Publisher: Elsevier   (Total: 3148 journals)

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Showing 1 - 200 of 3148 Journals sorted alphabetically
Academic Pediatrics     Hybrid Journal   (Followers: 39, SJR: 1.655, CiteScore: 2)
Academic Radiology     Hybrid Journal   (Followers: 26, SJR: 1.015, CiteScore: 2)
Accident Analysis & Prevention     Partially Free   (Followers: 106, SJR: 1.462, CiteScore: 3)
Accounting Forum     Hybrid Journal   (Followers: 28, SJR: 0.932, CiteScore: 2)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 44, SJR: 1.771, CiteScore: 3)
Achievements in the Life Sciences     Open Access   (Followers: 7)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 6)
Acta Astronautica     Hybrid Journal   (Followers: 446, SJR: 0.758, CiteScore: 2)
Acta Automatica Sinica     Full-text available via subscription   (Followers: 2)
Acta Biomaterialia     Hybrid Journal   (Followers: 30, SJR: 1.967, CiteScore: 7)
Acta Colombiana de Cuidado Intensivo     Full-text available via subscription   (Followers: 3)
Acta de Investigación Psicológica     Open Access   (Followers: 2)
Acta Ecologica Sinica     Open Access   (Followers: 12, SJR: 0.18, CiteScore: 1)
Acta Histochemica     Hybrid Journal   (Followers: 5, SJR: 0.661, CiteScore: 2)
Acta Materialia     Hybrid Journal   (Followers: 324, SJR: 3.263, CiteScore: 6)
Acta Mathematica Scientia     Full-text available via subscription   (Followers: 5, SJR: 0.504, CiteScore: 1)
Acta Mechanica Solida Sinica     Full-text available via subscription   (Followers: 9, SJR: 0.542, CiteScore: 1)
Acta Oecologica     Hybrid Journal   (Followers: 12, SJR: 0.834, CiteScore: 2)
Acta Otorrinolaringologica (English Edition)     Full-text available via subscription  
Acta Otorrinolaringológica Española     Full-text available via subscription   (Followers: 2, SJR: 0.307, CiteScore: 0)
Acta Pharmaceutica Sinica B     Open Access   (Followers: 2, SJR: 1.793, CiteScore: 6)
Acta Psychologica     Hybrid Journal   (Followers: 26, SJR: 1.331, CiteScore: 2)
Acta Sociológica     Open Access   (Followers: 1)
Acta Tropica     Hybrid Journal   (Followers: 6, SJR: 1.052, CiteScore: 2)
Acta Urológica Portuguesa     Open Access   (Followers: 1)
Actas Dermo-Sifiliograficas     Full-text available via subscription   (Followers: 3, SJR: 0.374, CiteScore: 1)
Actas Dermo-Sifiliográficas (English Edition)     Full-text available via subscription   (Followers: 2)
Actas Urológicas Españolas     Full-text available via subscription   (Followers: 3, SJR: 0.344, CiteScore: 1)
Actas Urológicas Españolas (English Edition)     Full-text available via subscription   (Followers: 1)
Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 7, SJR: 0.19, CiteScore: 0)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 3)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 8)
Acute Pain     Full-text available via subscription   (Followers: 15, SJR: 2.671, CiteScore: 5)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.53, CiteScore: 4)
Addictive Behaviors     Hybrid Journal   (Followers: 18, SJR: 1.29, CiteScore: 3)
Addictive Behaviors Reports     Open Access   (Followers: 9, SJR: 0.755, CiteScore: 2)
Additive Manufacturing     Hybrid Journal   (Followers: 13, SJR: 2.611, CiteScore: 8)
Additives for Polymers     Full-text available via subscription   (Followers: 22)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 190, SJR: 4.09, CiteScore: 13)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 13, SJR: 1.167, CiteScore: 4)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.694, CiteScore: 3)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.277, CiteScore: 1)
Advances in Agronomy     Full-text available via subscription   (Followers: 17, SJR: 2.384, CiteScore: 5)
Advances in Anesthesia     Full-text available via subscription   (Followers: 30, SJR: 0.126, CiteScore: 0)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 2)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 12, SJR: 0.992, CiteScore: 1)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 12, SJR: 1.551, CiteScore: 4)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 24, SJR: 2.089, CiteScore: 5)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 15, SJR: 0.572, CiteScore: 2)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.61, CiteScore: 7)
Advances in Botanical Research     Full-text available via subscription   (Followers: 1, SJR: 0.686, CiteScore: 2)
Advances in Cancer Research     Full-text available via subscription   (Followers: 35, SJR: 3.043, CiteScore: 6)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 1.453, CiteScore: 2)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 1.992, CiteScore: 5)
Advances in Cell Aging and Gerontology     Full-text available via subscription   (Followers: 5)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 14)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 29, SJR: 0.156, CiteScore: 1)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 11, SJR: 0.713, CiteScore: 1)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 11, SJR: 1.316, CiteScore: 2)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 26, SJR: 1.562, CiteScore: 3)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 21, SJR: 1.977, CiteScore: 8)
Advances in Computers     Full-text available via subscription   (Followers: 14, SJR: 0.205, CiteScore: 1)
Advances in Dermatology     Full-text available via subscription   (Followers: 16)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 14)
Advances in Digestive Medicine     Open Access   (Followers: 13)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 7)
Advances in Drug Research     Full-text available via subscription   (Followers: 26)
Advances in Ecological Research     Full-text available via subscription   (Followers: 44, SJR: 2.524, CiteScore: 4)
Advances in Engineering Software     Hybrid Journal   (Followers: 30, SJR: 1.159, CiteScore: 4)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 9)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 51, SJR: 5.39, CiteScore: 8)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 2)
Advances in Fluorine Science     Full-text available via subscription   (Followers: 9)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 68, SJR: 0.591, CiteScore: 2)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 17)
Advances in Genetics     Full-text available via subscription   (Followers: 21, SJR: 1.354, CiteScore: 4)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11, SJR: 12.74, CiteScore: 13)
Advances in Geophysics     Full-text available via subscription   (Followers: 8, SJR: 1.193, CiteScore: 3)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 26, SJR: 0.368, CiteScore: 1)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 11, SJR: 0.749, CiteScore: 3)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 26)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 4, SJR: 0.193, CiteScore: 0)
Advances in Immunology     Full-text available via subscription   (Followers: 37, SJR: 4.433, CiteScore: 6)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 1.163, CiteScore: 2)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 2, SJR: 1.938, CiteScore: 3)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6, SJR: 0.176, CiteScore: 0)
Advances in Intl. Accounting     Full-text available via subscription   (Followers: 3)
Advances in Life Course Research     Hybrid Journal   (Followers: 9, SJR: 0.682, CiteScore: 2)
Advances in Lipobiology     Full-text available via subscription   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Marine Biology     Full-text available via subscription   (Followers: 21, SJR: 0.88, CiteScore: 2)
Advances in Mathematics     Full-text available via subscription   (Followers: 17, SJR: 3.027, CiteScore: 2)
Advances in Medical Sciences     Hybrid Journal   (Followers: 9, SJR: 0.694, CiteScore: 2)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 6)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 5, SJR: 1.158, CiteScore: 3)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 26)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 8)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.182, CiteScore: 0)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 5)
Advances in Oncobiology     Full-text available via subscription   (Followers: 2)
Advances in Organ Biology     Full-text available via subscription   (Followers: 2)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 18, SJR: 1.875, CiteScore: 4)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.174, CiteScore: 0)
Advances in Parasitology     Full-text available via subscription   (Followers: 6, SJR: 1.579, CiteScore: 4)
Advances in Pediatrics     Full-text available via subscription   (Followers: 27, SJR: 0.461, CiteScore: 1)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 19)
Advances in Pharmacology     Full-text available via subscription   (Followers: 17, SJR: 1.536, CiteScore: 3)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 10, SJR: 0.574, CiteScore: 1)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.109, CiteScore: 1)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 11)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 6)
Advances in Porous Media     Full-text available via subscription   (Followers: 5)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 19)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 0.791, CiteScore: 2)
Advances in Psychology     Full-text available via subscription   (Followers: 69)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 7, SJR: 0.371, CiteScore: 1)
Advances in Radiation Oncology     Open Access   (Followers: 3, SJR: 0.263, CiteScore: 1)
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.101, CiteScore: 0)
Advances in Space Biology and Medicine     Full-text available via subscription   (Followers: 7)
Advances in Space Research     Full-text available via subscription   (Followers: 430, SJR: 0.569, CiteScore: 2)
Advances in Structural Biology     Full-text available via subscription   (Followers: 6)
Advances in Surgery     Full-text available via subscription   (Followers: 13, SJR: 0.555, CiteScore: 2)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 37, SJR: 2.208, CiteScore: 4)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 20)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 15)
Advances in Virus Research     Full-text available via subscription   (Followers: 6, SJR: 2.262, CiteScore: 5)
Advances in Water Resources     Hybrid Journal   (Followers: 57, SJR: 1.551, CiteScore: 3)
Aeolian Research     Hybrid Journal   (Followers: 6, SJR: 1.117, CiteScore: 3)
Aerospace Science and Technology     Hybrid Journal   (Followers: 394, SJR: 0.796, CiteScore: 3)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.42, CiteScore: 2)
African J. of Emergency Medicine     Open Access   (Followers: 6, SJR: 0.296, CiteScore: 0)
Ageing Research Reviews     Hybrid Journal   (Followers: 12, SJR: 3.671, CiteScore: 9)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 489, SJR: 1.238, CiteScore: 3)
Agri Gene     Hybrid Journal   (Followers: 1, SJR: 0.13, CiteScore: 0)
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 18, SJR: 1.818, CiteScore: 5)
Agricultural Systems     Hybrid Journal   (Followers: 32, SJR: 1.156, CiteScore: 4)
Agricultural Water Management     Hybrid Journal   (Followers: 47, SJR: 1.272, CiteScore: 3)
Agriculture and Agricultural Science Procedia     Open Access   (Followers: 4)
Agriculture and Natural Resources     Open Access   (Followers: 3)
Agriculture, Ecosystems & Environment     Hybrid Journal   (Followers: 58, SJR: 1.747, CiteScore: 4)
Ain Shams Engineering J.     Open Access   (Followers: 5, SJR: 0.589, CiteScore: 3)
Air Medical J.     Hybrid Journal   (Followers: 8, SJR: 0.26, CiteScore: 0)
AKCE Intl. J. of Graphs and Combinatorics     Open Access   (SJR: 0.19, CiteScore: 0)
Alcohol     Hybrid Journal   (Followers: 12, SJR: 1.153, CiteScore: 3)
Alcoholism and Drug Addiction     Open Access   (Followers: 12)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 2, SJR: 0.604, CiteScore: 3)
Alexandria J. of Medicine     Open Access   (Followers: 1, SJR: 0.191, CiteScore: 1)
Algal Research     Partially Free   (Followers: 11, SJR: 1.142, CiteScore: 4)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 2)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.504, CiteScore: 1)
Allergology Intl.     Open Access   (Followers: 5, SJR: 1.148, CiteScore: 2)
Alpha Omegan     Full-text available via subscription   (SJR: 3.521, CiteScore: 6)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 11, SJR: 0.201, CiteScore: 1)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 55, SJR: 4.66, CiteScore: 10)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6, SJR: 1.796, CiteScore: 4)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 6, SJR: 1.108, CiteScore: 3)
Ambulatory Pediatrics     Hybrid Journal   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 58, SJR: 3.267, CiteScore: 4)
American J. of Cardiology     Hybrid Journal   (Followers: 67, SJR: 1.93, CiteScore: 3)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 48, SJR: 0.604, CiteScore: 1)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 13)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 15, SJR: 1.524, CiteScore: 3)
American J. of Human Genetics     Hybrid Journal   (Followers: 40, SJR: 7.45, CiteScore: 8)
American J. of Infection Control     Hybrid Journal   (Followers: 29, SJR: 1.062, CiteScore: 2)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 37, SJR: 2.973, CiteScore: 4)
American J. of Medicine     Hybrid Journal   (Followers: 50)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3, SJR: 1.967, CiteScore: 2)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 266, SJR: 2.7, CiteScore: 4)
American J. of Ophthalmology     Hybrid Journal   (Followers: 67, SJR: 3.184, CiteScore: 4)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5, SJR: 0.265, CiteScore: 0)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.289, CiteScore: 1)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, CiteScore: 1)
American J. of Pathology     Hybrid Journal   (Followers: 32, SJR: 2.139, CiteScore: 4)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 30, SJR: 2.164, CiteScore: 4)
American J. of Surgery     Hybrid Journal   (Followers: 39, SJR: 1.141, CiteScore: 2)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.767, CiteScore: 1)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 7)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.144, CiteScore: 3)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 67, SJR: 0.138, CiteScore: 0)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 25, SJR: 0.411, CiteScore: 1)
Anales de Cirugia Vascular     Full-text available via subscription   (Followers: 1)
Anales de Pediatría     Full-text available via subscription   (Followers: 3, SJR: 0.277, CiteScore: 0)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription  
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 6, SJR: 4.849, CiteScore: 10)
Analytica Chimica Acta     Hybrid Journal   (Followers: 44, SJR: 1.512, CiteScore: 5)
Analytica Chimica Acta : X     Open Access  
Analytical Biochemistry     Hybrid Journal   (Followers: 216, SJR: 0.633, CiteScore: 2)
Analytical Chemistry Research     Open Access   (Followers: 13, SJR: 0.411, CiteScore: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 14)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 2)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 25, SJR: 0.683, CiteScore: 2)
Angiología     Full-text available via subscription   (SJR: 0.121, CiteScore: 0)
Angiologia e Cirurgia Vascular     Open Access   (Followers: 1, SJR: 0.111, CiteScore: 0)
Animal Behaviour     Hybrid Journal   (Followers: 236, SJR: 1.58, CiteScore: 3)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 8, SJR: 0.937, CiteScore: 2)
Animal Reproduction Science     Hybrid Journal   (Followers: 7, SJR: 0.704, CiteScore: 2)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 3, SJR: 0.451, CiteScore: 1)

