东北黑土区不同垄作坡面产流产沙过程

起垄种植是东北黑土区普遍的耕作模式,不同垄作坡面产流产沙规律尚不明晰、亟需研究。为此,基于野外放水冲刷试验,设计3个冲刷流量(30 L/min,60 L/min,90 L/min)和4种处理坡面(横坡垄作、斜坡垄作、无垄作、顺坡垄作),探究东北黑土区不同垄作坡面的土壤侵蚀差异。结果表明:(1)3种冲刷流量产流率和含沙量均随垄作措施改变呈持续波动趋势,但受冲刷流量影响二者变化规律不同。(2)4种垄作措施状况下,产流时间与冲刷流量均不相关,含沙量与产流时间均呈负相关; 其他试验条件下,因冲刷流量和垄作措施的差异出现不同相关性。(3)30 L/min,60 L/min两种冲刷流量下,侵蚀强弱表现为:顺坡垄作>无垄作>斜坡垄作>横坡垄作。冲刷流量90 L/min时,侵蚀规律变为:横坡垄作>顺坡垄作>斜坡垄作>无垄作,且横坡垄作与斜坡垄作的累积产沙量较30 L/min冲刷流量比分别增加了12.78倍和10.11倍。综上,小流量冲刷条件下横垄和斜垄可有效控制径流和水土流失,当冲刷强度增大后二者发生断垄恰是径流和泥沙发生变异的最主要因素。

Process of Runoff and Sediment Generation on Different Slopes with Ridged Cropping in the Black Soil Area of Northeast China

Ridged planting is a common cropping pattern in the black soil area of northeast China, and the runoff and sediment generation patterns on different slopes with ridged cropping are not clear and need to be studied. Based on the field scouring test, three drainage flow rates(30 L/min, 60 L/min, 90 L/min)and four slopes(cross-slope ridge, slope ridge, no ridge, and down-slope ridge)were designed to investigate the differences in soil erosion on different slopes with ridged cropping in the northeast black soil area. The results show that:(1)the runoff generation rate and sediment content of the three kinds of scouring flows both showed a continuous fluctuation trend with the change of ridged cropping measures, but the change patterns of the two were different by the scouring flow;(2)under the four ridged cropping conditions, the time of runoff generation was not correlated with the drainage flow, and the sediment content was negatively correlated with the time of runoff generation; under the other test conditions, different correlations were observed due to the differences in drainage flow and ridged cropping measures;(3)at the drainage flow rates of 30 L/min and 60 L/min, the erosion intensity decreased in the order: downhill ridge>no ridge>slope ridge>cross-slope ridge; when the drainage flow rate was 90 L/min, the erosion intensity decreased in the order: cross-slope ridge>down-slope ridge>slope ridge>no ridge. And the cumulated amounts of sediment generation of cross-slope ridge and slope ridge increased 12.78 times and 10.11 times, respectively compared with those under drainage flow rate of 30 L/min. Under the condition of small flow erosion, horizontal ridge and oblique ridge can effectively control runoff and soil erosion, and when the erosion intensity increases, the fracture of the two ridges is the most important factor in the variation of runoff and sediment.