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Showing 1 - 200 of 3043 Journals sorted alphabetically
AASRI Procedia     Open Access   (Followers: 15)
Academic Pediatrics     Hybrid Journal   (Followers: 22, SJR: 1.402, h-index: 51)
Academic Radiology     Hybrid Journal   (Followers: 21, SJR: 1.008, h-index: 75)
Accident Analysis & Prevention     Partially Free   (Followers: 84, SJR: 1.109, h-index: 94)
Accounting Forum     Hybrid Journal   (Followers: 25, SJR: 0.612, h-index: 27)
Accounting, Organizations and Society     Hybrid Journal   (Followers: 30, SJR: 2.515, h-index: 90)
Achievements in the Life Sciences     Open Access   (Followers: 4)
Acta Anaesthesiologica Taiwanica     Open Access   (Followers: 5, SJR: 0.338, h-index: 19)
Acta Astronautica     Hybrid Journal   (Followers: 352, 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: 235, 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)
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Actas Urológicas Españolas     Full-text available via subscription   (Followers: 4, SJR: 0.383, h-index: 19)
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Actualites Pharmaceutiques     Full-text available via subscription   (Followers: 5, SJR: 0.141, h-index: 3)
Actualites Pharmaceutiques Hospitalieres     Full-text available via subscription   (Followers: 4, SJR: 0.112, h-index: 2)
Acupuncture and Related Therapies     Hybrid Journal   (Followers: 4)
Acute Pain     Full-text available via subscription   (Followers: 13)
Ad Hoc Networks     Hybrid Journal   (Followers: 11, SJR: 0.967, h-index: 57)
Addictive Behaviors     Hybrid Journal   (Followers: 15, SJR: 1.514, h-index: 92)
Addictive Behaviors Reports     Open Access   (Followers: 5)
Additive Manufacturing     Hybrid Journal   (Followers: 7, SJR: 1.039, h-index: 5)
Additives for Polymers     Full-text available via subscription   (Followers: 21)
Advanced Drug Delivery Reviews     Hybrid Journal   (Followers: 135, SJR: 5.2, h-index: 222)
Advanced Engineering Informatics     Hybrid Journal   (Followers: 11, SJR: 1.265, h-index: 53)
Advanced Powder Technology     Hybrid Journal   (Followers: 17, SJR: 0.739, h-index: 33)
Advances in Accounting     Hybrid Journal   (Followers: 9, SJR: 0.299, h-index: 15)
Advances in Agronomy     Full-text available via subscription   (Followers: 15, SJR: 2.071, h-index: 82)
Advances in Anesthesia     Full-text available via subscription   (Followers: 25, SJR: 0.169, h-index: 4)
Advances in Antiviral Drug Design     Full-text available via subscription   (Followers: 3)
Advances in Applied Mathematics     Full-text available via subscription   (Followers: 6, SJR: 1.054, h-index: 35)
Advances in Applied Mechanics     Full-text available via subscription   (Followers: 11, SJR: 0.801, h-index: 26)
Advances in Applied Microbiology     Full-text available via subscription   (Followers: 22, SJR: 1.286, h-index: 49)
Advances In Atomic, Molecular, and Optical Physics     Full-text available via subscription   (Followers: 16, SJR: 3.31, h-index: 42)
Advances in Biological Regulation     Hybrid Journal   (Followers: 4, SJR: 2.277, h-index: 43)
Advances in Botanical Research     Full-text available via subscription   (Followers: 3, SJR: 0.619, h-index: 48)
Advances in Cancer Research     Full-text available via subscription   (Followers: 25, SJR: 2.215, h-index: 78)
Advances in Carbohydrate Chemistry and Biochemistry     Full-text available via subscription   (Followers: 9, SJR: 0.9, h-index: 30)
Advances in Catalysis     Full-text available via subscription   (Followers: 5, SJR: 2.139, h-index: 42)
Advances in Cellular and Molecular Biology of Membranes and Organelles     Full-text available via subscription   (Followers: 12)
Advances in Chemical Engineering     Full-text available via subscription   (Followers: 26, SJR: 0.183, h-index: 23)
Advances in Child Development and Behavior     Full-text available via subscription   (Followers: 10, SJR: 0.665, h-index: 29)
Advances in Chronic Kidney Disease     Full-text available via subscription   (Followers: 9, SJR: 1.268, h-index: 45)
Advances in Clinical Chemistry     Full-text available via subscription   (Followers: 29, SJR: 0.938, h-index: 33)
Advances in Colloid and Interface Science     Full-text available via subscription   (Followers: 18, SJR: 2.314, h-index: 130)
Advances in Computers     Full-text available via subscription   (Followers: 16, SJR: 0.223, h-index: 22)
Advances in Dermatology     Full-text available via subscription   (Followers: 12)
Advances in Developmental Biology     Full-text available via subscription   (Followers: 11)
Advances in Digestive Medicine     Open Access   (Followers: 6)
Advances in DNA Sequence-Specific Agents     Full-text available via subscription   (Followers: 5)
Advances in Drug Research     Full-text available via subscription   (Followers: 22)
Advances in Ecological Research     Full-text available via subscription   (Followers: 41, SJR: 3.25, h-index: 43)
Advances in Engineering Software     Hybrid Journal   (Followers: 25, SJR: 0.486, h-index: 10)
Advances in Experimental Biology     Full-text available via subscription   (Followers: 7)
Advances in Experimental Social Psychology     Full-text available via subscription   (Followers: 41, SJR: 5.465, h-index: 64)
Advances in Exploration Geophysics     Full-text available via subscription   (Followers: 3)
Advances in Food and Nutrition Research     Full-text available via subscription   (Followers: 50, SJR: 0.674, h-index: 38)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 16)
Advances in Genetics     Full-text available via subscription   (Followers: 15, SJR: 2.558, h-index: 54)
Advances in Genome Biology     Full-text available via subscription   (Followers: 11)
Advances in Geophysics     Full-text available via subscription   (Followers: 6, SJR: 2.325, h-index: 20)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 22, SJR: 0.906, h-index: 24)
Advances in Heterocyclic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 0.497, h-index: 31)
Advances in Imaging and Electron Physics     Full-text available via subscription   (Followers: 2, SJR: 0.396, h-index: 27)
Advances in Immunology     Full-text available via subscription   (Followers: 35, SJR: 4.152, h-index: 85)
Advances in Inorganic Chemistry     Full-text available via subscription   (Followers: 9, SJR: 1.132, h-index: 42)
Advances in Insect Physiology     Full-text available via subscription   (Followers: 3, SJR: 1.274, h-index: 27)
Advances in Integrative Medicine     Hybrid Journal   (Followers: 6)
Advances in Life Course Research     Hybrid Journal   (Followers: 8, SJR: 0.764, h-index: 15)
Advances in Lipobiology     Full-text available via subscription   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Marine Biology     Full-text available via subscription   (Followers: 16, SJR: 1.645, h-index: 45)
Advances in Mathematics     Full-text available via subscription   (Followers: 10, SJR: 3.261, h-index: 65)
Advances in Medical Sciences     Hybrid Journal   (Followers: 6, SJR: 0.489, h-index: 25)
Advances in Medicinal Chemistry     Full-text available via subscription   (Followers: 5)
Advances in Microbial Physiology     Full-text available via subscription   (Followers: 4, SJR: 1.44, h-index: 51)
Advances in Molecular and Cell Biology     Full-text available via subscription   (Followers: 22)
Advances in Molecular and Cellular Endocrinology     Full-text available via subscription   (Followers: 10)
Advances in Molecular Toxicology     Full-text available via subscription   (Followers: 7, SJR: 0.324, h-index: 8)
Advances in Nanoporous Materials     Full-text available via subscription   (Followers: 4)
Advances in Oncobiology     Full-text available via subscription   (Followers: 3)
Advances in Organometallic Chemistry     Full-text available via subscription   (Followers: 15, SJR: 2.885, h-index: 45)
Advances in Parallel Computing     Full-text available via subscription   (Followers: 7, SJR: 0.148, h-index: 11)
Advances in Parasitology     Full-text available via subscription   (Followers: 7, SJR: 2.37, h-index: 73)
Advances in Pediatrics     Full-text available via subscription   (Followers: 24, SJR: 0.4, h-index: 28)
Advances in Pharmaceutical Sciences     Full-text available via subscription   (Followers: 13)
Advances in Pharmacology     Full-text available via subscription   (Followers: 15, SJR: 1.718, h-index: 58)
Advances in Physical Organic Chemistry     Full-text available via subscription   (Followers: 8, SJR: 0.384, h-index: 26)
Advances in Phytomedicine     Full-text available via subscription  
Advances in Planar Lipid Bilayers and Liposomes     Full-text available via subscription   (Followers: 3, SJR: 0.248, h-index: 11)
Advances in Plant Biochemistry and Molecular Biology     Full-text available via subscription   (Followers: 8)
Advances in Plant Pathology     Full-text available via subscription   (Followers: 5)
Advances in Porous Media     Full-text available via subscription   (Followers: 4)
Advances in Protein Chemistry     Full-text available via subscription   (Followers: 17)
Advances in Protein Chemistry and Structural Biology     Full-text available via subscription   (Followers: 20, SJR: 1.5, h-index: 62)
Advances in Psychology     Full-text available via subscription   (Followers: 61)
Advances in Quantum Chemistry     Full-text available via subscription   (Followers: 5, SJR: 0.478, h-index: 32)
Advances in Radiation Oncology     Open Access  
Advances in Small Animal Medicine and Surgery     Hybrid Journal   (Followers: 3, SJR: 0.1, h-index: 2)
Advances in Space Research     Full-text available via subscription   (Followers: 353, SJR: 0.606, h-index: 65)
Advances in Structural Biology     Full-text available via subscription   (Followers: 8)
Advances in Surgery     Full-text available via subscription   (Followers: 7, SJR: 0.823, h-index: 27)
Advances in the Study of Behavior     Full-text available via subscription   (Followers: 30, SJR: 1.321, h-index: 56)
Advances in Veterinary Medicine     Full-text available via subscription   (Followers: 17)
Advances in Veterinary Science and Comparative Medicine     Full-text available via subscription   (Followers: 13)
Advances in Virus Research     Full-text available via subscription   (Followers: 5, SJR: 1.878, h-index: 68)
Advances in Water Resources     Hybrid Journal   (Followers: 43, SJR: 2.408, h-index: 94)
Aeolian Research     Hybrid Journal   (Followers: 5, SJR: 0.973, h-index: 22)
Aerospace Science and Technology     Hybrid Journal   (Followers: 325, SJR: 0.816, h-index: 49)
AEU - Intl. J. of Electronics and Communications     Hybrid Journal   (Followers: 8, SJR: 0.318, h-index: 36)
African J. of Emergency Medicine     Open Access   (Followers: 5, SJR: 0.344, h-index: 6)
Ageing Research Reviews     Hybrid Journal   (Followers: 8, SJR: 3.289, h-index: 78)
Aggression and Violent Behavior     Hybrid Journal   (Followers: 406, SJR: 1.385, h-index: 72)
Agri Gene     Hybrid Journal  
Agricultural and Forest Meteorology     Hybrid Journal   (Followers: 16, 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: 11, SJR: 0.922, h-index: 66)
Alcoholism and Drug Addiction     Open Access   (Followers: 8)
Alergologia Polska : Polish J. of Allergology     Full-text available via subscription   (Followers: 1)
Alexandria Engineering J.     Open Access   (Followers: 1, SJR: 0.436, h-index: 12)
Alexandria J. of Medicine     Open Access  
Algal Research     Partially Free   (Followers: 8, SJR: 2.05, h-index: 20)
Alkaloids: Chemical and Biological Perspectives     Full-text available via subscription   (Followers: 3)
Allergologia et Immunopathologia     Full-text available via subscription   (Followers: 1, SJR: 0.46, h-index: 29)
Allergology Intl.     Open Access   (Followers: 4, SJR: 0.776, h-index: 35)
Alpha Omegan     Full-text available via subscription   (SJR: 0.121, h-index: 9)
ALTER - European J. of Disability Research / Revue Européenne de Recherche sur le Handicap     Full-text available via subscription   (Followers: 8, SJR: 0.158, h-index: 9)
Alzheimer's & Dementia     Hybrid Journal   (Followers: 48, SJR: 4.289, h-index: 64)
Alzheimer's & Dementia: Diagnosis, Assessment & Disease Monitoring     Open Access   (Followers: 6)
Alzheimer's & Dementia: Translational Research & Clinical Interventions     Open Access   (Followers: 5)
American Heart J.     Hybrid Journal   (Followers: 49, SJR: 3.157, h-index: 153)
American J. of Cardiology     Hybrid Journal   (Followers: 47, SJR: 2.063, h-index: 186)
American J. of Emergency Medicine     Hybrid Journal   (Followers: 39, SJR: 0.574, h-index: 65)
American J. of Geriatric Pharmacotherapy     Full-text available via subscription   (Followers: 8, SJR: 1.091, h-index: 45)
American J. of Geriatric Psychiatry     Hybrid Journal   (Followers: 15, SJR: 1.653, h-index: 93)
American J. of Human Genetics     Hybrid Journal   (Followers: 31, SJR: 8.769, h-index: 256)
American J. of Infection Control     Hybrid Journal   (Followers: 25, SJR: 1.259, h-index: 81)
American J. of Kidney Diseases     Hybrid Journal   (Followers: 32, SJR: 2.313, h-index: 172)
American J. of Medicine     Hybrid Journal   (Followers: 45, SJR: 2.023, h-index: 189)
American J. of Medicine Supplements     Full-text available via subscription   (Followers: 3)
American J. of Obstetrics and Gynecology     Hybrid Journal   (Followers: 233, SJR: 2.255, h-index: 171)
American J. of Ophthalmology     Hybrid Journal   (Followers: 58, SJR: 2.803, h-index: 148)
American J. of Ophthalmology Case Reports     Open Access   (Followers: 5)
American J. of Orthodontics and Dentofacial Orthopedics     Full-text available via subscription   (Followers: 6, SJR: 1.249, h-index: 88)
American J. of Otolaryngology     Hybrid Journal   (Followers: 25, SJR: 0.59, h-index: 45)
American J. of Pathology     Hybrid Journal   (Followers: 26, SJR: 2.653, h-index: 228)
American J. of Preventive Medicine     Hybrid Journal   (Followers: 22, SJR: 2.764, h-index: 154)
American J. of Surgery     Hybrid Journal   (Followers: 34, SJR: 1.286, h-index: 125)
American J. of the Medical Sciences     Hybrid Journal   (Followers: 12, SJR: 0.653, h-index: 70)
Ampersand : An Intl. J. of General and Applied Linguistics     Open Access   (Followers: 5)
Anaerobe     Hybrid Journal   (Followers: 4, SJR: 1.066, h-index: 51)
Anaesthesia & Intensive Care Medicine     Full-text available via subscription   (Followers: 57, SJR: 0.124, h-index: 9)
Anaesthesia Critical Care & Pain Medicine     Full-text available via subscription   (Followers: 11)
Anales de Cirugia Vascular     Full-text available via subscription  
Anales de Pediatría     Full-text available via subscription   (Followers: 2, SJR: 0.209, h-index: 27)
Anales de Pediatría (English Edition)     Full-text available via subscription  
Anales de Pediatría Continuada     Full-text available via subscription   (SJR: 0.104, h-index: 3)
Analytic Methods in Accident Research     Hybrid Journal   (Followers: 4, SJR: 2.577, h-index: 7)
Analytica Chimica Acta     Hybrid Journal   (Followers: 37, SJR: 1.548, h-index: 152)
Analytical Biochemistry     Hybrid Journal   (Followers: 167, SJR: 0.725, h-index: 154)
Analytical Chemistry Research     Open Access   (Followers: 8, SJR: 0.18, h-index: 2)
Analytical Spectroscopy Library     Full-text available via subscription   (Followers: 11)
Anesthésie & Réanimation     Full-text available via subscription   (Followers: 1)
Anesthesiology Clinics     Full-text available via subscription   (Followers: 22, SJR: 0.421, h-index: 40)
Angiología     Full-text available via subscription   (SJR: 0.124, h-index: 9)
Angiologia e Cirurgia Vascular     Open Access  
Animal Behaviour     Hybrid Journal   (Followers: 161, SJR: 1.907, h-index: 126)
Animal Feed Science and Technology     Hybrid Journal   (Followers: 5, SJR: 1.151, h-index: 83)
Animal Reproduction Science     Hybrid Journal   (Followers: 5, SJR: 0.711, h-index: 78)
Annales d'Endocrinologie     Full-text available via subscription   (Followers: 1, SJR: 0.394, h-index: 30)
Annales d'Urologie     Full-text available via subscription  
Annales de Cardiologie et d'Angéiologie     Full-text available via subscription   (SJR: 0.177, h-index: 13)
Annales de Chirurgie de la Main et du Membre Supérieur     Full-text available via subscription  
Annales de Chirurgie Plastique Esthétique     Full-text available via subscription   (Followers: 2, SJR: 0.354, h-index: 22)
Annales de Chirurgie Vasculaire     Full-text available via subscription   (Followers: 1)

