堆存时间对不同土地类型堆积表土产沙量影响

Impact of Storage Time on the Sediment Yields of Piled Surface Soil in Different Types of Lands

以沈阳棕壤区建设项目开挖堆置的表土为研究对象,设置3个堆存时间(新堆积、6个月、12个月),采用不同降雨强度(0.64,1.05,1.52mm/min),对3种土地利用类型堆土(农田、荒地、林地)进行模拟降雨试验,探讨堆存时间对堆积表土产沙量的影响。结果表明:不同土地类型土壤产沙量存在较大差异,在3个降雨强度条件下,新堆积农田土产沙量分别为95.7,170.2,241.1g;荒地土产沙量分别为75.8,89.9,126.6g;林地土产沙量分别为65.9,81.2,139.1g;经过12个月堆积后,3种土地类型土壤产沙量平均分别减少了60.3%,16.01%,29.3%。随堆存时间增加,3种类型土壤容重、植被覆盖率均呈递增趋势,与堆存时间呈正相关,土壤孔隙度均逐渐减小,与堆存时间呈负相关。3种土壤中有机质、团聚体含量均呈先减小后增加趋势;在相同降雨强度条件下,3种类型土壤产沙量与堆存时间均呈负相关,但荒地土产沙量随堆存时间增加,变化差异不显著。农田与林地土壤径流量与堆存时间均呈负相关,荒地土呈正相关;随降雨强度增加,3种类型土壤产流产沙量均呈上升趋势。总体上,3种堆积表土土壤侵蚀量随堆存时间增加呈减小趋势,故开挖堆置表土的水土流失防治应注重堆放初期的防治。

This research was based on the piled surface soil of excavation earthwork in the construction project in brown soil region of Shenyang,and was set up with 3levels of storage time（new accumulation,6months,12months）,and different rainfall intensities（0.64mm/min,1.05mm/min,1.52mm/min）.Then simulated rainfall experiment was conducted on the piled soil of 3land use types（farmland,wasteland,and forestland）so as to study the effects of storage time on the sediment yield of surfare soil.The results showed that：There was a big difference about the sediment yield of soil in different land types;under the 3rainfall intensities,the sediment yields of new accumulated farmland soil were 95.7g,170.2g,and 241.1g,respectively,while the sediment yields of wasteland soil were 75.8g,89.9g,and 126.6g,respectively,and the sediment yields of woodland soil were respectively 65.9g,81.2g,and 139.1g;after 12-month deposition,the sediment yields of 3types of land soil were reduced on average by 60.3%,16.01%,and 29.3%.With the increase of storage time,soil bulk density and vegetation coverage of 3types of land soil had an increasing trend,which were positively correlated with storage time,but soil porosity decreased and negatively correlated with storage time.The organic matter and aggregate content of 3types of soil decreased at first and then increased;under the same rainfall intensity,the sediment yields of the 3types of soil were negatively correlated with storage time,but the changes in sediment yield of wasteland soil became insignificant with the increase of storage time The runoff of farmland and forest soil were negatively correlated with storage time,but the runoff of wasteland soil were positively related to storage time.With the increase of rainfall intensity,the runoff and sediment yields of 3types of soil were on the rise;Soil erosion in piled soil showed a decreasing trend with the increase of storage time,so much attention should be paid to the early stage of piled soil so asto prevent and control the piled soil erosion.