both livestock production and resin extraction from the fire resistant pine Pinus oocarpa. However, fire suppression and the presence of exotic grasses are reducing the tree recruitment. The main research question was to what degree can cattle grazing replace fire in its role of biomass removal and thereby stimulate pine recruitment and maintain the desired savanna state. We determined current savanna extension in the region and interviewed farmers to reconstruct past savannazation processes and expansion of exotic grasses. We related adult species-specific tree density to the herbaceous-grass cover, and pine and oak seedling and sapling densities to understory vegetation cover, canopy closure, and cattle grazing history. Finally, a field experiment was conducted to examine the effects of livestock grazing on survival and growth of planted pine saplings. The savanna currently covers 20% of the study site; it is the result of past slash-and-burn agriculture and selective logging, which have favored the expansion of several exotic grass species. In savannas where exotic grasses are abundant, sapling density was lower compared to sites with a native grass cover. While livestock grazing seemed to increase pine seedling density likely as a consequence of reduced grass cover, pine sapling survival however, was significantly reduced by livestock trampling. By seeking a balance between the livestock’s benefits and adverse effects on pine recruitment, farmers may develop an integrated management system adapted to their specific biotic rangeland conditions. It should allow forage production, while controlling the negative effects of exotic grasses on pine recruitment, thus maintaining a productive pine savanna system.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.08.033
      Issue No: Vol. 250 (2017)
  • Exotic plants growing in crop field margins provide little support to
           mango crop flower visitors
    • Authors: Lyndré Nel; James S. Pryke; Luísa G. Carvalheiro; Elisa Thébault; F.J. Frank van Veen; Colleen L. Seymour
      Pages: 72 - 80
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Lyndré Nel, James S. Pryke, Luísa G. Carvalheiro, Elisa Thébault, F.J. Frank van Veen, Colleen L. Seymour
      Introduced plant species integrate into native trophic networks, often disrupting flower-visitation patterns. Although non-native invasive plants frequently occur in disturbed natural vegetation bordering crop fields, their impact on crop pollination has not been studied. We investigated whether an invasive plant (Lantana camara) influences flower visitation to mango (Mangifera indica), a pollinator-dependent crop, and whether the invasive supports mango pollinators when mango is not flowering. We surveyed insect flower-visitation in mango orchards bordering natural vegetation and within adjacent natural vegetation, with and without L. camara present, before, during and after mango flowering. We used these data to calculate the indirect effect of L. camara on mango through shared flower visitors before, during and after mango flowering, and the effects of the invasive on crop productivity. Lantana camara had a positive effect on mango flower visitation at low to medium mango flower density, but not at high mango flower densities. Although L. camara and mango shared flower visitor species, the frequency with which these flower visitor species visited the crop and the invasive differed markedly before, during and after mango flowering. Furthermore, the potential indirect effect of L. camara on mango via shared visitors was greatest when mango was flowering, but significantly lower before and after mango flowering, suggesting that the invasive is unimportant in the diet of mango flower visitors when the crop is not flowering. Contrary to findings in previous studies using native species in mango fields, there was a trend (not significant) for lower mango fruit production in fields with L. camara. This suggests that Lantana does not contribute to an increase in successful pollination of mango. Although our focal alien invasive plant species facilitated flower visitation of crops, it had no effect on mango production, and provided little support to mango flower visitor species that live longer than the crop’s flowering period. Given that L. camara is detrimental to grazing and was not associated with increased mango production, the removal of this invasive is advisable.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.09.002
      Issue No: Vol. 250 (2017)
  • Carbon storage in hedge biomass—A case study of actively managed
           hedges in England
    • Authors: Matthew S. Axe; Ian D. Grange; John S. Conway
      Pages: 81 - 88
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Matthew S. Axe, Ian D. Grange, John S. Conway
      Farmland hedges could be managed for carbon sequestration, but empirical data on their carbon (C) stock in the UK is lacking. Lowland hedges managed by hedge laying and triennial trimming using a mechanical flail formed a dense woody structure (mean 81,368 stems ha−1). Hedges untrimmed for 3 years (mean height 3.5m, widths 2.6–4.2m), contained an above ground biomass (AGB) C stock of 42.0±3.78tCha−1 (14.0±1.94tCkm−1); when trimmed to 2.7m high, and subsequently 1.9m high, AGB C stocks were reduced to 40.6±4.47tCha−1 (11.4tCkm−1) and 32.2±2.76tCha−1 (9.9tCkm−1), respectively. A 4.2m wide hedge contained 9.7tCkm−1 more AGB C stock than a 2.6m wide hedge (mean height 3.5m). Below ground biomass (BGB) was 38.2±3.66tCha−1 (11.5tCkm−1). Near horizontal stems, arranged by hedge laying, 12–18 years prior to sampling, accounted for 5.2tCha−1 (1.6tCkm−1) of AGB C. The empirical data demonstrated how changing management practices to wider/taller hedges sequestered C in AGB. These estimates of hedgerow C stocks fill a knowledge gap on C storage and identified the need for a more comprehensive biomass inventory of hedgerows to strengthen the national carbon accounting of agro-ecosystems in the UK.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.08.008
      Issue No: Vol. 250 (2017)
  • Evaluating integrated pest management tactics for onion thrips and
           pathogens they transmit to onion
    • Authors: Ashley Leach; Stephen Reiners; Marc Fuchs; Brian Nault
      Pages: 89 - 101
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Ashley Leach, Stephen Reiners, Marc Fuchs, Brian Nault
      Onion thrips (Thrips tabaci) is a significant pest of onion worldwide, causing both direct and indirect damage to the crop. Integrated pest management of onion thrips should improve profitability and sustainability of onion production. Promising management approaches include reducing nitrogen application rates, using thrips-resistant cultivars and implementing action threshold-based insecticide programs. However, the impact of these integrated pest management approaches on thrips densities and damage, crop yield, and thrips-associated plant diseases like iris yellow spot (IYS) (caused by Iris yellow spot virus) and bacterial center rot (caused by Pantoea agglomerans and P. ananatis) remains largely unknown. In a two-year field trial in New York, combinations of varying levels of nitrogen applied at planting (67, 101 and 140kgha−1) and different insecticide programs (standard weekly insecticide program and action threshold-based insecticide program) were evaluated for onion thrips management in onion cultivars that had moderate resistance (‘Avalon’), low resistance (‘Delgado’) and no resistance (‘Bradley’) to onion thrips. Results indicated that regardless of cultivar, nitrogen did not affect larval thrips densities, onion yields, IYS or bacterial center rot. Across all cultivars, insecticide use (both programs) significantly reduced larval thrips densities and damage, IYS severity and incidence, and increased onion yield. Insecticide use did not consistently affect the incidence of bacterial center rot. Both insecticide programs reduced onion thrips larval densities by 60–81% relative to the untreated control, but the action threshold-based application program used 2.8 fewer applications than the standard program. ‘Avalon’ had low thrips densities and IYS disease, but required the same number of insecticide applications as ‘Bradley’. Onion yields in both insecticide programs were statistically similar in both years, and bulb weights averaged 10–54% more than those in the untreated control. Our results indicated that growers can reduce nitrogen levels at planting and insecticide use without compromising control of either onion thrips or IYS disease or onion bulb yields.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.08.031
      Issue No: Vol. 250 (2017)
  • Greenhouse gas emissions following land application of pulp and paper mill
           sludge on a clay loam soil
    • Authors: Patrick Faubert; Catherine Lemay-Bélisle; Normand Bertrand; Sylvie Bouchard; Martin H. Chantigny; Simon Durocher; Maxime C. Paré; Philippe Rochette; Pascal Tremblay; Noura Ziadi; Claude Villeneuve
      Pages: 102 - 112
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Patrick Faubert, Catherine Lemay-Bélisle, Normand Bertrand, Sylvie Bouchard, Martin H. Chantigny, Simon Durocher, Maxime C. Paré, Philippe Rochette, Pascal Tremblay, Noura Ziadi, Claude Villeneuve
      Pulp and paper mill sludge (PPMS) is applied on agricultural soils as an organic fertilizer. Although it is well accepted that land application of PPMS has benefits for soils and crops, information on PPMS-induced soil N2O emissions is still limited. We assessed the effect of substituting mineral N fertilizer for PPMS on soil N2O emissions after a single application at planting on a clay loam cropped to wheat (Triticum aestivum L.) over two snow-free seasons in eastern Canada. Fertilization treatments consisted of 0, 25, 50, 75, and 100% of crop N requirements derived from N supplied by PPMS, the remaining N being supplied as urea-N. Soil CO2 and CH4 emissions were also measured and not affected by the fertilizer addition; a slight CH4 oxidation occurred. Area-based N2O emissions from PPMS fertilization (4.4 to 12.1kgN2O-Nha−1) were similar or higher than from urea alone (3.4 and 6.2kgN2O-Nha−1). Although crop yields were not affected by the type of fertilizer, yield-based N2O emissions, N uptake efficiency and N surplus (appliedN minus aboveground N uptake in crop biomass) indicated that N availability from the mineral fertilizer was higher than from PPMS for the wheat crop. However, treatments with PPMS had fertilizer-induced N2O emission factors (FIEF, applied N lost as N2O-N; 0.8 to 3.1%) similar to urea alone (−0.3 and 4.5%). Although substituting urea-N with PPMS in agricultural fields might reduce N2O emissions under moderate soil moisture conditions, PPMS land application produced greater N2O emissions under high soil moisture conditions. Further research on a variety of agricultural practices is needed before concluding that including PPMS in the fertilization plan could result in a global GHG abatement as compared to mineral fertilizers under the cool climate of eastern Canada.