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Journal Cover Agricultural Water Management
  [SJR: 1.546]   [H-I: 79]   [39 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0378-3774
   Published by Elsevier Homepage  [3043 journals]
  • Soil and irrigation heterogeneity effects on drainage amount and
           concentration in lysimeters: A numerical study
    • Authors: Iael Raij; Alon Ben-Gal; Naftali Lazarovitch
      Pages: 1 - 10
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): Iael Raij, Alon Ben-Gal, Naftali Lazarovitch
      Water and solute fluxes measured from lysimeters located in the field can be used to estimate evapotranspiration, for irrigation scheduling and in solute leaching management. System-imposed heterogeneities are expected to affect the variability of the measured fluxes, and therefore the uncertainty of data obtained using lysimeters. In this study, local heterogeneities in soil hydraulic conductivity and dripper discharge rate were studied and their effect on drainage amount and concentration assessed. Three-dimensional simulations were performed with HYDRUS (2D/3D) with 100 simulations per treatment. The effect of three levels of soil and irrigation heterogeneities was studied for lysimeters of two different sizes (1m2 and 0.5m2). Additionally, three leaching fraction levels and water uptake reduction due to solute stress were evaluated. Coefficient of variations of the drainage amount and solute concentrations were evaluated for the different scenarios. Irrigation heterogeneity caused higher variability in drainage amount while soil heterogeneity caused higher variability in drainage concentration. The larger the lysimeter, or the higher the leaching fraction, the lower the variability for both drainage concentration and amount. Combined soil and irrigation heterogeneities produced no synergistic effect, suggesting that the variability measured in lysimeters was governed by the factor that caused the highest variability. When water uptake reduction due to salinity was considered, the same trends were observed. The results from this study can help to decide if to use either drainage concentration or amount values, for saline water irrigation management using lysimeters, according to the soil or irrigation heterogeneity levels.

      PubDate: 2017-10-08T15:27:58Z
      DOI: 10.1016/j.agwat.2017.09.012
      Issue No: Vol. 195 (2017)
  • How water amounts and management options drive Irrigation Water
           Productivity of rice. A multivariate analysis based on field experiment
    • Authors: Federica Monaco; Guido Sali
      Pages: 47 - 57
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): Federica Monaco, Guido Sali
      Rice cultivation is globally hampered by several conditions, which urge farmers to maintain adequate production levels while properly managing irrigation water. This has noticeable repercussions on the efficient use of the resource and on water productivity. Nonetheless, more often, this latter topic is addressed by estimating the respective values, without deeply investigating the possible causes behind such discrepancies. The main objective of this paper is to overcome such limitations, by (i) providing a comprehensive and updated overview of Irrigation Water Productivity (IWP) for rice, and (ii) exploring the role of irrigation water in determining IWP value. The analysis of experimental data collected from 51 studies reveals IWP to vary between 0.09 and 8.10kgm−3, with mean and median values of 1.36 and 0.85kgm−3 respectively; moreover, a non-linear relationship between irrigation water amounts and IWP (r2 =0.81) is depicted. Further on, data are analyzed using an econometric approach. Specifically, a multivariate linear regression model is used to shed light on the joint contribution of water inputs, regime and irrigation method to productivity. This demonstrates the significant roles of irrigation (β=−1.006) and rainfall (β=0.062) amounts, while aerobic regime and irrigation method is proved to be a further key driver (β=−0.305). Such results enable identifying the elements to be enforced, if increasing IWP for rice is the prime objective. Finally, some implications are derived for water policy and the connections with weather-climatic and environmental conditions that are globally affecting the availability of water in agriculture.

