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尽管人们趋向于采用时针式机组喷灌系统和滴灌系统,然而在美国仍有差不多一半的水浇地采用沟灌技术。不过,当水在土壤上流淌时造成土壤冲蚀是一个常有的问题。冲蚀引发的问题既有田间的,也有非田间的。在田间,往往上游端的土壤被冲蚀,使水沟变深,被冲蚀的土壤在下游端沉积,水沟淤积造成水漫过地面。严重的冲蚀还会使植物根部裸露。但只要在水沟的土壤中或灌溉的水里加入少量的聚丙烯酰胺(PAM),就差不多可以消除灌溉水沟的冲蚀问题。在过去10年里,设在爱达荷州金伯利的美国农业部农业
Although people tend to use hourglass sprinkler systems and drip irrigation systems, about half of the irrigated land is still ditched in the United States. However, soil erosion is a common problem when water is flowing through the soil. The problems caused by erosion are both in the field and in the non-field. In the field, the soil at the upstream end is often eroded, causing the ditch to become deeper. The eroded soil is deposited at the downstream end, and the gully siltation causes the water to diffuse across the ground. Severe erosion also exposes the plant roots. However, adding a small amount of polyacrylamide (PAM) to the soil in the ditch or into the irrigated water will almost eliminate the erosion of the irrigated gutter. USDA Agriculture at Kimberley, Idaho for the past 10 years