基于熵权TOPSIS模型评价不同施氮水平下水稻灌排模式

Entropy weight TOPSIS model-based evaluation of rice irrigation and drainage modes at different nitrogen application levels

为了选取实现高效、节水、控污3个目标的水稻灌排模式,以农田水位为调控指标,在3个施氮水平下设置了不同的灌排模式,研究水稻在不同模式下的产量及其构成因素,利用基于熵权法的TOPSIS模型对这些灌排模式进行评价.结果表明:分蘖期旱涝交替胁迫对水稻的产量、控污指标的抑制作用最明显;乳熟期旱涝交替胁迫的处理对节水指标的负面影响最大.在旱涝交替胁迫下氮肥施用量低时,对水稻发育有较明显的抑制作用;高氮肥施用量处理的水稻产量并没有显著增长,高氮肥处理氮素的淋溶量比低氮肥处理高.利用TOPSIS模型得到施氮量300 kg/hm^2下的控制灌排模式的相对贴合度为0.694 5.分蘖期旱涝交替不仅对于水稻的生长发育的不利影响最大,其控污效果也最差.通过模型计算,最优的灌排方案是施氮水平为300 kg/hm^2的控制灌排模式.

Different rice irrigation and drainage modes were set up at three nitrogen application levels by taking farmland water level as control index.The yield and yield components of rice under these modes were studied.TOPSIS model based on entropy weight method was used to evaluate these irrigation and drainage modes to screen a rice irrigation and drainage mode that can achieve three goals such as high efficiency,water saving and pollution control.The results show the alternate stress of drought and waterlogging at tillering stage has the most obviously inhibitory effect on the yield and pollution control index of rice but affects a little on water saving index.Under the alternate stress of drought and waterlogging,a low nitrogen fertilizer application level has an obviously inhibitory effect on rice growth and development.There is no significant increase in rice yield at a high nitrogen fertilizer application level.The leaching capacity of nitrogen at a high nitrogen fertilizer application level is larger than that at a low nitrogen fertilizer application level.The good-fitness of the controlled irrigation and drainage mode at a 300 kg/hm^2 nitrogen fertilizer application is level 0.6945 based on TOPSIS model.The alternation stress of drought and flood at tillering stage has the greatest adverse effect on rice growth and development,and has the worst effect on pollution control and emission reduction.Through model eva-luation the optimal irrigation and drainage scheme is the controlled irrigation and drainage mode with the nitrogen application level of 300 kg/hm^2.