      PubDate: 2017-10-13T23:03:31Z
      DOI: 10.1016/j.agwat.2017.09.014
      Issue No: Vol. 195 (2017)
  • Predicting design water requirement of winter paddy under climate change
           condition using frequency analysis in Bangladesh
    • Authors: A.R.M.Towfiqul Islam; Shuang-He Shen; Shen-Bin Yang
      Pages: 58 - 70
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): A.R.M.Towfiqul Islam, Shuang-He Shen, Shen-Bin Yang
      The effects of climate change on the agricultural sector are tremendous. Thus, it is essential to determine its impacts on agricultural water resources and to minimize adverse effects on crop production. The present study aims to simulate climate data based on SRES A1B scenario from the outputs of three General Circulation Models (GCMs) namely, FGOAL, HADCM3 and IPCM4 and examine the design water requirement (DWR) of winter paddy using frequency analysis under climate change condition in Bangladesh. The average change rates of DWR in four climatic zones were compared to baseline and the results were −12.16% (2020s), −0.28% (2055s), and 1.25% (2090s) for the FGOAL, −4.44% (2020s), 0.57% (2055s) and 1.25% (2090s) for the HADCM3, and −1.12% (2020s), 2.22% (2055s) and 6.69% (2090s) for the IPCM4. The change rates of gross paddy water demand (GPWD) for three GCMs ranged from −3.01% to 11.16%. In both cases of the DWR and GPWD, the change rates were above 3%, indicating a warning signal to the future winter paddy water management. The outcomes of this study can be used as basic data for the development of agricultural water resource management, which will help to minimize the drought-risk and to implement future agricultural water resource policies in Bangladesh.

      PubDate: 2017-10-13T23:03:31Z
      DOI: 10.1016/j.agwat.2017.10.003
      Issue No: Vol. 195 (2017)
  • Deficit irrigation provokes more pronounced responses of maize
           photosynthesis and water productivity to elevated CO2
    • Authors: Xiaojie Li; Shaozhong Kang; Xiaotao Zhang; Fusheng Li; Hongna Lu
      Pages: 71 - 83
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): Xiaojie Li, Shaozhong Kang, Xiaotao Zhang, Fusheng Li, Hongna Lu
      It is very significant to study the impact of deficit irrigation on crop growth and water use under the future scenarios with elevated CO2 concentrations and reduced water availability. This study investigated the growth and yield differences of maize grown in a phytotron in response to elevated CO2 concentrations under different irrigation treatments. Two irrigation treatments were carried out: regular irrigation (RI) and deficit irrigation (DI), in which the irrigation amounts were respectively 100 and 70% of evapotranspiration (ET), with four CO2 concentrations (400, 550, 700, and 900μmolmol−1). Thus eight treatments, i.e. RI400, RI550, RI700, RI900, DI400, DI550, DI700, and DI900 were included in this study. Results show that, the relative reductions of stomatal conductance (gs ) and transpiration rate (Tr ) in response to elevated CO2 concentrations were higher under DI than RI, thus causing leaf temperature (Tleaf ) rose higher under DI due to the transpiration cooling effect. As photosynthetic rate (Pn ) and its physiological process were positively correlated with Tleaf , the relative increases of Pn and the resulting maximum leaf area index (LAImax ), total dry matter weight (TDW), and grain yield (GY) react to elevated CO2 concentrations were higher under DI than RI, as well as the leaf water use efficiency (WUEL ) and water productivity (WP). The DI900 treatment in which the irrigation amount was reduced by 30% only decreased the TDW and GY by 7 and 5% when compared with RI900. The variation of GY was consistent with the variation of kernels per ear (KPE), but was not directly related to hundred-grain weight (HGW). The above results show that when atmospheric CO2 concentrations rise in the future, deficit irrigation would be an effective way of saving water and would not only have a mitigating effect on water crises, but would also contribute to improving WP, which is more important in terms of actual production.

      PubDate: 2017-10-13T23:03:31Z
      DOI: 10.1016/j.agwat.2017.09.017
      Issue No: Vol. 195 (2017)
  • Water use of irrigated almond trees when subjected to water deficits
    • Authors: Manuel López-López; Mónica Espadador; Luca Testi; Ignacio Jesús Lorite; Francisco Orgaz; Elías Fereres
      Pages: 84 - 93
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): Manuel López-López, Mónica Espadador, Luca Testi, Ignacio Jesús Lorite, Francisco Orgaz, Elías Fereres
      Recently planted intensive almond plantations may have access to limited water supply due to water scarcity thus, information on almond water use under limited irrigation is needed. Here, the soil water balance was used to assess the consumptive use (ET) of full irrigated, moderately stressed and severely stressed almond trees over a three-year study, as well as the relation between applied water and ET. Sap flow measurements in eight experimental trees were used to obtain independent transpiration (T) measurements. Evaporation from soil (ES) was modelled to estimate tree T from the water balance. Relative consumptive use in the deficit irrigation (DI) treatments largely exceeded the relative applied water, highlighting the need to measure ET in stressed treatments for hydrologic purposes. The moderately stressed treatments (irrigated at 65.5% of full irrigation) consumed 79.0% of maximum evapotranspiration (ET of 897mm), while the severely stressed treatment consumed 63.6% of ETc (ET of 722mm) when applied water was only 39.6% of control. On average, almond ETc approached 1200mm, Seasonal evolution of the transpiration coefficient yielded maximum peak values ranging from 0.99 to 1.08, and minimum peak values of 0.33 attained with a severe deficit irrigation strategy. Transpiration measured by Compensated Heat Pulse-Calibrated Average Gradient sap-flow (x), was compared to water balance T estimates (y), and yielded a very good relation over the three years of study (y=0.90x+4.23, r2 =0.81). The sap flow measurements proved to be useful to overcome the limitations of the soil water balance technique, revealing that almond trees were able to extract water from below the monitored depths and suggesting that deep percolation event must have occurred in spring and autumn.

      PubDate: 2017-10-13T23:03:31Z
      DOI: 10.1016/j.agwat.2017.10.001
      Issue No: Vol. 195 (2017)
  • Response of sap flux and evapotranspiration to deficit irrigation of
           greenhouse pear-jujube trees in semi-arid northwest China
    • Authors: Yu Feng; Ningbo Cui; Taisheng Du; Daozhi Gong; Xiaotao Hu; Lu Zhao
      Pages: 1 - 12
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Yu Feng, Ningbo Cui, Taisheng Du, Daozhi Gong, Xiaotao Hu, Lu Zhao
      The objective of this study was to investigate the response of sap flux (SF) and evapotranspiration (ET) to deficit irrigation (DI) at different growth stages of greenhouse pear-jujube trees (Zizyphus jujube Mill.). Taking full irrigation (FI) as the control treatment (CK), moderate water deficit (50% of FI) at bud burst to leafing stage (stage I) (T2), flowering to fruit set stage (stage II) (T3), fruit growth stage (stage III) (T4), and fruit maturation stage (stage IV) (T5) were treated on greenhouse 8-year old pear-jujube trees in two growing seasons. Water deficit at different growth stages reduced SF, after the re-watering, SF had significant compensatory effects. Therefore, compared with CK, water deficit treatments (T2–T5) didn’t decrease SF significantly for the whole growing seasons, with maximum decrease of 10.5%. Simultaneously, SF under T2–T5 showed typical diurnal patterns on sunny and cloudy days, and nighttime SF accounted for 23.7%–52.3% of total SF for all the weather conditions. There was significantly positive relationship between SF and reference evapotranspiration, with R2 of 0.349–0.594. Principal component analysis (PCA) indicated that 97% of SF of pear-jujube can be characterized by relative humidity (RH), solar radiation (Rs), air temperature (Ta), and vapor pressure deficit (VPD), and VPD was the main variable affecting SF for all the treatments (P<0.001). Averaging the two years, ET of pear-jujube were 258–288mm for all the treatments, compared with CK, T2–T5 could decrease ET by 2.3%–10.3%.

      PubDate: 2017-09-06T05:13:40Z
      DOI: 10.1016/j.agwat.2017.08.019
      Issue No: Vol. 194 (2017)
  • Field and numerical experiment of an improved subsurface drainage system
           in Huaibei plain
    • Authors: Yuan Tao; Shaoli Wang; Di Xu; Hongwei Yuan; Haorui Chen
      Pages: 24 - 32
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Yuan Tao, Shaoli Wang, Di Xu, Hongwei Yuan, Haorui Chen
      New requirements are put forward for agricultural drainage system due to frequent floods and cultivated land shortage in Huaibei plain, China. The improved subsurface drainage is a more efficient drainage system by laying high permeability materials as filter above the drains based on conventional subsurface drainage whose function is limited by soil hydraulic conductivity. Field experiments was used to evaluate the performance of the improved subsurface drainage preliminarily and numerical experiments was used to explore the capacity of the improved subsurface drainage deeply. Based on calibration and validation by field experiment data, HYDRUS model was used to evaluate the impacts of design parameters of filter hydraulic conductivity, filter width and height, drain spacing and depth on improved subsurface drainage discharge with constant ponding depth. Then, water table depths at different distances from the pipe drain for improved and conventional subsurface drainage were simulated under initial conditions of saturated soil and no surface ponding. Besides, the daily water balance under improved subsurface drainage had been also studied. The result of field experiment showed that the discharge of improved subsurface drainage was about 1.9 times of the conventional subsurface drainage discharge under conditions of same surface ponding depths. The results of numerical experiments indicated that the improved subsurface drainage had a real-time drainage function for the reason that cumulative outflow increased by about 87% than conventional subsurface drainage within 12h after beginning draining. The improved subsurface drainage lowered water table to an appropriate depth faster than conventional ones, which could provide a more favourable soil moisture condition for crop growth. Furthermore, through daily water balance analysis of improved and conventional subsurface drainage with different rainfalls and initial water table depths, the results showed that subsurface drainage could reduce surface runoff effectively, especially for improved subsurface drainage. Good drainability of the improved subsurface drainage was beneficial to decrease the amount of soil water storage after rainfall and helpful to shorten subsequent draining time of water table drawdown. The research results could provide scientific basis for improved subsurface drainage design and lay a good foundation for its application. Meanwhile, it would be beneficial to enrich agricultural drainage technologies and promote development of agricultural drainage in China.

