علوم و مهندسی آبیاری (Apr 2018)
Calibration and assessment of AquaCrop Model for Managing the quantity and time of applying wheat deficit irrigation
Abstract
When water resources are limited, the type of plant, growth stage and soil type should be considered for optimal water consumption. Also, it is necessary to calculate the reliable values of soil moisture content, moisture stress and yield function in order to apply deficit irrigation. Management of water consumption in agricultural sector, regardless of water, soil and plant relationships, requires time and cost. Therefore, models of water, soil and plant relationships have been developed due to the limitations of these experiments regarding farm conditions, the short duration of the experiment and the limited number of scenarios examined in the experiment. Optimal irrigation planning is one of the main factors in promoting water productivity and yield. Models such as the AquaCrop which simulate the effects of water levels on yield are useful tools for on-farm water use optimization. Alizadeh et al. (2010), with irrigation on wheat in Karaj on five treatments with 100, 80, 60, 40 and 20% water requirement as well as a single-irrigation treatment and evaluation of the Aquacrop model for these treatments, concluded that the model was efficient for predicting the amount of seed yield, plant evapotranspiration and water use for 7-day irrigation intervals. The model was, however, less efficient for 14-day irrigation intervals. Babazadeh and Saraei Tabrizi (2012) in their research on soybean plant in Karaj showed that this model had a good performance in simulating product yield, evapotranspiration and water productivity, and that it could simulate the amount of evapotranspiration with an error of less than 4%. Although some studies have been conducted to evaluate the performance of the model in simulating the effects of irrigation on different products since the development of Version 4 of the Aquacrop model, there have been no comprehensive studies on how the model reacts to water stress in different growth stages. Therefore, the main objective of this study was to calibrate and evaluate the Aquacrop model in simulating the response of wheat under deficit irrigation conditions in different periods of plant growth in Shahrekord climate by comparing the results of field experiments to verify its accuracy in predicting different parameters such as grain yield and total dry matter in wheat.
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