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Similar Journals
Journal Cover
Agricultural and Forest Meteorology
Journal Prestige (SJR): 1.818
Citation Impact (citeScore): 5
Number of Followers: 18  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 0168-1923 - ISSN (Online) 0168-1923
Published by Elsevier Homepage  [3148 journals]
  • Biophysical controls on nocturnal sap flow in plantation forests in a
           semi-arid region of northern China
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Zuosinan Chen, Zhiqiang Zhang, Ge Sun, Lixin Chen, Hang Xu, Shengnan ChenAbstractRecent studies have recognized the importance of nocturnal sap flow (Qn) in affecting forest carbon and water budgets and responses to climate change at stand, regional, and global scales. However, biophysical controls on Qn are not fully understood, and their implications for land surface and vegetation models are unclear. We measured growing season sap flow of two widely distributed afforestation species, Pinus tabuliformis and Acer truncatum, in a middle-aged and a young monoculture forest stand, respectively, in a semi-arid mountainous area of northern China. We found a convergence in Qn between the two species and in the proportion of Qn to the total sap flow (12.2–15.0%) across species and ages. Total growing season Qn was higher for middle-aged stands than for young stands because of larger diameters at breast height of older stands. Nighttime vapor pressure deficit (VPDn) influence on Qn of young stands was soil moisture dependent. Nighttime wind speed indirectly controlled Qn through enhancing VPDn in young stands and directly promoted Qn in middle-aged stands with relatively low tree densities. For each species, both increased and decreased soil water content were able to promote Qn in stands with relatively dry soils, which might be due to enhanced nighttime water recharge for capacitance refilling and for avoiding hydraulic failure under prolonged water stress, respectively. Total effects of these three environmental factors explained less than 55% of the Qn variations. This study highlights uncertain physiological influences of VPDn on nighttime stomatal water loss, the nighttime water loss induced by wind, region-specific patterns of nighttime water recharge, and the importance of biotic controls on Qn. Our findings help to improve the existing VPD-based method for partitioning nighttime transpiration and water recharge at tree and stand levels, and suggest the importance of incorporating nocturnal sap flow into large-scale models.
       