      PubDate: 2017-09-11T03:03:49Z
      DOI: 10.1016/j.agwat.2017.07.015
      Issue No: Vol. 194 (2017)
  • Identifying changes in irrigation return flow with gradually intensified
           water-saving technology using HYDRUS for regional water resources
    • Authors: Qiuli Hu; Yonghui Yang; Shumin Han; Yanmin Yang; Zhipin Ai; Jiusheng Wang; Fengyun Ma
      Pages: 33 - 47
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Qiuli Hu, Yonghui Yang, Shumin Han, Yanmin Yang, Zhipin Ai, Jiusheng Wang, Fengyun Ma
      Irrigation return flow is critical for both surface and groundwater resources in downstream catchments. However, studies sufficiently clarifying the dynamics of hydrological processes in relation to irrigation return flow are scarce. In this study, HYDRUS-2D/3D model was used to analyze four irrigation development scenarios in Aksu River Basin, a major tributary of Tarim River. The study determined the effect of agricultural water saving on the dynamics of irrigation return flow in the basin. The results showed that for the 1990s, the irrigation return flow coefficient for flood irrigation was 0.50. This suggested that 50% of the water used in irrigation returned as discharge in the lower reaches. With increasing water scarcity, irrigation amount dropped while drip irrigation with plastic mulch was intensified. Accordingly, the irrigation return flow coefficient dropped from 0.44 in the 2000s to 0.34 in the 2010s under flood irrigation and from 0.42 to 0.23 under drip irrigation. With the drastic drop, irrigation was no longer enough to stabilize soil salinity in the region. The recent irrigation plan requires further reduction in irrigation amount. Based on the projected effects of the new irrigation scheme on soil salt build-up, an optimized irrigation scheme showed that the irrigation return flow coefficient should remain at 0.25. And with the use of water-saving technology, irrigation return flow has dropped from 594.01mm in the 1990s to 164.62mm in the 2010s, which should be maintained at 186.37mm for the sustainability of the optimized irrigation scheme. The study also suggested that salinity was increasing in the downstream water systems due to irrigation return flow from land reclamation and water saving. This was a potential threat to the fragile riparian ecosystems in the study area.

      PubDate: 2017-09-11T03:03:49Z
      DOI: 10.1016/j.agwat.2017.08.023
      Issue No: Vol. 194 (2017)
  • Interactive effects of pH, EC and nitrogen on yields and nutrient
           absorption of rice (Oryza sativa L.)
    • Authors: Lihua Huang; Xuan Liu; Zhichun Wang; Zhengwei Liang; Mingming Wang; Miao Liu; Donald L. Suarez
      Pages: 48 - 57
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Lihua Huang, Xuan Liu, Zhichun Wang, Zhengwei Liang, Mingming Wang, Miao Liu, Donald L. Suarez
      Soil salinity and sodicity can not only directly restrain crop growth by osmotic and specific ion stresses, it also may reduce grain yield indirectly by impacting plant absorption of essential nutrients. Ensuring adequate nitrogen is an important management aspect of rice production in saline-sodic soils. The objective of this study was to investigate the interaction of soil pH, salinity and nitrogen application on rice yield and nutrient absorption. We conducted a rice experiment in containers in a greenhouse. The soils were first leached with 9 target salt solutions of pH 7, 8 and 9 and electrical conductivity (EC) of 2, 6 and 10dSm−1. Nitrogen application rates were 100, 200 and 300kgNha−1. Rice grain yield and shoot weight significantly decreased with increasing soil pH and increasing soil EC, and significantly increased with increasing nitrogen application (P <0.001). However, at high EC and/or high pH yield was not significantly increased by increased N. High pH and high EC in soil significantly influenced the mineral nutrient content of rice shoots (P <0.05). High soil pH and soil EC stresses were superimposed on each other, the negative effects on rice were compounded. The results by stepwise regression analysis showed that soil pH very significantly and adversely impacts grain yield and was the major factor impacting rice grain yield (R2 =0.565, P <0.001). Nitrogen application provided a positive response under control and pH 7 at all salinity values, and at pH 8 under low salinity only. There was no significant response to additional N under pH 8 and elevated EC and no significant response at pH 9 for all EC values. Thus, adequate nitrogen application is an important technical measure for improving rice yield and promoting nutrient absorption in rice of high EC soils but not of high pH soils where pH is the major limiting factor for rice production in saline-sodic soils.

      PubDate: 2017-09-11T03:03:49Z
      DOI: 10.1016/j.agwat.2017.08.012
      Issue No: Vol. 194 (2017)
  • Identifying best crop management practices for chickpea (Cicer arietinum
           L.) in Northeastern Ethiopia under climate change condition
    • Authors: Adem Mohammed; Tamado Tana; Piara Singh; Adamu Molla; Ali Seid
      Pages: 68 - 77
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Adem Mohammed, Tamado Tana, Piara Singh, Adamu Molla, Ali Seid
      Chickpea (Cicer arietinum L.) is one of the important cool season food legumes in the semi-arid northeastern Ethiopia; however, its productivity is adversely affected by a number of abiotic and biotic factors. The objectives of this study were to assess impacts of projected climate change on grain yield of chickpea by 2030s (2020–2049) and 2050s (2040–2069) and to identify crop management options that increase productivity of the crop. The CROPGRO-chickpea model in DSSAT (Decision Support System for Agrotechnology Transfer) was used to assess impacts of projected climate change on chickpea and to identify adaptation options. The crop model was first calibrated and evaluated in the study area for simulating growth, yield and water balance of the soil. The result of the model calibration and evaluation showed that there were close agreement between the simulated and observed values that showed the performance of the model to simulate growth, phenology and yield of chickpea under semi-arid northeastern Ethiopian condition. The calibrated model was used to assess impacts of projected climate changes on chickpea and identify crop management options. The impact of projected climate change was assessed for 2030s and 2050s time periods under all the RCPs with and without CO2 fertilization. To identify crop management options, different varieties of chickpea, supplemental irrigation and change in planting dates have been evaluated. The result of climate change impact analysis on chickpea showed that grain yield is predicted to significantly increase both by 2030s and 2050s under CO2 fertilization condition across all the RCPs as compared to baseline grain yield (1961–1990). However, simulation without CO2 showed that grain yield will not significantly increase by 2030s and 2050s across all the scenarios. Based on the prediction result it can be generalized that chickpea will be benefited from the projected climate changes in northeastern Ethiopia. According to the simulation result application of two supplemental irrigation (flower initiation and pod setting stages) and early sowing significantly (P <0.05) increase grain yield of chickpea in northeastern Ethiopia under the present and future climate conditions. Selection of appropriate cultivars based on the agroecology of the area has paramount important to increase chickpea productivity under the present and future climate condition.

      PubDate: 2017-09-11T03:03:49Z
      DOI: 10.1016/j.agwat.2017.08.022
      Issue No: Vol. 194 (2017)
  • Water saving practices enhance regional efficiency of water consumption
           and water productivity in an arid agricultural area with shallow
    • Authors: Jingyuan Xue; Huade Guan; Zailin Huo; Fengxin Wang; Guanhua Huang; Jan Boll
      Pages: 78 - 89
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Jingyuan Xue, Huade Guan, Zailin Huo, Fengxin Wang, Guanhua Huang, Jan Boll
      Improving the efficiency of water consumption and water productivity is the key approach to satisfy sustainable water resource supply and food demand. As effective measures, water saving practices are implemented in arid and semi-arid regions. For areas with shallow groundwater, water used for irrigation is not entirely consumptively used. The majority of irrigation water infiltrations below the root zone are stored in shallow groundwater. This can be reused as groundwater based evapotranspiration (ETg) at the regional scale. Thus, actual regional efficiency of water consumption (REWC) based on all water within the hydrological system is greater than based on consumptive use only. Accurately evaluating the response of REWC and regional water productivity (RWP) to water saving practices is essential due to the complexity of the hydrological system. In this study, regional ETg and regional evapotranspiration (ET) of the past 20 years were reproduced in a typical arid irrigation district with shallow groundwater based on the water balance method. Furthermore, REWC and RWP were estimated to investigate the impact of water saving practices to regional water use. Simulation results show that groundwater is a significant water source of regional ET in arid regions with a shallow aquifer and contributes more than 16% of regional ET for the irrigation district. Water saving practice implementation enhances the contribution of groundwater to ET. After water saving practices implementation, annual REWC and RWP have been improved by 0.07 and 0.1kg/m3, respectively. Furthermore, negative correlation between REWC and I+P (the total water supply including rainfall and irrigation water diversion) and positive correlation between RWP and REWC demonstrate that water saving practices can reduce the non-beneficial water losses by evaporation and enhance productivity by a lower groundwater table. Overall, shallow groundwater plays an important role to enhance REWC and RWP and the contribution of groundwater to regional water use needs to be considered as part of a reasonable water saving strategy towards a sustainable agricultural system.

      PubDate: 2017-09-18T01:34:50Z
      DOI: 10.1016/j.agwat.2017.09.003
      Issue No: Vol. 194 (2017)
  • Essential irrigation and the economics of strawberries in a temperate
    • Authors: J. Morris; M.A. Else; D. El Chami; A. Daccache; D. Rey; J.W. Knox
      Pages: 90 - 99
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): J. Morris, M.A. Else, D. El Chami, A. Daccache, D. Rey, J.W. Knox
      Strawberries are a high value crop in the UK soft fruit sector, with the majority of production grown at field-scale and under protected (polytunnel) conditions. Despite its importance to the rural economy, there is surprisingly little published scientific evidence on the economics of irrigated strawberry production and the value of water in this horticultural sector. A survey of growers, supplemented by secondary data and industry sources, shows considerable variation in key physical and financial performance indicators, both within and between different strawberry production systems, as well as evidence of good practice. Water application depths ranged widely from 800 to over 2000m3 ha−1 according to grower and crop variety. Irrigation costs typically range between £1.30 and £2.50m−3 of water applied, highest where storage reservoirs and public water supplies are used. The average value of irrigation water for strawberry net of costs was about £6m−3, much higher than for field crops such as potatoes. The importance of a reliable water supply to support irrigated strawberry production is highlighted. Climate change and growing pressures on water resources are likely to force a greater interest in irrigation economics in the soft fruit sector, especially in the face of restrictions on summer abstraction and rising competition and charges for using public water supply.

      PubDate: 2017-09-18T01:34:50Z
      DOI: 10.1016/j.agwat.2017.09.004
      Issue No: Vol. 194 (2017)
  • Food and water security: Analysis of integrated modeling platforms
    • Authors: Kelsie McNeill; Kiera Macdonald; Ashutosh Singh; Andrew D. Binns
      Pages: 100 - 112
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Kelsie McNeill, Kiera Macdonald, Ashutosh Singh, Andrew D. Binns
      Food and water security are directly linked through the agricultural sector and food production and processing. Increasing stresses on food and water resources, influenced by factors such as population growth and climate change, threaten global food and water security. Previous studies have attempted to address this issue with the development of various modeling frameworks, often combining food security and water security models to address the inter-relationship between the two concepts. This study first introduces some of the background and foundational principles behind food and water security models, then critically reviews models that jointly analyze the two concepts. Initially, the dynamic definitions and historic development of water and food security concepts are reviewed. Current global hydrological models and food production/consumption models are then discussed to provide requisite background on available modeling platforms that separately assess water and food security. This study then focuses on an evaluation of ten models that assess food and water security from an interdisciplinary perspective, providing in-depth analysis regarding input parameters, model processes, advantages and limitations. Results suggest that there is a need to further develop input datasets as well as spatial and temporal resolution in existing food and water security models. This will provide the foundation for the development of effective policies and strategies to mitigate future food and water security issues, while considering the protection of the natural environment.

