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通过膜下滴灌田间试验,研究了塔里木灌区棉田土壤盐分运移特征。结果表明:膜下滴灌的棉田土壤盐分呈“Y”状垂直分布,膜下土壤盐分含量小于膜间,膜间土壤盐分从表层到深层呈逐渐增减的趋势。随滴灌量增加,膜下土壤盐分峰值位置下移。滴灌量从2 618 m3/hm2增大到4 265m3/hm2,湿润峰位置从40 cm下移至100 cm,盐分峰值位置从30 cm下移至60 cm。滴灌结束后,膜下0~60 cm及0~100 cm土壤平均含盐量均减小。脱盐程度随滴灌量增大而增加,0~60 cm土层脱盐率从6.0%增加到34.8%;而膜间土壤呈积盐状态,积盐程度随滴灌量减小而增大。随滴灌年限增加,0~60 cm的土层平均含盐量逐年增加,从2005年到2007年,4 265、3 926、3 600、3 271m3/hm2灌溉定额下的土壤平均含盐量年均增加了0.4、0.6、1.1、1.1 g/kg。研究结果指出了塔里木灌区现行棉花膜下滴灌制度存在的积盐问题,成果对完善干旱区膜下滴灌灌溉制度具有一定得指导意义。
The field experiment of drip irrigation under mulch was carried out to study the characteristics of soil salinity in cotton fields in Tarim irrigation district. The results showed that the soil salt content in cotton field dripped under the drip irrigation was vertically vertical, and the content of soil salinity under the membrane was less than that between the membrane and the soil salinity increased gradually from the surface to the depth. With the increase of drip irrigation, the peak position of soil salinity under the film moved downwards. Drip irrigation increased from 2 618 m 3 / hm 2 to 4 265 m 3 / h m 2, the wetting peak moved from 40 cm to 100 cm, and the peak position of salt moved from 30 cm to 60 cm. After drip irrigation, the average salinity of 0-60 cm and 0-100 cm soil layers decreased. The degree of desalination increased with the increase of drip irrigation, while the desalination rate increased from 6.0% to 34.8% in 0 ~ 60 cm soil layer. However, the inter-membrane soil was salt accumulation and the salt accumulation increased with the decrease of drip irrigation. With the increase of drip irrigation years, the average salinity of soil layers in 0 ~ 60 cm increased year by year. From 2005 to 2007, the average soil salinity of 4 265,3 926,3 600,3 271m3 / hm2 irrigation quota averaged Increased 0.4,0.6,1.1,1.1 g / kg. The results indicate that the present salt accumulation problem exists in the present cotton drip irrigation system in Tarim irrigation district and the results are of guiding significance in perfecting the irrigation drip irrigation system in the arid area.