      PubDate: 2017-09-23T03:46:06Z
      DOI: 10.1016/j.agee.2017.07.040
      Issue No: Vol. 250 (2017)
  • Farm and landscape factors interact to affect the supply of pollination
    • Authors: Charlie C. Nicholson; Insu Koh; Leif L. Richardson; Anna Beauchemin; Taylor H. Ricketts
      Pages: 113 - 122
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Charlie C. Nicholson, Insu Koh, Leif L. Richardson, Anna Beauchemin, Taylor H. Ricketts
      Farms can harbor substantial biodiversity, which in turn sustains the supply of ecosystem services. The effectiveness of farm management to enhance biodiversity, however, may be modified by land cover in the surrounding landscape beyond a farmer’s direct control. We examined how landscape pattern and farm management affect the abundance and diversity of native bees visiting highbush blueberry in Vermont, USA. We quantified landscape pattern at multiple scales and created an agricultural intensity index that represents farm management practices such as pesticide use, mowed and grain crop area. We observed native bee visitation to assess the supply of pollination service provided to blueberry growers. Across 15 farms, 84 wild bee species were observed visiting highbush blueberry, almost a third of bee species recorded in Vermont. Visitation rate, abundance and species richness increased with the amount of natural area surrounding farms. Less intensively managed farms had higher levels of bee visitation, abundance and a more diverse bee community. Bee communities and the pollination services they provide are influenced by interactions between local management and landscape pattern. In particular, intensive farm management appears to compound the negative effects of landscape simplification. To support native pollinators on their farms, growers should consider farming approaches in the context of the broader landscape.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.08.030
      Issue No: Vol. 250 (2017)
  • Inter-colony differences in hepatic element concentrations of European
           flagship farmland bird, the Rook Corvus frugilegus, breeding in rural
           habitats in East Poland
    • Authors: Ignacy Kitowski; Dariusz Jakubas; Dariusz Wiącek; Agnieszka Sujak
      Pages: 123 - 132
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Ignacy Kitowski, Dariusz Jakubas, Dariusz Wiącek, Agnieszka Sujak
      Concentration of 12 trace elements (Cd, Cr, Cu, Hg, Mg, Mn, Ni, Pb, Se, Sr, V, Zn) in livers of 29 adult Rooks Corvus frugilegus breeding in agriculture landscape in the Lublin Voivodship (South-East Poland) were determined. The presented study aimed to compare elements concentration between colonies and sexes, as well as to determine common sources of metals and elements. Analyses for particular elements revealed exclusively one significant effect of colony location on hepatic concentration of cadmium. No sex differences were found what may be explained by the lack of diet differences and/or low sequestration of the surplus of non-essential elements in females to the eggs during their formation. Bioaccumulation of Cd appears to be strongly site-dependent. The highest concentrations of this element were recorded in rookeries located in big size farms with large monocultural cultivated areas with intensive use of fertilizers. Cluster analysis suggests that fertilizers and other agrochemicals, are likely sources of tissues contamination in species foraging on soil invertebrates. The intense agriculture production with regular use of agrochemicals, promoted nowadays may lead to pronounced absorption of toxic elements by species associated with farmland.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.08.027
      Issue No: Vol. 250 (2017)
  • Pollen beetle mortality is increased by ground-dwelling generalist
           predators but not landscape complexity
    • Authors: Laura G. Riggi; Vesna Gagic; Adrien Rusch; Gerard Malsher; Barbara Ekbom; Riccardo Bommarco
      Pages: 133 - 142
      Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250
      Author(s): Laura G. Riggi, Vesna Gagic, Adrien Rusch, Gerard Malsher, Barbara Ekbom, Riccardo Bommarco
      Biological control of crop pests by naturally occurring arthropods depends on the entire community of natural enemies, but generalist predators and parasitoids are rarely considered in the same study. Also, the level of biological control in the field is affected by both within-field and landscape scale management. A multi-taxa approach that integrates multiple scales of management is needed to understand drivers for pest mortality. We examined local (weed cover and soil characteristics) and landscape (proportions of semi-natural and oilseed rape habitat) effects on natural enemy communities and biological control of pollen beetles in 15 oilseed rape (OSR) fields in Sweden. We found that agricultural intensification at the local (low weed cover) and landscape scale (low proportion of semi-natural area) increased evenness of generalist predators, but had no effect on the densities of pests and their natural enemies. This suggests that the generalist predators in OSR are well adapted to crop lands, at least within the examined gradient. Increasing OSR in the landscape decreased parasitoid densities and increased pest density, indicating a potential loss of pest control services by specialist natural enemies in landscapes with a high proportion of OSR. Finally, pollen beetle mortality increased with ground-dwelling generalist predator abundance and soil clay content. Parasitism rates did not affect pest mortality, which is interesting as parasitoids have been considered major control agents in OSR. The hypothesis that increasing semi-natural habitat in the landscape enhances natural enemy abundances and species richness in agricultural landscapes was not supported. Local measures targeting generalist predators appear as a reasonable strategy to maximize pollen beetle control.