      PubDate: 2017-09-23T03:45:31Z
      DOI: 10.1016/j.agwat.2017.09.001
      Issue No: Vol. 194 (2017)
  • Sticks and carrots to manage groundwater over-abstraction in La Mancha,
    • Authors: Alvar Closas; François Molle; Nuria Hernández-Mora
      Pages: 113 - 124
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Alvar Closas, François Molle, Nuria Hernández-Mora
      Over recent decades, groundwater-fed irrigation has sustained the social and economic development of La Mancha, Spain. Without much initial regulation and control, groundwater resources and aquifer levels decreased dramatically, threatening agriculture and also highly valuable groundwater-dependant wetland ecosystems. This paper presents as a historical analysis of the different policy tools used to manage and regulate groundwater abstraction in the Western Mancha Aquifer after Spain approved its 1985 Water Law. It analyses the panoply of control and management instruments laid out by the state to counter the resource depletion trend, demonstrating the necessity by regulatory bodies to complement soft incentives (carrots) with the threat of sanctions and groundwater access limitations (sticks). As this case study shows however, each policy modality has its legal and practical loopholes which can be negotiated and exploited by groundwater users to their own advantage. Improvements in groundwater levels starting in 2010 seem to be linked to aquifer recharge following an unprecedented wet cycle rather than the effectiveness of the policy tools.

      PubDate: 2017-09-18T01:34:50Z
      DOI: 10.1016/j.agwat.2017.08.024
      Issue No: Vol. 194 (2017)
  • A modified soil water deficit index (MSWDI) for agricultural drought
           monitoring: Case study of Songnen Plain, China
    • Authors: Huicai Yang; Huixiao Wang; Guobin Fu; Haiming Yan; Panpan Zhao; Meihong Ma
      Pages: 125 - 138
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Huicai Yang, Huixiao Wang, Guobin Fu, Haiming Yan, Panpan Zhao, Meihong Ma
      Available soil water in the root zone is an essential component of the water balance process since it greatly affects the crop water uptake and crop growth. In this study, a modified soil water deficit index (MSWDI) was established on the basis of the concept of readily available water (RAW), with the accumulated effect considered. This modified index was applied in six agro-meteorological stations in Songnen Plain of China to monitor the agricultural drought. The results showed that: 1) The MSWDI showed similar spatial and temporal agricultural drought patterns as its inherent indices, such as the soil water deficit (SWD), soil moisture deficit index (SMDI) and atmospheric water deficit (AWD), but exhibited a delay between atmospheric and soil water processes; 2) The MSWDI has a better correlation with the crop yield than its inherent indices. For example, its overall correlation coefficient is about 0.6 with the crop yields among six study stations and −0.7 for the number of droughts, while their corresponding values are 0.5 and −0.6, 0.5 and −0.6, and 0.3 and −0.4 for SMDI, SWD and AWD, respectively; 3) The MSWDI could also identify a slightly higher number of reported drought events during the 2000–2012 in comparison with SMDI, SWD and AWD, although it also over-predicts the number of drought events same as other indices. It mainly comes from the uncertainty of reported drought events. The proposed index can be used for agricultural drought monitoring and provides a useful tool for agricultural meteorology and water resource management.

      PubDate: 2017-09-18T01:34:50Z
      DOI: 10.1016/j.agwat.2017.07.022
      Issue No: Vol. 194 (2017)
  • Effects of microbial community variation on bio-clogging in drip
           irrigation emitters using reclaimed water
    • Authors: Bo Zhou; Tianzhi Wang; Yunkai Li; Vincent Bralts
      Pages: 139 - 149
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Bo Zhou, Tianzhi Wang, Yunkai Li, Vincent Bralts
      Drip irrigation emitter clogging is one of the key barriers to the development and application of reclaimed water drip irrigation technology. Reclaimed water typically contains large amounts of bacteria, and their excretions, the sticky extracellular polymeric substances (EPS). Indeed, different amounts and types of microorganisms affect drip irrigation emitter clogging, especially bio-clogging process, via excretive EPS. Therefore, it is important to study the dynamic microbial community structure and its effect on the emitter bio-clogging process. In this paper, a drip irrigation experiment using reclaimed water was carried out. Phospholipid fatty acids (PLFAs) in biofilm (bio-clogging substance) were taken as the biomarker of microbial community inside emitters, and the dynamic variation of microbial community in drip irrigation emitter and its effect on the clogging process were studied. The results showed that the microbial growth of biofilms inside 9 types of drip irrigation emitters could enhance emitter clogging, and the PLFAs showed S-shaped pattern with emitter clogging degrees (R2 >0.95, p< 0.01), which was closely associated with the variation of microbial community. There were 3–7 types of PLFAs commonly in biofilms within drip irrigation emitters, among which gram positive bacteria (i15:0, 16:0 and 18:0) were dominant in amounts, with the close contents of 24.4%–34.2%, 24.8%–37.2% and 24.2%–39.0%, respectively, and their total proportion exceeding 76.3%. The Pseudomonas (16:0) was found to be the most critical bacteria to affect emitter clogging as it performed better to decompose and utilize organic matters, and showed the best relation with clogging degrees, along with significant relations with other types of bacteria. Therefore, controlling gram positive bacteria, especially Pseudomonas was the most effective way to relieve emitter clogging. Their variation also changed the microbial community structure, and the diversity index (H), evenness index (J) and dominance index (D) of microbial community in biofilms varied within 1.08–1.53, 0.75–1.11 and 0.65–0.75. The diversity index and dominance index both decreased as the amounts and types of microorganisms increased. The total amount of the gram positive bacteria increased after their decrement, and resulted in the similar variation of the microbial community evenness index. The results of this study will establish a theoretical basis for exploring the effects of microbial community variation on emitter bio-clogging, and provide insight into the emitter clogging mechanisms and possible mitigation strategies.

      PubDate: 2017-09-23T03:45:31Z
      DOI: 10.1016/j.agwat.2017.09.006
      Issue No: Vol. 194 (2017)
  • Socio-economic factors influencing utilisation of rain water harvesting
           and saving technologies in Tharaka South, Eastern Kenya
    • Authors: F.W. Muriu-Ng’ang’a; M. Mucheru-Muna; F. Waswa; F.S Mairura
      Pages: 150 - 159
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): F.W. Muriu-Ng’ang’a, M. Mucheru-Muna, F. Waswa, F.S Mairura
      Low levels of soil moisture makes rain water harvesting and saving technologies important interventions for water supply and food production in arid and semi-arids lands of Kenya. Despite much research around this theme, factors affecting utilisation of these technologies by farmers have not been well understood and the low adoption and adaptation levels of these beneficial technologies remains a challenge. This paper extends this dimension with emphasis on Tharaka South sub-county where water scarcity, unreliable rainfall and soil water stress is a major cause of household food insecurity. Farm and social data were collected using a cross-sectional survey design targeting a total of 351 household heads. Data was analysed using descriptive statistics and logistic regression. The utilization of in situ rainwater harvesting and saving technologies was higher for trashlines (73%) as compared to micro-catchments, Zai pits (26%) and Negarims (13%). Socio-economic characteristics that were positively and significantly associated with Zai pit utilisation included household size (p<0.01), training in Zai pits (p<0.002), while total farm size (p<0.01) and land tenure (p<0.01) showed negative co-efficients. Both formal and informal sources of training were important tools in disseminating rain-water harvesting and saving technologies. The study concluded that farmer age, household size, farm size, farming history, training, and formal education were important factors which influenced utilisation of rain water harvesting and saving technologies in Tharaka sub-county. Specific approaches are needed to scale-up resource-intensive technologies (Fanya juu, Zai pits, and Negarims) compared to less resource-intensive technologies.

      PubDate: 2017-09-23T03:45:31Z
      DOI: 10.1016/j.agwat.2017.09.005
      Issue No: Vol. 194 (2017)
  • Evaluation of the best management practices in a semi-arid region with
           high agricultural activity
    • Authors: Zeynep Özcan; Elçin Kentel; Emre Alp
      Pages: 160 - 171
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Zeynep Özcan, Elçin Kentel, Emre Alp
      The arid and semi-arid regions with water scarcity are vulnerable to several stressors such as urbanization, high water demand created by agricultural and industrial activities, point and non-point pollution sources, and climate change. Hence, proactive policies and sustainable water management strategies that are based on decision support systems are crucial in arid and semi-arid regions. Because of large expenses and implementation difficulties associated with the diffuse pollution abatement plans, many authorities are hesitant to initiate, especially those that may present a financial burden on population. Lake Mogan, a shallow lake, is located in a semi-arid region dominated by dry agricultural activities and has been in eutrophic state for the past 20 years. There has been several management alternatives suggested to improve the water quality in Lake Mogan and one of the alternative is the application of BMPs that include fertilizer management, conservation/no tillage, contouring, and terracing to reduce the amount of diffuse source pollutants. In this study, Soil and Water Assessment Tool (SWAT) Model is applied to evaluate the effectiveness of agricultural best management practices (BMPs) in the Lake Mogan watershed located in a semi-arid region. The most effective BMP scenario was found as the one in which three individual BMP scenarios (30% fertilizer reduction, no tillage, and terracing) were combined. With this scenario average annual load reductions of 9.3%, 8.6%, 8.0%, and 11.1% were achieved in sediment, nitrate, total nitrogen, and total phosphorus, respectively. Even with the most effective BMP strategy, high levels of nutrient reduction will not be achieved since non-irrigated agriculture and intermittent low-flow streams accounts majority of the study area. The outcomes suggest integrated solutions should be developed to improve water quality in Lake Mogan. It is aimed that this study will aid decision makers to implement effective best management practices in watersheds showing similar characteristics (i.e. topographical, hydrologic processes, LULC (Land use land cover) characteristics, agricultural activities, meteorological etc.) with the study area.

      PubDate: 2017-09-23T03:45:31Z
      DOI: 10.1016/j.agwat.2017.09.007
      Issue No: Vol. 194 (2017)
  • Evapotranspiration and crop coefficients of Golden Delicious/M793 apple
           trees in the Koue Bokkeveld
    • Authors: Theresa Volschenk
      Pages: 184 - 191
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Theresa Volschenk
      Irrigation scheduling is key to efficient irrigation water use. The objective of this research was to determine the evapotranspiration (ETc) and crop coefficients (Kc) of Golden Delicious/M793 apple (Malus domestica L.) trees in a semi-arid climate to promote optimal usage of limited water resources in South Africa. The ETc and Kc values for trees irrigated at 50% plant available water depletion throughout the season were determined from 2005/06 to 2007/08. Over three seasons, ETc amounted to c. 870mm between October and April, whereas reference evapotranspiration was c. 1262mm. The ETc during vegetative growth and fruit cell division (Phase 1), fruit cell enlargement until end of shoot extension growth (Phase 2), ripening until harvest (Phase 3) and postharvest (Phase 4) contributed c. 15%, c. 41%, c. 20% and c. 24% to the seasonal water requirements of the trees, respectively. Since the seasonal ETc amounts exceed the current annual water allocation of 800mm per hectare, accurate irrigation scheduling is crucial to ensure efficient irrigation water use. Means to estimate Kc values for the development and late stages are provided. A Kc of 0.79 applies during the mid and late stages until the onset of leaf fall.

