东北黑土区横垄坡耕地的产流产沙过程

目的] 在漫川漫岗黑土区开展横垄坡耕地冲刷试验研究，为黑土地保护工作提供理论依据。方法] 采用野外现场放水冲刷试验，研究了10，30，50和70 m横垄坡耕地径流小区，在不同上方来水量下的产流、产沙过程。结果] 3种冲刷流量（0.34，0.67和1.00 L/min）条件下的径流系数和含沙量均随坡长的增加持续波动，但不同冲刷流量达到稳定的大小和时间不同；累积产流量和累积产沙量均随冲刷流量的增强而增大，但相同冲刷流量下受坡长变化影响二者最大值出现的坡长却不同；冲刷流量为0.34 L/min时，10，30，50和70 m这4种坡长的径流系数和含沙量相关性均显著；累积产沙量随累积流量的增加而增加，坡长越短，且线性关系越强。0.34 L/min冲刷流量侵蚀量大小顺序依次为：30 m>10 m>70 m>50 m；冲刷流量为0.67和1.00 L/min侵蚀量大小顺序为：30 m>50 m>70 m>10 m。1.00 L/min冲刷流量情形下30 m坡长侵蚀量是10 m坡长的4.2倍。结论] 坡面侵蚀量随冲刷流量增大而增大，30 m坡长是横垄坡耕地侵蚀的临界坡长，细沟发育是横垄坡耕地坡面土壤侵蚀的主要来源。

Process of Flow and Sand Production at Cross-ridge Slope Land in Black Soil Area of Northeast China

Objective] The scouring of cross-ridge slope land in the Manchuan-Manggang black soil area was studied, in order to provide a theoretical basis for black land conservation.Methods] Field scouring experiments were performed on runoff plots in 10, 30, 50, and 70 m sloping farmland with ridge farming, to investigate the processes of runoff and sediment production with different volumes of upslope inflow.Results] Under the three scouring flow rates of 0.34, 0.67, and 1.00 L/min, the runoff coefficients and sediment contents fluctuated continuously with increasing slope length, but they stabilized at different magnitudes and times at different scouring flow rates. The cumulative runoff production and cumulative sediment production both increased with increasing scouring flow rate, but the maximum values of both occurred at different slope lengths under the same scouring flow rate. When the scouring flow rate was 0.34 L/min, there was a significant correlation between the runoff coefficient and sediment content for the four slope lengths (10, 30, 50, and 70 m). The cumulative sediment production increased with the increase of the cumulative flow rate, with shorter slope lengths exhibiting a stronger linear relationship. When the scouring flow rate was 0.34 L/min, the ranking of the different slope lengths by the amount of soil erosion was 30 m> 10 m > 70 m > 50 m. At scouring flow rates of 0.67 and 1.00 L/min, the order was 30 m > 50 m > 70 m > 10 m. Under the scouring flow rate of 1.00 L/min, the erosion of the 30 m slope was 4.2 times the erosion of the 10 m slope.Conclusion] Slope erosion increases with increase of scouring flow rate; However, 30 m is the critical slope length for erosion of cross-ridge slope land, and rill development is the main source of soil erosion on cross-ridge slope land.