      PubDate: 2017-09-30T06:16:02Z
      DOI: 10.1016/j.agee.2017.06.039
      Issue No: Vol. 250 (2017)
  • Extending the ‘resource concentration hypothesis’ to the
           landscape-scale by considering dispersal mortality and fitness costs
    • Authors: Megan E. O’Rourke; Matthew J. Petersen
      Pages: 1 - 3
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Megan E. O’Rourke, Matthew J. Petersen
      The ‘resource concentration hypothesis’ proposes mechanisms by which polycultures (local plant diversity) can directly reduce densities of insect pests in agriculture. It predicts that herbivore loads are directly reduced because host plant cues are disrupted and herbivore residency times are shorter in polycultures than in monocultures. The hypothesis has been similarly applied to landscape-scale investigations; however, the mechanisms by which diverse landscapes can directly suppress herbivores are likely different than those operating at the polyculture scale and have not been clearly articulated. Here, we discuss how landscape-scale habitat diversity may directly reduce agricultural pest loads by requiring more dispersal activity, which, in turn, can increase mortality and decrease fitness. We also lay out a research agenda and argue that a better understanding of the mechanisms by which landscape-scale habitat diversity affect insect pest populations can lead to better predictions of pest control as an ecosystem service provided by diverse agricultural landscapes.

