表土结皮影响坡地产流产沙及养分流失的试验研究

采用人工降雨方法,模拟在无结皮、轻微结皮和严重结皮3种不同发育程度下,表土结皮对坡地产流产沙及磷钾流失过程的影响。结果表明,严重结皮具有降低产流、减少产沙的作用;坡地土壤磷钾流失过程均呈幂函数衰减趋势,无结皮坡地衰减速率最快;随着结皮不断发育,钾素流失形式以浸提态为主,逐步被溶解态所取代,磷素始终以泥沙浸提态流失占优势;与无结皮相比较,轻微结皮坡地磷和钾流失总量分别降低了20%和9%,严重结皮分别降低了52%和77%。因此,表土结皮具有减少土壤养分流失和延缓坡地土壤质量退化的作用。

Impact of Soil Crust on Runoff, Sediment and Nutrient Loss from Sloping Land

Through simulating artificial rainfall in sloping land,this study investigated the impact of soil surface crust on runoff,sediment,and phosphorus and potassium losses from the different lands with no crust,light crust or heavy crust.Results showed that,heavy curst decreased runoff discharge and sediment loss.The declining process of phosphorus and potassium losses with runoff and sediment was a power equation,and the losing velocity of phosphorus and potassium was the fastest for no crust land.With the different development status of soil crust from no crust to heavy crust,the dominant position of the sediment extractable potassium loss was replaced gradually by the dissolved potassium loss,but the extractable phosphorus loss was dominant all the time.As compared with no crust land,the total amount of phosphorus and potassium loss was decreased by 20% and 9% for light crust land respectively,and reduced by 52% and 77% for heavy crust land respectively.It implies that soil crust may decrease soil nutrient loss and control soil quality degeneration tendency.