水氮盐调控对膜下滴灌棉花产量的影响及耦合模型

Effects of water,nitrogen and salt regulation on cotton yield under mulch film drip irrigation and its coupled model

为探讨水、盐、氮三因素对棉花生长的耦合效应及最优水肥制度,分别设置了4种灌溉定额(1575,2100,2625,3150 m^(3)/hm^(2))、4种施氮量(0,150,300,450 kg/hm^(2))和4种土壤盐分(非盐化土、轻度、中度和重度盐化土),通过盆栽试验,研究了水、氮、盐对膜下滴灌棉花产量的影响.结果表明:灌溉定额、施氮量和土壤盐分与棉花产量之间符合回归模型,模型对水氮盐的耦合效果较好;单因素对棉花产量影响按因素排序由大到小为灌水量,土壤含盐量,施氮量;耦合作用的影响按因素排序由大到小为盐氮,水氮,水盐;水氮施加量对棉花产量的影响均存在阈值,低于此阈值,棉花增产效果较为明显;中、重度土壤盐分含量明显抑制棉花生长;通过回归模型进行耦合分析,最适合研究区的水肥盐耦合方式为轻盐土壤、灌溉定额2677 m^(3)/hm^(2)和施氮量202 kg/hm^(2).本研究可为盐碱区棉田水肥高效利用提供科学依据.

In order to explore the comprehensive effects of water,salt and nitrogen on cotton growth,the optimal water and fertilizer system,four irrigation quotas(1575,2100,2625,3150 m^(3)/hm^(2)),four nitrogen application rate(0,150,300,450 kg/hm^(2))and four soil salinity(non-salinized soil,slightly saline soil,moderate salt chemical soil and heavily saline soil)were set respectively.The effects of water,nitrogen and salt on cotton yield under film drip irrigation were studied through pot experiment.The results show that the relationship between irrigation quota,nitrogen application rate,soil salt and cotton yield is in line with the regression model,and the model has a good coupling effect on the effects of water,nitrogen and salt on cotton.The effect of single factor on cotton yield is ranked as irrigation amount>soil salt content>nitrogen application amount.The influence order of two factors is the coupling effect of salt and nitrogen>the coupling effect of water and nitrogen>the coupling effect of water and salt.There is a threshold value for the effects of water and nitrogen application on cotton yield,below which the cotton yield increase effect is obvious.The cotton growth is inhibited obviously under medium and severe soil salt content.The most suitable system of water,fertilizer and salt in the study area is determined by the regression model,which is light salt soil,irrigation quota 2677 m^(3)/hm^(2) and nitrogen application rate 202 kg/hm^(2).This study can provide a scientific basis for the efficient utilization of water and fertilizer in drip irrigation cotton field under film in saline-alkali area.