陕北黄土丘陵区主要作物需水与降水耦合分析

Analysis of Coupling Degree between Water Demand of Main Crops and Rainfall in Loess Hilly Region of Northern Shaanxi

为探讨陕北黄土丘陵区旱作玉米、谷子和马铃薯在各生育期需水与降水耦合程度,基于绥德县2000-2014年逐日气象资料,分析了3种作物在生育期(5-9月)的需水特征、气候干旱状况和作物需水与降水耦合情况。结果表明:玉米、谷子和马铃薯在全生育期需水量大于同期降水量,谷子全生育期需水量分别显著低于玉米和马铃薯168.75和142.44 mm(p<0.05),3种作物需水量在6月份最大,分别占各自全生育期需水量的30.12%、40.13%和27.46%,干旱在6月份发生频率最大,可达28.57%;3种作物需水与降水的耦合度和月份呈现良好的3次多项式关系(R^2>0.80),在6月份最小(0.14~0.16),谷子需水与降水的耦合度在7、8和9月份显著高于玉米和马铃薯(p<0.05);干旱现象在未来5和9月会持续,在6-8月会出现减弱趋势,3种作物需水与降水耦合度趋势在未来5-6月保持不变,在未来7-8月增加。建议加大高附加值的绿色有机谷子种植面积,缩减玉米和马铃薯种植面积,并在作物生育期采用集雨补灌和沟垄覆盖种植相结合的技术,以充分利用降水资源。

In order to explore the coupling degree of water demand and precipitation of drought-grown maize,millet and potato in loess hilly area of northern Shaanxi province,the characteristics of water demand,climate drought and coupling of water demand and precipitation of three crops during the growth period(May to September)were analyzed based on the daily meteorological data of Suide county from 2000 to 2014.The results showed that:the water demand of maize,millet and potato in the whole growth period was higher than rainfall in the same period,and the water demand of millet in the whole growth period was significantly lower than that of maize and potato by 168.75 and 142.44 mm,respectively(p<0.05);the water demand of the three crops was the largest in June,accounting for 30.12%,40.13%and 27.46%of the water demand of the whole growth period,respectively;drought occurred most frequently in June,reaching 28.57%;the coupling degree of water demand and rainfall of three crops showed a good three-order polynomial relationship with time(R^2>0.80),which were the smallest in June(0.14~0.16);the coupling degree between water demand of millet and rainfall was significantly higher than that of maize and potato in July,August and September(p<0.05);drought will continue in May and September,and will weaken from June to August.The coupling degree of water demand and precipitation of three crops will continue to keep the same trend in May and June,but will increase from July to August.It is suggested to increase the planting area of green organic millet with high added value,reduce the planting area of corn and potato,and adopt the combination technology of rain-collecting irrigation and furrow mulching to make full use of precipitation resources.