      PubDate: 2017-08-28T10:08:54Z
      DOI: 10.1016/j.agee.2017.07.022
      Issue No: Vol. 249 (2017)
  • Predicting potential rice damage by insect pests using land use data: A
           3-year study for area-wide pest management
    • Authors: Ken Tabuchi; Taro Murakami; Shigeru Okudera; Shunsuke Furihata; Mitsutaka Sakakibara; Akihiko Takahashi; Tetsuya Yasuda
      Pages: 4 - 11
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Ken Tabuchi, Taro Murakami, Shigeru Okudera, Shunsuke Furihata, Mitsutaka Sakakibara, Akihiko Takahashi, Tetsuya Yasuda
      To mitigate crop damage by insect pests, it is important to determine priority areas for the allocation of available pest management resources, which are usually limited. We tested whether the occurrence of pecky rice damage caused by the sorghum plant bug Stenotus rubrovittatus (Hemiptera: Miridae), a major rice pest in Japan, could be predicted using a spatial model based on land use data. Using a data from a 3-year field study, we examined the relationships among the land use of the area within a 300-m radius around each focal paddy field, the abundance of S. rubrovittatus, and level of pecky rice damage in the Maesawa region of northern Honshu Island, Japan. We also used mapping to visualize potential priority areas using a model and GIS software. From a linear mixed model analysis and model selection by Akaike’s information criterion values, areas of source habitats, soybean fields and rice paddies were selected for the best model, but the abundance of S. rubrovittatus was not. Based on the model’s evaluation, the predicted value of pecky rice damage, when compared with the observed value, was not sensitive enough for a quantitative prediction. However, the model was accurate enough to predict whether the brown rice was first grade, which is of greatest importance to local farmers. Therefore, it is possible that potential pecky rice damage by S. rubrovittatus could be predicted when the spatial arrangement of arable fields in a certain year is determined. Our results will be useful to support decision-making that involves insecticide applications to mitigate pecky rice damage.
      Graphical abstract image

      PubDate: 2017-09-17T15:04:08Z
      DOI: 10.1016/j.agee.2017.08.009
      Issue No: Vol. 249 (2017)
  • Crop-wild sunflower hybridization can mediate weediness throughout
           growth-stress tolerance trade-offs
    • Authors: Alejandro Presotto; Fernando Hernández; Marina Díaz; Ivana Fernández-Moroni; Claudio Pandolfo; Jessica Basualdo; Selva Cuppari; Miguel Cantamutto; Mónica Poverene
      Pages: 12 - 21
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Alejandro Presotto, Fernando Hernández, Marina Díaz, Ivana Fernández-Moroni, Claudio Pandolfo, Jessica Basualdo, Selva Cuppari, Miguel Cantamutto, Mónica Poverene
      Agricultural weeds are plants well-adapted to agricultural environments interfering directly and indirectly with crop production and causing important economic losses worldwide. Crop-wild hybridization is one of the main forces that have ruled weed evolution along with adaptation to agricultural (or benign) environments. Considering the competing demands for resources in any plant, adaptation to agricultural environments might result in an increase in growth but with lower tolerance to stress. In Argentina, most of the non-native H. annuus populations grow on roadsides, ditches, fences, hedgerows (ruderals), but there are also a few cases of H. annuus growing in agricultural field as weeds (agrestals). We asume that weediness of these agrestal biotypes came after crop hybridization as result of growth-stress tolerance trade-offs. Ruderal, agrestal (with evidence of crop introgression), and crop biotypes were contrasted under studies of drought and defoliation stresses, as well as for plant growth under non-stressful conditions and sequences of stress-related genes. The agrestal biotype was less tolerant to defoliation and drought than the ruderal biotype. Drought tolerance variation was largely explained by plant height rate (growth) and defoliation tolerance variation was mainly explained by biomass accumulation (resource allocation). Agrestal biotype sequences of two genes encoding transcription factors involved in stress response, DREB2 and NAC, showed evidence of positive selection in the crop direction. Therefore, selection in the agricultural environment combined with crop hybridization driver the evolution of a well-adapted genetic variant of H. annuus with fast growth but reduced stress tolerance.

      PubDate: 2017-09-17T15:04:08Z
      DOI: 10.1016/j.agee.2017.08.003
      Issue No: Vol. 249 (2017)
  • Influence of farmland abandonment on the species composition of wetland
           ground beetles in Kushiro, Japan
    • Authors: Satoshi Yamanaka; Takumi Akasaka; Yuki Yabuhara; Futoshi Nakamura
      Pages: 31 - 37
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Satoshi Yamanaka, Takumi Akasaka, Yuki Yabuhara, Futoshi Nakamura
      Depopulation trends in many developed regions are resulting in an increase in areas of abandoned farmland, which could provide an alternative habitat for species endangered by past conversion of wetlands for agriculture. Additionally, various spatial and temporal factors (landscape structure, local habitat quality, and abandonment age) could influence species composition in abandoned farmland. In this study, we explored the spatio-temporal effects of land abandonment on the species composition of wetland ground beetles (Coleoptera: Carabidae) to examine whether abandoned farmland can contribute to conserve wetland species’ habitats. We first compared ground beetle assemblages among four land uses (grassland, wetland, and newly and previously abandoned farmland) in the Kushiro region, eastern Hokkaido, Japan. We then examined the factors influencing differences in wetland species composition between abandoned farmland and wetland. We found that the composition of wetland species in abandoned farmland was more similar to that of wetland than that of grassland. Our results also showed that soil moisture in abandoned farmland was positively related to the land abandonment age and that differences in wetland species composition between abandoned farmland and wetland were negatively related to both soil moisture and surrounding wetland area. Our findings suggest that abandoned farmland can serve as an alternative habitat for wetland ground beetles. Maintaining a high level of soil moisture in abandoned farmland and conserving the surrounding wetland could be an effective strategy for restoring natural habitats for these species.