  • Modification of surface energy balance during springtime: The relative
           importance of biophysical and meteorological changes
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Minkyu Moon, Dan Li, Weilin Liao, Angela J. Rigden, Mark A. FriedlAbstractIn ecosystems characterized by strong seasonality in leaf area, the emergence of leaves during springtime modifies land surface energy balance by altering surface biophysical properties during a period when atmospheric conditions are also changing. However, the relative importance and interactions among surface biophysical and atmospheric variables in modifying the surface energy balance are not well understood. In this study, we use a physically-based attribution method to quantify the relative importance of covarying surface biophysical and atmospheric variables in modifying the surface energy balance during springtime. Results show that the widely observed decrease in the Bowen ratio that occurs with leaf emergence is not solely attributable to the sharp decrease in surface resistance caused by increasing leaf area. Rather, decreases in the Bowen ratio reflect the combined effects of changes in surface properties and atmospheric conditions. Specifically, decreasing surface resistance and increasing air temperature both act to reduce the Bowen ratio, while concurrent increases in specific humidity provide a negative feedback that constrains evaporative fluxes. In parallel, aerodynamic resistance tends to increase after leaf emergence largely because wind speed tends to decrease during springtime. These findings provide a refined characterization of surface energy balance dynamics during springtime when both surface and atmospheric conditions are changing rapidly and reveal previously understudied properties of the near-surface atmosphere that influence surface Bowen ratio and aerodynamic resistance.
       
  • Impacts of a partial rainfall exclusion in the field on growth and
           transpiration: consequences for leaf-level and whole-plant water-use
           efficiency compared to controlled conditions
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Maxime Durand, Oliver Brendel, Cyril Buré, Pascal Courtois, Jean-Baptiste Lily, André Granier, Didier Le Thiec• Water use efficiency (WUE), oftentimes estimated as transpiration efficiency (TE): the amount of biomass produced with regard to the water used, has not yet been used as a breeding trait to select poplar genotypes with simultaneously high productivity and conservation of water. Before its application as a selection target, evidence must be presented showing that WUE or its estimators remain constant with age and across environmental conditions.• We conducted a rainfall exclusion experiment in the field on two Populus euramericana (Moench.) and two Populus nigra (L.) genotypes, and assessed leaf-level (A/gs) and whole-plant WUE (DMT/WU as well as their components and related traits. Then, we aimed to compare these results with the same poplar genotypes grown in a glasshouse under contrasting water availability.• Despite a reduction of soil water content and whole-plant transpiration, growth was stimulated in the rainfall exclusion plot, likely as a result of an increased nitrogen assimilation. However, TE values between the glasshouse and the field were similar, and genotype ranking remained fairly constant for transpiration, carbon isotopic discrimination (∆, as a proxy for Wi) and TE. Moreover, even though the drivers of WUE in both experiments were different, increases of WUE measured as ∆ or TE was not associated with lower biomass production. Relatively good agreement was found between ∆ and TE in the field, absence of a similar correlation in the glasshouse is discussed.• These results suggest that ∆ may be a good proxy for TE, and could be used, both as a breeding target for genotype selection in glasshouses without impacting biomass production when planted in the field. However, reduced water availability modified the genotype ranking more significantly than between the field/glasshouse experiments, suggesting a diversity of poplar response to drought that should be considered in breeding strategies.Graphical abstractImage, graphical abstract
       
  • What controls post-harvest growth rates in the caatinga forest'
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Frans G.C. Pareyn, Walter E. Pereira, Ignacio H. Salcedo, Enrique M. Riegelhaupt, Elmo C. Gomes, Humberto T.F. Menecheli, Margaret SkutschAbstractAll over the world, there is increasing demand for wood and other goods from seasonally dry tropical forests; the “Caatinga” forest in northeast Brazil is a case in point. In order to set up sustainable forest management protocols, a comprehensive understanding of the main drivers of forest growth is needed, but few studies have focused on this subject in the Caatinga biome. Traditionally, periodic annual increment (PAI) has been calculated by dividing standing stock by the legally imposed minimum cutting cycle of 15 years, but it is doubtful that this guarantees sustainability. We use data from 20 coupes spread over 10 managed areas and apply both multiple regression and tree regression techniques to correlate PAI with 27 environmental variables including mean annual rainfall and many soil properties. We find that neither the time since harvesting nor the stock before harvest are significantly related to PAI. Instead, using a simple linear regression model, we show that rainfall can explain most (72%) of the variation, while a tree regression model, which captures non-linear relations between rainfall and PAI, explains 96% of the variation. On the other hand, no soil factors contribute significantly to the overall explanation of growth after harvest. We conclude that planning of sustainable management could be greatly improved by use of our regression models and rainfall data which are widely available at local level across the Caatinga. Moreover, this would obviate the need for costly forest inventories.
       
  • AqYield-N: A simple model to predict nitrogen leaching from crop fields
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): H. Tribouillois, J. Constantin, B. Guillon, M. Willaume, G. Aubrion, A. Fontaine, P. Hauprich, P. Kerveillant, F. Laurent, O. TherondAbstractEvaluating and improving cropping systems is essential to reduce nitrate leaching, improve drinking water quality and prevent eutrophication. Since the intensity of nitrogen (N) leaching varies greatly spatially and is difficult to measure, crop models are useful tools to quantify the influence of climate, soil and agricultural practices on N leaching. Our objective was to develop a simple model with low input data and calibration requirements to predict nitrate leaching from a variety of crop fields over large areas, such as watersheds, for which data are often limited. The AqYield model is a simple model with few inputs that has estimated sufficiently well drainage and water flows for several crops and rotations. Based on this model, we developed AqYield-N, which considers the major N flows in the soil–plant system, including mineralization, plant uptake and leaching at a daily time step. The present study presents the development and formalisms of AqYield-N. We developed AqYield-N based on simple and robust formalisms and low requirements for input data and parameters. As much as possible, we used equations already published and validated in the scientific literature. We then evaluated AqYield-N using observed experimental N leaching data. Its estimates were satisfactory for three contrasting pedoclimatic situations and for various crops and bare soil. Although the model is simple and requires only a few inputs, it was as accurate as more complex crop models widely used and evaluated in the agronomic literature, such as STICS. The study demonstrated the potential of AqYield-N to estimate the influence of management practices on N leaching. AqYield-N, whether alone or integrated in larger-scale modeling approaches, can be used to predict leaching during crop rotations at field and large scale to evaluate the influence of various agroecological practices on N leaching.
       
