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Publisher: Elsevier   (Total: 3044 journals)

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Showing 1 - 200 of 3044 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: 23, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 29, 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: 343, 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: 215, 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: 3)
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: 134, 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: 10, 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: 10, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 28, 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: 5)
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: 40, 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: 48, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 15)
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: 21, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 8, 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: 15, 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: 7, 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: 18)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 19, 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: 2, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 348, 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: 16)
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: 318, 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: 408, 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: 9, 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: 47, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 5)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 3)
American Heart J.     Hybrid Journal   (Followers: 48, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 45, 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: 6, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 16, 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: 24, 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: 46, 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: 193, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 56, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 4)
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: 24, 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: 21, 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: 55, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 9)
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: 2, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 37, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 166, 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: 157, 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 Advances in Agronomy
  [SJR: 2.071]   [H-I: 82]   [15 followers]  Follow
    
   Full-text available via subscription Subscription journal
   ISSN (Print) 0065-2113
   Published by Elsevier Homepage  [3044 journals]
  • National Comparison of the Total and Sequestered Organic Matter Contents
           of Conventional and Organic Farm Soils
    • Authors: Elham A. Ghabbour; Geoffrey Davies; Tracy Misiewicz; Reem A. Alami; Erin M. Askounis; Nicholas P. Cuozzo; Alexia J. Filice; Jennifer M. Haskell; Andy K. Moy; Alexandra C. Roach; Jessica Shade
      Abstract: Publication date: Available online 14 September 2017
      Source:Advances in Agronomy
      Author(s): Elham A. Ghabbour, Geoffrey Davies, Tracy Misiewicz, Reem A. Alami, Erin M. Askounis, Nicholas P. Cuozzo, Alexia J. Filice, Jennifer M. Haskell, Andy K. Moy, Alexandra C. Roach, Jessica Shade
      Intensive agriculture has been linked to declining soil fertility and is a known source of greenhouse gas emissions. Decline in soil organic matter (SOM) is of particular concern due to its key role in maintaining soil health. Previous research supports the view that fertility management practices utilized in organic agriculture can maintain and even grow the SOM pool, but fewer studies examine what proportion of SOM is sequestered over long periods of time. Using data from the National Soil Project SOM sequestration between soils from organically and conventionally managed farms from across the United States is compared. Total %SOM ranged from 0.63 to 46.1 for conventional farm samples (mean 7.37) and 0.5 to 88.9 for the organic samples (mean 8.33). %FA ranged from 0.08 to 2.20 (mean 0.26) for conventional and 0.04 to 14.8 (mean 0.65) organic farm soils. %HA ranged from 0.17 to 23.0 (mean 2.85) for conventional and 0.25 to 48.9 (mean 4.1) for organic samples. Mean %humification (i.e., sequestration) was 45.6 for conventional soils and 57.3 for organic. Results presented here support previous assertions that FA are the precursors of HA. With the exception of water retention, comparisons of SOM, FA, HA, and humification suggest that organic farming practices support healthy soils and build and/or or maintain SOM more effectively than conventional farming practices. The data from this study can serve as benchmarks for other soils, and the spectroscopic analytical approaches employed should be useful in tracking the effects of changes in farm soil management practices over space and time.

      PubDate: 2017-09-18T19:26:32Z
      DOI: 10.1016/bs.agron.2017.07.003
       
  • Harvest Index of Maize (Zea mays L.): Are There Possibilities for
           Improvement'
    • Authors: Birgit W. Hütsch; Sven Schubert
      Abstract: Publication date: Available online 12 September 2017
      Source:Advances in Agronomy
      Author(s): Birgit W. Hütsch, Sven Schubert
      During the last decades, the harvest index (HI) of many agricultural crops (e.g., wheat) was genetically or agronomically increased, whereas the HI of hybrid maize (Zea mays L.) remained almost unchanged in the major growing areas. In maize, opposite to wheat, a close positive correlation exists between dry matter accumulation and grain yield. However, the production of vegetative biomass which is usually not utilized requires high amounts of water and nutrients. In this review two main ways for improvement of maize HI are suggested: Increase in kernel setting and decrease of vegetative shoot biomass. In salt-stressed maize plants which are particularly prone to kernel abortion, a decrease in plasma membrane H+-ATPase activity in kernels was found around pollination. It is hypothesized that with application of phytohormones, specifically auxins, H+-ATPase activity can be enhanced, leading to an improved transport of hexoses into the developing kernels and thus to a better kernel set. For the reduction of vegetative biomass, the focus lies on the the phytohormones gibberellins (GAs). We demonstrated that after shoot growth reduction, achieved either by application of a GA biosynthesis inhibitor or under drought stress, the HI was significantly increased with a concomitant improvement of resource use efficiencies. After this proof of concept (increase of maize HI is possible without grain yield losses), the identification of the responsible physiological mechanisms is necessary in order to apply the knowledge to other maize genotypes and to a broader range of growth conditions, eventually contributing to a more sustainable crop production.

      PubDate: 2017-09-18T19:26:32Z
      DOI: 10.1016/bs.agron.2017.07.004
       
  • Enhanced Plant Rooting and Crop System Management for Improved N Use
           Efficiency
    • Authors: Ciro A. Rosolem; Karl Ritz; Heitor Cantarella; Marcelo V. Galdos; Malcolm J. Hawkesford; Willian R. Whalley; Sacha J. Mooney
      Abstract: Publication date: Available online 12 September 2017
      Source:Advances in Agronomy
      Author(s): Ciro A. Rosolem, Karl Ritz, Heitor Cantarella, Marcelo V. Galdos, Malcolm J. Hawkesford, Willian R. Whalley, Sacha J. Mooney
      Despite the significant inroads into increasing agricultural productivity in recent decades, nitrogen remains a key limiting factor for crop growth and yield. Though highly variable globally, the amount of reactive N added yearly onto cropland that is subsequently lost to the environment remains high. As such the interest in agronomic approaches to address this and improve nitrogen use efficiency (NUE) is currently very high. Here, we have shown the combined approaches of management interventions such as no-till, intercropping with leguminous and grass species, use of nitrogen inhibitors, and combined crop–livestock systems offer considerable potential for enhancing NUE and are already being readily deployed in the tropics. Grass species such as Brachiaria in particular have demonstrated enormous potential via their deep root architectures to reduce losses by leaching. However, the potential for increases in NUE through interaction and association of the root systems with the soil microbial community via rhizodeposits remains a major area for future research. Increasingly it is recognized that truly enhancing NUE requires consideration of the whole system. Improving NUE is not simply a matter of how much fertilizer is used but also the need for a deeper understanding of the interactions between nutrients, plants, microbes, and soils under specific agronomic situations such as the integrated maize/grass–livestock systems that are now regularly employed in the tropics. This more holistic approach to the management of nitrogen offers considerable benefits that can hopefully be realized not only from an agricultural perspective but also from an environmental and socioeconomic view point.

