南疆机采棉田灌溉制度对土壤水盐变化和棉花产量的影响

土壤盐渍化在南疆干旱区的持续加重威胁到棉花生产,如何通过制定精准的膜下滴灌灌溉策略控制盐分累积是目前研究的一个关键科学问题.本研究从改善土壤状况、保证棉花产量出发,在南疆主要棉花产区设置生育期不同灌水定额试验,研究灌溉定额对土壤水盐运移和棉花产量、品质的影响.结果表明: 灌溉定额的增加有助于棉花光合产物的积累,但对生殖器官分配比例无显著影响;土壤脱盐程度与灌溉定额呈正相关关系,当棉花生育期灌溉定额高于2577.83 m³·hm^-2时,土壤盐渍化程度不会加深;灌溉定额显著影响灌溉水利用效率(WUE_I),但纤维品质没有显著差异,且棉花产量随灌溉定额增加呈现先增加后减少的趋势.研究认为生育期灌溉定额4200 m³·hm^-2(蕾期灌水间隔7 d,花铃期灌水间隔5 d)是南疆干旱区较为适宜的灌溉制度.

Effects of irrigation regimes on the variation of soil water and salt and yield of mechanically harvested cotton in Southern Xinjiang,China

The expansion of soil salinization area is a threat to cotton production in Southern Xinjiang. How to control soil salt accumulation by developing precise irrigation strategy is currently a hot topic for the film mulching drip-irrigated cotton field. With aims for soil quality improvement and high yield, we investigated the effects of irrigation regimes on soil water and salt distribution, yield and fiber quality in major cotton production area of Southern Xinjiang. Results showed that the increase of irrigation amount contributed to a higher cotton photosynthetic product accumulation, but had no significant effect on the ratio of reproductive organs to total biomass. The degree of soil desa-lination had a positive correlation with the irrigation quotas. When the seasonal total irrigation amount exceeded 2577.83 m³·hm^-2, soil salinization would not deteriorate. Irrigation amount had significant effect on WUE_I, but had no effect on fiber quality. With the increasing of irrigation amount, cotton yield increased first and then decreased. In conclusion, applying 4200 m³·hm^-2 seasonal irrigation amount in total and 7 d and 5 d irrigation interval for the budding and flowering stage respectively could be a suitable irrigation regime for mechanically-harvested cotton in the arid area of Southern Xinjiang