咸水灌溉对棉花耗水特性和水分利用效率的影响

Effects of Saline Water Irrigation on Water Consumption Characteristics and Water Use Efficiency of Cotton

采用田间对比试验,连续3 a研究了1、3、5、7 g/L 4个矿化度咸水(记作S1、S2、S3、S4)灌溉对棉田土壤水盐、土壤蒸发、棉花阶段耗水量、籽棉产量和水分利用效率的影响。结果表明,棉花生育期内根系层土壤含水率和电导率有随灌溉水矿化度的增加而增大的趋势,土壤电导率增加尤为明显;年际间,各处理土壤含水率和电导率差异非常大,经过连续3 a灌溉,根系层土壤电导率均未逐年增加。S3和S4处理的平均土壤蒸发强度大于S1处理,S2与S1处理间的差异很小;7 g/L以下咸水灌溉对棉花耗水过程产生了一定影响,但对总耗水量影响并不明显。3 a的平均籽棉产量和水分利用效率由大到小顺序均为:S2、S1、S3、S4,S2比S1处理增产2.43%,水分利用效率增加1.15%,S3和S4比S1处理减产1.67%和8.88%,水分利用效率降低0.25%和7.31%,其中,S2和S3与S1处理间差异不显著,S4处理产量和水分利用效率降低显著。

To make effective use of shallow ground saline water resource for relieving the water crisis in Hebei Low Plain,a three-year field experiment was conducted to study the effects of irrigation with saline water of different salinities on soil water and salt contents,soil evaporation,stage water consumption of cotton,seed cotton yield and water use efficiency. The experiment included four treatments with different salinity levels of 1 g/L,3 g/L,5 g/L and 7 g/L of irrigation water,which were denoted as S1,S2,S3 and S4. Results showed that during cotton growing period,soil water and salt contents were increased with the increment of irrigation water salinity,especially for soil salt content. Significant differences of soil water and salt contents for each treatment were appeared during experimental years. In wet years,soil water content of root zone was high and a large proportion of salt was leached out; while in arid years,soil water content in root zone was low and salt was accumulated. After three-year continuous irrigation with saline water,soil salt content in cotton root zone was not accumulated year by year. During the whole growth period,average soil evaporation intensity was higher in S3 and S4 treatments than that in S1 treatment,but there was little difference between S1 and S2 treatments. Irrigation with saline waterof salinity lower than 7 g/L had a certain influence on cotton water consumption process,but the differences in total water consumption were not significant. S2 treatment obtained the highest average seed cotton yield and water use efficiency,which was followed by S1,S3 and S4 treatments. Compared with S1 treatment,the average seed cotton yield and water use efficiency of S2 treatment were increased by2. 43% and 1. 15%,and those for S3 and S4 treatments were decreased by 1. 67% and 0. 25%,8. 88%and 7. 31%,respectively. There were no significant differences in seed cotton yield and water use efficiency among S1,S2 and S3 treatments,however,those for S4 treatment were significantly reduced.The study can provide important theoretical support for developing the use of shallow ground saline water resource in cotton irrigation.