      PubDate: 2017-09-18T19:26:32Z
      DOI: 10.1016/bs.agron.2017.07.002
       
  • Purine-Derived Ureides Under Drought and Salinity
    • Authors: Bikash Baral; Maria Luisa Izaguirre-Mayoral
      Abstract: Publication date: Available online 18 August 2017
      Source:Advances in Agronomy
      Author(s): Bikash Baral, Maria Luisa Izaguirre-Mayoral
      Purine-derived ureides (allantoin and allantoate) are the dominant nitrogenous (N) products transported from the root nodules to the aerial plant organs by rhizobia-nodulated (Rh+) ureidic legumes. However, ureides are not exclusively synthesized in Rh+ legumes as some evidence suggest a more universal ureide metabolism in C3 and C4 plants to recycle N for growth maintenance. Metabolism of ureides is tightly regulated and highly modulated by abiotic factors, with accumulating evidence describing large similarities among ureidic or amide-producing Rh+, nonrhizobia-nodulated (Rh−) legumes and nonlegumes, in terms of the critical role played by ureides on plant drought and salinity tolerance. Most reports relate drought or salt sensitivity with increased ureide content in different plant organs, and relate drought or salinity tolerance with the growth trait of high rates of ureide catabolism, regardless of the species and their root nodulating status. However, a considerable number of research articles argue for a hindered rather than active ureide catabolism as the survival trait for plants subjected to periods of mild drought or salinity due to the alternative prime stress signaling function of uric acid and allantoin. Therefore, the selection between the growth or survival trait for breeding programs requires a deep understanding of the purine pathway in Rh+, Rh− legumes and nonlegumes subjected to drought and salinity, based on relevant examples. Finally, this review may benefit both plant scientists and growers in providing detailed insights into ureide metabolism as it relates to abiotic stress responses.

      PubDate: 2017-08-31T11:17:11Z
      DOI: 10.1016/bs.agron.2017.07.001
       
  • Significance and Role of Si in Crop Production
    • Authors: Richard J. Haynes
      Abstract: Publication date: Available online 2 August 2017
      Source:Advances in Agronomy
      Author(s): Richard J. Haynes
      Silicon is a beneficial plant nutrient, and yield responses to its application on Si-deficient soils have been frequently demonstrated in Si-accumulator crops such as rice, sugarcane, maize, and wheat as well as a wide range of other crops. Plants take up silicic acid from soil solution and it is translocated to the shoots where it is deposited mainly as phytolith silica in the outer walls of epidermal leaf cells. Uptake of Si by accumulator plants has been shown to be an active process mediated by influx and efflux protein transporters. Yield increases are the result of increased plant resistance to a combination of biotic (plant pathogens, insect pests) and abiotic (water shortage, excess salts, metal toxicities) stresses. Addition of substantial quantities of soluble Si via plant roots is required to increase the intracellular Si status of the plant and elicit such stress resistance. Present knowledge suggests that added Si accelerates/intensifies basal defense responses to a range of stresses and it may act, at least partially, through influencing signaling systems in plants generated by endogenous phytohormones (GA, SA, ABA, JA, and ET). In natural ecosystems, phytogenic Si is returned to the soil in plant litter where it slowly dissolves and is recycled for plant uptake. However, continual removal of Si from agricultural soils, via harvested crop and crop residues, enhances soil desilification and means that Si will need to be applied more extensively and frequently in the future. Soil testing, plant analysis, and irrigation water analysis can all be important in assessing the need for application of soluble Si fertilizers (mainly industrial by-product slags) in the field.

      PubDate: 2017-08-31T11:17:11Z
      DOI: 10.1016/bs.agron.2017.06.001
       
  • Series Page
    • Abstract: Publication date: 2017
      Source:Advances in Agronomy, Volume 145


      PubDate: 2017-07-28T09:43:57Z
       
  • Conservation Agriculture Effects on Dynamics of Soil C and N under Climate
           Change Scenario
    • Authors: Nanak S. Pasricha
      Abstract: Publication date: Available online 21 June 2017
      Source:Advances in Agronomy
      Author(s): Nanak S. Pasricha
      Anthropogenic release of greenhouse gases is fast affecting climate change and global warming. This will increase soil organic matter decomposition and soil water deficits in future. Greater frequency of high intensity rainfall events, runoff, and flooding in future would cause high soil erosion losses unless offsetting conservation measures are taken. Mitigation strategy of diverting CO2 from atmosphere to soil as SOC by adopting conservation agricultural practices of reduced or no-tillage, crop residue retention, and diverse cropping system is now a recognized such method which has the potential of offsetting a significant portion of the future atmospheric increase in CO2 concentration. Cropping intensification combined with no-tillage or reduced tillage systems and optimum fertilizer management targeted to production level of the system affects favorably the SOC and N stocking. Such a stocking is more pronounced in the surface soil layer which fosters productivity and regulates terrestrial water flow, high infiltration rate, and higher amount of water storage in soil profile. Increased soil profile stored water, by facilitating increased cropping intensity, helps in overcoming the problem from keeping the soil fallow, a management system which is responsible for rapid loss of SOC and N and soil erosion in dry land and rain fed conditions. Conservation tillage practice also reduces the relative quantity of residual soil NO3-N available for leaching and/or denitrification even under situations of higher fertilizer N applications, thus preventing their possible leakage to the environment. Some residual NO3 may be denitrified to N2O gas especially in SOC-rich heavy soils prone to excessive wetness after several years of no-till practice.

      PubDate: 2017-06-27T07:39:53Z
      DOI: 10.1016/bs.agron.2017.05.004
       
  • Potential Hotspot Areas of Nitrous Oxide Emissions From Grazed Pastoral
           Dairy Farm Systems
    • Authors: Jiafa Luo; Justin Wyatt; Tony J. van der Weerden; Steve M. Thomas; Cecile A.M. de Klein; Yan Li; Mike Rollo; Stuart Lindsey; Stewart F. Ledgard; Jie Li; Weixin Ding; Shuping Qin; Nannan Zhang; Nanthi Bolan; M.B. Kirkham; Zhaohai Bai; Lin Ma; Xiying Zhang; Hailong Wang; Hongbin Liu; Gerald Rys
      Abstract: Publication date: Available online 21 June 2017
      Source:Advances in Agronomy
      Author(s): Jiafa Luo, Justin Wyatt, Tony J. van der Weerden, Steve M. Thomas, Cecile A.M. de Klein, Yan Li, Mike Rollo, Stuart Lindsey, Stewart F. Ledgard, Jie Li, Weixin Ding, Shuping Qin, Nannan Zhang, Nanthi Bolan, M.B. Kirkham, Zhaohai Bai, Lin Ma, Xiying Zhang, Hailong Wang, Hongbin Liu, Gerald Rys
      Nitrous oxide (N2O) is a potent greenhouse gas with a global warming potential 265–298 times greater than carbon dioxide (CO2) and causes destruction of stratospheric ozone. In soil, N2O is produced through the process of incomplete microbial denitrification or as a by-product of nitrification. Agricultural soils are the main source of N2O emissions globally. Total N2O emissions from dairy grazed farm systems can be dominated by large emissions within a small area (hotspots). Typically, N2O hotspots are areas with high stocking density, high excretal inputs (resulting in high soil N), and situations when soil water filled pore space is elevated. Different pasture grazing systems can be used on dairy farms, including year-round low input dairy systems and higher input systems with some animal confinement component. Potential N2O hotspot areas can be categorized into the following: areas of manure accumulation, storage, and spreading; areas of high stocking intensity leading to soil compaction and high inputs of urine and dung; cultivation and grazing of forage crops; and landscape features including topography, riparian areas, and soil property effects. High input systems can lead to a greater potential for N2O emission hotspots. To demonstrate the effect of hotspot zones on the calculation of total farm N2O emissions, a model was developed and used to assess the N2O emissions from a New Zealand case-study farm. Emission factor (EF3) values for cow urine in the gateway and water-trough areas were measured on the case-study farm and were both found to be about five times that of the rest of the paddock. Using these values for the total farm emissions calculation, it was found that gateways could be significant hotspots for N2O emission with 3.2% of the farm area contributing 9.4% of the total farm N2O emissions. Knowledge of the significance of hotspot zones would enable more accurate calculation of total farm emissions and more efficient targeting of N2O mitigation strategies. There is a paucity of studies which specifically examine hotspots of N2O emissions from farm-scale features and the full magnitude of the emissions from possible hotspot areas and their contributions to the total farm emissions require further investigation.

