人工降雨条件下耕翻面积对水土流失的影响

目的]探讨耕翻面积对水土流失的影响,为黄土高原地区农田水土流失防治提供依据。方法]通过人工模拟降雨试验,研究了3种坡度下不同耕翻面积的产流和产沙特性。结果]耕地的产流和产沙特征除了与坡度、雨强以及土壤前期含水量等因素有关外,还与耕翻面积有密切关系。坡度相同时,随耕翻面积的增加初始产流逐渐延后;耕翻面积相同时,随着坡度的增大径流量有增大的趋势,在坡度15°的情况下,耕翻50%时径流量最大。相同坡度下,随耕翻面积的增加,产沙量呈持续上升趋势;坡度为10°时,耕翻面积对产沙量的影响表现最为明显,翻耕的产沙量平均为不耕翻的8.66倍。15°坡度下径流量对累积产沙量的影响最显著。不同耕翻面积下的产流率在产流开始后10min左右趋于稳定。在不同坡度下全耕的产沙率均最大,不耕翻的最小。结论]随着耕翻面积逐渐增大,初始产流时间逐渐延后,径流量逐渐减小,产沙量逐渐增大。

Effects of Ploughing Area on Soil and Water Loss Under Stimulated Rainfall Conditions

Objective] The aim of this study is to investigate the effects of ploughing area on soil and water loss, in order to provide basis for soil and water loss in Loess Plateau.Methods] By artificial rainfall experiments, we studied runoff and sediment yield characteristics at three different slopes with different ploughing area.Results] The runoff and sediment yield characteristics of cultivated land were not only related to the slope, rainfall intensity and soil moisture content, but also closely related to ploughing area. Under the same slope gradient, the initial runoff occurring time was delayed and the sediment yield was increased with the increase of ploughing area. Under the same ploughing area, runoff and sediment yield rate showed an increasing trend with the increase of slope gradient. And runoff reached to the maximum when the slope was 15ånd the ploughing area was 50%. Under the same gradient, the sediment yield showed an increasing trend with the increase of ploughing area. When the slope gradient was 10°, ploughing area had the greatest influence on sediment yield, and the average sediment yield of ploughing treatment was 8.66 times of no-till treatment. The runoff had the most significant influence on the cumulative sediment yield when the slope gradient was 15°. Runoff rate under different ploughing area became stable approximately 10 min after the initial runoff occurring. Under different slope gradient, sediment production rate of full-tillage was the largest in whole-ploughing, while the smallest in no-till.Conclusion] With the increasing of ploughing area, the initial runoff occurring time is delayed, runoff decreased, and the sediment yield increased.