      PubDate: 2017-09-23T03:45:31Z
      DOI: 10.1016/j.agwat.2017.09.002
      Issue No: Vol. 194 (2017)
  • Economic and policy drivers of agricultural water desalination in
           California’s central valley
    • Authors: Paul D. Welle; Josué Medellín-Azuara; Joshua H. Viers; Meagan S. Mauter
      Pages: 192 - 203
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): Paul D. Welle, Josué Medellín-Azuara, Joshua H. Viers, Meagan S. Mauter
      Water desalination is a proposed solution for mitigating the effects of drought, soil salinization, and the ecological impacts of agricultural drainage. In this study, we assess the public and private costs and benefits of distributed desalination in the Central Valley (CV) of California. We employ environmental and economic modeling to estimate the value of reducing the salinity of irrigation water; the value of augmenting water supply under present and future climate scenarios; and the human health, environmental, and climate change damages associated with generating power to desalinate water. We find that water desalination is only likely to be profitable in 4% of the CV during periods of severe drought, and that current costs would need to decrease by 70–90% for adoption to occur on the median acre. Fossil-fuel powered desalination technologies also generate air emissions that impose significant public costs in the form of human health and climate change damages, although these damages vary greatly depending on technology. The ecosystem service benefits of reduced agricultural drainage would need to be valued between $800 and $1200 per acre-foot, or nearly the full capital and operational costs of water desalination, for the net benefits of water desalination to be positive from a societal perspective.

      PubDate: 2017-09-30T17:34:51Z
      DOI: 10.1016/j.agwat.2017.07.024
      Issue No: Vol. 194 (2017)
  • Water use and crop performance of two wild rocket genotypes under salinity
    • Authors: M.I. Schiattone; V. Candido; V. Cantore; F.F. Montesano; F. Boari
      Pages: 214 - 221
      Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194
      Author(s): M.I. Schiattone, V. Candido, V. Cantore, F.F. Montesano, F. Boari
      In literature, the parameters of salinity tolerance of the main cultivated species are known, but are missing for many minor species such as wild rocket, whose cultivation in many areas of southern Italy affected by salinity is growing. Therefore, a research has been carried out i) to evaluate the response to salinity in water use, water use efficiency, yield characteristics and morfological features, and ii) identify the salinity tolerance parameters of two genotypes of wild rocket: Diplotaxis tenuifolia (L.) DC and D. muralis (L.) DC. The study was carried out in the spring of 2007 and 2008 in Policoro (MT), southern Italy, under unheated plastic greenhouse conditions. Wild rocket was sown in plastic pots containing 20dm3 of soil. For each genotype, six soil salinity levels were compared, obtained by accurately mixing before sowing the soil with 0.0, 0.5, 1.0, 2.0, 3.5 and 5.5gdm−3 of NaCl+CaCl2 1:1 (on a weight basis). Irrigation was performed with fresh water having electrical conductivity of 0.5dSm−1. In each year, 3 harvests were performed; water use and the main production and plant growth parameters were recorded. D. tenuifolia provided a yield 47.3% higher than D. muralis. By rising salinity, progressive decline in marketable yield and growth of the leaves was recorded, while the dry matter content increased. The increase in salinity has led to the progressive reduction of water use in both genotypes. From moderate salinity values (about 5.5dSm−1), the reduction in yield water use efficiency as a result of increased salinity has been observed. In addition, salinity reduced specific leaf area and increased leaf succulence. Both genotypes rank among moderately salt sensitive species, according to Maas and Hoffman's model (1977). However, D. tenuifolia, with a critical threshold of 1.98dSm−1 and a slope of 6.61%mdS−1, showed a slightly higher tolerance than D. muralis (threshold 1.34dSm−1 and slope 7.25%mdS−1). Reduction in yield due to salinity occurred mainly for the decrease in leaf size and, secondly, number of leaves.

      PubDate: 2017-09-30T17:34:51Z
      DOI: 10.1016/j.agwat.2017.09.009
      Issue No: Vol. 194 (2017)
  • Mission Impossible' Maintaining regional grain production level and
           recovering local groundwater table by cropping system adaptation across
           the North China Plain
    • Authors: Honglin Zhong; Laixiang Sun; Günther Fischer; Zhan Tian; Harrij van Velthuizen; Zhuoran Liang
      Pages: 1 - 12
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Honglin Zhong, Laixiang Sun, Günther Fischer, Zhan Tian, Harrij van Velthuizen, Zhuoran Liang
      Insufficient precipitation and continuous over-exploitation of groundwater for agricultural irrigation led to rapid drop of groundwater table in a large part of the North China Plain (NCP), the bread basket of China. It has become widely acknowledged that current practice of winter wheat-summer maize sequential cropping system (WM-S) in the NCP will have to come to an end as soon as possible. Great research efforts have been made at the local level via both field experiments and model simulations to construct groundwater neutral cropping systems but virtually all such constructs show a substantial penalty on total output per unit of land per year. In this research, we propose a strategy to meet the double challenge of maintaining regional grain production level and recovering local groundwater table: 1) Widely adopt winter fallow and early-sowing summer maize monocropping (E-M) in water scarce part of the region to enable groundwater recovery; 2) replace WM-S by wheat-maize relay intercropping system (WM-R) in the water richer part of the NCP to increase grain production so as to compensate yield losses in the water scarce part of the region. Our simulations using DSSAT 4.6 at the site level show that both yield and water productivity of E-M are 33.7% and 41.8% higher than those of existing summer maize, with less than 20% of increase in water requirement. In comparison with spring maize, E-M requires 62.4% less irrigation water, with a yield penalty of only 4.52%. At the regional scale, the simulations targeting at maximizing groundwater saving in water scarce area subject to maintaining the current level of regional total output indicate that about 20.45% of the wheat planting area can be put on fallow in winter, most of which is located in the driest regions of the NCP. This can result in a large amount of groundwater saving at 5.62×109 m3 and a substitution of wheat by maize at 24.3% of the total wheat output. These findings provide new rooms for the relevant policy makers and stakeholders to address the urgent groundwater recovering issues in the northern NCP without compromising the level of food grain production of the region.