      PubDate: 2017-06-27T07:39:53Z
      DOI: 10.1016/bs.agron.2017.05.006
       
  • Weed Dynamics and Management in Wheat
    • Authors: Khawar Jabran; Khalid Mahmood; Bo Melander; Ali A. Bajwa; Per Kudsk
      Abstract: Publication date: Available online 21 June 2017
      Source:Advances in Agronomy
      Author(s): Khawar Jabran, Khalid Mahmood, Bo Melander, Ali A. Bajwa, Per Kudsk
      Wheat is among the most important cereal and food crops of world and is grown in almost all parts of the world. It is a staple for a large part of the world population. Any decline in wheat yield by biotic or abiotic factors may affect global food security adversely. Weeds are the most damaging pest of wheat causing in total 24% losses in wheat grain yield. In this chapter, we discuss the (i) weed flora in different wheat-growing regions of world; (ii) the yield losses caused by weeds in wheat; (iii) the preventive and cultural options for weed management; (iv) physical weed control; (v) chemical weed control; and (vi) integrated weed management strategy in wheat. A critical analysis of recent literature indicated that broadleaved weeds are the most common group of weeds in wheat fields followed by grass weeds, while sedges were rarely noted in wheat fields. Across the globe, the most important weeds in wheat fields were Avena fatua L., Chenopodium album L., Phalaris minor Retz., Galium aparine L., Stellaria media (L.) Vill., and Veronica persica Poir., respectively. Adoption of wise weed management strategies may help control weeds and avoid yield losses. Both preventive measures and cultural practices have proved their significance for improving weed control in wheat; physical and chemical tools are the other options. Moreover, site-specific herbicide application may help to make weed control economical and reduce the herbicide input. Nonetheless, integrated strategies should be opted for effective and ecofriendly weed management in wheat.

      PubDate: 2017-06-27T07:39:53Z
      DOI: 10.1016/bs.agron.2017.05.002
       
  • Allelopathic Potential of Sorghum (Sorghum bicolor (L.) Moench) in Weed
           Control: A Comprehensive Review
    • Authors: Lilianna Głąb; Józef Sowiński; Raven Bough; Franck E. Dayan
      Abstract: Publication date: Available online 9 June 2017
      Source:Advances in Agronomy
      Author(s): Lilianna Głąb, Józef Sowiński, Raven Bough, Franck E. Dayan
      Weeds constitute the largest biotic threat affecting the yield of cultivated plants. While conventional agriculture relies principally on chemicals for weed control, alternative biological methods may be important tools to reduce weed pressure in agroecosystems. Furthermore, as the problem of excessive residue of plant protection agents in agroecosystems and the growing number of herbicide resistant weed biotypes continue to increase, new solutions that have smaller impacts on the environment are becoming increasingly desirable. One promising such method is the use of crops that exert a negative phytotoxic influence on weeds. This natural phenomenon describing the ability of certain plant species to produce compounds that affect the growth of other plants in their surroundings is called allelopathy. Managing weed infestations in cultivated fields by planting allelopathic crops is a sustainable, economic, and environmentally friendly approach that has been strongly articulated in the international arena. Among cultivated crops, sorghum (Sorghum bicolor (L.) Moench) has been intensively studied because of demonstrated allelopathic potential. This report provides a comprehensive literature review of the applications of sorghum allelopathy in agriculture. A critical analysis of the allelopathic properties of sorghum identified the following areas contributing to its ability to reduce weed infestation in agroecosystems: 1. a large number of compounds produced by sorghum have allelopathic properties, 2. allelopathic compounds can be applied in the form of mixed plant extracts or in combination with herbicides, 3. sorghum extracts have a broad spectrum of activity, 4. sorghum may be used to produce bioherbicides.

      PubDate: 2017-06-14T19:18:47Z
      DOI: 10.1016/bs.agron.2017.05.001
       
  • Series Page
    • Abstract: Publication date: 2017
      Source:Advances in Agronomy, Volume 144


      PubDate: 2017-05-16T13:01:06Z
       
  • Grain Legume Production and Use in European Agricultural Systems
    • Authors: Christine A. Watson; Moritz Reckling; Sara Preissel; Johann Bachinger; Göran Bergkvist; Tom Kuhlman; Kristina Lindström; Thomas Nemecek; Cairistiona F.E. Topp; Aila Vanhatalo; Peter Zander; Donal Murphy-Bokern; Fred L. Stoddard
      Abstract: Publication date: Available online 2 May 2017
      Source:Advances in Agronomy
      Author(s): Christine A. Watson, Moritz Reckling, Sara Preissel, Johann Bachinger, Göran Bergkvist, Tom Kuhlman, Kristina Lindström, Thomas Nemecek, Cairistiona F.E. Topp, Aila Vanhatalo, Peter Zander, Donal Murphy-Bokern, Fred L. Stoddard
      There is a great demand for high-protein materials for livestock feed in Europe and European agriculture has a deficit of about 70% high-protein materials of which 87% is met by imported soybean and soy meal. This reflects the fact that grain legumes are currently under represented in European agriculture and produced on only 1.5% of the arable land in Europe compared with 14.5% on a worldwide basis. Several grain legumes have the potential to replace at least some of the soya currently used in the diets of monogastric animals, ruminants, and fish. There are also opportunities for greater use of legumes in new foods. Here we review the contribution of ecosystem services by grain legumes in European agriculture starting with provisioning services in terms of food and feed and moving on to the contribution they make to both regulating and supporting services which are in part due to the diversity which these crops bring to cropping systems. We explore the need to understand grain legume production on the time scale of a rotation rather than a cropping season in order to value and manage the agronomic challenges of weed, pests, and diseases alongside the maintenance or improvement of soil structure, soil organic matter, and nutrient cycling. A review of policy interventions to support grain legumes reveals that until very recently these have failed to make a difference in Europe. We contrast the European picture with the interventions that have allowed the development of grain legume production in both Canada and Australia. Whether farmers choose to grow more legumes will depend on market opportunities, the development of supply chains, and policy support as well as technical improvements of grain legume production such as breeding of new varieties and management development to improve yield stability. However, to really increase the production of grain legumes in Europe, the issues are far more wide reaching than agronomy or subsidy and require a fundamental rethinking of value chains to move grain legumes from being niche products to mainstream commodities.

      PubDate: 2017-05-06T03:48:41Z
      DOI: 10.1016/bs.agron.2017.03.003
       
  • Current Approaches and Future Trends in Compost Quality Criteria for
           Agronomic, Environmental, and Human Health Benefits
    • Authors: M. Pilar Bernal; Sven G. Sommer; Dave Chadwick; Chen Qing; Li Guoxue; Frederick C. Michel
      Abstract: Publication date: Available online 29 April 2017
      Source:Advances in Agronomy
      Author(s): M. Pilar Bernal, Sven G. Sommer, Dave Chadwick, Chen Qing, Li Guoxue, Frederick C. Michel
      Organic wastes are composted to stabilize organic matter, reduce the moisture content, increase the concentrations of plant nutrients, eliminate pathogens and weed seeds, develop disease suppressiveness, and reduce greenhouse gas emissions. The requirements for compost quality depend on its final destination, which includes agriculture, horticulture, and urban landscaping. The development of a market for compost greatly depends on the definition and adoption of quality standards. Several countries and public and private organizations have established quality standards for compost, where certain properties are prioritized and different limits are established according to the end use. However, there is a need to harmonize such criteria at the international level. Also, if the process of composting is not managed properly, then it can result in excessive emissions of ammonia (NH3), nitrous oxide (N2O), and methane (CH4). This review compares compost quality criteria across different countries, addresses strategies for reducing the environmental impacts of composting processes, and evaluates new analytical and microbiological approaches to define compost quality. An overview of compost quality standards in Europe, China, and the United States of America is given, including a characterization of the plant residues, livestock manure, and organic wastes that can be composted.