      PubDate: 2017-09-17T15:04:08Z
      DOI: 10.1016/j.agee.2017.07.027
      Issue No: Vol. 249 (2017)
  • Soil fertility regulates invasive herbivore performance and top-down
           control in tropical agroecosystems of Southeast Asia
    • Authors: K.A.G. Wyckhuys; D.D. Burra; D.H. Tran; I. Graziosi; A.J. Walter; T.G. Nguyen; H.N. Trong; B.V. Le; T.T.N. Le; S.J. Fonte
      Pages: 38 - 49
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): K.A.G. Wyckhuys, D.D. Burra, D.H. Tran, I. Graziosi, A.J. Walter, T.G. Nguyen, H.N. Trong, B.V. Le, T.T.N. Le, S.J. Fonte
      In terrestrial ecosystems, changes in soil nutrient availability, plant growth or natural enemies can generate important shifts in abundance of organisms at various trophic levels. In agroecosystems the performance of (invasive) herbivores and their impacts on crops is of particular concern. Scientists are presently challenged with making reliable inferences on invader success, natural enemy performance and efficacy of biological control, particularly in tropical agroecosystems. In this study, we assess how trophic regulatory forces (bottom-up vs. top down) influence the success of three globally important pests of cassava. We examine the mealybug species (Hemiptera: Pseudococcidae) of differing host breadth and invasion history: Phenacoccus manihoti, Paracoccus marginatus, and Pseudococcus jackbeardsleyi. Potted plant fertilizer trials were combined with a regional survey in Vietnam, Laos and Cambodia of 65 cassava fields of similar size and age, but with varying soil fertility. Relative abundance of each mealybug invader was mapped along a soil fertility gradient, and contrasted with site-specific measures of parasitism. Potted plant trials revealed strong bottom-up effects for P. manihoti, such that impacts of nitrogen and potassium additions were propagated through to higher trophic levels and substantially boost development and fitness of its specialist parasitoid, Anagyrus lopezi (Hymenoptera: Encyrtidae). Field surveys indicate that mealybug performance is highly species-specific and context-dependent. For example, field-level abundance of P. jackbeardsleyi and P. marginatus, was related to measures of soil fertility parameters, soil texture and plant disease incidence. Furthermore, for P. manihoti, in-field abundance is equally associated with soil texture (i.e., silt content). Principal component analysis (PCA) and regression suggested that P. manihoti and P. marginatus are disproportionately favored in low-fertility conditions, while P. jackbeardsleyi prospers in settings with high organic carbon and phosphorus. Parasitism of P. manihoti by A. lopezi varied greatly with field and soil fertility conditions, and was highest in soils with intermediate fertility levels and where management practices include the addition of fertilizer supplements. Our characterization of the relative performance of invasive mealybugs and strength of parasitism across variable soil fertility conditions will help guide parasitoid release programs and soil management practices that enhance mealybug biological control.

      PubDate: 2017-08-28T10:08:54Z
      DOI: 10.1016/j.agee.2017.08.006
      Issue No: Vol. 249 (2017)
  • Grazing intensity influence soil microbial communities and their
           implications for soil respiration
    • Authors: Fazhu Zhao; Chengjie Ren; Shelby Shelton; Ziting Wang; Guowei Pang; Ji Chen; Jun Wang
      Pages: 50 - 56
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Fazhu Zhao, Chengjie Ren, Shelby Shelton, Ziting Wang, Guowei Pang, Ji Chen, Jun Wang
      Soil microorganisms regulate carbon (C) transfer from terrestrial sources to the atmosphere, therefore playing a pivotal role in soil C dynamics. Worldwide, grazing is one of the most prevalent grassland management strategies, yet the effects of grazing on soil microbial community size and soil respiration (SR) are still active areas of debate. We conducted a meta-analysis of 71 publications to synthesize the responses of soil microbial community size and SR to grazing. Our results showed that grazing significantly decreased soil total microbial, bacterial and fungal community size by 11.74, 8.85 and 11.45%, respectively. However, this effect were differed when the studies were grouped by the grazing intensity. Briefly, light and moderate grazing intensity had no effect on soil microbial, bacterial and fungal community size, but heavy grazing intensity significantly reduced soil’s total microbial, bacterial and fungal community size by 14.79, 16.48 and 28.12%, respectively. The responses of microbial community size to grazing were positively correlated with those of SR both under moderate and heavy grazing intensity. Our findings indicate that soil microbial community size could be an important underlying mechanism involved in determining soil C dynamics under grazing. Hence better understanding of the responses of soil microbial community size would greatly contribute to our understanding of soil C dynamics. Lastly, our results underscore the importance of factoring grazing intensity into consideration to further improve the model’s projection of soil C dynamics.

