Abstract:

【Objective】 The aim of this project is to evaluate the salt drainage effect by subsurface pipe and shaft technology on secondary salinized soil in southern Xinjiang and select out the suitable layout spacing of subsurface pipe project.【Methods】 The paper took the secondary salinized soil of the 38th regiment of the second division in Southern Xinjiang as an experimental area, and the field test of water and salt drainage by shaft (vertical drainage) + subsurface pipe (horizontal drainage) was carried out from 2016 to 2019. The 3 adjacent plots were selected and the layout spacing of subsurface pipe was set to 6, 8, 10 m (marked as T₁, T₂, T₃), respectively; the buried depth of subsurface pipe was set to 1.2 m and the depth and spacing of shaft was set to 20 and 120 m in each treatment. 【Results】 The results showed that (1) the soil salinity significantly decreased after 2 years salt drainage and the soil electrical conductivity (EC) in root layer of T₁, T₂ and T₃ was decreased by 31.83%, 50.35% and 46.09%, respectively; the varies of soil pH was not significant but was decreased with the salt drainage time increase, generally; (2) the soil EC was decreased with the soil depth increase, and the decrease rate of salt content in the 0-0.8 m soil layer was significantly higher than that in deep soil layers; moreover, the effect of salt drainage was more obvious when the distance was closer to the shaft; (3) the salinity of drainage water was increased after 1 year salt drainage, however which of T₁, T₂ and T₃ was decreased by 21.41%, 33.24% and 18.57% after 2 years salt drainage, respectively; the underground water level dropped down year by year and decreased by 1.5 m on the average; (4) the average maize yield of different treatments was 329.70 kg/667m², and the yield was T₂>T₁>T₃, which indicated that the salt drainage effect was in proportion to the maize yield.【Conclusion】 According to the effect of water and salt drainage and maize yield, the layout spacing of 8 m (T₂) was the suitable parameter for subsurface pipe project; it is suggested to apply the model of shaft and subsurface pipe drainage in in areas of southern Xinjing, which could effectively reduce groundwater level and salt content and maintain the stability and sustainability of the improvement effect of salinization soil.

Key words: secondary salinization soil; subsurface pipedrainage; shaft drainage; soil desalination effect; maize yield

摘要：

【目的】评价暗管、竖井工程在新疆南疆次生盐渍化土上的排盐效果,筛选出适宜的暗管布设间距。【方法】以新疆南疆垦区兵团第二师38团撂荒地次生盐渍化土为对象,于2016~2019年设置暗管+竖井田间排水控盐试验,选取3个相邻地块,暗管布设间距分别为6、8和10 m(依次记为T₁、T₂、T₃),每个地块暗管埋深1.2 m,竖井井深20 m、间距120 m。【结果】 (1)各处理土壤盐分在排水2年后均显著降低,T₁、T₂、T₃根层土壤电导率较排盐前分别下降了31.83%、50.35%、46.09%;(2)垂直方向上土壤电导率随土层深度增加而降低,各排盐处理0~0.8 m根层土壤电导率降低幅度显著高于深层土壤,水平方向上距离竖井越近脱盐效果越明显;(3)各处理排水矿化度在排盐1年后均升高,但在排盐2年后T₁、T₂ 、T₃处理分别下降了21.41%、33.24%、18.57%,排盐后地下水位深度平均降低了1.5 m;(4)脱盐2年后种植玉米,各处理平均籽粒单产达到329.70 kg/667m²,单产水平T₂>T₁>T₃,降盐效果与玉米产量呈正相关。【结论】优选出布设间距8 m(T₂)为试验区暗管排盐工程适宜参数。采用竖井+暗管排水控盐模式,通过降低地下水位和排水控盐共同作用,以维持南疆灌区盐渍土改良效果的稳定性和持续性。

关键词: 次生盐渍化土, 暗管排水, 竖井排水, 脱盐效果, 玉米产量