  • Elevation gradients affect the differences of arbuscular mycorrhizal fungi
           diversity between root and rhizosphere soil
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Fazhu Zhao, Xiuxiu Feng, Yaoxing Guo, Chengjie Ren, Jun Wang, Russell DoughtyDespite the evident importance of arbuscular mycorrhizal fungi (AM fungal) associated with the root and rhizosphere system of elevation gradients, limit is known about the difference in AM fungal diversity between root and rhizosphere and their influencing factors along elevation gradients. AM fungal Here, we designed an elevation gradient experiment, which covered six elevations and three vegetation types, and collected plant and soil samples. We used Illumina gene sequencing to analyze AM fungal diversity in roots and rhizosphere soils; other potential factors, such as plant diversity, leaf C, N, and P, litter, soil and microbial biomass, extracellular enzymes activity, and the bacterial and ITS broad-fungal diversity, were also determined. We found that AM fungal diversity differences between root and rhizosphere soil diminished as elevation increased, despite that AM fungal diversity had a well-known pattern with elevation (unimodal patterns). Compared with plant characteristics, soil properties (soil C, N, P, C:N, C:P, N:P) were stronger effect on AM fungal diversity between root and rhizosphere. Particularly, soil extracellular enzymes activity and bacterial and ITS broad-fungal diversity explained more variation in AM fungal diversity dynamics along the elevation gradients. Our findings indicate that the diminishment of AM fungal diversity in root and rhizosphere soil are a response to elevation gradients through changes of soil extracellular enzymes activity and the bacterial and fungi communities, which provided evidence that AM fungal community dynamics link to climate change.Graphical abstractImage, graphical abstract
       
  • Statistical emulators of irrigated crop yields and irrigation water
           requirements
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Élodie BlancAbstractThis study provides statistical emulators of global by gridded crop models included in the Inter-Sectoral Impact Model Intercomparison Project Fast Track project to estimate irrigated crop yields and associated irrigation water withdrawals simulated at the grid cell level. An ensemble of crop model simulations is used to build a panel of monthly summer weather variables and corresponding annual yields and irrigation water withdrawals from five gridded crop models. This dataset is then used to estimate crop-specific response functions for each crop model. The average normalized root mean square errors for the response functions range from 3% to 6% for irrigated yields and 2% to 8% for irrigated water withdrawal. Further in- and out-of-sample validation exercises confirm that the statistical emulators are able to replicate the crop models’ spatial patterns of irrigated crop yields and irrigation water withdrawals, both in levels and in terms of changes over time, although accuracy varies by model and by region. The emulators estimated in this study therefore provide a reliable and computationally efficient alternative to global gridded crop yield models.
       
  • Modeling light below tree canopies overestimates net photosynthesis and
           radiation use efficiency in understory crops by averaging light in space
           and time
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Adolfo Rosati, Kevin J Wolz, Lora Murphy, Luigi Ponti, Shibu JoseAbstractBy averaging in time and/or space, models predict less variable light patterns under tree canopies than in reality. We measured light every minute in 24 positions in a grid under different chestnut orchards, for several clear and overcast days. We also modelled this light with a purposely created 3D, spatially explicit, ray-tracing light interception model, where canopy porosity was calibrated to match measured daily light. Finally, we used both the measured and modeled light patterns transmitted under the tree canopies to estimate the daily net photosynthesis (An) and radiation use efficiency (RUE) of an understory wheat leaf. As expected, modeled light was more uniform than measured light, even at equal daily light. This resulted in large overestimation of daily An and RUE of the understory leaf. Averaging light in time increased the overestimations even further. A sensitivity analysis showed that this overestimation remained substantial over the range of realistic values for leaf photosynthetic parameters (i.e. Vc,max, Jmax, Rd) of the understory crop.
       
  • Assessment of black globe thermometers employing various sensors and
           alternative materials
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Felipe Andrés Obando Vega, Ana Paola Montoya Ríos, Jairo Alexander Osorio Saraz, Luis Gonzalo Vargas Quiroz, Flávio Alves DamascenoAbstractThe black globe temperature (Tg) is employed in thermal comfort studies. It is mainly used to compute the Mean Radiant Temperature (MRT) required in bioclimatic analysis. A set of low cost Black Globe Thermometers (BGT) was developed to establish a suitable combination of temperature transducers, materials and globe diameters. The dynamic and static responses of the BGT were studied. A total of 18 BGT was deployed along with a data acquisition system based in the Arduino open-source platform. It was analyzed the influence of the globe material (metallic and polyethylene), globe diameter (100 mm and 67 mm for the metallic and 78 mm for polyethylene) and six types of temperature transducers (K type thermocouple, infrared temperature sensor, thermistor, RTD and two semiconductor-based transducers). It was observed that Tg estimation and response time were transducer and stimuli dependent. The BGT presents good responses for indoor measurements and it was established that the most accurate combination was achieved by the DS18B20 digital temperature sensor with a metallic globe of 67 mm of diameter.
       
  • Modelling cherry full bloom using ‘space-for-time’ across climatically
           diverse growing environments
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Rebecca Darbyshire, Jose Navas López, Xinxin Song, Bénédicte Wenden, Dugald CloseAbstractA dataset of cherry full bloom dates across the full diversity of Australian growing regions was compiled and utilised for the first time. The primary data source was from growers located across Australia's major cherry growing districts. Records were of varying length and were used to investigate the potential of using data that substitute ‘space-for-time’ in phenology assessments. Full bloom timing for three cultivars, Bing, Lapins and Van, were collated. The data showed variation in full bloom time across the sites as well as inter-annual variability within sites. This highlighted the potential benefit of a predictive model for growers to better manage the flowering period. The performance of the sequential and the chill overlap models were evaluated using this data. Both models resulted in good statistical representation of the data with RMSE of 3.2 to 5.3 days and 3.3 to 5.4 days for the training and validating data, respectively. The parameterisations of the models differed with the sequential model estimating higher chilling requirement (65–68 CP) than the chill overlap model (46–48 CP). The sequential model estimated similar heat requirements between the cultivars, with Van marginally higher (7250–8000 GDH). The chill overlap model estimated a larger difference in the minimum heat requirement with Van higher (8223 GDH) than Bing and Lapins (6262 and 6486 GDH, respectively). Collation of grower records proved to be a valuable data source which, in the absence of funded programs, could be better utilised for further research that aligns outcomes with industry needs, such as decision support around polliniser varieties, design of growing systems and use of dormancy breakers to synchronise flowering for optimal fruit set and quality.
       
  • Retrieval of tree branch architecture attributes from terrestrial laser
           scan data using a Laplacian algorithm
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Yumei Li, Yanjun Su, Xiaoxia Zhao, Mohan Yang, Tianyu Hu, Jing Zhang, Jin Liu, Min Liu, Qinghua GuoAbstractTree architecture, defined as the three-dimensional arrangement of tree above-ground elements, directly influences the biological and physical processes of vegetation such as photosynthesis and evapotranspiration. Accurate description of tree architecture is of central importance to understand the above biophysical processes. Terrestrial laser scanning (TLS) has been proved to be a promising tool to quantitatively describe tree architecture parameters. However, previous studies using TLS usually focused on architectural parameter measurements at individual tree, crown scale and leaf scales. Very few studies have achieved a comprehensive quantitative description of branch architecture (including angle, diameter, length and volume). In this study, we improved the Laplacian-Based Contraction skeletonization algorithm using the Dijkstra algorithm, developed a new path discrimination method to identify and encode branch orders, and retrieved branch architecture parameters based on branch order and topology information. To assess the influence of branching complexity and branching pattern on the estimation accuracy, we scanned 15 different sized magnolia trees without a leading stem and simulated 10 different sized trees with a leading stem. Results showed the overall branch order identification and parameters retrieval accuracy of trees with a leading stem was obviously higher than trees without a leading stem. The identification accuracy of branch order decreased with the increase in the number of branch and tree branching complexity. The estimated branch architecture parameters agreed well with ground truth measurements (R2 up to 0.99), except for the second- and third-order branch volume. Compared with branch angle and diameter, branch length showed the best correlations with manually measured values (0.14 vs 0.002, 8.48 in RMSE; 0.99 vs 0.99, 0.78 in R2). The second-and third-order branch volume estimations were highly underestimated compared with the ground truth values (R2 = 0.53, RMSE = 0.0239 and R2 = 0.70, RMSE = 0.0257 respectively). This study demonstrated that TLS was an effective way to retrieve branch architecture parameters and provided a useful tool for comprehensive studies of biophysical processes and metabolic theories in ecology.
       
