次降雨条件下鲁中南山区砂质壤土赤松林地产流与氮磷流失特征

为了研究水源地上游林地产流及其氮磷运移规律,采用人工模拟次降雨试验方法,选择鲁中南山区泰安市黄前水库上游药乡小流域赤松林地作为研究对象,以荒草地为对照,对其地表径流和壤中流及其氮磷流失特征进行研究。结果表明:(1)次降雨条件下赤松林地地表径流量低于荒草地,而荒草地壤中流量低于赤松林地,赤松林地及荒草地土壤入渗量与植被覆盖度呈正相关。随着降雨的进行,赤松林地和荒草地地表径流产流量不断增加且趋于稳定,壤中流产流时间比地表径流晚,径流量较平稳。(2)次降雨条件下地表径流全氮(TN)流失量呈现初期输出浓度较高,随降雨的进行,输出浓度减少并逐渐趋于稳定状态,壤中流呈现相对稳定的状态。TN流失量与输出浓度呈正相关。赤松林地地表径流及壤中流TN流失量均低于荒草地。(3)次降雨条件下赤松林地地表径流全磷(TP)的输出浓度与流失量呈正相关;赤松林地地表径流及壤中流TP流失量均低于荒草地的。(4)赤松林地及荒草地前期降雨TN、TP总流失量均低于次降雨的;次降雨TN总流失量是前期降雨的1.11倍;次降雨TP总流失量是前期降雨的1.15倍。同时,次降雨赤松林地TN、TP流失量均低于荒草地的。因此,与荒草地相比,赤松林地具有较好的调控氮磷流失的作用。

Characteristics of Runoff and Loss of Nitrogen and Phosphorus Losses in Pinus densiflora Forest in Sandy Loam Soil in the Mountain Area of South Central in Shandong Province Under the Artificial Simulated Secondary Rainfall

In order to study the production flow and nitrogen and phosphorus migration of forestland in the upstream of water source,the artificial simulated secondary rainfall test method was adopted to select Pinus densiflora forest and barren grassland in the upstream of Tai’an City Huangqian reservoir in the mountain area of south central in Shandong province as the research objects to study the characteristics of surface runoff and subsurface runoff and nitrogen and phosphorus loss.The results indicate that:(1)Under the condition of secondary rainfall,the surface runoff of Pinus densiflora forest is less than that of barren grassland.The subsurface runoff of barren grassland is less than that of Pinus densiflora forest.Soil infiltration of Pinus densiflora forest and barren grassland is proportion to vegetation coverage.The characteristics of surface runoff are small in the early stage,with the progress of rainfall,the runoff of Pinus densiflora forest and barren grassland is increasing and beconing stable,the subsurface runoff is later than the surface runoff,and the runoff is relatively stable.(2)Under the condition of secondary rainfall,the total nitrogen(TN)loss of surface runoff presented a higher output concentration in the initial stage.With the progress of rainfall,the output concentration decreased and gradually tended to be stable.TN loss is proportional to the loss concentration.The loss of TN in surface runoff and subsurface runoff in Pinus densiflora forest is lower than that in barren grassland.The TN loss of surface runoff in Pinus densiflora forest is less than that in barren grassland.The interflow presents a relatively stable state.The TN loss in the interflow of Pinus densiflora forest is less than that in barren grassland.(3)Under the condition of secondary rainfall,the total phosphorus(TP)output concentration of surface runoff in Pinus densiflora forest is positively proportional to the loss.The amount of surface runoff and subsurface runoff TP loss in Pinus densiflora forest is lower than that in barren grassland.The total amount of surface runoff TP loss in Pinus densiflora forest was lower than that in barren grassland,and the total amount of interflow TP loss in Pinus densiflora forest is lower than that in barren grassland.(4)The total loss of TN and TP in Pinus densiflora forest and barren grassland is less than that in the secondary rainfall.The total loss of TN is 1.11 times of the previous rainfall.The total loss of TP was 1.15 times of the previous rainfall.At the same time,the loss of TN and TP in Pinus densiflora forest is less than that in the barren grassland.Therefore,compared with the barren grassland,Pinus densiflora forest has a better role in regulating the loss of nitrogen and phosphorus.