淋洗定额与覆盖方式对北疆棉花生长和产量的影响

Combined Effect of Drip Irrigation Amount and Straw Mulch on Growth and Yield of Cotton in Salinized Soils in Northern Xinjiang

【目的】探讨生育期灌溉淋洗定额与膜间秸秆覆盖对棉花生长和产量的影响。【方法】通过田间试验,设置4个灌溉水平:W0=80%ET_(c)、W1=120 mm+80%ET_(c)、W2=240 mm+80%ET_(c)和W3=360 mm+80%ETc(120、240 mm和360 mm为生育期灌溉淋洗定额,80%ETc为棉花蒸散量)和2种覆盖方式:膜间裸地(N)和膜间秸秆覆盖(S),共8个处理。探究生育期不同灌溉淋洗定额和膜间覆盖方式对棉花株高、叶面积指数、地上干物质积累量、棉花产量和灌溉水利用效率的影响。【结果】同一覆盖方式下,W0处理棉花生长指标和产量显著低于其他处理;提高灌溉淋洗定额对棉花生长指标和产量有显著促进作用,淋洗定额从0提高到240 mm,棉花株高、叶面积指数、干物质量和产量分别提高了53.75%、116.91%、110.45%和80.14%,当淋洗定额由240 mm提高至360 mm时,棉花生长指标和产量并没有显著提高,且灌溉水利用效率显著降低。淋洗定额为240mm时,棉花产量和灌溉水利用效率分别达到了5 972.46 kg/hm^(2)和0.92 kg/m^(3)。【结论】综合考虑节水和棉花高效用水,北疆棉花生育期灌溉定额为240 mm+80%ET_(c)是最适宜当地发展的高效节水控盐策略。

【Objective】Irrigation management and agronomic practice are critical to crop production in salinized soils.The objective of this paper is to investigate the efficacy of regulating drip irrigation amount combined with straw mulching in improving growth and the ultimate yield of cotton grown in salinized soils.【Method】The field experiments consisted of four irrigation treatments with their irrigation amounts calculated as 80% of the potential evapotranspiration(ET_(c)) that meets the physiological demand of the crop for water,added by additional water to leach the root-zone salt:80% of ET_(c)(W0),120 mm+80% of ET_(c)(W1),240 mm+80% of ET_(c)(W2),and 360 mm+80%of ET_(c)(W3).In all treatments,the intra-rows were mulched by plastic films,and the inter-rows were either mulched by straw(S) or nothing(N).In each treatment,we measured plant height,leaf area index,dry matter accumulation,irrigation water use efficiency at different growth stages,as well as the cotton yield.【Result】The growth index and yield of W0 were significantly lower than those in other treatments with or without straw mulching.Increasing the leaching irrigation amount to 240 mm increased the plant height,leaf area index,dry matter quality and cotton yield by 53.75%,116.91%,110.45% and 80.14%,respectively,compared with those without leaching-aimed irrigation water.After the leaching irrigation amount increased from 240 to 360 mm,no significant changes were found in the growth index and yield,and it hence reduced the irrigation water use efficiency.Keeping the leaching irrigation amount at 240 mm was optimal for both yield and irrigation water use efficiency,reaching 5 972.46 kg/hm^(2)and 0.92kg/m^(3),respectively.【Conclusion】The field experimental results showed that irrigating 240 mm+80% of ET_(c) combined with the intra-rows mulched by plastic films and the inter-row mulched by straw is optimal to leach the salt out of root zone while in the meantime improving irrigation water use efficiency and cotton yield in the salinized soils in northern Xinjiang.