基于节水灌溉技术的民勤绿洲土地利用空间布局和利用方式调整

为改善导致民勤绿洲下游地区土地次生盐化严重、土地退化和生态失衡的不合理土地利用模式,通过历史文献法研究了民勤绿洲农业开发与土地利用空间格局演变史,用遥感方法获取了2008年绿洲土地利用/覆被数据,结合对地貌、地下水和土壤的分布规律的分析,研究表明:1)绿洲农业开垦起源于水源充足、土壤持水性好的中下游区域,并逐渐向外围及上游发展;2)绿洲种植结构不合理,农业用水空间配置不合理,下游灌溉且主要用矿化度高的地下水灌溉导致严重次生盐渍化;3)传统农业模式下绿洲下游已出现生产-生活-生态环境恶化,且农民生计无法保证。为此,本研究提出通过"流"的方式重构土地利用空间布局,即农村居民点向上游迁移,使用膜下滴灌技术发展特色林果,在提高农业经济效益的同时,节约农业用水并利用上游回水为下游地区腾退的农业用地恢复耐盐植被,从而改善绿洲生态系统。

Adjustment of land use spatial structure and use pattern based on modern agriculture in Minqin oasis

In order to solve serious secondary salinization,land degradation and ecological imbalance and optimize unreasonable land use,the progress of agricultural exploitation and land use evolution in Minqin is summarized.Integrated with local geomorphology,groundwater,soil,and the land use data obtained by remote sensing technology,the spatial heterogeneity of land use pattern and distribution of irrigated agriculture are investigated.The results show that:1) Agricultural reclamation is originated from middle and lower regions,where water is abundant with high water-holding capacity of soils,then,expanding outward and toward upper reach gradually;2) The inappropriate plantation structure,spatial allocation in agricultural and irrigation water with hypersalinity cause the secondary salinization in downstream area;3) Under the background of traditional agriculture,the deterioration of production-life-ecology environment has appeared in downstream region,moreover,the livelihood of peasants cannot be guaranteed.Reconfigure the spatial allocation of land use by the transfer of "Flow" is suggested in this review.A new land use structure should be constructed in which residents gather in the upper region to develop characteristic forestry and fruit industry using drip irrigation technique under membrane.The improvement of agricultural economic benefit and saving of agricultural water make it possible to recover eco-environment and grow haloduric vegetation in agricultural land of downstream region.