水氮互作对南疆膜下滴灌棉花生长及水氮利用效率的影响

Effects of Water-nitrogen Interactions on the Growth and Water and Nitrogen Use Efficiency of Drip-irrigated Cotton under Membrane in Southern Xinjiang

水肥是影响作物生产力水平的重要物质基础,探索水氮互作对南疆膜下滴灌棉花生长、籽棉产量以及水氮利用效率的影响。试验设计4个施氮水平(底肥+追肥:0+0、84+225 kg/hm~2、84+300 kg/hm~2、84+375 kg/hm~2),分别记为N1、N2、N3、N4;每个施氮水平设计3个依据潜在作物需水量与降雨量差值(W=ETc-P)确定的不同灌水水平(0.8 W、1.0 W、1.2 W,分别记为W1、W2、W3)。结果显示,土壤中硝态氮主要分布于0~40 cm土层,随灌水量的增大而降低,随施氮量的增大而增大。株高、茎粗、干物质重则随着灌水量的增加而增加,随着氮肥用量的增加,表现为先增大后减小的趋势。株高、茎粗、地上干物质量的最大值均出现在W3N3处理,分别为85.97 cm、11.86 mm、94.37 g。籽棉产量随灌水量的增加而增加,与W1处理相比,W2和W3的平均籽棉产量分别提高了15.54%和1.33%。二元二次回归分析得出,当施氮量为342.67~410.0 kg/hm~2,灌水量为381.7~445.9 mm(0.92~1.07 W)。可以使南疆膜下滴灌棉花的产量、水分利用效率、氮肥农学利用效率的综合效益最大化。研究成果可为南疆膜下滴灌棉花的水氮优化管理提供理论依据和技术支撑。

Water and fertilizer is an important material basis affecting crop productivity.To explore the effects of water and nitrogen interaction on cotton growth,seed cotton yield and water and nitrogen use efficiency under film drip irrigation in southern Xinjiang.Four nitrogen application levels (base fertilizer+topdressing:0+0,84+225 kg/hm~2,84+300 kg/hm~2,84+375 kg/hm~2) were designed and recorded as N1,N2,N3,N4,respectively.For each nitrogen application level,three different irrigation levels (0.8 W,1.0 W and 1.2 W,denoted as W1,W2 and W3,respectively) were designed according to the difference between potential crop water demand and rainfall (W=ETc-P).The results showed that the nitrate nitrogen in soil mainly distributed in 0-40 cm soil layer,decreased with the increase of irrigation amount,and increased with the increase of nitrogen application amount.Plant height,stem diameter and dry matter weight increased with the increase of irrigation amount,and increased first and then decreased with the increase of nitrogen fertilizer dosage.The maximum values of plant height,stem diameter and above-ground dry matter mass were 85.97 cm,11.86mm and 94.37 g respectively in W3N3 treatment.Compared with W1 treatment,the average seed cotton yield of W2 and W3 increased by 15.54%and 1.33%,respectively.The results of binary quadratic regression analysis showed that when the nitrogen application rate was 342.67~410.0 kg/hm~2,the irrigation amount was 381.7~445.9 mm (0.92~1.07 W).It can maximize the comprehensive benefit of yield,water use efficiency and nitrogen fertilizer use efficiency of cotton under film drip irrigation in southern Xinjiang.The research results can provide theoretical basis and technical support for optimal water and nitrogen management of cotton under film drip irrigation in southern Xinjiang.