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针对膜下滴灌棉田土壤次生盐渍化问题,从年内变化与年际变化两个方面,分析新疆典型绿洲区膜下滴灌棉田土壤盐分演变特征。研究结果表明:在年内,土壤盐分整体随生育期的顺延而呈下降趋势,其中5月上旬(苗期)、7月中旬(花铃期)、9月中旬(收获期)土壤盐分呈现积盐趋势;膜下滴灌4~12 a的棉田土壤存在稳定积盐层,其深度大约在60~150 cm范围内,其盐分值基本保持在0.6%上下;60 cm以上土层基本处于脱盐状态,其盐分值保持在0.2%~0.4%左右,属于非盐化土壤;膜下滴灌15 a的棉田,土壤盐分随生育阶段变化幅度较大,呈现中度盐化土特征。在年际间,膜下滴灌最初1~6 a,土壤盐分呈现持续脱盐趋势,尤其20 cm以下土层脱盐效果较为明显;实施膜下滴灌6~7 a,土壤盐分变化趋于稳定状态,各棉田出现稳定积盐层,其深度大约在80~100 cm土层,积盐层盐分值大部分保持在0.25%上下,属于非盐化土。
According to the secondary salinization of cotton under plastic film drip irrigation, the evolution characteristics of soil salinity in drip irrigation cotton under typical driftway conditions in Xinjiang were analyzed from two aspects: the year change and interannual change. The results showed that during the year, the overall soil salinity showed a downward trend with the extension of the growth period. The soil salinity showed salt accumulation in early May (seedling stage), mid-July (bloom stage) and mid-September (harvest stage) The soil salinity of cotton fields with drip irrigation for 4 ~ 12 days under film mulching was stable, and its depth was in the range of 60-150 cm. The salinity value remained at about 0.6%. The soil above 60 cm was in desalination state, The salinity value kept at about 0.2% -0.4%, belonging to non-salinized soil. Under 15-year drip irrigation, the salinity of soil varied greatly with the growth stage and showed moderate salinization soil characteristics. During the first 1 to 6 years of drip irrigation, the desalination of soil showed a continuous desalting effect, especially in the soil below 20 cm. In the period of 6 to 7 days after drip irrigation, the change of soil salinity tended to be stable. The stable saline layer appeared in the cotton field, and its depth was about 80 ~ 100 cm soil layer. Most of the salt content in the salt layer remained at 0.25%, which belonged to non - saline soil.