不同矿化度咸水造墒灌溉对棉花生长发育和产量的影响
Effect of irrigation water salt content on cotton growth and yield
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摘要: 采用裂区设计, 灌溉量作为主处理, 灌溉水的矿化度作为副处理, 研究了播前不同灌溉量下不同矿化度咸水对棉花生长发育及产量的影响。研究结果表明, 不同矿化度咸水灌溉对棉花出苗时间和出苗率的影响差异较大, 随灌溉水矿化度的增大, 棉花出苗速度变缓, 出苗率降低, 其中4 g·L-1 以下的咸水灌溉处理棉花出苗率在90%以上, 6 g·L-1 矿化度处理平均出苗率仍可达85%左右, 但出苗时间推迟。播种前咸水灌溉量以22.5~34.0 mm 为宜。灌溉水矿化度对棉花生长发育的影响程度前期大于后期, 前期大于4 g·L-1 矿化度处理表现出明显的抑制生长作用, 后期大于6 g·L-1 矿化度处理才表现出明显的抑制生长作用。从产量上看, 棉花的咸水矿化度计算阈值为3.38 g·L-1, 即在矿化度小于3.38 g·L-1 时, 咸水灌溉的棉花产量与淡水灌溉产量差异不明显, 高于此矿化度阈值时, 棉花产量呈直线下降趋势; 但低于8 g·L-1 咸水灌溉的棉花产量均显著高于纯旱地的棉花产量。Abstract: A split-plot design was adopted in an irrigation experiment before cotton sowing with irrigation water amount as the main treatment and water mineral salinity as sub-treatments. The experiment results showed that the rate of cotton emergence decreased with increased irrigation water salt content. The rate of cotton emergence was over 90% at 4 g·L-1 of irrigation water salinity. At 6 g·L-1 of irrigation water salinity, cotton emergence was 85%, but delayed. The optimum irrigation range was 22.5~34.0 mm. Inhibitory actions of water salt on cotton growth and development at early stage was more obvious than at late stage. There was no significant difference in cotton yield between the fresh water and salt water (<3.38 g·L-1) irrigation. At irrigation water salinity >3.38 g·L-1, cotton yield linearly dropped. Yield was, however, much higher at irrigation water salinity <8 g·L-1 than that under rainfed conditions.
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