      PubDate: 2017-04-30T10:40:51Z
      DOI: 10.1016/bs.agron.2017.03.002
       
  • Preventive Weed Management in Direct-Seeded Rice: Targeting the Weed
           Seedbank
    • Authors: Adusumilli N. Rao; Daniel C. Brainard; Virender Kumar; Jagdish K. Ladha; David E. Johnson
      Abstract: Publication date: Available online 23 April 2017
      Source:Advances in Agronomy
      Author(s): Adusumilli N. Rao, Daniel C. Brainard, Virender Kumar, Jagdish K. Ladha, David E. Johnson
      In Asia, direct-seeded rice (DSR) is becoming popular as an alternative to puddled transplanted rice (PTR) due to its potential to save scarce resources (labor, water, and energy), reduce greenhouse gas emissions, improve soil physical properties, and increase yields in rotational crops. However, weed management in DSR is more difficult because the initial size differential between weeds and rice is small, reducing crop competitiveness and limiting opportunities for selective control measures including flooding. In this context, preventive approaches—those which focus primarily on limiting dispersal and persistence of weed propagules—may play a critical role in complementing the current reliance on curative tactics such as herbicides. Greater understanding and integration of preventive approaches in DSR may reduce the risks of herbicide resistance development, limit adverse effects of herbicides on human health and the environment, and lower the overall weed management costs. However, information on preventive weed management in DSR is relatively limited. Therefore, the central objectives of this review are to: (i) summarize existing knowledge regarding preventive strategies; (ii) discuss key integrated preventive weed management approaches that have the greatest potential for practical application in DSR systems; and (iii) identify knowledge gaps that limit our ability to optimize preventive approaches. Based on an extensive review of existing literature, we conclude that (i) Minimizing weed seed production in the field is critically important for managing weed seedbanks in DSR, but that given seed dispersal in both time and space, prevention of seed production from neighboring bunds, rice–fallow land and irrigation channels bordering DSR areas may be equally important; (ii) Minimizing dispersal of weed seeds into DSR fields may be a practical approach for species that are dispersed primarily by humans (e.g., as contaminants in crop seeds or through irrigation canals), but not for species that are dispersed primarily by other means (wind and birds); (iii) Promotion of seed predation may be a useful strategy in managing certain weed species in DSR—especially where zero-tillage is used—but more research is needed on the identity of seed predators and management factors that promote their activity; (iv) available evidence suggests that the potential for promotion of seed decay is limited in scope but may be valuable for the management of certain relatively nonpersistent weeds in some cropping systems; (v) strategies that stimulate fatal germination of weed seeds (e.g., stale seedbed) appear to be one of the most promising means of prevention in DSR, but increased information on the mechanisms and timing of dormancy release for key species is needed to optimize and enhance the value of this approach; (vi) Prevention of weed germination and emergence in DSR through mulching—especially in zero-till systems—has proven benefits, but its widespread applicability is limited by the economic tradeoffs associated with using mulch as a source of livestock feed; and (vii) development of anaerobic germination (AG)-tolerant rice cultivars and complementary flooding strategies which can tolerate anaerobic conditions/flooding hold great potential for the suppression of weeds in DSR. Successful integration of preventive approaches for managing weeds in DSR will depend on the development of multidisciplinary approaches which are biologically effective, economically feasible, and socially acceptable. Preventive weed control measures alone are unlikely to be sufficient for the effective and economical management of weeds in DSR systems, but their integration with curative approaches should reduce weed management costs and increase both the likelihood of adoption of DSR and the realization of its benefits for food security.

      PubDate: 2017-04-23T10:37:29Z
      DOI: 10.1016/bs.agron.2017.02.002
       
  • An Important Tool With No Instruction Manual: A Review of Gypsum Use in
           Agriculture
    • Authors: Samuel M. Zoca; Chad Penn
      Abstract: Publication date: Available online 18 April 2017
      Source:Advances in Agronomy
      Author(s): Samuel M. Zoca, Chad Penn
      Land application of gypsum has been studied and utilized in agriculture and environmental remediation for many years. Most of the published literature has focused on gypsum application impacts on soil properties rather than crop yields. This literature review was conducted to (i) gather results from gypsum application studies relevant to crop grain yield, soil physical–chemical properties, and environmental impact; (ii) report different methods for determining gypsum application rates; (iii) suggest recommendations for future studies on land application of gypsum. Improvement in plant nitrogen use efficiency was rarely discussed as a potential mechanism for improving yield. Free Al activity has been demonstrated to be more correlated with plant yield responses to gypsum application than exchangeable Al or Al saturation. However, few authors reported Al speciation and Al activity. While gypsum is reported to improve soil chemical properties in most cases, these changes do not necessarily translate to increases in yield. Improvements in physical properties for nonsodic soils are not consistent. It is difficult to exactly determine the positive effects from gypsum application that are responsible for yield increases, since there are often many simultaneous physical and chemical changes occurring in the soil. Improvement in crop yield may be a result of an additive or synergistic effect of each of these potential changes. In addition, these potential changes, as varied as they are, appear to also vary with crop, soil type, and rainfall regime. Therefore, meta-analysis of gypsum experiments is highly recommended in order to improve gypsum recommendations across diverse environments.

      PubDate: 2017-04-23T10:37:29Z
      DOI: 10.1016/bs.agron.2017.03.001
       
  • Series page
    • Abstract: Publication date: 2017
      Source:Advances in Agronomy, Volume 143


      PubDate: 2017-04-23T10:37:29Z
       
  • Humin: Its Composition and Importance in Soil Organic Matter
    • Authors: Michael H.B.; Hayes Rosaleen Mylotte Roger Swift
      Abstract: Publication date: Available online 12 April 2017
      Source:Advances in Agronomy
      Author(s): Michael H.B. Hayes, Rosaleen Mylotte, Roger S. Swift
      Humin is the insoluble component of soil organic matter (SOM) that remains after extraction of the other components of SOM that are soluble in aqueous base. Humin usually makes up a substantial component of SOM, but its lack of solubility and intractable nature have made it difficult to study. To put this contemporary review of humin into perspective, a summary of the historical development of SOM studies and the terminology used to describe the various components of SOM is presented. Two major recent advances, namely, sophisticated nuclear magnetic resonance (NMR) techniques and the introduction of a solvent system (acidified dimethylsulfoxide) capable of dissolving humin, have facilitated studies of its composition. The NMR techniques used are briefly explained and the results obtained from their application are presented. Based on this information, the possible contributions to humin of various plant/soil components are assessed. The major components of the humin are predominantly aliphatic hydrocarbon functionalities, especially those found in lipids, waxes, cuticular materials, cutin/cutan, and suberin/suberan, which are relatively minor components of plants. There is also evidence for small amounts of carbohydrate (possibly highly ordered cellulose), peptide, and peptidoglycans; but there is little evidence for lignin-derived structures. The composition of humin differs considerably from the base-soluble components of the SOM. All components of SOM eventually decompose but at different rates, but the accumulation of humin constituents relative to their levels in plants indicates that they are relatively resistant to decomposition. The environmental consequences of humin composition and the opportunities presented are discussed and future possibilities outlined.