      PubDate: 2017-08-28T10:08:54Z
      DOI: 10.1016/j.agee.2017.08.007
      Issue No: Vol. 249 (2017)
  • Nitrous oxide emissions from winter oilseed rape cultivation
    • Authors: Reiner Ruser; Roland Fuß; Monique Andres; Hannes Hegewald; Katharina Kesenheimer; Sarah Köbke; Thomas Räbiger; Teresa Suarez Quinones; Jürgen Augustin; Olaf Christen; Klaus Dittert; Henning Kage; Iris Lewandowski; Annette Prochnow; Heinz Stichnothe; Heinz Flessa
      Pages: 57 - 69
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Reiner Ruser, Roland Fuß, Monique Andres, Hannes Hegewald, Katharina Kesenheimer, Sarah Köbke, Thomas Räbiger, Teresa Suarez Quinones, Jürgen Augustin, Olaf Christen, Klaus Dittert, Henning Kage, Iris Lewandowski, Annette Prochnow, Heinz Stichnothe, Heinz Flessa
      Winter oilseed rape (Brassica napus L., WOSR) is the major oil crop cultivated in Europe. Rapeseed oil is predominantly used for production of biodiesel. The framework of the European Renewable Energy Directive requires that use of biofuels achieves GHG savings of at least 50% compared to use of fossil fuel starting in 2018. However, N2O field emissions are estimated using emission factors that are not specific for the crop and associated with strong uncertainty. N2O field emissions are controlled by N fertilization and dominate the GHG balance of WOSR cropping due to the high global warming potential of N2O. Thus, field experiments were conducted to increase the data basis and subsequently derive a new WOSR-specific emission factor. N2O emissions and crop yields were monitored for three years over a range of N fertilization intensities at five study sites representative of German WOSR production. N2O fluxes exhibited the typical high spatial and temporal variability in dependence on soil texture, weather and nitrogen availability. The annual N2O emissions ranged between 0.24kg and 5.48kgN2O-Nha−1 a−1. N fertilization increased N2O emissions, particularly with the highest N treatment (240kgNha−1). Oil yield increased up to a fertilizer amount of 120kgNha−1, higher N-doses increased grain yield but decreased oil concentrations in the seeds. Consequently oil yield remained constant at higher N fertilization. Since, yield-related emission also increased exponentially with N surpluses, there is potential for reduction of the N fertilizer rate, which offers perspectives for the mitigation of GHG emissions. Our measurements double the published data basis of annual N2O flux measurements in WOSR. Based on this extended dataset we modeled the relationship between N2O emissions and fertilizer N input using an exponential model. The corresponding new N2O emission factor was 0.6% of applied fertilizer N for a common N fertilizer amount under best management practice in WOSR production (200kgNha−1 a−1). This factor is substantially lower than the linear IPCC Tier 1 factor (EF1) of 1.0% and other models that have been proposed.

      PubDate: 2017-08-28T10:08:54Z
      DOI: 10.1016/j.agee.2017.07.039
      Issue No: Vol. 249 (2017)
  • Practices of conservation agriculture prevail over cropping systems and
           landscape heterogeneity in understanding the ecosystem service of aphid
    • Authors: Ariane Chabert; Jean-Pierre Sarthou
      Pages: 70 - 79
      Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249
      Author(s): Ariane Chabert, Jean-Pierre Sarthou
      Aphidophagous natural enemies significantly lower yield losses induced by aphids in cereals. This natural biocontrol is threatened, and conserving this ecosystem service requires better understanding of the factors that influence it. Natural enemies are mainly responsive to habitat diversity in the surrounding landscape. However, their positive response to landscape heterogeneity does not necessarily translate into more effective pest control. In this study, we investigated combined effects of production situation (including landscape heterogeneity) and agricultural practices, especially soil management, on an aerial natural biocontrol. Grain aphid populations and predation by a hoverfly species were assessed in 52 wheat fields under plowed, reduced-tillage or direct seeding systems, under conventional or organic management, at two nearby locations. The hoverfly populations that prey on aphids were studied by counting their pupae shells on ear barbs. Crop management and production situation were studied to describe pest occurrence and natural biocontrol. Both integrated (e.g. tillage type, organic management) and specific (e.g. nitrogen fertilization, rotation duration) variables were compared. Our main finding was that the integrated variables did not sufficiently explain aphid abundance and their biocontrol. Conversely, specific variables related to types of management were informative. Nitrogen fertilization induced an increase in aphid populations and the number of hoverfly pupae as the time since last plowing increased. Semi-natural habitats had considerable influence on the pest and its natural enemy; however, the strong influence of location observed in this study was not related to landscape composition. We showed that although the landscape did influence the potential for biological regulation, crop management enabled its expression and thus its effectiveness. Categorizing crop management practices too coarsely may masks effects of individual practices. Future studies on biological control of pests in agroecosystems will gain to finely describe cropping systems as well as landscape heterogeneity, if they are to unravel the explanatory variables on this utmost important ecosystem service for ecological intensification of agriculture.

