伊犁新垦区大坡降砂质薄层土不同灌溉方式下灌溉侵蚀机理与侵蚀过程研究

The new reclaimed wasteland of Ili river basin almost lie in the 3-4 terrace of Piedmont proluvial-alluvial plain and river alluvium plain, and, in this basin, soil erosion is severe, which can be attributed to the large terrain gradient, thin sandy soil, and bad soil structure. On the law of soil erosion, the domestic and foreign researchers had carried out a large number of studies in the field runoff or runoff plot about artificial simulation of rainfall, but for irrigation water erosion, especially the law of soil erosion and erosion process to different irrigation methods in the new reclaimed wasteland of Ili river basin was seldom reported. This research studies on the irrigation water erosion test of flood irrigation, runnel furrow irrigation,sprinkler irrigation and drip irrigation; (1) This research tries to make clear the effect of rainfall and different irrigation methods on the surface runoff and the amount of soil erosion; (2)This research preliminarily reveals the law of soil erosion and erosion process of thin runoff in slope through the influence of different irrigation methods on irrigation runoff yield and sediment yield under the crop growth conditions; (3) This research makes it clear that moisture and nutrient loss by deep percolation under the three irrigation methods. This will provide the theory basis for understanding and evaluating correctly the soil erosion problems on the comprehensive utilization of land and water resources in this basin, establishing reasonable irrigation method and irrigation system.

伊犁河流域新垦荒地多处于山前洪积-冲积平原和河流冲积平原的三、四级阶地上，地形坡降大，砂质薄土，土壤结构差，水土流失严重。当前对土壤侵蚀的研究主要集中在水土保持领域，国内外研究者在野外径流场或径流小区人工模拟降雨开展了大量研究，而对农田灌溉引起的土壤侵蚀问题未给予足够的重视，特别是新疆伊犁新垦区不同灌溉方式下灌溉侵蚀机理与侵蚀过程。本研究针对现有漫灌、细流沟灌、喷灌和滴灌4种灌溉方式开展水力侵蚀试验：（1）通过模拟天然降水和不同灌溉方式下新垦荒地的水蚀试验，明确其对地表径流量、泥沙侵蚀量的影响；（2）通过在作物生长条件下不同灌溉方式对灌溉产流产沙的影响研究，初步揭示坡面薄层径流侵蚀机理与侵蚀过程；（3）明确4种灌溉方式因深层渗漏造成的水分和养分的流失规律。以期为正确认识和评价该流域水土资源综合开发中的灌溉水力侵蚀问题，确定合理灌溉方式和灌溉制度制定提供理论依据。

本文主要针对伊犁新垦荒地地形坡降大，砂质薄土，土壤结构差，水土流失严重的问题，研究了漫灌、细流沟灌、喷灌和滴灌4种不同灌溉方式下灌溉侵蚀机理与侵蚀过程。通过2013年—2015年的野外径流小区观测法和放水法模拟试验，开展了模拟天然降水条件和不同灌溉方式下新垦荒地水力侵蚀与侵蚀过程和作物生长条件下不同灌溉方式下新垦荒地的灌溉水蚀机理及规律研究，初步探明了伊犁新垦区大坡降砂质薄层土，在不同灌溉方式下坡面流的水动力学特征、坡面产流产沙特征及坡面细沟的发育特征等灌溉侵蚀机理及规律，为确立合理灌溉方式和灌溉制度提供科学理论依据。主要结论如下：.（1）坡度在7°～8°的新垦荒地上，当降雨量在17～58mm，连续降雨30～480min，雨强在0.12～0.80mm/min，10min和30min最大雨强在0.20～0.90mm/min和0.25～1.95mm/min条件下，不会产生水土流失。.（2）对于新垦荒地采用漫灌、细流沟灌、喷灌和滴灌方式，随着灌水流量的增加，径流流速、雷诺数、Darcy-Weisbach阻力系数均增大，佛汝德数减小。输沙率随着灌水流量的增加呈递增趋势，含沙量随流量增加呈先增后减的趋势；随着灌水定额的增加，输沙率、含沙量均呈递减趋势，但灌水定额对输沙率及含沙量的影响不如灌水流量的影响明显。漫灌和细流沟灌方式下径流流速与灌水流量、阻力系数与雷诺数之间均呈良好的幂函数关系。漫灌和细流沟灌的坡面水流为紊流、急流状态。喷灌和滴灌的坡面水流为紊流、缓流状态。灌水定额对水力学参数的影响没有灌水流量明显，随灌水定额增加，径流流速与雷诺数增加，Darcy-Weisbach阻力系数减小，佛汝德数变化复杂。.（3）作物生长坡面径流流速、雷诺数、阻力系数随着流量增加而增大，佛汝德数减小。流速与流量、阻力系数与雷诺数均呈良好的幂函数关系。含沙量随灌水流量增加呈波动形式的变化，输沙率与径流系数均表现为随灌水流量增加而增大。.（4）作物生长面较新垦荒地具有显著的减流减沙效应，其削减径流作用明显弱于减沙效应，作物地与新垦荒地土壤入渗率随着灌水流量的增加呈现递增的趋势。