基于PI模型的阿拉善绿洲节水型种植结构优化

针对阿拉善沙漠绿洲区干旱缺水、农业种植结构单一和土壤质地复杂多变问题,于2013年和2014年进行了滴灌条件下不同灌溉定额和土壤质地的玉米、谷子和油葵种植试验,并依据土壤生产力指数PI对种植结构进行了优化。研究结果表明:均质沙壤土区玉米、谷子和油葵的生产力指数依次为为0.833、0.828 1、0.825 1,非均质土区玉米、谷子、油葵的生产力指数依次为0.729 3、0.767 9、0.809 1;种植结构优化后低灌溉定额水平条件下粮食总产量提高2.8%,总净效益提高7.7元/hm2,高灌溉定额水平条件下粮食总产量可提高0.93%,总净效益提高249.84元/hm2。可见由于土壤质地的差异导致土壤理化性质和水力特性不同,进而影响作物的产量,通过优化种植结构,可以明显提高粮食总产量和总净效益。

A Study on Alxa Oasis Water-saving Planting Structure Optimization Based on PI Model

Aiming at the problems of drought and water shortage, sole agricultural planting structure, complex and varied soil texture, a planting experiment of corn, millet and oil sunflower under the condition of different irrigation quota and soil texture with drip irrigation was conducted at 2013 and 2014, and the planting structure was optimized based on PI.The result showed that: Productivity index (PI) of corn, millet and oil sunflower was 0.833, 0.828 1 and 0.825 1, respectively, in sandy loan area, while 0.729 3, 0.767 9 and 0.809 1, respectively, in non-homogeneous soil area;through optimizing the planting structure, the grain total output increased by 2.8 percents and 0.93, and the total net benefits increased by RMB7.7 per ha and RMB249.84per ha, respectively, under low level irrigation quota and high level irrigation quota.It can be concluded that soil texture difference leads to the difference of physical and chemical properties of soil and hydraulic characteristics, and then affects crop yield.Optimizing planting structure can obviously improve the total output and total net benefits of grain.