退耕林地麻栎刺槐林壤中流及其磷素流失特征

为研究退耕还林后林地对壤中流磷素的调控效果,探究雨强对壤中流磷素流失的影响,选取鲁中南山区典型麻栎林、刺槐林和麻栎—刺槐混交林为研究对象,以荒草地为对照,采用模拟降雨试验方法,研究林地壤中流及磷素流失特征。结果表明:(1)林地壤中流占总产流的36.16%～46.93%,荒草地壤中流比例为18.58%,林地雨水下渗能力高于荒草地的,其中麻栎—刺槐混交林雨水下渗能力最好。随着雨强的增大,林地壤中流比例由54.34%减小到37.62%。(2)林地壤中流TP流失量低于荒草地的,为荒草地的45.88%～63.25%。林地TP总流失量比荒草地少55.32%～77.43%,与荒草地相比,林地对磷素的调控效果更优,其中麻栎—刺槐混交林的调控效果最好。随雨强的增大,林地壤中流TP流失量增加了0.68～1.33倍。(3)林地和荒草地的壤中流TP流失量占TP总流失量的12.12%～25.00%,壤中流TP流失在TP总流失中占据一定比例,在磷素流失中不容忽视。随着雨强增加,林地壤中流TP流失比例由30.66%下降到10.62%。研究成果对探究林地壤中流磷素流失规律和改善生态环境具有重要参考价值。

Characteristics of Subsurface Runoff and Phosphorus Loss in Quercus Acutissima and Robinia Pseudoacacia Forest in the Grain to Green Program

In order to study the effects of forest land and rain intensities on the phosphorus loss regulation in subsurface runoff, the typical Quercus acutissima forest, Robinia pseudoacacia forest and Quercus acutissima-Robinia pseudoacacia mixed forest in hilly area of middle southern Shandong Province were selected as the research objects. And simulated artificial rainfall experiments were carried out. The results showed that:(1) Subsurface runoff accounted for 36.16%~46.93% of the total runoff in forest, and for 18.58% in grassland. The rainwater infiltration capacity was higher in forest land than that in grassland, and the mixed forest gave the highest rainfall infiltration capacity. With the increase of rainfall intensities, the proportions of subsurface runoff decreased from 54.34% to 37.62% in forest. (2) TP losses with subsurface runoff in forest were only 45.88%~63.25% of those in grassland. Total TP losses in forest land were 55.32%~77.43% lower than thoseof grassland. Compared with grassland, the control effect of phosphorus in forest land was better, especially for the mixed forest, which gave the best control effect on phosphorus loss. With the increase of rainfall intensities, TP losses with subsurface runoff in forest increased by 0.68 times to 1.33 times. (3) TP losses with subsurface runoff accounts for 12.12%~25.00% of the total TP losses in forest and grassland. TP losses in subsurface runoff occupied the certain proportions of the total TP losses, so the subsurface runoff could not be ignored in TP loss control. With the increase of rainfall intensities, the proportions of TP losses with subsurface runoff decreased from 30.66% to 10.62% in forest. These findings could provide important reference for phosphorus loss control in forestland and the improvement of ecological environment.