  • Satellite-based soybean yield forecast: Integrating machine learning and
           weather data for improving crop yield prediction in southern Brazil
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Raí A. Schwalbert, Telmo Amado, Geomar Corassa, Luan Pierre Pott, P.V.Vara Prasad, Ignacio A. CiampittiAbstractSoybean yield predictions in Brazil are of great interest for market behavior, to drive governmental policies and to increase global food security. In Brazil soybean yield data generally demand various revisions through the following months after harvest suggesting that there is space for improving the accuracy and the time of yield predictions. This study presents a novel model to perform in-season (“near real-time”) soybean yield forecasts in southern Brazil using Long-Short Term Memory (LSTM), Neural Networks, satellite imagery and weather data. The objectives of this study were to: (i) compare the performance of three different algorithms (multivariate OLS linear regression, random forest and LSTM neural networks) for forecasting soybean yield using NDVI, EVI, land surface temperature and precipitation as independent variables, and (ii) evaluate how early (during the soybean growing season) this method is able to forecast yield with reasonable accuracy. Satellite and weather data were masked using a non-crop-specific layer with field boundaries obtained from the Rural Environment Registry that is mandatory for all farmers in Brazil. Main outcomes from this study were: (i) soybean yield forecasts at municipality-scale with a mean absolute error (MAE) of 0.24 Mg ha−1 at DOY 64 (march 5) (ii) a superior performance of the LSTM neural networks relative to the other algorithms for all the forecast dates except DOY 16 where multivariate OLS linear regression provided the best performance, and (iii) model performance (e.g., MAE) for yield forecast decreased when predictions were performed earlier in the season, with MAE increasing from 0.24 Mg ha−1 to 0.42 Mg ha−1 (last values from OLS regression) when forecast timing changed from DOY 64 (March 5) to DOY 16 (January 6). This research portrays the benefits of integrating statistical techniques, remote sensing, weather to field survey data in order to perform more reliable in-season soybean yield forecasts.
       
  • Epicuticular wax and its effect on canopy temperature and water use of
           Sorghum
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Henrique D.R. Carvalho, James L. Heilman, Kevin J. McInnes, William L. Rooney, Katie L. LewisAbstractEpicuticular wax is thought to enable sorghum [Sorghum bicolor (L.) Moench] plants to cope with drought. Increased reflectivity of solar radiation and reduced conductance of water vapor are mechanisms responsible for aiding plants in water conservation. Increased reflectivity should lead to a decrease in canopy temperature and water use, whereas decreased conductance should lead to an increase in canopy temperature because of a decrease in evaporative cooling. It is not clear how these competing effects exert control over water use in a crop such as sorghum. To better understand the role of epicuticular waxes on the energy balance of sorghum, experiments were conducted to determine the effects of waxes on field-scale energy fluxes using near-isogenic lines of grain sorghum having different levels of epicuticular wax loading. Waxes caused an overall 2% increase in albedo, and about 86% of the reflected energy between 400 and 1100 nm was from near-infrared wavelengths. This is at variance with recent reports that suggest that waxes can substantially increase the reflectivity of sorghum. Instead, our results indicated that the amount of reflected radiant energy due to waxes was small. When water was non-limiting, waxes caused a 22% decrease in canopy conductance compared to a 2% increase in albedo on average. Consequently, at the expense of higher canopy temperatures, waxes caused a 5% reduction in latent heat flux when water was not limiting. Without rain, water became limiting to plants with lower wax load sooner than it did for plants with higher wax load. The high wax load canopy then was on average 0.4 °C cooler, had 24% greater canopy conductance and 13% greater latent heat fluxes compared to the low wax one. Results suggested that the primary mechanism through which waxes affect the energy balance of sorghum is by means of reduced conductance of water vapor.
       
  • Corrigendum to “Characteristics of ground surface temperature at
           Chalaping in the Source Area of the Yellow River, northeastern Tibetan
           Plateau” [Agricultural and Forest Meteorology] 281 (2020) 107819
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Dongliang Luo, Lei Liu, Huijun Jin, Xufeng Wang, Fangfang Chen
       
  • Light interactions, use and efficiency in row crop canopies under optimal
           growth conditions
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): M.S. Kukal, S. IrmakAbstractAccurate estimates of light (Photosynthetically Active Radiation or PAR) absorption, in addition to other interactions is imperative to quantify growth, productivity, energy and water balance and other physiological and biophysical processes in any vegetative surface. Currently, a comparative assessment of light interaction patterns across row crops is lacking, especially under current levels of productivity achieved in the U.S. High Plains. Here, we continuously measured canopy light balance components at high-frequency (15 min) to characterize transmittance (R), reflectance (R), fraction of intercepted PAR (fIPAR), fraction of absorbed PAR (fAPAR), light extinction coefficients (k), and light use efficiency (LUE) comparatively across maize, soybean, sorghum and winter wheat under optimal growth conditions. While maximum fAPAR was 88-96% of incoming PAR in all crops, mean fAPAR varied from 82% in sorghum to 46% in winter wheat; while k ranged from 0.36 (winter wheat) to 0.48 (sorghum and soybean), and these differences reflect highly crop-specific signatures. Conversion factors among fIPAR and fAPAR and LUE based on either component (LUEi and LUEa) were quantified that were substantially different from the conventionally used values; especially during early and late growth stages. A commonly employed approach of solar-noon light sampling was evaluated, and it was found that early and late stages of crop growth experience greater potential errors (as high as 110%) under this sampling approach, and hence should be avoided. LUEa was the highest for maize (5.3 g MJ−1), followed by sorghum (4.1 g MJ−1), winter wheat (4.0 g MJ−1) and soybean (3.1 g MJ−1). The datasets measured, analyzed and interpreted here present unprecedented quantities of biomass productivity and canopy light use parameters for four major cropping systems, and hence, should be accounted for in crop growth and productivity modeling applications to enhance predictive accuracy and robustness.
       
  • Comparison of satellite remote sensing derived precipitation estimates and
           observed data in Kenya
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Joseph M. Macharia, Felix K. Ngetich, Chris A. ShisanyaAbstractThis study evaluated the accuracy of four satellite remote sensing (SRS) based products in predicting rainfall (amounts and spatial distribution) over Kenya between 1998 and 2013. The four SRS products used include; two satellite products (Climate Hazards Group InfraRed Precipitation with Station (CHIRPS 2.0) and Tropical Rainfall Measuring Mission - Multi-satellite Precipitation Analysis (TMPA) 3B42 version 7 (TRMM)), one gauge-interpolated product (Global Precipitation Climatology Centre (GPCC)) and one re-analysis product (Modern-Era Retrospective Analysis for Research and Application (MERRA)). The monthly precipitation data were evaluated for completeness, converted to individual raster files, projected to the World Geodetic System (WGS) 1984 - Universal Transverse Mercator (UTM) zone 37 N ensuring a similar processing extent, rescaled to a common resolution and reclassified following defined uniform intervals for ease of comparison. Thereafter, they were subjected to five different metrics based on eight agro-ecological zones (AEZs) of Kenya, in reference to observed rainfall data obtained from Kenya meteorological department (KMD). Results show that all SRS products both overestimated or underestimated rainfall amounts on a pixel to pixel comparison. Based on point to point proportion of variance evaluation (r2), TRMM best-estimated rainfall in the tropical cool humid (r2 = 0.64), tropical warm humid (r2 = 0.58) and tropical cool subhumid (r2 = 0.39) zones and can be used for agricultural advisory services. The GPCC product best-estimated rainfall in the tropical warm semiarid (r2 = 0.46) and warm tropical sub-humid (r2 = 0.21), while CHIRPS 2.0 best-estimated rainfall in the tropical warm arid (r2 = 0.33) and therefore the two products could be best used to predict rainfall in the ASALs and drought-related studies, with potential for irrigation. The MERRA product best-estimated rainfall in tropical cool arid (r2 = 0.97) and tropical cool semiarid (r2 = 0.53) and could, therefore, be best used for high elevation and drought-related studies. These results demonstrate the promising potential of the satellite remote sensed data in complementing the existing meteorological observed data which are often marred by inconsistency and scarcity, and hence unreliable in the existing agricultural advisory and other climate-based applications in Kenya, and sub-Saharan Africa at large. However, given the observed AEZ dependant variations in the satellite estimates, it is advisable to choose the most suitable SRS product for specific activities per AEZ and calibrate before utilisation.
       
