基于AquaCrop模型的玉米需水和降水匹配度变化特征研究

Research on the Matching Degree of Maize Water Demand and Precipitation Based on AquaCrop Model

雨热同期为我国大部分地区农业生产提供了充足的水热资源,但从需水机理的角度评估作物生长和降水过程匹配度的变化特征还有待深入。基于AquaCrop模型模拟了关中地区1978-2017年夏玉米生育期内需水量、灌溉需水量、有效降水量和产量的变化特征,并在充分考虑玉米不同生育阶段对水分需求程度差异的基础上,分析了作物需水与降水匹配度的变化特征。结果表明:关中地区玉米生育期内累积降雨量变化幅度相对较小,但降水过程明显后移,且更多的以暴雨的形式发生;玉米生育期内需水量和灌溉需水量均呈现明显的增加趋势,增加幅度分别为4.10 mm/10a和13.38 mm/10a,而有效降水量则以-10.28 mm/10a的速率减小;玉米生育期内需水与降水的平均匹配度为58%,且整体以-2.7%/10a的速率下降。上述结果表明关中地区降水模式越来越难以满足夏玉米的水分需求,延迟播种可作为提高作物需水与降水匹配度的应对措施之一。

Rain and heat synchronization provides sufficient water and heat resources for agricultural production in most areas of China,but it is still to be further studied to evaluate the change characteristics of crop growth and precipitation process matching degree from the perspective of water demand mechanism.Based on AquaCrop model,this study simulated the changes of crop water demand,irrigation water requirement,effective precipitation and yield of summer maize during 1978-2017 in Guanzhong Area,and analyzed the changes of crop water demand and precipitation matching degree on the basis of fully considering the difference in water demand at different growth stages of maize.The results showed that the changes of cumulative precipitation during maize growth period in Guanzhong Area was relatively small,but the precipitation process shifted significantly backward,and most of them occurred in the form of heavy rainfall;During the growth period of maize,both water requirement and irrigation water requirement showed significant increase trends,which increased by 4.1 mm/10a and 13.38 mm/10a,respectively.While the effective rainfall decreased at a rate of-10.28 mm/10a;the average matching degree of water demand and precipitation during maize growth period was 58%,and the overall rate decreased at-2.7%/10a;The above results show that the change of precipitation pattern in Guanzhong Area is becoming more and more difficult to meet the water demand process of summer maize,and delaying sowing can be used as one of the countermeasures to improve the matching between crop water demand and precipitation.