      PubDate: 2017-08-28T10:08:54Z
      DOI: 10.1016/j.agee.2017.08.005
      Issue No: Vol. 249 (2017)
  • Impact of floral nectar limitation on life-history traits in a grassland
           butterfly relative to nectar supply in different agricultural landscapes
    • Authors: Julie Lebeau; Renate Wesselingh Hans Van Dyck
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Julie Lebeau, Renate A. Wesselingh, Hans Van Dyck
      Wild flower diversity and abundance are strongly reduced in intensive agricultural landscapes. Flower-visiting insects may, therefore, experience limited nectar quantities and qualities. Adult insects that rely on energy-rich nectar income for flight, survival and reproduction are expected to be much more affected than insects that rely on their larval reserves. We dealt with this issue at the intraspecific level by comparing the responses of several life-history traits to different nectar diets between meadow brown butterflies (Maniola jurtina) originating from relative intensively managed and extensively managed agricultural landscapes. We used outdoor flight cages in which we simulated factorial treatments of low/high nectar quality and low/high quantity. Survival was highest in the high nectar quantity and quality treatment. Individuals from intensive landscapes were heavier, which is in line with predictions on increased capital breeding, and they survived better than those from extensive landscapes, of which the females lost body mass in all treatments. Females from intensive landscapes were able to buffer, or even increase, their body mass in the high nectar quantity treatments, but the differences with females from extensive landscapes disappeared under low nectar quantities (independent of nectar quality). In males, body mass losses were always larger for individuals from extensive landscapes compared to individuals from intensive landscapes. Forty percent of the females showed complete reproductive failure in the low quantity/low quality treatment compared to c. 7% in the other treatments. In the low quantity/low quality treatment, realized fecundity decreased strongly in females from intensive, but not extensive landscapes. Egg size was not affected by landscape of origin in the high-quality nectar treatments, but showed very different responses relative to landscape of origin in the treatments with low-quality nectar. Our results showed strong effects of reduced nectar supply on fitness-related traits, and responses were different between butterflies originating from landscapes with contrasted nectar diet. Hence, different levels of agricultural intensification changing the quantity and quality of the local nectar supply could pave the way for ecological differentiation of the organism’s behaviour, physiology and life history.

      PubDate: 2017-10-08T13:16:47Z
  • The adaptive capacity of maize-based conservation agriculture systems to
           climate stress in tropical and subtropical environments: A meta-regression
           of yields
    • Authors: Peter Steward; Andrew Dougill Christian Thierfelder Cameron Pittelkow Lindsay Stringer
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Peter R. Steward, Andrew J. Dougill, Christian Thierfelder, Cameron M. Pittelkow, Lindsay C. Stringer, Maxwell Kudzala, Gorm E. Shackelford
      Conservation agriculture is widely promoted across sub-Saharan Africa as a sustainable farming practice that enhances adaptive capacity to climate change. The interactions between climate stress, management, and soil are critical to understanding the adaptive capacity of conservation agriculture. Yet conservation agriculture syntheses to date have largely neglected climate, especially the effects of extreme heat. For the sub-tropics and tropics, we use meta-regression, in combination with global soil and climate datasets, to test four hypotheses: (1) that relative yield performance of conservation agriculture improves with increasing drought and temperature stress; (2) that the effects of moisture and temperature stress exposure interact; (3) that the effects of moisture and temperature stress are modified by soil texture; and (4) that crop diversification, fertilizer application rate, or the time since no-till implementation will enhance conservation agriculture performance under climate stress. Our results support the hypothesis that the relative maize yield performance of conservation agriculture improves with increasing drought severity or exposure to high temperatures. Further, there is an interaction of moisture and heat stress on conservation agriculture performance and their combined effect is both non-additive and modified by soil clay content, supporting our second and third hypotheses. Finally, we found only limited support for our fourth hypothesis as (1) increasing nitrogen application rates did not improve the relative performance of conservation agriculture under high heat stress; (2) crop diversification did not notably improve conservation agriculture performance, but did increase its stability with heat stress; and (3) a statistically robust effect of the time since no-till implementation was not evident. Our meta-regression supports the narrative that conservation agriculture enhances the adaptive capacity of maize production in sub-Saharan Africa under drought and/or heat stress. However, in very wet seasons and on clay-rich soils, conservation agriculture yields less compared to conventional practices.

      PubDate: 2017-10-08T13:16:47Z
  • Landsharing vs landsparing: How to reconcile crop production and
           biodiversity' A simulation study focusing on weed impacts
    • Authors: Nathalie Colbach; Cordeau Alexia Garrido Sylvie Granger Daniel Laughlin Ricci
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Nathalie Colbach, Stéphane Cordeau, Alexia Garrido, Sylvie Granger, Daniel Laughlin, Benoît Ricci, Fiona Thomson, Antoine Messéan
      Weeds are harmful for crop production but are crucial for biodiversity in agricultural landscapes. Two contrasting strategies exist for reconciling these ecosystem services: landsharing, where crop production and biodiversity are maximised in individual fields, or landsparing, where some fields or habitats are assigned for biodiversity conservation while the remaining fields aim to maximise production. The objective of the present study was to evaluate these two strategies in silico, based on a case study with maize-based cropping systems including genetically modified varieties that allow the use of the highly efficient herbicide glyphosate in crops. The virtual-field model FLORSYS simulates multi-species weed floras and their impact on crop production and biodiversity depending on cropping systems and pedoclimate. It was scaled up to the landscape level by simulating several fields in parallel, including semi-natural habitats and integrating between-field seed dispersal depending on plant height, seed mass and dispersal mode. Three series of scenarios were simulated over 28 years and 10 weather repetitions in a small landscape consisting of four 3-ha fields in Aquitaine (South-Western France): (1) landsharing scenarios based on a single diverse rotation (soybean/maize/wheat/maize), with different crop patterns in the landscape, (2) landsparing scenarios with varying proportions (ranging from 0 to 100%) of contrasting cropping systems in the landscape, either cropping system aiming to maximise biodiversity or one aiming to maximise production, and (3) landsparing scenarios including permanent grass strips (10% of each field). The landsharing scenario combining fields aiming to maximise crop production with either fields aiming to maximise biodiversity (25% of landscape) or grass strips (10% of landscape) were best, resulting in high crop production and medium biodiversity at the landscape scale. Landsharing scenarios always produced less biodiversity and less production. When more crops and cropping systems were grown each year in the landscape, the weed impact on production and biodiversity was higher and more stable over the years. These results are case-specific; new simulations and rules are needed for different types of cropping systems, landscapes and pedoclimates, and the performance of the best solutions should be tested in field studies.