      PubDate: 2017-09-11T03:03:49Z
      DOI: 10.1016/j.agwat.2017.07.014
      Issue No: Vol. 193 (2017)
  • Changes in soil soluble salts and plant growth in a sandy soil irrigated
           with treated water from oil extraction
    • Authors: Adervan Fernandes Sousa; Olmar Baller Weber; Lindbergue Araújo Crisostomo; Maria Eugenia Ortiz Escobar; Teógenes Senna de Oliveira
      Pages: 13 - 21
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Adervan Fernandes Sousa, Olmar Baller Weber, Lindbergue Araújo Crisostomo, Maria Eugenia Ortiz Escobar, Teógenes Senna de Oliveira
      The adverse effects of the use of wastewater can vary, and depend on several factors, possibly causing an accumulation of toxic minerals in the soil, making it necessary to evaluate its effect when used in the irrigation of crops. The aim of this study was to evaluate changes that take place in the soluble salts and organic matter fractions of the soil, and in the growth of plants of the BRS 321 cultivar of the sunflower (Helianthus annuus L.) cultivated in soil of a sandy texture and irrigated with wastewater obtained from oil extraction and treated by filtration and reverse osmosis. Soil samples were collected from the same area after each of the three periods of cultivation, and measurements taken of pH, electrical conductivity (EC), Na, Cl, Mg, Ca, K, HCO3 −, Cl−, metals (Ag, As, B, Ba, Cd, Co, Cr3+, Hg, Ni and Pb) and organic fractions. The plants were evaluated for growth, the accumulation of root and shoot biomass, and achene production. It was found that salt concentrations and EC increased when the soil was irrigated with water treated by filtration, as did the pH, irrespective of the type of water used. Only the C of the fulvic acid fraction in the surface layer was affected by the type of water, resulting in a smaller content in the soil irrigated with FPW. Changes in the carbon content of the humic substances can be attributed in part to mobilisation of the organic fractions in the soil. The increase in salinity and alkalinity of the soil reduced plant growth and the accumulation of plant biomass. Depending on the treatment, the re-use of wastewater from oil wells may be a good option, particularly in regions with severe and extensive drought. Treatment with reverse osmosis improved the quality of the wastewater from oil wells, but for such wastewater to be used, the cumulative effects must be assessed, as alkalisation was seen to have occurred even in a sandy soil.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.07.027
      Issue No: Vol. 193 (2017)
  • Semi-arranged demand as an energy saving measure for pressurized
           irrigation networks
    • Authors: I. Fernández García; R. González Perea; M.A. Moreno; P. Montesinos; E. Camacho Poyato; J.A. Rodríguez Díaz
      Pages: 22 - 29
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): I. Fernández García, R. González Perea, M.A. Moreno, P. Montesinos, E. Camacho Poyato, J.A. Rodríguez Díaz
      In many regions, water resource scarcity has required adapting irrigated agriculture towards more efficient water distribution networks and irrigation systems. These systems, however, have higher energy requirements. To overcome this problem, a new semi-arranged demand model combining network sectoring and critical points have been developed. The model computes a new indicator known as the optimal number of disabled hydrants (ONDHY) to determine the number of critical hydrants in the sector that are only allowed to irrigate at off-peak hours, while the rest of non-critical hydrants can irrigate at any time. The proposed model has been applied to each of the 11 irrigation networks in the Bembezar MD irrigation district located in southern Spain. The results showed potential energy savings of 5.6%–25.8% with 14.5% and 7.8% of critical hydrants that could only operate during off-peak hours, respectively, thus satisfying crop irrigation requirements. The proposed methodology is a useful and easy tool to optimize energy consumption in pressurized irrigation networks.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.07.025
      Issue No: Vol. 193 (2017)
  • Modeling spatial and temporal variability of the impact of climate change
           on rice irrigation water requirements in the middle and lower reaches of
           the Yangtze River, China
    • Authors: Yimin Ding; Weiguang Wang; Ruiming Song; Quanxi Shao; Xiyun Jiao; Wanqiu Xing
      Pages: 89 - 101
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Yimin Ding, Weiguang Wang, Ruiming Song, Quanxi Shao, Xiyun Jiao, Wanqiu Xing
      Accounting for over 70% of global water withdrawals, irrigation plays a crucial role in the development of agriculture. Irrigation water requirement (WIRR) will be influenced by climate change due to the alteration in soil water balances, evapotranspiration, physiology and phenology under global warming. This is particularly true for rice, a high water-consuming crop. Therefore, exploring the impact of climate change on rice WIRR is of great significance for the sustainable utilization of water resources and food security. This paper aims to investigate spatially and temporally the responses of rice WIRR to climate change in the middle and lower reaches of the Yangtze River (MLRYR), which is one of the most important rice farming districts in China. With the help of the specially developed rice growing period calculation method and water balance model coupled with rice irrigation scheduling, the impacts of climate change on WIRR for early rice, late rice and single cropping rice during the historical (1961–2012) and future (2011–2100) periods were evaluated. Meanwhile, to consider the uncertainty from climate models in future projection, four GCMs under RCP2.6, RCP4.5 and RCP8.5 emission scenarios from the 5th Coupled Model Intercomparison Project (CMIP5) were employed as the input of the water balance model. The results indicate the following: (1) The days of growing period (DGP) for all three types of rice display shortened trends in historical and most future periods. However, in the middle region of the MLRYR, the DGP for early rice and late rice would increase by up to10days in 2080s under RCP8.5 scenario. (2) Over the past 50 years, the WIRR significantly decreased by 1.58 and 2.10mmyr−1 for late rice and single cropping rice, respectively. While for early rice, the WIRR only slightly decreased by 0.13mmyr−1. (3) Projected future WIRR would increase for all three types of rice in the whole region under RCP4.5 and RCP8.5 scenarios (up to 100mm), but decrease for single cropping and late rice in the southeast region (up to 40mm). The results can provide beneficial reference and comprehensive information to understand the impact of climate change on the agricultural water balance and improve the regional strategy for water resource utilization and agricultural management in the middle and lower reaches of the Yangtze River.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.08.008
      Issue No: Vol. 193 (2017)
  • Development and application of a dynamic in-river agrochemical fate and
           transport model for simulating behavior of rice herbicide in urbanizing
    • Authors: Kei Kondo; Julien Boulange; Kazuaki Hiramatsu; Phong K. Thai; Tsuyoshi Inoue; Hirozumi Watanabe
      Pages: 102 - 115
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Kei Kondo, Julien Boulange, Kazuaki Hiramatsu, Phong K. Thai, Tsuyoshi Inoue, Hirozumi Watanabe
      This study aimed to develop and validate a Dynamic in-River Agrochemical Fate and Transport (DRAFT) model simulating one-dimensional advective and dispersive pesticide transport processes under unsteady flow regime in a riverine system. The DRAFT model was coupled with two other modeling components, the PCPF-B model and the land use based tank model, which simulated hydrological/pesticide process in paddy fields and hydrological process in other land uses such as city, agricultural field and forest, respectively. The PCPF-B/DRAFT model was fed with the spatial information of the target catchment by incorporating the Geographical Information System (GIS). For the model validation, a full catchment monitoring data of a rice herbicide, mefenacet, along the Kose River, Fukuoka, Japan was utilized. After model calibration, hourly river discharge and daily mefenacet concentration were simulated by the PCPF-B/DRAFT model at individual observed points of the Kose River and model performance was evaluated by graphical assessment and multiple statistical indices (e.g. Nash-Sutcliffe efficiencies were 0.84–0.86 for streamflow and 0.16–0.72 for herbicide, respectively). The predicted mefenacet concentrations were strongly affected by: (1) water managements practiced in rice fields and (2) intensive rainfall events. The former concentrations were characterized by broad peak while for the latter the peak concentration was sharp and narrow. We used the PCPF-B/DRAFT model to further evaluate the applications of 7days of water holding period after herbicide application in paddy fields, which was shown to effectively reduce the total loss of mefenacet from 18.9 to 12.8% of applied mass. Consequently, the broad peak concentrations of mefenacet in the Kose River decreased remarkably while the water management practice was less effective to reduce the sudden and sharp peak concentration resulting from intensive rainfall events.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.08.006
      Issue No: Vol. 193 (2017)
  • Conjunctive use of surface and ground water resources in a
           community-managed irrigation system — The case of the Sidi Okba palm
           grove in the Algerian Sahara
    • Authors: Meriem Farah Hamamouche; Marcel Kuper; Jeanne Riaux; Christian Leduc
      Pages: 116 - 130
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Meriem Farah Hamamouche, Marcel Kuper, Jeanne Riaux, Christian Leduc
      Surface water and groundwater for irrigation are frequently used conjunctively, especially in semiarid and arid regions. Planning conjunctive management involves several difficulties, one of which is adapting irrigation institutions and infrastructure to coordinate the management of multiple water resources. This article focuses on the social and material dimensions of the conjunctive use of multiple water resources in a community-managed irrigation system when integrating new water resources. It explores the way the physical characteristics of these new water resources shape and are shaped by human-made arrangements, in particular irrigation institutions and infrastructure. The study was conducted in the ancient palm grove of Sidi Okba, located close to the city of Biskra in the Algerian Sahara. This palm grove has a long irrigation history based on the exploitation of several water resources: floodwater, intentional dam releases, uncontrolled dam leakages, and groundwater. Despite state interventions based on a mono-resource view of the irrigation system, the irrigation community developed the conjunctive use of multiple resources. Throughout its eventful history, the community adapted the irrigation institutions and infrastructure inherited from the spate irrigation period to incorporate new water resources. It also acquired the ability to negotiate with the state to manage its own system of water allocation and distribution. The social practices inherited from surface water irrigation played a crucial role in the integration of groundwater in the irrigation network. This study concludes that the ability of long-standing irrigation communities to renew their irrigation systems and to adapt to different global changes is decisive in explaining the sustainability of these systems. However, the boundaries of these irrigation systems changed with the incorporation of groundwater pumped from the confined aquifers, which means that the water resources cannot only be managed at the local level, putting at risk the sustainability of such irrigation systems.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.08.005
      Issue No: Vol. 193 (2017)
  • A probabilistic assessment of agricultural water scarcity in a semi-arid
           and snowmelt-dominated river basin under climate change
    • Authors: Hossam Moursi; Daeha Kim; Jagath J. Kaluarachchi
      Pages: 142 - 152
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Hossam Moursi, Daeha Kim, Jagath J. Kaluarachchi
      Water resources planning and management is crucial and challenging in semi-arid regions to minimize water scarcity. Potential impacts due to climate change are a concern to water managers and stakeholders in semi-arid river basins with limited water availability. This study provides a probabilistic assessment of climate change impacts on water scarcity in the Sevier River Basin of Utah, which has a snowmelt-driven water supply and high agricultural water demands, using a decision-scaling framework. The methodology consists of a bottom-up approach that uses climate response functions, together with projections from 31 general circulation models (GCMs), to assess vulnerability to water scarcity for 2000–2099. Water scarcity is defined using an index comparing water availability to crop water demand predicted by the AquaCrop model from the Food and Agriculture Organization. Results showed that off-season precipitation is the most sensitive factor affecting water scarcity in the basin, followed by precipitation and temperature during the growing seasons. The GCM projections of temperature and precipitation suggest an increasing availability of water for agriculture in the basin. Still, a considerable risk probability of agricultural water shortage was found in years 2025 through 2049 with the emission scenario RCP4.5, suggesting the need for adaptation and mitigation strategies. The bottom-up decision scaling approach used here with a wide range of GCMs was practical to explore climate risk to agricultural water scarcity given the simplicity and minimal computational requirement.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.08.010
      Issue No: Vol. 193 (2017)
  • Two-dimensional modeling of nitrogen and water dynamics for various
           N-managed water-saving irrigation strategies using HYDRUS
    • Authors: Fatemeh Karandish; Jiří Šimůnek
      Pages: 174 - 190
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Fatemeh Karandish, Jiří Šimůnek
      Nitrate losses are the dominant cause of the non-point source pollution under agricultural fields. In this study, the HYDRUS-2D model was first calibrated and validated using data collected during a two-year field investigation in a drip-irrigated maize field and then applied to evaluate the influence of 176 different N-managed water-saving irrigation scenarios on water and N dynamics and maize grain yield. Various scenarios were defined by combining 11 irrigation levels (IL=0–100% with a 10% interval), 8N fertilization rates (NR=0–400kgha−1 with a 50kgha−1 interval) and two water-saving irrigation strategies: deficit irrigation (DI) and partial root-zone drying (PRD). Reliable estimates of soil NO3 −-N concentrations (RMSE=0.39–10.9mgl−1 and MBE=−8.9–8.4mgl−1), crop N uptake (RMSE=3.9–8.9kgha−1 and MBE=−5.3–6.25kgha−1), and soil water contents (RMSE=2.3–5.11mm and MBE=1.63–4.93mm) were provided by HYDRUS-2D. Based on the simulated results, the fertigation strategy with NR=200kgha−1 is an optimum strategy. For the higher fertigation rates (NR≥250kgha−1), the NO3 −-N leaching out of the surface layers (0–20cm) increased by 0.1–183% while N uptake was enhanced by only 0.3–15%. On the other hand, reducing NR below this level would have resulted in severe economic losses. A 30% reduction in IL at NR=200kgha−1 shows an enormous potential in lowering N leaching below different soil layers (12–99%) while reducing crop N uptake by only 5.4%. In addition, higher crop yield by 0.2–20.2% can be expected under PRD since crop N uptake is enhanced by more water available in the surface layers. While on the one hand, PRD ensures environmentally safer fertilizer applications, on the other hand, the economic objectives are met more easily under PRD than under DI. Additionally, it could be concluded that the HYDRUS-2D model, instead of labor- and time-consuming and expensive field investigations, could be reliably used for determining the optimal scenarios under both the DI and PRD strategies.