  • Nationwide crop yield estimation based on photosynthesis and
           meteorological stress indices
    • Abstract: Publication date: 15 April 2020Source: Agricultural and Forest Meteorology, Volume 284Author(s): Yang Chen, Randall J. Donohue, Tim R. McVicar, François Waldner, Gonzalo Mata, Noboru Ota, Alireza Houshmandfar, Kavina Dayal, Roger A. LawesAbstractThere is considerable demand for nationwide grain yield estimation during the cropping season by growers, grain marketers, grain handlers, agricultural businesses, and market brokers. In this paper, we developed a semi-empirical model (Crop-SI) to estimate the yield of the three major crops in the dryland Australian wheatbelt by combining a radiation use efficiency approach with meteorology driven Stress Indices (SI) at critical crop growth stages (e.g., anthesis and grain filling). These crop-specific SI (e.g., drought, heat and cold stress) help explain the impact of high spatial agro-environmental heterogeneity, which lead to substantial improvement in grain yield prediction. Crop-SI explains 87%, 69% and 83% of the observed field-scale grain yield variability with root mean square error of ~0.4, 0.4 and 0.5 t/ha for canola, wheat, and barley, respectively. At the pixel-level, Crop-SI reduces the relative error in grain yield estimation to 34%, 25%, and 20% for canola, wheat, barley, respectively, compared to two benchmark models. By incorporating water- and temperature-driven stresses, Crop-SI's predictive skill in highly variable environments is enhanced. As such, it paves the way for the next generation of agricultural systems models, knowledge products and decision support tools that need to operate at various scales.
       
  • Towards a physics-based understanding of fruit frost protection using wind
           machines
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Vincent W.J. Heusinkveld, J. Antoon van Hooft, Bart Schilperoort, Peter Baas, Marie-claire ten Veldhuis, Bas J.H. van de WielAbstractWind machines are used in the agricultural sector to prevent or mitigate the adverse effects of night frost in spring. In this study we aim to quantify the impact of wind machine operation on the local temperature field in an orchard. To this end, a field experiment is conducted and experimental analysis is combined with numerical simulation studies in order to assess the functional relations between wind machine performance and the dominating physical processes occurring during radiative frost events.Experimental observations showed that the temperature response strongly depends on the radial distance to the fan and the height above the surface. In agreement with previous studies, the wind machine was able to achieve rotation-averaged temperature increases of up to 50% of the inversion strength ( ≈ 3 K) in an area of 3–5 ha at 1 m height. Furthermore, it was observed that even weak ambient winds (
       
  • Limiting factors of aspen radial growth along a climatic and soil water
           budget gradient in south-western Siberia
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Félix Brédoire, Zachary E. Kayler, Jean-Luc Dupouey, Delphine Derrien, Bernd Zeller, Pavel A. Barsukov, Olga Rusalimova, Polina Nikitich, Mark R. Bakker, Arnaud LegoutAbstractUnderstanding how climate and soil hydrology control tree growth is critical to predict the response of Siberian ecosystems to climate change. The general aim of this study was to (i) characterize the soil water budget and identify the factors controlling aspen (Populus tremula L.) radial growth in south-western Siberia, and (ii) assess its potential response to future climate change. Along a gradient of climate and soil hydrological conditions, soil water budgets were reconstructed by modeling at four sites, and dendrochronological analyses were performed. Aspen growth potential was simulated in response to different climate change scenarios represented by shifts in soil water budgets. Simulated soil water budgets varied with climate variables, specifically increased temperature and drier summer combined with varying winter precipitation occurring as snowfall.We show that plant-available soil water and drainage gradually increased while stress decreased from the warmest and driest (south, forest-steppe zone) site to the coldest and wettest (north, southern taiga zone) site. Aspen radial growth was mainly limited by summer temperature in the north and by summer water deficit in the south. Surprisingly, we did not find clear evidence of snow level impact on radial growth, either positively in the south (water supply and protection against soil freezing) or negatively in the north (water-logging and drainage). In the context of climate change, water stress intensity could increase dramatically in the south inhibiting aspen growth; in those places summer soil water content depends on the refilling that occurs at snow-melt and increasing winter precipitation could alleviate stress levels. Conversely, in the north, aspen growth may mostly benefit from rising temperature.
       
  • Photosynthetic and environmental regulations of the dynamics of soil
           respiration in a forest ecosystem revealed by analyses of decadal time
           series
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Xiuping Liu, Junyi Liang, Lianhong GuAbstractAlthough photosynthetic and environmental regulations of the dynamics of soil respiration have been frequently reported, few studies have so far tested their generality and interactive effects. Using decade-long continuous measurements of soil respiration and eddy covariance records of net ecosystem exchange of CO2 at a forest site in the central USA, we examined the linkage of photosynthesis and environmental factors with soil respiration. Results showed that gross primary production (GPP) regulated soil respiration with monthly mean time lags that varied between four to twelve hours. The variations in this time lag were affected by past trajectories of moisture and temperature. GPP played a more important role in regulating soil respiration during dry than wet seasons, probably due to stronger water limitation on soil respiration under dry conditions. Finally, we found that models incorporating GPP as an input explained more variation in soil respiration than using soil temperature and moisture alone. Our findings suggest that photosynthesis and environmental conditions interactively drive the dynamics of soil respiration.
       
  • Identifying optimal sowing and flowering periods for barley in Australia:
           a modelling approach
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Ke Liu, Matthew Tom Harrison, James Hunt, Tefera Tolera Angessa, Holger Meinke, Chengdao Li, Xiaohai Tian, Meixue ZhouAbstractFrost, drought and heat are key abiotic constraints to barley production in Australia. To maximise grain yield, crop life-cycle needs to be timed to minimise growth stresses associated with insufficient radiation, frost, heat and drought stress during the critical period for yield determination that occurs prior to and during flowering. To identify optimal flowering times for commercial Australian barley genotypes, we conducted a genotype (G) × environment (E) × management (M) analysis using climate data from locations distributed throughout the Australian barley growing regions. Prior to conducting the G×E×M, we parameterised key phenological variables in the APSIM-Barley module for all genotypes using photoperiod and vernalisation data from experimental treatments, then we verified the model using seven independent field experiments. The verification process showed an average RMSE of 1.4–7.2 days and R2 values of 0.83–1.00 depending on genotype, indicating reasonable performance of the model in simulating phenology. Using the parameterised model, we then characterised water, frost and heat stress patterns for a range of sowing date × genotype combinations. The G×E×M showed that optimal flowering period (OFP) was a function of the environment more so than the genotype, and the relative importance of insufficient radiation, frost, heat and water stress varied signficantly with location. OFP was earlier (mid August to late September), in Western Australia and South Australia, while OFP was later (mid-October to mid-November) in Tasmania and Victoria. In low rainfall environments, the duration of the OFP was shorter in most cases than in high rainfall environments. In general, earlier sowing (1 April to 22 April) resulted in lower yield across sites, and this was more pronounced for fast developing genotypes La Trobe, Fathom, Compass and Alestar. Later sowing (1 June to 30 June) at Condobolin (NSW), Hopetoun (WA) and Loxton (SA) also resulted in a lower yield for all genotypes. Knowledge of OFPs based on long-term abiotic stresses will allow breeders to develop genotypes with phenological durations that are pertinent to each location. This will also allow farmers to select sowing dates according to genotype duration and thus minimise the combined risk of frost, heat and water stresses, which collectively should allow yield to approach its maximum potential.
       