      PubDate: 2017-04-16T10:24:52Z
       
  • Soil: The Forgotten Piece of the Water, Food, Energy Nexus
    • Authors: Jerry L. Hatfield; Thomas J. Sauer; Richard M. Cruse
      Abstract: Publication date: Available online 15 March 2017
      Source:Advances in Agronomy
      Author(s): Jerry L. Hatfield, Thomas J. Sauer, Richard M. Cruse
      The water, food, energy nexus has prompted sustainability concerns as interactions between these interdependent human needs are degrading natural resources required for a secure future world. Discussions about the future needs for food, water, and energy to support the increasing world population have ignored our soil resource that is the cornerstone or our capacity to produce food, capture water, and generate energy from biological systems. Soil scientists often recognize soils as a critical component of food, energy, or water security; however, the translation of that awareness into action strategies to either enhance public recognition of soil resource importance or improve soil management is lacking. Food, water, and energy security represents the current and future challenge of sustaining humankind while protecting the environment. These interactions are recognized by scientists, but the linkage to policy decisions or implementation of strategies to create positive outcomes for food, energy, or water enhancement is lacking. If we consider that soil is responsible for 99% of the world's food production, then the importance of soil in the food, energy, water nexus becomes apparent. If we further consider that soil erosion is the major factor, affecting soil degradation and declines in productivity are directly related to degradation of the soil resource, then the implications of soil in the context of increasing food, energy, and water security becomes more evident. However, if the attitude is one that technology will provide answers to these problems, then the soil degradation rate will continue to increase and we will reach a tipping point in which technological advances will not be able to overcome the impacts of a reduced topsoil depth coupled with a more variable climate. Soil is the forgotten piece of the food, energy, water nexus; however, the oversight extends beyond this nexus to include many of the ecological services required by humankind.

      PubDate: 2017-03-18T13:25:36Z
      DOI: 10.1016/bs.agron.2017.02.001
       
  • Delineation of Soil Management Zones for Variable-Rate Fertilization: A
           Review
    • Authors: Said Nawar; Ronald Corstanje; Graham Halcro; David Mulla; Abdul M. Mouazen
      Abstract: Publication date: Available online 27 February 2017
      Source:Advances in Agronomy
      Author(s): Said Nawar, Ronald Corstanje, Graham Halcro, David Mulla, Abdul M. Mouazen
      Different methods of management zone (MZ) delineation have been established over the past 2 decades based on approaches, which have been largely constrained by the available data collection methods that are often time consuming and expensive. This situation is being changed by recent advances in sensor technology, making a huge amount of data available. Advances in computing power make it possible to analyze and utilize this large amount of data. These current advances in technology are gradually turning MZ maps into commercially viable agricultural products for large-scale adoption. The aim of this paper is to provide a critical overview of MZ delineation approaches for precision agriculture applications, and to compare and contrast traditional with advanced sensing technologies for delineating MZs. This review illustrates how recent development in sensing technologies, geostatistical analysis, data fusion, and interpolation techniques have improved precision and reliability of MZ delineation, making it a viable strategy in commercial agriculture. Studies from the last decade showed that when MZ delineation techniques are used for variable-rate nutrient application, farm efficiency increased when this is compared to traditional uniform-rate application methods. This improved farm production efficiency is accompanied by a reduction in environmental impacts. Implementation of MZ therefore often provides financial and environmental benefits, and we can foresee an increase in the diffusion and application of precision agriculture techniques in the near future.

      PubDate: 2017-03-05T18:12:38Z
      DOI: 10.1016/bs.agron.2017.01.003
       
  • Series Page
    • Abstract: Publication date: 2017
      Source:Advances in Agronomy, Volume 142


      PubDate: 2017-03-05T18:12:38Z
       
  • Soil Water Characteristics of European SoilTrEC Critical Zone
           Observatories
    • Authors: S. Rousseva; M. Kercheva; T. Shishkov; G.J. Lair; N.P. Nikolaidis; D. Moraetis; P. Krám; S.M. Bernasconi; W.E.H. Blum; M. Menon; S.A. Banwart
      Abstract: Publication date: Available online 26 January 2017
      Source:Advances in Agronomy
      Author(s): S. Rousseva, M. Kercheva, T. Shishkov, G.J. Lair, N.P. Nikolaidis, D. Moraetis, P. Krám, S.M. Bernasconi, W.E.H. Blum, M. Menon, S.A. Banwart
      Most of soil functions depend directly or indirectly on soil water retention and transmission, which explains their importance for many environmental processes within Earth's Critical Zones. Soil hydraulic properties are essential in irrigation and drainage studies for closing water balance equation, for predicting leaching of nutrients, for water supply to plants, and for other agronomical and environmental applications. Soil hydraulic properties reflect the structure of the soil porous system comprising pores of different geometry and sizes. This investigation comprises a detailed analytical study of soil hydraulic properties and climate conditions at 18 methodologically selected sites in Damma Glacier, Slavkov Forest, Marchfeld, and Koiliaris Critical Zone Observatories of SoilTrEC project. The local moisture regimes were assessed on a long-term basis by the Newhall model. The experimental data for soil water content at different potentials were used for assessing water storage capacity, pore size distribution, parameters of fitted retention curve equation, curve slope at the inflection point, and water permeability characteristics of each soil horizon. The differences of soil water retention and transmission characteristics—as fundamental properties describing soil structure—were explained by the different stages of soil profile development, parent materials, organic matter content, and land use histories.

      PubDate: 2017-01-29T20:50:45Z
      DOI: 10.1016/bs.agron.2016.10.004
       
  • Soil Functions in Earth's Critical Zone: Key Results and Conclusions
    • Authors: S.A. Banwart; S.M. Bernasconi; W.E.H. Blum; D.M. de Souza; F. Chabaux; C. Duffy; M. Kercheva; P. Krám; G.J. Lair; L. Lundin; M. Menon; N. Nikolaidis; M. Novak; P. Panagos; K.V. Ragnarsdottir; D.A. Robinson; S. Rousseva; P. de Ruiter; P. van Gaans; L. Weng; T. White; B. Zhang
      Abstract: Publication date: Available online 12 January 2017
      Source:Advances in Agronomy
      Author(s): S.A. Banwart, S.M. Bernasconi, W.E.H. Blum, D.M. de Souza, F. Chabaux, C. Duffy, M. Kercheva, P. Krám, G.J. Lair, L. Lundin, M. Menon, N. Nikolaidis, M. Novak, P. Panagos, K.V. Ragnarsdottir, D.A. Robinson, S. Rousseva, P. de Ruiter, P. van Gaans, L. Weng, T. White, B. Zhang
      This chapter summarizes the methods, results, and conclusions of a 5-year research project (SoilTrEC: Soil Transformations in European Catchments) on experimentation, process modeling, and computational simulation of soil functions and soil threats across a network of European, Chinese, and United States Critical Zone Observatories (CZOs). The study focused on the soil functions of biomass production, carbon storage, water storage and transmission, water filtration, transformation of nutrients, and maintaining habitat and genetic diversity. The principal results demonstrate that soil functions can be quantified as biophysical flows and transformations of material and energy. The functions can be simulated with mathematical models of soil processes within the soil profile and at the critical zone interfaces with vegetation and atmosphere, surface waters and the below-ground vadose zone and groundwater. A new dynamic model for soil structure development, together with data sets from the CZOs, demonstrate both seasonal fluctuations in soil structure dynamics related to vegetation dynamics and soil carbon inputs, and long-term trends (decadal) in soil carbon storage and soil structure development. Cross-site comparison for 20 soil profiles at seven field sites with variation in soil type, lithology, land cover, land use, and climate demonstrate that sites can be classified, using model parameter values for soil aggregation processes together with climatic conditions and soil physical properties, along a trajectory of soil structure development from incipient soil formation through productive land use to overly intensive land use with soil degradation. A new modeling code, the Integrated Critical Zone model, was applied with parameter sets developed from the CZO site data to simulate the biophysical flows and transformations that quantify multiple soil functions. Process simulations coupled the new model for soil structure dynamics with existing modeling approaches for soil carbon dynamics, nutrient transformations, vegetation dynamics, hydrological flow and transport, and geochemical equilibria and mineral weathering reactions. Successful calibration, testing, and application of the model with data sets from horticulture plot manipulation experiments demonstrate the potential to apply modeling and simulation to the scoping and design of new practices and policy options to enhance soil functions and reduce soil threats worldwide.

