“以肥调水”缓解干旱对无膜滴灌棉花生理特性和产量的影响

Mitigating the impact of drought on physiological characteristics and yield of non-film drip-irrigated cotton through fertigation regulation

【目的】研究“以肥调水”缓解干旱对南疆无膜滴灌棉花生理生长的调控作用,提高水资源限制条件下棉花产量。【方法】以中棉619为供试材料,设置亏缺灌溉(W1:45 mm)和充分灌溉(W2:54 mm)2种灌水定额,低氮(F1:150 kg·hm^(-2))、中氮(F2:225 kg·hm^(-2))和高氮(F3:300 kg·hm^(-2))3个施氮量,分析不同灌水定额和施氮量对棉花生理生长指标和籽棉产量的影响。【结果】灌水定额的增加促进了棉花生长,提高了棉花2年平均叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD值)和净光合速率(net photosynthetic rate,Pn),降低了棉花超氧化物歧化酶(superoxide dismutase,SOD)、过氧化氢酶(catalase,CAT)、过氧化物酶(peroxidase,POD)活性和丙二醛(malondialdehyde,MDA)含量。随着施氮量的增加,棉花2年平均LAI、SPAD值、抗氧化酶活性和Pn随之增加,MDA含量减少,棉花受水分亏缺的影响减轻。W1处理下施氮量的增加提高了棉花产量,W2处理下随着施氮量的增加棉花产量呈先增后减趋势,在水氮交互作用下,W2F2处理下2年平均产量最高(6821.86 kg·hm^(-2)),其次是W1F3处理(6717.72 kg·hm^(-2))。在优劣解距离法(technique for order preference by similarity to ideal solution,TOPSIS)分析中,W1F3和W2F2处理的综合评分较为接近,分别为0.57和0.56,并且W1F3和W2F2处理下籽棉产量差异不显著。【结论】亏缺灌溉下增加施氮量可有效缓解干旱对棉花生理性状和籽棉产量的不利影响。推荐南疆无膜滴灌棉田45 mm灌水定额(生育期灌水10次)搭配300 kg·hm^(-2)施氮量作为灌溉和施肥策略,以保障在水资源限制条件下的棉花产量。

[Objective]This study aims to investigate the regulatory effect of"fertigation adjusted water management"on the physiology and the growth of drip-irrigated cotton in alleviating drought stress,and to enhance cotton yield under limited water resource.[Methods]Using Zhongmian 619 as the test material,two types of irrigation quotas for deficient irrigation(W1:45 mm)and full irrigation(W2:54 mm)in combination of three nitrogen input doses,including low nitrogen(F1:150 kg·hm^(-2)),medium nitrogen(F2:225 kg·hm^(-2)),and high nitrogen(F3:300 kg·hm^(-2))were set.The effects of different irrigation quotas and nitrogen doses on cotton physiological growth indicators and seed cotton yield were analyzed.[Results]The results indicated that increased irrigation quotas promoted cotton growth,enhanced two-year average leaf area index(LAI),relative chlorophyll content(soil and plant analyzer development,SPAD value),and net photosynthetic rate(Pn),while redued the activities of cotton superoxide dismutase(SOD),catalase(CAT),peroxidase(POD),and malondialdehyde(MDA)content.With the increase of nitrogen application,LAI,SPAD,Pn,and antioxidant enzyme activity were increased,MDA content was decreased on average,and the influence of water deficiency on cotton development was alleviated.Under W1 treatment,increased nitrogen application improved cotton yield,while under W2 treatment,cotton yield showed the trend of increasing first and then decreasing with the increase of nitrogen application.Under water-nitrogen interaction,the highest two-year average seed cotton yield(6821.86 kg·hm^(-2))was recorded under W2F2 treatment followed by W1F3 treatment(6717.72 kg·hm^(-2)).In the technique for order preference by similarity to ideal solution(TOPSIS)analysis,the comprehensive scores of W1F3 and W2F2 were 0.57 and 0.56,respectively,and the differences between the two-year yield of W1F3 and W2F2 treatments were not significant.[Conclusion]Increased nitrogen application under deficit irrigation effectively alleviates the adverse effects of drought on the physiological characteristics and yield in cotton.It is recommended to use 45 mm irrigation quota combined with 300 kg·hm^(-2) nitrogen application as the fertigation strategy for the filmless drip-irrigated cotton in southern Xinjiang,to effectively ensure cotton yield under limited water resource.