新疆玛纳斯河流域灌溉技术对土壤盐渍化的影响

评价新疆玛纳斯河流域灌区灌溉技术对土壤盐渍化的影响程度。以石河子垦区为例,着重分析不同阶段灌溉技术对土壤盐渍化的影响;根据土壤盐渍化与灌溉技术水平的关系,用类比法对灌区盐渍化耕地的发展趋势进行初步预测。结果表明:在无排水条件下漫灌、畦灌等传统灌溉技术造成地下水位迅速上升,土层出现严重积盐。井灌井排技术有效地降低了地下水位,土壤明显脱盐,作物产量不断提高。目前大力推广的膜下滴灌由于其良好的节水和压盐效果,土壤中盐分含量逐年下降,随着滴灌年限的增加,土壤平均脱盐率逐渐提高;预计2010年大部分地区水资源达到合理利用后,灌区次生盐渍化耕地比例将下降到35%~40%,2020年区域水资源实现高效利用后,盐渍化耕地将减少到30%以内。随着灌溉技术水平的不断提高,不同类型土壤出现明显脱盐,灌区盐渍化耕地也将逐渐减少,但不会全部消失。

Assessment on the effect of irrigation technology on soil salinization in Manas River valley, Xinjiang

In order to assess the effect of irrigation technology on soil salinization in Manas River Valley, Xinjiang, the historical information on characteristics of irrigation technology, groundwater depth and soil salts accumulation in Shihezi cultivated area at key four periods, was analyzed emphatically. Besides, the trends of cultivated land salinization for 2010 and 2020 were also predicted by analogism according to the relationship between soil salinization and irrigation technology. The results revealed that the application of the traditional irrigation methods, such as flood and ridge irrigation, resulted in a rapid increase of groundwater depth and salts accumulation in soil surface layers. With the massive groundwater pumped for irrigation, there was an apparent decrease of groundwater depth and desalinization in soil layers that led to a substantial increase of crop production. Currently the application of mulched drip irrigation decreased the salt content in soil layers and increased the crop yield. With the continuous application of drip irrigation, average soil desalinization efficiency in soil layers was increasing. It was predicted that the percent of salinized land would be reduced to 3,5% -40% when water resource was utilized reasonably in 2010. With the high efficient utilization of water resources after 2020 the salinized land ratio would remain below 30%. It was concluded that with the increase of technological level of irrigation, an obvious desalinization appeared in the soil surface layers and the salinized land area in this study area would decrease, but the land salinization problem would be still existed.