      PubDate: 2017-01-16T07:12:01Z
      DOI: 10.1016/bs.agron.2016.11.001
       
  • Modeling the Impact of Carbon Amendments on Soil Ecosystem Functions Using
           the 1D-ICZ Model
    • Authors: M. Kotronakis; G.V. Giannakis; N.P. Nikolaidis; E.C. Rowe; J. Valstar; N.V. Paranychianakis; S.A. Banwart
      Abstract: Publication date: Available online 11 January 2017
      Source:Advances in Agronomy
      Author(s): M. Kotronakis, G.V. Giannakis, N.P. Nikolaidis, E.C. Rowe, J. Valstar, N.V. Paranychianakis, S.A. Banwart
      In the next four decades, humanity needs to double food and energy production and increase the supply of clean water by over 50% while mitigating and adapting to climate change. A central element in the strategy of addressing these major environmental challenges is to maintain the central role of Earth's essential soil functions and related ecosystem services. Many soil functions are affected by soil structure in terms of particle aggregation and porosity. The objective of this work is to model soil structure and biomass dynamics, nutrients uptake, and yields using the 1D Integrated Critical Zone (1D-ICZ) model which is a mechanistic mathematical description of soil processes and functions. The 1D-ICZ model simulates the coupled processes that underpin major soil functions including water flow and storage, biomass production, carbon and nutrient sequestration, pollutant transformation, and supporting biological processes, and thus is capable of quantifying essential soil ecosystem services. The model was validated using data derived from a field experiment where tomato plants were grown using different treatments of commercial mineral fertilizers, compost, manure, and a 30% manure–70% compost amendment. Detailed data have been collected over four growing seasons on soil and soil solution chemistry, aggregate formation, and plant production. The model has been able to capture the biomass production, the temporal dynamics of the water-stable aggregate formation and the dynamics of carbon and nutrient sequestration in the different sizes aggregates as well as the variability of water filtration and transformation efficiency in the different amendment treatments. The model results demonstrate the value of applying computational simulation tools such as the 1D-ICZ model to test options for improved land management measures and to support sustainable land care practices.

      PubDate: 2017-01-16T07:12:01Z
      DOI: 10.1016/bs.agron.2016.10.010
       
  • Soil Mineralogy Changes With Different Agricultural Practices During
           8-Year Soil Development From the Parent Material of a Mollisol
    • Authors: Y.-L. Liu; S.-H. Yao; X.-Z. Han; B. Zhang; S.A. Banwart
      Abstract: Publication date: Available online 11 January 2017
      Source:Advances in Agronomy
      Author(s): Y.-L. Liu, S.-H. Yao, X.-Z. Han, B. Zhang, S.A. Banwart
      Clay minerals are involved in the formation of soil structure and soil cation exchange capacity through interaction with soil organic matter. Through these interactions, clay minerals contribute to soil functions and the delivery of soil ecosystem services. Although clay minerals are considered stable over long periods of time, recent studies have demonstrated that the crystallographic structures and types of clay minerals can undergo spontaneous modification and transformation with changes in environmental conditions. However, little is known whether and how soil organic matter affects the evolution of clay minerals during these transitions. We examined changes in soil mineralogy during the 8 years of soil development from the parent material (PM) of a Mollisol under different agricultural practices in Northeastern China. Mineralogical changes were determined by X-ray diffraction and data analysis through spectra decomposition. The mineral composition varied with initial particle size classes and showed rapid changes, including transformation between illite and vermiculite or illite and smectite, depending on K+ availability and transformations between smectite and vermiculite under acidic conditions. The mineral composition changed with soil depth due to transport of vermiculite and well-crystallized illite as fine particles. Soil organic matter was more strongly bound to vermiculite and smectite than to kaolinite and illite and therefore influenced the transport of these mineral particles. However, the soil organic matter–mineral association did not affect transformation between illite and vermiculite or smectite. Therefore, the effects of particle size, organic matter, and soil depth on soil mineral composition were exhibited to different extents and interacted differently under different agricultural practices. These results of the 8-year field experiment suggest that soil mineral composition of the more intensely weathered PM of the studied Mollisols can change after agricultural restoration more quickly than previously known. The rate and extent of these transformations must be considered in agricultural practices that are used to manage soil functions and associated ecosystem services of soil systems.

      PubDate: 2017-01-16T07:12:01Z
      DOI: 10.1016/bs.agron.2016.10.015
       
  • Modeling Soil Aggregation at the Early Pedogenesis Stage From the Parent
           Material of a Mollisol Under Different Agricultural Practices
    • Authors: N. Li; M.-Y. You; B. Zhang; X.-Z. Han; S.K. Panakoulia; Y.-R. Yuan; K. Liu; Y.-F. Qiao; W.-X. Zou; N.P. Nikolaidis; S.A. Banwart
      Abstract: Publication date: Available online 11 January 2017
      Source:Advances in Agronomy
      Author(s): N. Li, M.-Y. You, B. Zhang, X.-Z. Han, S.K. Panakoulia, Y.-R. Yuan, K. Liu, Y.-F. Qiao, W.-X. Zou, N.P. Nikolaidis, S.A. Banwart
      Soil aggregation and development of soil structure play a crucial role in determining soil functions and ecosystem services in Earth's Critical Zone. Soil organic matter (SOM) is the main constituent that binds mineral particles together into larger-sized aggregates. Many theoretical concepts have been proposed to explain soil aggregation and SOM accrual processes, but quantification of the processes remains lacking. We observed changes in aggregate size mass distribution and aggregate carbon content in 2 discrete years from an 8-year field experiment, which was conducted to determine how to speed up soil development and restoration with different agricultural practices. The 2-year data showed that the proportion of macroaggregates (>250μm) increased with the decreasing proportions of microaggregates (53–250μm) and soil texture units (<53μm) and increasing proportion of particulate organic matter occluded in the macroaggregates. This aggregation process was more noticeable in the field treatments with higher organic carbon input. By using these data, we successfully calibrated the recently developed CAST mathematical model, which assumes that primary macroaggregates are first formed around plant-derived organic matter and primary microaggregates are then formed within the macroaggregates as the occluded organic materials are decomposed. The secondary microaggregates and macroaggregates are assumed to form after the breakdown of primary macroaggregates. The calibration processes separated the plant growth season from the frozen winter season. Some calibrated parameters were the same for all of the field treatments, and these parameters included the first-order rate constants of the fragmentation and decomposition of plant litter within the macroaggregates, the decomposition rates of organic matter incorporated and protected in microaggregates, and organic carbon associated with the free soil texture units. Other calibrated parameter values were affected by the field treatments, and the parameters were the first-order decay rate constants of the plant-derived organic matter in nonaggregated soils and in the secondary macroaggregates, the least carbon sources for the formation of the secondary macroaggregates, and the correction factor to adjust carbon with the mass flow of the soil texture units. The differences in the calibrated parameter values suggested that the rates of the primary macroaggregation and the secondary microaggregation were likely controlled by the intrinsic properties of the parent material rather than by the land use and agricultural practices, whereas the rates of the secondary macroaggregation process were likely affected by land use through controlling plant litter quality and quantity and by agricultural practices, such as soil tillage, and to a less extent by fertilizers that control organic input and then carbon and mass content of the soil texture units and microaggregates. The model results were consistent with measured changes over time of the aggregate mass distribution by size class, the total organic matter content, and the SOM bound in aggregates. However, the CAST model did not reproduce particularly well the mass of the soil texture units within different aggregate size classes nor the relative contribution of carbon stocks from different carbon pools within aggregates. The gap between observations and model results points the way forward to develop further the detailed process descriptions in the CAST modeling approach, for example, to consider primary microaggregation directly from basic soil texture units. Nevertheless, this study demonstrates that the CAST model is very powerful to predict the dynamics of soil aggregation and concurrent SOM change in response to changes in land use and soil management.