      PubDate: 2017-08-27T16:28:21Z
      DOI: 10.1016/j.agwat.2017.07.023
      Issue No: Vol. 193 (2017)
  • Impact of maintenance operations on the seasonal evolution of ditch
           properties and functions
    • Authors: Jeanne Dollinger; Fabrice Vinatier; Marc Voltz; Cécile Dagès; Jean-Stéphane Bailly
      Pages: 191 - 204
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Jeanne Dollinger, Fabrice Vinatier, Marc Voltz, Cécile Dagès, Jean-Stéphane Bailly
      Ditch networks were traditionally designed to protect fields from soil erosion or control waterlogging. They are still frequently managed by either mowing, chemical weeding, dredging or burning to ensure their optimal hydraulic capacity. Ditches were recently reported also to improve water quality and sustain biodiversity. These ditch functions are related to specific ditch properties. By contrastingly modifying ditch properties, maintenance operations were supposed to regulate these functions. There is, therefore, a need to re-examine the design and maintenance strategies of ditches to optimize the whole range of ecosystem services that they provide. In this study, we address the innovator question of how maintenance operations affect the yearly evolution of ditch properties, and in turn, the panel of functions that ditches support. During one year, we monitored the vegetation, litter, soil properties, and ash cover of five ditches that were being unmanaged, dredged, mowed, burned, and chemically weeded, respectively, with timing and frequency as generally operated by farmers in the study area. We then used indicators to evaluate the effect that the evolution of these properties has on the ditch water conveyance, herbicide retention and biodiversity conservation functions. We found that the evolution of these properties significantly contrasted among the 5 maintenance strategies. All the maintenance operations cleared the vegetation, which improves the hydraulic capacity by up to 3 times. The optimal hydraulic capacity is maintained longer after chemical weeding and dredging, but these operations have negative impacts on the herbicide retention and biodiversity conservation functions. The litter and ash layers generated by mowing and burning, respectively, improve the herbicide retention by up to 45%. Our results confirm that maintenance can be an efficient tool for optimizing ditch functions. The choice of maintenance operation and timing are key to successfully optimizing most of the functions that ditches can support.

      PubDate: 2017-09-06T05:13:40Z
      DOI: 10.1016/j.agwat.2017.08.013
      Issue No: Vol. 193 (2017)
  • Field capacity, a valid upper limit of crop available water'
    • Authors: Quirijn de Jong van Lier
      Pages: 214 - 220
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Quirijn de Jong van Lier
      “Field capacity” (FC) is an agronomic measure with prime application in irrigation management, allowing the determination of irrigation gift without excessive leaching. FC can be determined by performing or simulating an internal drainage experiment until percolation reaches a “negligible” value. Alternatively, a static value of pressure head is often used to estimate FC, commonly −3.3m, −1m or −0.6m. FC is also used in definitions regarding soil water availability to crops and has been adopted in soil water balance models to define the maximum water storage. Nevertheless, crop water uptake may occur at water contents higher than FC. This uptake may represent a significant share of total uptake, and FC would then not be a true upper limit of available water. To investigate if FC can be considered an efficient soil physical quantity to characterize soil water availability we used information of unsaturated hydraulic properties (retention and hydraulic conductivity) of 8 soil profiles in Brazil. Using the hydrological model SWAP we estimated FC based on pressure head and bottom flux criteria and evaluated water uptake by pasture and maize from the soil drier than FC (hence: from the “available water” pool between FC and permanent wilting point) as well as from the water held at tensions between saturation and FC. Results show a considerable (10–50%) fraction of transpired water is taken up from the soil at water contents above FC, making FC a questionable quantity to truly estimate crop available water and casting doubt on the reliability of bucket-type soil water balance models.

      PubDate: 2017-09-06T05:13:40Z
      DOI: 10.1016/j.agwat.2017.08.017
      Issue No: Vol. 193 (2017)
  • Lateral hydraulic performance of subsurface drip irrigation based on
           spatial variability of soil: Simulation
    • Authors: Changjiang Ren; Yong Zhao; Jianhua Wang; Dan Bai; Xinyu Zhao; Jiyang Tian
      Pages: 232 - 239
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Changjiang Ren, Yong Zhao, Jianhua Wang, Dan Bai, Xinyu Zhao, Jiyang Tian
      Soil physical properties (initial water content, bulk density, and mass fractal dimension) have a major influence on subsurface drip capillary water systems. The spatial distribution of lateral hydraulic performance varies along with the spatial variability of soil and is thus highly complex. In this paper, initial soil water content, soil bulk density, and mass fractal dimension generated according to a Gaussian distribution were used as input variables to a nonlinear lateral hydraulic mathematical model of subsurface drip irrigation. The numerical simulation indicated the following. 1) The greater the initial moisture content, soil bulk density and mass fractal dimension, the smaller was the lateral distribution of emitter discharge, and the smaller was the deviation rate of lateral flow. 2) The greater the standard deviation of initial moisture content, soil bulk density, and mass fractal dimension, the higher was the deviation rate of lateral flow, and the more laterally dispersed was the emitter discharge. 3) The greater the initial moisture content, soil bulk density, mass fractal dimension, and inner lateral diameter, the greater was the uniformity of lateral flow; The higher the inlet lateral pressure and emitter spacing, the lower was the uniformity of lateral flow; The uniformity of lateral flow increased with slope in the range −0.0003 to 1 and decreased with the increase of slope in the range 0–0.0005. The improved lateral hydraulic model by taking into account the influence of soil physical properties on subsurface drip capillary water systems, which permits identification of the critical points of the irrigation lateral

      PubDate: 2017-09-06T05:13:40Z
      DOI: 10.1016/j.agwat.2017.08.014
      Issue No: Vol. 193 (2017)
  • Modeling the effect of biodegradable paper and plastic mulch on soil
           moisture dynamics
    • Authors: Mustafa Saglam; Henry Y. Sintim; Andy I. Bary; Carol A. Miles; Shuresh Ghimire; Debra A. Inglis; Markus Flury
      Pages: 240 - 250
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): Mustafa Saglam, Henry Y. Sintim, Andy I. Bary, Carol A. Miles, Shuresh Ghimire, Debra A. Inglis, Markus Flury
      Plastic mulch films are often used in agriculture to conserve soil moisture. Most of the plastic mulch currently used worldwide is made of non-biodegradable polyethylene, which has to be removed and disposed after harvest, incurring significant environmental costs. Biodegradable paper or plastic mulch could offer a valuable alternative to polyethylene. The objective of this study was to compare the effects of biodegradable mulches and standard polyethylene mulch on soil moisture dynamics during a growing season. A field experiment was carried out with pumpkin (Cucurbita pepo), which were irrigated and grown on raised beds covered with the following mulch treatments: no mulch, biodegradable paper, biodegradable plastic, and polyethylene. Soil moisture was measured at 10- and 20-cm depths. A numerical model (HYDRUS-2D) was used to simulate the moisture dynamics under the different mulch treatments, each represented by different boundary conditions at the soil surface. Polyethylene mulch, which created an impermeable surface layer, effectively reduced evaporation and maintained highest water content among the treatments. Biodegradable paper mulch, which was partially permeable to evaporation and rainfall throughout the growing season, resulted in soil moisture that was intermediate between that obtained for no mulch and polyethylene. Biodegradable plastic mulch, which was similar to that of polyethylene mulch initially in terms of effects on soil moisture, disintegrated during the growing season and allowed rainfall to penetrate and water to evaporate from the soil surface. Field data and model simulations both indicate that the biodegradable paper and plastic mulches provide comparable soil moisture dynamics as polyethylene mulch.
      Graphical abstract image

      PubDate: 2017-09-06T05:13:40Z
      DOI: 10.1016/j.agwat.2017.08.011
      Issue No: Vol. 193 (2017)
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: December 2017
      Source:Agricultural Water Management, Volume 194

      PubDate: 2017-10-13T23:03:31Z
  • Spatio-temporal salinity dynamics and yield response of rice in
           water-seeded rice fields
    • Authors: Mathias Marcos; Hussain Sharifi Stephen Grattan Bruce Linquist
      Abstract: Publication date: 1 January 2018
      Source:Agricultural Water Management, Volume 195
      Author(s): Mathias Marcos, Hussain Sharifi, Stephen R. Grattan, Bruce A. Linquist
      The scarcity of high quality irrigation water is a global issue facing rice growers, forcing many to adopt water management systems that may result in increased salinity and yield reductions. While salt concentrations in field water have been shown to vary depending on water management, the distribution and build-up patterns of dissolved salts are unclear. This study was conducted to elucidate the within field spatial and temporal salinity dynamics in water-seeded rice cropping systems, and to assess current salinity thresholds for rice yield reduction. In this two-year study, water and soil salinity concentrations of eleven field sites were monitored weekly, with three sampling points being established in the top, middle and bottom basins of each field. There was a consistent spatio-temporal water salinity pattern among all fields: the maximum water salinity within a field occurred during week 2 to week 7 after planting, and was greatest farther from the irrigation inlet and where soil salinity was high. A model developed to predict water salinity within a field indicates that, averaged over an entire growing season, the position within a field contributed to 82% of the variation explained by the model, while preseason soil salinity contributed to 18%. Importantly, field water salinity was determined to be the most sensitive salinity metric for rice yield, as preseason soil salinity was a poor predictor of yield loss. The threshold field water salinity concentration was estimated at 0.88dSm−1, lower than the previous report of 1.9dSm−1. These results illustrate the ability to predict water salinity in a rice field with few parameters, while highlighting the importance of field water salinity as the main salinity metric for rice cropping systems.

      PubDate: 2017-10-08T15:27:58Z
  • Inside Front Cover - Editorial Board Page
    • Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193

      PubDate: 2017-09-11T03:03:49Z
  • Improving the prediction of soil evaporation for different soil types
           under dryland cropping
    • Authors: Kodur
      Abstract: Publication date: November 2017
      Source:Agricultural Water Management, Volume 193
      Author(s): S. Kodur
      Soil evaporation (ES) is a major fraction of water loss in dryland farming worldwide. Precise estimation of ES is therefore crucial for improved decision-making in agriculture water management. Ritchie’s two-stage ES algorithm is commonly used in crop models to estimate ES. However, use of different ES input values for the same soil type, and lack of understanding on how different soil types affect ES and crop yield in these models can negatively impact the prediction accuracy. To address these issues, a range of input values for stage 1 and stage 2 ES were collated, and their effects on modelled ES and yield were compared for a dryland wheat crop. The results using APSIM farming system model suggest that while in-crop ES increases and yield decreases with the increase of both stage 1 and stage 2 ES input values, the stage 2 values can have a greater effect, especially under lower rainfall conditions across the soil types. Fallow ES and in-crop ES were higher (by 7 and 12mmyr−1 respectively) and yield was lower (by 0.27tha−1 yr−1) under Empirical datasets that used higher stage 2 ES input values than the default datasets. With all the datasets, ES and yield were higher (by 4–51mmyr−1 and 1.51–1.98tha−1 yr−1 respectively) for Black Vertosol than the other soil types. As rainfall and/or ES input values increased, variability in both ES and yield (in turn the modelling error between the datasets) increased, and was higher for Black Vertosol and Red Kandosol soils. These insights will improve the prediction accuracy of ES and dependent factors in the models that apply Ritchie’s algorithm for ES estimation.

      PubDate: 2017-08-27T16:28:21Z
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