控制排水对宁夏银南灌区水稻田盐分动态变化的影响

本文结合2004～2005年在宁夏银南灌区水稻田进行的一项控制排水大田试验，研究分析了控制排水措施对田间盐分动态变化的影响。结果表明：控制排水条件下0.3m深度地下水盐分的平均浓度略高于常规排水，并且该深度地下水盐分浓度在总体上比较稳定；在0.8m和1.2m深度，控制排水条件下的地下水盐分浓度明显大于常规排水条件下盐分的浓度，而且盐分受灌溉的影响程度要小于常规排水；最后，控制排水措施减小了田间浅层地下水盐分浓度的差异，而对深层地下水盐分浓度的空间差异影响较小。两年的试验研究结果说明控制排水措施对水稻田地下水盐分动态产生了一定程度的影响，但是并没有出现明显的积盐现象。因此，具有环保意义的农田控制排水措施可以在当地进行推广使用。

The effect of controlled drainage on salt dynamics inirrigated rice fields of the Yinnan Irrigation District

Based on a field experiment of controlled drainage conducted in the Yinnan Irrigation District, Ningxia, China, this paper analyzed the effect of controlled drainage on salt dynamics of irrigated rice fields. The results showed that the average salt concentration of groundwater at depth of 0.3m was a little higher than that of the conventional drainage, and the fluctuation of salt concentration was small; salt concentrations of groundwater at depths of 0.8m and 1.2m under controlled drainage are much higher than those of the conventional drainage because salt movement at these depths was less affected by irrigation under controlled drainage. Controlled drainage reduced the spatial difference of salt concentration of shallow groundwater but had little influence on that of deep groundwater. From this study, it can be concluded that controlled drainage will affect groundwater salinity of irrigated rice fields, but the increment is not significant enough to cause salt accumulation. Therefore, it is feasible to implement drainage control in the study area for water quality benefit.