      PubDate: 2017-01-16T07:12:01Z
      DOI: 10.1016/bs.agron.2016.10.007
       
  • Valuation of Soil Ecosystem Services
    • Authors: J.Ö.G. Jónsson; B. Davíðsdóttir; N.P. Nikolaidis
      Abstract: Publication date: Available online 30 December 2016
      Source:Advances in Agronomy
      Author(s): J.Ö.G. Jónsson, B. Davíðsdóttir, N.P. Nikolaidis
      Soil natural capital and soil ecosystem services (ES) are under increasing pressure because of human activities. Soils provide multiple benefits to humans, and the role of soil in Earth's Critical Zone is fundamental to its functions that provide these benefits. Despite their importance, soils are rarely appreciated for the values they provide. One reason is the absence of their economic value in land-use decision making. We present a framework for categorizing and economically valuing soil ES and illustrating the use of the framework in a case study for three soil ES in the Koiliaris watershed on the Greek island of Crete. The value of the soil ES estimated was crop and livestock biomass 740–7560id$ha−1 year−1; filtering of nutrients and contaminants 0–278id$ha−1 year−1; and climate regulation −2200 to −5610id$ha−1 year−1. Highlights • Soils provide multiple economic benefits that are rarely accounted for. • A framework for the classification and economic valuation of soil ecosystem services (ES) is presented. • The soil framework is applied at Koiliaris, Crete, Greece for three soil ES. • This chapter illustrates soil ES values from −5610 to 7560id$ha−1 year−1 depending on the specific soil ES.

      PubDate: 2017-01-09T06:05:06Z
      DOI: 10.1016/bs.agron.2016.10.011
       
  • Effects of Dry and Wet Sieving of Soil on Identification and
           Interpretation of Microbial Community Composition
    • Authors: A. Blaud; M. Menon; B. van der Zaan; G.J. Lair; S. Banwart
      Abstract: Publication date: Available online 29 December 2016
      Source:Advances in Agronomy
      Author(s): A. Blaud, M. Menon, B. van der Zaan, G.J. Lair, S. Banwart
      Soil aggregates are microhabitats for microorganisms, and directly influence microorganisms that live within and are influenced by microorganisms in return. Two methods are used to isolate soil aggregates by their size: dry sieving (sieving air-dried soil) and wet sieving (sieving soil in water). Wet-sieving methods are generally considered to represent separation of aggregate classes that are stable to physical disaggregation in water, a condition considered favorable for protecting soil structure over time. However, little is known about the effect of sieving methods on microbial abundance, diversity, and functions, hindering the understanding of the relationship between soil structure and soil aggregates as habitat and soil microorganisms. In this study, the effect of dry and wet sieving on bacterial diversity, and abundance of microorganisms involved in N fixation (nifH gene), nitrification (amoA bacteria and archaea), and denitrification (narG, nirS and nosZ genes), was determined for four sizes of soil aggregates from a cropland and grassland. Quantitative-PCR (Q-PCR) showed little differences in relative gene abundance between size fractions of soil aggregates, but wet-sieving method significantly increased gene abundance for amoA bacteria, nirS and nosZ genes. When the N functional genes were expressed as percentage of the bacterial 16S rRNA genes, the wet sieving resulted in significantly higher genes percentage for all the genes (except for narG gene), and significant differences between soil aggregate size fractions at the grassland site. The different sieving methods resulted in different bacterial community compositions, but only the wet-sieving method was able to reveal significant differences in bacterial community composition between soil fractions in grassland. The results demonstrate significantly different quantitative and qualitative interpretation of soil microbial community depending on whether aggregate samples were obtained from wet or dry sieving, highlighting the importance in the choice of the sieving method.

      PubDate: 2017-01-09T06:05:06Z
      DOI: 10.1016/bs.agron.2016.10.006
       
  • Integrated Critical Zone Model (1D-ICZ): A Tool for Dynamic Simulation of
           Soil Functions and Soil Structure
    • Authors: G.V. Giannakis; N.P. Nikolaidis; J. Valstar; E.C. Rowe; K. Moirogiorgou; M. Kotronakis; N.V. Paranychianakis; S. Rousseva; F.E. Stamati; S.A. Banwart
      Abstract: Publication date: Available online 24 December 2016
      Source:Advances in Agronomy
      Author(s): G.V. Giannakis, N.P. Nikolaidis, J. Valstar, E.C. Rowe, K. Moirogiorgou, M. Kotronakis, N.V. Paranychianakis, S. Rousseva, F.E. Stamati, S.A. Banwart
      Food security should be addressed in relation to soil sustainability and sustainable land care, and examined within the science framework of Earth's critical zone as an integrated system that includes Earth surface interactions, connected to soil functions, and ecosystem services. There is a great need to develop critical zone mathematical models that will simulate and quantify soil functions and that can be used as management tools to address soil sustainability and land care practices. The integrated critical zone model, 1D-ICZ, couples computational modules for soil organic matter dynamics, soil aggregation and structure dynamics, bioturbation, plant productivity and nutrient uptake, water flow, solute speciation and transport, and mineral weathering kinetics. The 1D-ICZ model, coupled with new pedotransfer functions to predict bulk soil properties, introduces for the first time a model that dynamically links soil structure characteristics and hydraulic soil properties by simulating their changes under varying meteorological conditions and plant growth. Field data from a Mediterranean olive grove at the Koiliaris Critical Zone Observatory (CZO) were used to simulate carbon addition to soil and agricultural management scenarios, in order to illustrate the model's ability to quantify soil management impact on soil functions and biogeochemical transformations and fluxes. The 1D-ICZ model can be used to assess, understand, and quantify the complex interactions between the different processes in the soil-plant-water system and can be applied as a tool to design sustainable agricultural management practices, taking into consideration synergy and trade-offs among soil functions.

      PubDate: 2016-12-28T10:49:22Z
      DOI: 10.1016/bs.agron.2016.10.009
       
  • Factors Controlling Soil Structure Dynamics and Carbon Sequestration
           Across Different Climatic and Lithological Conditions
    • Authors: S.K. Panakoulia; N.P. Nikolaidis; N.V. Paranychianakis; M. Menon; J. Schiefer; G.J. Lair; P. Kram; S.A. Banwart
      Abstract: Publication date: Available online 24 December 2016
      Source:Advances in Agronomy
      Author(s): S.K. Panakoulia, N.P. Nikolaidis, N.V. Paranychianakis, M. Menon, J. Schiefer, G.J. Lair, P. Kram, S.A. Banwart
      Soil organic carbon (SOC) is a strong determinant of soil fertility through its positive effects on soil structure and soil chemical and biological properties which in turn stimulate primary production. The objective of this work was to simulate field sites that represent different land uses and management practices in three continents, in order to identify the most important factors controlling soil structure dynamics and C sequestration across different climatic and lithological conditions as well as to quantify the rates of the aforementioned processes. The carbon, aggregation, and structure turnover (CAST) model was used to simulate SOC sequestration, aggregate formation, and structure dynamics in three field sites including nontilled soils of natural ecosystems and tilled soils of agricultural fields in Europe (Critical Zone Observatories (CZO) of the SoilTrEC network) and one site in North America. Derived data from the simulations’ results of SOC stocks and water-stable aggregate (WSA) particle size distribution, together with the respective results of three additional sites (Damma Glacier CZO, Milia (Greece), and Heilongjiang Mollisols (China)), were statistically analyzed in order to determine the factors affecting SOC sequestration and soil structure development. The natural ecosystems include nontilled soils covered with natural local vegetation, while the agricultural sites include cultivated and tilled soils covered with crops. The natural ecosystems were represented by Damma Glacier CZO (Switzerland), Heilongjiang Mollisols (China), Koiliaris CZO (Greece), Clear Creek (United States), and the Slavkov Forrest CZO (Czech Republic), whereas the agricultural field sites were located at Heilongjiang Mollisols (China), Koiliaris CZO (Greece), Clear Creek (United States), Marchfeld CZO (Austria), and Milia (Greece). Principal component analysis (PCA) identified clay content, bulk density, climatic conditions (precipitation and evapotranspiration), organic matter (OM), and its decomposition rates as the most important factors that controlled soil structure development. The relative importance of each of these factors differs under differing climatic and lithological conditions and differing stages of soil development. Overall, the modeling results for both natural ecosystems and agricultural fields were consistent with the field data. The model reliably simulated C and soil structure dynamics in various land uses, climatic conditions, and soil properties providing support for the underlying conceptual and mathematical modeling and evidence that the CAST model is a reliable tool to interpret soil structure formation processes and to aid the design of sustainable soil management practices.

