微咸水膜下滴灌对土壤和棉花元素组成及产量的影响

通过微咸水和淡水膜下滴灌对比试验，研究灌溉水质对土壤和棉花元素组成及产量的影响.结果表明:微咸水灌溉处理，土壤窄行和膜间微量元素(尤其是铜、铁、锌)含量明显高于宽行，Na+增长率低于宽行；多数棉花器官中钾钠比、钙钠比并未因灌溉水质的区别而产生显著差异；微咸水滴灌有利于促进棉花前期营养生长及后期生殖生长，棉花干物质、单铃重、单位面积铃数及籽棉产量均高于淡水处理；棉株内锰、硼与钙元素间存在显著的相关关系，在一定阈值内，硼、锰促进棉花对钙的吸收.试验证明:微咸水中含有一定量的微量元素，合理利用微咸水灌溉，不会对棉花生长造成胁迫，相反能有效抑制土壤中Na+增长，增强棉花对盐分胁迫的抵抗能力、提高棉花产量. 

Influence of Mulched Drip-Irrigation with Brackish Water on Element Composition of Soil,Cotton, and Cotton Yield

Irrigation with brackish water has a long history throughout the world. Irrational use of brackish or saline waters, however, may lead to soil salinization and reduction of crop yields. In order to promote reasonable applications of brackish water and fertilizer irrigation, a series of experiments of mulched drip-irrigation with brackish and fresh waters were carried out at Bazhou Irrigation Experimental Station (Korla, Xinjiang, China). Plant and soil samples were collected at every growth stage. Cotton yields were measured at boll opening stage. Nine elements (Ca, Na, Mg, K, Cu, Fe, Mn, Zn and B) of each sample were tested in triplicate by ICP-OES (ICAP6300) after pretreated. The influence of water quality on the element compositions of soil and cotton and cotton yield were discussed based on the experiment. The results show that growth rate of Na+ in narrow rows and interspace of mulches was lower than that in wide rows because of higher content of Cu, Fe, Zn. The ratios of K+/Na+ and Ca2+/Na+, however, in most cotton organs show no significant differences between the two treatments. From buds to boll stages, brackish water irrigation enhanced the accumulation of above ground dry matters, which was favorable for vegetative development. From boll to boll opening stages, root and reproductive growth under brackish water were superior to that for fresh water. Furthermore, dry matters, boll weight, numbers of boll per unit area and cotton yield under brackish water were higher than those for fresh water. According to the correlations analyses, relationship between most trace and macro elements was weak. High correlations, however, were found among manganese, boron, and calcium. Within a certain threshold, boron, manganese promoted the absorption of calcium in cotton. It has been proved that a rational use of brackish water will not lead to the growth stress. On the contrary, it would not only lower the growth rate of Na+ in the soil effectively, but also strengthen cotton's resistibility to salt stress and increase cotton yields as well.