北疆十户滩灌区棉田土壤盐分时空变异特征

Spatial and temporal variability of soil salinity in cotton field in Shihutan irrigation area in the northern Xinjiang

【目的】探究新疆玛纳斯河流域十户滩灌区棉田土壤盐分在棉花不同生育时期的空间变异特征,为北疆绿洲灌区盐渍化土壤的改良与可持续利用提供理论依据。【方法】采用田间实测、地质统计学与GIS(geography information system,地理信息系统)技术相结合的方法,探究棉花生育期内地下水埋深和土壤盐分的空间变异。【结果】灌区内地下水埋深在3.5~9.0 m范围内变化,相较播种前,现蕾期、开花期北部地下水埋深增加,出苗期、开花期南部地下水埋深减小。十户滩灌区农田土壤总体上属于中度盐渍化,其中在20~40 cm土层土壤盐分呈强变异,其他土层土壤盐分呈中等变异。播种前20~40 cm土层在西北方位有明显的积盐现象,出苗期和现蕾期土壤盐分开始向中部和东南方向聚集,开花期整体土壤盐分降为最低水平。在20~100 cm土层,随着土层深度的增加,含盐量3~5 g·kg^(-1)(中度盐渍化)和5~10 g·kg^(-1)(重度盐渍化)的2类土壤的面积占比呈上升趋势。【结论】十户滩灌区内20~40 cm土层土壤总盐含量在整个生育期相对变异性最强,40~100 cm土层土壤存在潜在积盐风险,该结果为十户滩地区盐渍化土壤治理方案的制定与实施提供了一定科学依据。

[Objective]This study explored the spatial variation of soil salinity of the cotton field during different cotton growth stages in Shihutan irrigation area,Manas river region,Xinjiang,and provided the theoretical basis for the improvement and sustainable utilization of saline soil in this area.[Method]The spatial variation of groundwater depth and soil salinity during the cotton growth period was explored by combining field measurement,geo statistics,and GIS(geography information system)technology.[Results]The groundwater depth in the irrigation area varied in the range of 3.5-9.0 m.Compared with the period of before sowing,the groundwater depth in the north of Shihutan at the squaring stage and flowering stage were increased,and the groundwater depth in the south of Shihutan at the seedling stage and flowering stage were decreased.In general,the total salt content of farmland soil in the Shihutan irrigation area belonged to the moderate salinization soil category.The salt content in the20-40 cm soil layer showed strong variation,and the salt content in other soil layers showed moderate variation.Before sowing,the 20-40 cm soil layer had obvious salt accumulation in the northwest of Shihutan.Soil salinity gradually increased in the middle and southeast of Shihutan at the seedling stage and squaring stage,and the overall soil salinity decreased to the lowest level at the flowering stage.In the 20-100 cm soil layer,the proportion of moderately and severely salinized soil area increased along with the increased soil depth,and the deep soil layer were facing a potential risk of salt accumulation.[Conclusion]The total soil content of the 20-40 cm soil layer in the study area had the strongest variability during the overall growth period,and there was a potential risk of salt accumulation at the 40-100 cm soil layer.These results provided a scientific basis for formulating and implementing the restoration measurement of saline soil in Shihutan area.