      PubDate: 2016-12-28T10:49:22Z
      DOI: 10.1016/bs.agron.2016.10.008
       
  • Interception of Subsurface Lateral Flow Through Enhanced Vertical
           Preferential Flow in an Agroforestry System Observed Using Dye-Tracing and
           Rainfall Simulation Experiments
    • Authors: Y. Wang; B. Zhang
      Abstract: Publication date: Available online 24 December 2016
      Source:Advances in Agronomy
      Author(s): Y. Wang, B. Zhang
      Surface soil hydrology is a major control on the terrestrial water cycle in Earth's Critical Zone (CZ). Partitioning of vertical preferential flow and subsurface lateral flow is commonly attributed to the heterogeneity of slope, soil profile horizon, and soil structure, but the influences of land-use types are largely unknown. Agroforestry systems (AF) can intercept subsurface lateral flow for reducing nitrogen losses to drainage water and for alleviating secondary salinity in central China and southeast Australia. These effects have been attributed to enhanced evapotranspiration and canopy interception in the agroforestry systems compared to monocropping systems (MC). Here, we show the differences in lateral and vertical soil hydrological pathways between AF and MC with dye-tracing experiments before and during a simulated rainfall event. Before the rainfall, the vertical and horizontal dye-staining patterns demonstrated that preferential flow occurred through isolated macropores with fine tree roots in AF and through connected cracks in MC. The dye coverage area and depth indicated greater vertical preferential flow in AF than in MC. During the 2-h rainfall event, the dye-staining area at different depths indicated that the preferential flow contributed to greater near-surface lateral flow in MC than in AF. The changes in the hydrological pathways were attributed to deep roots and no physical barrier from plough pan in AF and the presence of the plough pan in MC. These results suggest that land use has strong water partitioning effects not only above ground but also in the subsurface, and that understanding the landscape hydrology in the Earth's Critical Zone required quantification of the considering coupled pedological and biological processes.

      PubDate: 2016-12-28T10:49:22Z
      DOI: 10.1016/bs.agron.2016.10.014
       
  • Quantifying the Incipient Development of Soil Structure and Functions
           Within a Glacial Forefield Chronosequence
    • Authors: M. Andrianaki; S.M. Bernasconi; N.P. Nikolaidis
      Abstract: Publication date: Available online 20 December 2016
      Source:Advances in Agronomy
      Author(s): M. Andrianaki, S.M. Bernasconi, N.P. Nikolaidis
      In this study, we used the newly developed mathematical model CAST (carbon, aggregation, and structure turnover) to simulate the accumulation of soil organic carbon and the development of soil structure along the 150 years soil chronosequence of the Damma glacier Critical Zone Observatory (CZO). As first step in the modeling procedure, an adaptation of the widely used multipool Rothamsted carbon model RothC was tested. The calibration of the model is based on the extensive dataset available for the Damma glacier CZO and a published reconstruction of climate back to 1867. The adapted RothC model simulates effectively the dynamics of total organic carbon (TOC), microbial biomass (BIO), and humified organic matter (HUM) pools, while decomposable plant material (DPM) and resistant plant material (RPM) pools which are calculated by the model are slightly overestimated compared to measured values. In a second set of simulations, the CAST model was applied and captured effectively the carbon content of the three aggregate classes which are considered by the model (macroaggregates: >250μm (AC3), microaggregates: 53–250μm (AC2), silt–clay-sized aggregates: <53μm (AC1)). The major percentage of aggregates belongs to the AC3 class, which consists of the particulate organic matter primarily loosely bound with the mineral particles. The amount of aggregates within the AC1 aggregate class is low, while the formation of the AC2 aggregates has not been initiated at this stage of soil development. One of the most important finding of this study is that the CAST model realistically calculates the processes during the initial stages of soil structure development, even though the soils of the Damma glacier CZO soil chronosequence are characterized by very poor soil structure and low clay content. The main process for soil development at this early stage is identified to be the macroaggregation through the addition of particulate organic matter. Microaggregation of smaller-sized particles and aggregates is not found to be a major contribution to soil structure development at this stage and it is only observed at the end of the chronosequence. Finally, despite the extreme climatic conditions of the alpine environment, the young nature of the soils and the short growing season, both models performed very well after calibration of the carbon turnover rates.

      PubDate: 2016-12-21T11:40:16Z
      DOI: 10.1016/bs.agron.2016.10.013
       
  • Reduced Subsurface Lateral Flow in Agroforestry System Is Balanced by
           Increased Water Retention Capacity: Rainfall Simulation and Model
           Validation
    • Authors: Y. Wang; B. Zhang; S.A. Banwart
      Abstract: Publication date: Available online 20 December 2016
      Source:Advances in Agronomy
      Author(s): Y. Wang, B. Zhang, S.A. Banwart
      Soil hydrology controls the terrestrial water cycle and the transport of substances to influence the environmental quality of Earth's critical zone (CZ). Soil and water management in agroforestry systems (AF) is able to reduce soil nitrogen losses and to alleviate secondary salinity in some regions of the world by reducing subsurface lateral flow. Compared to monocropping (MC) system, the reduction of subsurface lateral flow in AF has been attributed not only to the enhanced evapotranspiration and canopy interception but also to changes in soil structure and related hydraulic properties. However, for AF, it remains unclear how changes in soil structure and hydraulic properties occur and can act to reduce the subsurface later flow. Rainfall simulation experiments were conducted in the field and soil matric potential was measured to determine the effect of AF and MC on the dynamics of rainfall infiltration, subsurface lateral flow, and soil water storage in the soil profile. The calculated isolines of soil matric potential showed that a physical domain of water saturation occurred in the subsoils during the rainfall and diminished after the rainfall. The water saturation domain was larger during the rainfall and drained more slowly after the rainfall in AF than in MC. These results illustrated that AF increased vertical preferential flow and retarded the subsurface lateral flow, resulting in increased water retention capacity in the soil profile, compared to MC. The changed water mass and flow distribution was attributed to the deep roots, which increase macropores oriented in the vertical direction and modify micro- and mesopores in the lateral direction, resulting in changes in anisotropy of soil hydraulic properties along transects of slope. These proposed mechanisms were successfully verified by mathematical modeling. Numerical experiments using the Hydrus-2D mathematical modeling code at the virtual condition of the same antecedent soil moisture condition along the slope at different rainfall events ruled out the effect of antecedent soil moisture or evapotranspiration on generation of subsurface flow. These findings suggest that land use has strong effects on water distribution not only above the ground but also in the subsurface. The changes in soil structure and hydraulic properties need to be considered in understanding landscape hydrology related to agricultural practices and their impacts on Earth's CZ.

      PubDate: 2016-12-21T11:40:16Z
      DOI: 10.1016/bs.agron.2016.10.005
       
 
 
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