麦后移栽棉适宜调亏灌溉模式研究

Regulated Deficit Irrigation for Transplanted Cotton after Winter Wheat Harvest

【目的】探讨麦后移栽棉适宜的调亏灌溉模式。【方法】在麦后移栽棉蕾期、花铃期分别设计不同亏水灌溉处理,研究了不同调亏灌溉处理对麦后移栽棉生长发育、产量、品质和灌溉水利用效率的影响。【结果】蕾期和花铃期的水分亏缺均会抑制棉花株高、茎粗等营养生长,其中蕾期水分亏缺影响程度相对较大;无论是蕾期还是花铃期,轻度亏水灌溉对棉花生长发育无明显影响;叶片相对含水率随缺水程度的增加呈下降趋势,蕾期或花铃期轻度亏缺灌溉均有利于地上干物质积累;与全生育期充分灌溉(CK2)处理相比,蕾期轻度调亏灌溉节省灌溉用水5.45%,增产9.16%,灌溉水利用效率提高15.05%;花铃期轻度调亏灌溉节省灌溉用水9.09%,增产2.34%,灌溉水利用效率提高12.90%;调亏灌溉对麦后移栽棉马克隆值和伸长效率影响不明显,但蕾期或花铃期轻度调亏灌溉都有提高棉纤维长度、整齐度和断裂比强度的趋势。【结论】在水资源供应较为充足时,蕾期轻度调亏灌溉、花铃期充分灌溉可获得最高的籽棉产量和较高的灌溉水利用效率;而在水资源不足的条件下,蕾期充分灌溉、花铃期轻度调亏灌溉是较为适宜的省水、高产、高效灌溉模式。

【Background】The Yellow River basin is one of the most important grain and cotton production bases in China,with wheat-cotton rotation as one of the dominant cultivation methods in which inter-wheat rows are reserved for cotton drilling.Such cultivation,however,reduces wheat yield and damages the cotton seedlings when harvesting the wheat.As an improved agronomic practice,transplanting the cotton after wheat harvest rather than directly drilling it has become increasingly popular due to its convenience for machine harvesting without compromising cotton yield.The transplantation reduces the growth duration of the cotton in the field and makes it more sensitive to soil moisture.Regulating water deficit is hence particularly important for transplanted cotton.【Objective】This paper is to experimentally seek suitable regulated deficit irrigation for transplanted cottons in Yellow river basin.【Method】The experiment was conducted in a field with different water deficits imposed at bud stage,or blossoming and boll-forming stage,respectively.In each treatment,we measured the growth,yield and quality,and water utilization efficiency of the cotton.【Result】Moderate or severe water deficit,especially that occurring at the bud stage,inhibited growth of the height and stem diameter of the cotton,while a slight water deficit occurring at either stage did not show significant effects on cotton growth and development.Relative water content in cotton leaves decreased with degree of the water deficit,and a slight water deficiency at the bud or boll stage enhanced accumulation of above-ground dry matter.Compared with control without water deficit,a moderate water deficit at the bud or blooming stage saved irrigation water by 5.45%and 9.09%respectively,increased cotton production by 9.16%and 2.34%respectively,and improved irrigation water use efficiency by 15.05%and 12.90%respectively.Regulated deficit irrigation did not show a noticeable impact on macron value and elongation of the cotton.A moderate water deficit at the bud or boll stage,or a slight water deficit at the bud or blossoming and boll-forming stage,improved length,uniformity and fracture specific strength of the cotton fiber.【Conclusion】When water supply is seriously scarce,imposing a slight water deficit at the bud stage gives the highest cotton-seed yield and irrigation water use efficiency.In contrast,when available water for irrigation is limited,sufficient irrigation at the bud stage coupled with a moderate water deficit at the flowering and boll stage is most effective for saving water while in the meantime improving water utilization efficiency and maintaining high cotton yield.