  • Temporal variation in soil respiration and its sensitivity to temperature
           
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Lingfei Yu, Hao Wang, Yonghui Wang, Zhenhua Zhang, Litong Chen, Naishen Liang, Jin-Sheng HeAbstractWetlands are predicted to experience lowered water tables due to permafrost degradation in the Tibetan Plateau. These changes may affect carbon cycle processes such as soil respiration (Rs). However, the magnitude, patterns and controls of Rs remain poorly understood in alpine wetlands with their distinct hydrological regimes. Here, we conducted a field study on Rs from 2012 to 2014 in three alpine ecosystems on the Tibetan Plateau—fen, wet meadow and meadow—with soil water decreases along hydrological gradients. From 2012 to 2014, the annual Rs was 128.9–193.3 g C m−2yr−1, 281.5–342.9 g C m−2yr−1, and 663.4–709.1 g C m−2yr−1 for the fen, wet meadow, and meadow, respectively. An abrupt increase in CO2 emissions was caused by the spring thawing of the frozen soil in the fen and wet meadow, contributing 20.4–37.6% and 13.2–17.4%, respectively, to the annual Rs. The diurnal variation in the Rs was site specific among the three ecosystems, with one peak at 1300 h in the fen and meadow and two peaks at 1300 h and 1900 h in the wet meadow. The temperature-independent components of the diurnal variation in Rs were generally explained by photosynthetically active radiation in the fen and wet meadow, but not in the meadow. The temperature sensitivity of the Rs (unconfounded Q10) varied significantly among the three ecosystems, with the highest values occurring in the wet meadow, implying that permafrost thaw-induced wetland drying from the fen to the wet meadow could enhance the response of CO2 emissions to climate warming but that further drying from the wet meadow to the meadow probably weakens the effect of warming on the Rs. Our study emphasized the important role of the hydrological regime in regulating the temporal variation in Rs and its response to climate warming.
       
  • The effects of projected climate change and extreme climate on maize and
           rice in the Yangtze River Basin, China
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Xinxin Chen, Lunche Wang, Zigeng Niu, Ming Zhang, Chang'an Li, Jiarui LiAbstractcrop yield is highly sensitive to climate change and extreme climate. Here, the impact of climate change and extreme climate was assessed based on the climate variable outputs from 17 General Circumstance Models (GCMs) in the Coupled Model Inter-comparison Project phase five (CMIP5) dataset, a statistically downscaling method, a series of 12 extreme climate indices selected from the Expert Team on Climate Change Detection and Indices (ETCCDI) calculated using the downscaled climate variable outputs and a process–base Crop Simulation Model (CSM). The climate variable outputs consist history data series (1961–2005) of GCMs simulation used as baseline, future period (2006–2050) including two Representative Concentration Pathways (RCPs), 4.5 and 8.5 in the Yangtze River Basin. The results showed that: (1) the mean temperature and precipitation in growing season would increase for 81 stations for the future period under RCP4.5 and RCP8.5 relative to baseline in the Yangtze River Basin. In contrast, the mean downward shortwave solar radiation in growing season at most sites presented an upward trend for the future period under RCP4.5 and RCP8.5 relative to baseline in the Yangtze River Basin; (2) the maize and rice yield was projected to decrease by approximately 5.36% and 2.55% under RCP4.5 and 6.04% and 2.48% under RCP8.5, respectively, relative to baseline with consideration of the CO2 effect; (3) The maize and rice yield would be lowered by 2.995% and 2.268% with a 1 °C increase in the mean growing season temperature, respectively. Conversely, the maize and rice yield would increase by approximately 6.947% and 2.885% with a 1 MJ m−2 increase in the mean growing season downward shortwave solar radiation, respectively. Extreme climate indices were strongly correlated with the maize and rice yield, especially in the number of days above temperature threshold, maximum number of consecutive days with precipitation
       
  • Adverse weather conditions for UK wheat production under climate change
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Caroline Harkness, Mikhail A. Semenov, Francisco Areal, Nimai Senapati, Miroslav Trnka, Jan Balek, Jacob BishopAbstractWinter wheat is an important crop in the UK, suited to the typical weather conditions in the current climate. In a changing climate the increased frequency and severity of adverse weather events, which are often localised, are considered a major threat to wheat production. In the present study we assessed a range of adverse weather conditions, which can significantly affect yield, under current and future climates based on adverse weather indices. We analysed changes in the frequency, magnitude and spatial patterns of 10 adverse weather indices, at 25 sites across the UK, using climate scenarios from the CMIP5 ensemble of global climate models (GCMs) and two greenhouse gas emissions (RCP4.5 and RCP8.5). The future UK climate is expected to remain favourable for wheat production, with most adverse weather indicators reducing in magnitude by the mid-21st century. Hotter and drier summers would improve sowing and harvesting conditions and reduce the risk of lodging. The probability of late frosts and heat stress during reproductive and grain filling periods would likely remain small in 2050. Wetter winter and spring could cause issues with waterlogging. The severity of drought stress during reproduction would generally be lower in 2050, however localised differences suggest it is important to examine drought at a small spatial scale. Prolonged water stress does not increase considerably in the UK, as may be expected in other parts of Europe. Climate projections based on the CMIP5 ensemble reveal considerable uncertainty in the magnitude of adverse weather conditions including waterlogging, drought and water stress. The variation in adverse weather conditions due to GCMs was generally greater than between emissions scenarios. Accordingly, CMIP5 ensembles should be used in the assessment of adverse weather conditions for crop production to indicate the full range of possible impacts, which a limited number of GCMs may not provide.
       
  • Applicability of a closed-path quantum cascade laser spectrometer for eddy
           covariance (EC) flux measurements of nitric oxide (NO) over a cropland
           during a low emission period
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Kai Wang, Dong Wang, Xunhua Zheng, David D. NelsonAbstractCroplands are important sources of atmospheric nitric oxide (NO). However, high-frequency measurements of NO fluxes over croplands using the eddy covariance (EC) technique are still scarce, mainly due to instrumental limitation. In this study, a closed-path NO analyzer based on a quantum cascade laser (QCL) absorption spectrometer was employed for EC flux measurements over a subtropical vegetable field during a two-month summer period with the lowest NO emission intensity of the year. The purpose was to investigate the detection limit of the EC system based on this NO analyzer and evaluate its applicability for measuring the turbulent fluxes of NO under field conditions. The performance of the analyzer was stable, showing an average precision (0.1 s) of 0.338 nmol mol−1 and a corresponding flux detection limit of 5.6 μg N m−2 h−1 at the 95% confidence interval. The measured turbulent NO fluxes ranged from −7.1 to 61.4 μg N m−2 h−1 (median: 3.5 μg N m−2 h−1), with a relative random error of 386% before field ploughing and 76% thereafter. The systematic errors due to the high-frequency loss and the use of lag times of carbon dioxide for NO flux calculation were estimated at 12% and 3%, respectively. During the measurement period, 37% of the observed half-hourly fluxes were larger than the detection limit; the magnitude of these fluxes is comparable with that measured by the static chambers. Nevertheless, this EC system could be still qualified for measuring turbulent NO fluxes over common croplands if the flux averaged at daily or longer timescales are of interest, because either flux detection limit or random error would decrease by an order of n, wherein n is the number of half-hourly fluxes being taken for averages. This study shows that the closed-path dual-QCL analyzer could be an effective option for EC measurements of turbulent NO fluxes with the advantages of (i) stable performance, (ii) high precision and fast response, and (iii) feasible instrumental maintenance for long-term field measurements. However, the observed turbulent fluxes still underestimated the soil NO emissions likely due to chemical reaction loss of NO below the sensor height. Further studies are necessary to address this systematic error.
       
