干旱区主要经济作物滴灌条件下作物系数和水分生产率试验研究

Experimental Research on Crop Coefficients and Water Productivity under Drip Irrigation for Major Cash Crops in Arid Regions

为摸清新疆主要经济作物滴灌条件下作物系数、水分生产率及生长指标的变化规律,进行了3年小区试验,以棉花、油菜、工业番茄、甜菜、胡萝卜、打瓜、葵花7种经济作物为试验对象,设置灌水定额单因素4水平:T1(300m 3/hm 2)、T2(375m 3/hm 2)、T3(450m 3/hm 2)、T4(525m 3/hm 2),采用随机分组的灌溉试验方案,利用测坑传感器实测各处理各年份作物需水量,通过气象数据计算作物参考蒸发蒸腾量,通过考种测产分析产量和灌水量关系,记录分析各作物年际间生长指标的变化规律。结果表明:7种滴灌作物系数总体趋势为前期由小到大,作物生长旺盛期最大,后期逐渐减小。各作物系数在不同生长阶段变化趋势及分布特征相似。灌溉水分生产率由小到大顺序为:油菜、打瓜、葵花、棉花、甜菜、胡萝卜、工业番茄。从建立的水分生产函数看,拟合度好,T3处理的产量较其他3个处理高,同一作物,随着灌水定额试验处理水平增加,产量和灌溉水量同步增加,而水分生产率则同步递减,高水分处理试验结果表现为灌溉水量增加而产量却相应减少。可见,作物水分生产率并非愈大愈好,灌水量并非越多越好,只有适宜取值,才能提高水分利用效率。

In order to understand the change law of crop coefficients,water productivity and growth indicators of main cash crops under drip irrigation conditions in Xinjiang,a three-year plot experiment was conducted.The study focused on seven cash crops:cotton,rapeseed,industrial tomato,sugar beet,carrot,cucumber,and sunflower.Four levels of irrigation quotas were set:T1(300m 3/ha),T2(375m 3/ha),T3(450m 3/ha),and T4(525m 3/ha).A randomized irrigation experiment plan was used,employing pit sensors to measure the water demand for each treatment in different years.Crop reference evapotranspiration was calculated using meteorological data,and the relationship between yield and irrigation volume was analyzed through crop yield measurements.The changes in growth indicators of each crop over the years were recorded and analyzed.The results showed that the overall trend of drip irrigation crop coefficients was from small to large in the early stages,reaching a maximum during the peak growth period,and then gradually decreasing.The trend and distribution characteristics of crop coefficients at different growth stages were similar across crops.The order of irrigation water productivity from low to high was:rapeseed,cucumber,sunflower,cotton,sugar beet,carrot,industrial tomato.According to the established water productivity functions,which showed a good fit,the yield under T3 treatment was higher than the other three treatments.For the same crop,as the irrigation quota increased,both yield and irrigation volume increased,but water productivity decreased correspondingly.The results of the high-water treatments showed that an increase in irrigation volume led to a decrease in yield.Therefore,water productivity does not always improve with higher values,and more irrigation is not always better.Appropriate values are crucial to improve water use efficiency.