      PubDate: 2017-10-08T13:16:47Z
  • Does precipitation affects soil respiration of tropical semiarid
           grasslands with different plant cover types'
    • Authors: Arredondo Delgado-Balbuena; Huber-Sannwald H.W. Loescher Rodriguez-Robles
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): T. Arredondo, J. Delgado-Balbuena, E. Huber-Sannwald, E. García-Moya, H.W. Loescher, C. Aguirre-Gutiérrez, U. Rodriguez-Robles
      Examination of the effects of altered precipitation and atmospheric temperature patterns on ecosystem processes are an active area of research. Influences of these climate factors may change when plant cover and species composition are disturbed as a consequence of land use change altering ecosystem processes, such as soil respiration. We addressed the following question: how does experimentally manipulated reduction in the size of each precipitation event influence soil respiration fluxes (Rs) in a tropical semiarid grassland with different plant cover and species composition' Rainout shelters were installed over eight yr old planted monospecific plots (4m2) of Bouteloua gracilis, the keystone species of the grassland biome, and over mixed grassland plots in sites that recovered from abandoned agricultural land, allowing full or a 50% reduction of ambient precipitation. Soil respiration rates as well soil temperature (Tsoil) and soil water content (SWC), as controlling factors, were monitored. Overall, SWC was the most important control for Rs explaining ∼70% of its variability, followed by Tsoil which explained ∼25% and plant cover type having a minor effect (3%) explaining Rs variability. Still, Rs exhibited differential responses when comparing plant cover types; SWC in the mixed grassland had up to 90% relative influence on Rs as compared to 10% by Tsoil. In contrast, Rs rates in monospecific B. gracilis plots exhibited less overall variability considering SWC (55–60%) and Tsoil (40–45%), suggesting that grasslands dominated by the keystone species are more resilient and better buffer the effects of extreme climatic drought conditions on ecosystem processes.

      PubDate: 2017-10-08T13:16:47Z
  • On-farm diversity offsets environmental pressures in tropical
           agro-ecosystems: A synthetic review for cassava-based systems
    • Authors: Erik Delaquis; Stefan Haan Kris A.G. Wyckhuys
      Abstract: Publication date: 1 January 2018
      Source:Agriculture, Ecosystems & Environment, Volume 251
      Author(s): Erik Delaquis, Stefan de Haan, Kris A.G. Wyckhuys
      Ecosystem integrity is at risk across the tropics. In the quest to meet global dietary and market demands, tropical agro-ecosystems face unrelenting agricultural intensification and expansion. Agro-biodiversity can improve ecosystem stability and functioning, but its promotion in smallholder-based systems faces numerous practical hurdles. In the tropics, cassava (Manihot esculenta Crantz) is cultivated on over 25 million hectares and features as the third most important source of calories. Cassava crops are often maintained by resource-poor farmers who operate on marginal lands, at the fringes of sensitive, biodiverse habitats. As traditional intercropping schemes are gradually abandoned, monoculture cassava systems face stagnating yields, resource-use inefficiencies and agro-ecosystem degradation. A global literature search identified 189 cassava intercropping studies, covering 330 separate instances of intercropping systems. We employed a vote-counting approach and simple comparative measure across a subset of 95 studies to document the extent to which intercropping sustains a bundle of ecosystem services. Across geographies and biophysical conditions, a broad range of intercrops provided largely positive effects on five key ecosystem services: pest suppression, disease control, land equivalency ratio (LER), and soil and water-related services. Ecosystem services were augmented through the addition of a diverse range of companion crops. Results indicated 25 positive impacts vs. 3 negative impacts with the addition of maize, 5 vs. 1 with gramineous crops, 23 vs. 3 with four species of grain legumes, and 9 vs. 0 with trees. Appropriate intercropping systems can help to strike a balance between farm-level productivity, crop resilience, and environmental health. Our work highlights an urgent need for interdisciplinary research and systems-level approaches to identify intensification scenarios in which crop productivity, provision of ecosystem services, biodiversity conservation, and human well-being are all balanced.

      PubDate: 2017-10-08T13:16:47Z
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: 1 December 2017
      Source:Agriculture, Ecosystems & Environment, Volume 250

      PubDate: 2017-09-30T06:16:02Z
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: 1 November 2017
      Source:Agriculture, Ecosystems & Environment, Volume 249

      PubDate: 2017-09-17T15:04:08Z
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