  • Fire foci related to rainfall and biomes of the state of Mato Grosso do
           Sul, Brazil
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): José Francisco de Oliveira-Júnior, Paulo Eduardo Teodoro, Carlos Antonio da Silva Junior, Fabio Henrique Rojo Baio, Ricardo Gava, Guilherme Fernando Capristo-Silva, Givanildo de Gois, Washington Luiz Félix Correia Filho, Mendelson Lima, Dimas de Barros Santiago, Welington Kiffer Freitas, Paulo José dos Santos, Micejane da Silva CostaThe state of Mato Grosso do Sul (SMS), located in the Midwest of Brazil, is devoid of climatological studies, mainly on the characterization of rainfall regime and producers’ meteorological systems and rain inhibitors. This state has different soil and climatic characteristics distributed among three biomes: Cerrado, Mata Atlântica, and Pantanal. This study aimed to investigate the temporal variability of fire foci in different SMS biomes. Data regarding fire foci and rainfall were obtained on an annual scale, collected from 15 municipalities (nine in Cerrado, four in Mata Atlântica, and two in Pantanal). Boxplot and distribution graphs were constructed for fire foci data and rainfall data associated with the biomes in each year. Subsequently, we applied the Mann–Kendall test to verify if there is a significant trend to the rainfall and fire foci data of the biomes. Pantanal revealed the higher occurrence of fire foci in relation to Cerrado and Mata Atlântica. The highest records of fire foci in Pantanal are caused by the longer drought period and anthropogenic activities (based on extensive agriculture). There is a tendency for positive growth in the occurrence of fire foci in the Pantanal, Cerrado and Mata Atlântica. Therefore, it is necessary to establish public policies to mitigate the occurrence of hot flashes in the SMS biomes, especially in the Pantanal.Graphical abstractImage, graphical abstract
       
  • The sustainability of a sugarcane plantation in Brazil assessed by the
           eddy covariance fluxes of greenhouse gases
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Osvaldo M.R. Cabral, Helber Custódio Freitas, Santiago Viana Cuadra, Cristiano Alberto de Andrade, Nilza Patricia Ramos, Priscila Grutzmacher, Marcelo Galdos, Ana Paula Contador Packer, Humberto Ribeiro da Rocha, Paulo RossiThe sustainability of sugarcane farming for biofuel has recently become a subject of debate, because its expansion may contribute significantly to global climate change mitigation. Here we report greenhouse gases (GHG) fluxes, measured by the eddy covariance method, from a commercial scale rain-fed sugarcane plantation representative of the leading bioethanol production area in southeast Brazil. The measurements covered two harvests, during which the field received nitrogen fertilization and trash was not removed.The cumulative fluxes for nitrous oxide (N2O) (62.4 ± 1.3 and 52.3 ± 1.8 g N2OCO2 eq. m−2 for the first and second years, respectively) and methane (CH4) (12.1 ± 1.7 and 10.4 ± 2.3 g CH4CO2 eq. m−2 for the first and second years, respectively) were minor sources to the atmosphere in comparison with the net ecosystem exchange (NEE) of carbon dioxide (CO2), whose sink dominated the balances (−7643. ± 129. and -4615. ± 124. g CO2 m−2 for the first and second years, respectively). Compared to the first year, the observed NEE in the second year decreased by 40%, as it covered the first re-growth from the stubble (ratoon) and exhibited a shorter growth cycle than the first year (304 versus 390 days). The second year also included the partial decomposition of the trash remaining on the soil after the first harvest (1581 ± 301 g CO2 m−2).The net ecosystem carbon balances (NECB), obtained as the cumulative fluxes of GHGs and the stalk dry biomass removed in the harvests (4923 ± 459 and 3929 ± 352 g CO2 m−2 for the first and second years, respectively) were -2646 ± 459 and -623 ± 352 g CO2 m−2 for the first and second years, respectively. Although the yields in stalk fresh weight (SFW) were representative of the region (9.9 and 8.2 kg SFW m−2, in the first and second year respectively) other factors caused a decrease of 76% in NECB, stressing the importance of the CO2 balance (assimilation versus respiration). Nevertheless, this sugarcane agro-system was an overall carbon sink with the N2O and CH4 emitted totals being offset by the net carbon gain.Graphical abstractImage, graphical abstract
       
  • Application of an open-path eddy covariance methane flux measurement
           system to a larch forest in eastern Siberia
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Taro Nakai, Tetsuya Hiyama, Roman E. Petrov, Ayumi Kotani, Takeshi Ohta, Trofim C. MaximovAbstractCanopy-Scale methane (CH4) flux measurement over a larch forest in eastern Siberia was conducted by eddy covariance method using an open-path CH4 gas analyzer. Though the uncorrected flux showed strong CH4 uptake in the daytime, this changed to CH4 emission after density and spectroscopic effects were corrected. Random flux errors calculated from cross-covariance functions suggested that CH4 flux was nearly the same as the upper boundary of the limit of flux detection at the 95th percentile, being barely resolved by the measurement system; and that most of the daytime CH4 flux remained positive even after uncertainties due to random flux errors were taken into consideration. CH4 flux showed clear diurnal variation, representing emission in the daytime and near-zero in the nighttime, irrespective of wind direction. The daytime CH4 flux was dependent on both air temperature and volumetric soil water content. The CH4 flux from May 29, to June 12, was calculated as net emissions of 4.9–13.8 nmol m−2 s−1 in daily average, ranging between the forest floor and a mesotrophic fen near this site measured by static chambers in a previous study.
       
  • Microclimate in Mediterranean pine forests: What is the influence of the
           shrub layer'
    • Abstract: Publication date: 15 March 2020Source: Agricultural and Forest Meteorology, Volumes 282–283Author(s): Bernard Prévosto, Manon Helluy, Jordane Gavinet, Catherine Fernandez, Philippe BalandierAbstractForest cover creates a specific microclimate by buffering most environmental variables. If the influence of the overstory on microclimatic variables has been well studied, the role of the understory has received less attention. In this study we investigated how the shrub layer modifies solar radiation, air temperature (T), relative air humidity (RH), vapor pressure deficit (VPD) and soil moisture under different thinning treatments in an Aleppo pine forest (Pinus halepensis Mill.). Microclimatic variables were measured along a vegetation cover gradient made up of three pine densities (dense, medium, low) and open conditions, with or without the presence of shrubs. The results were analyzed with a focus on the summer period which represents a major bottleneck for plant development in the Mediterranean area.Average T and VPD values increased with decreasing vegetation cover (+1.38 °C and +0.21 kPa for the whole year) while RH decreased (-2.34%). Along the same gradient, daily amplitude of T, RH, VPD increased while the buffering capacity decreased. These patterns were more pronounced during the summer period compared to the whole year and were primarily driven by overstory transmittance. However, the shrub layer played a significant role in the low pine cover treatment where it was developed and in open conditions. Soil water content in the forest area was higher under low pine cover without shrubs than it was in the other treatments, though differences were less marked during summer drought episodes. In open conditions, soil moisture was always significantly lower beneath the shrub canopy than outside it. Despite a reduction in soil moisture, shrubs may represent safe sites for woody seedling development in sparse pine forests and in treeless areas by buffering the microclimate during the summer period.
       
 
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