不同类型植被河岸缓冲带对模拟径流及总磷的消减研究

在九龙江上游北溪流域,选择杂交狼尾草(Pennisetum americanum×P.purpureum)、红花檵木(Loropetalum chinense var.rubrum)、红叶石楠(Photinia fraseri)3种植物及原生撂荒杂草地,构建对照(A)、草本(B)、灌草(C)和灌木(D)4种不同处理的植被缓冲带,通过模拟不同浓度面源污染下的农田径流,探讨不同植被组合对径流量及总磷的消减效果.结果表明:各缓冲带不同植被对径流量及总磷的消减效果均表现为草本灌草灌木,其中,草本缓冲带对径流量的消减率最高,达到86.93%,在高、低浓度进水时对总磷浓度的消减分别为95.20%、80.69%;4种不同植被缓冲带对总磷浓度的消减效果随缓冲带宽度的增加均出现上升的趋势,其中,前半段消减效果最佳,后半段消减趋势减缓;高浓度污染进水条件下缓冲带对总磷的消减效率高于低浓度进水;4种缓冲带对磷总量的消减量分别为27.70、28.02、28.06和26.94 g.研究成果可为九龙江上游河岸缓冲带建设及流域氮磷污染率治理和生态评价提供科学示范及理论依据.

Reduction of simulated runoff and total phosphorus in different vegetation riparian buffer

In the upper reaches of the north branch of the Jiulong River, the riparian buffer zone was constructed with different vegetative cover types of original weeds, Pennisetum americanum×P. purpureum, Loropetalum chinense var. rubrum and Photinia fraseri. Field simulated runoff experiments were performed to study the reduction effects on runoff volumes and total phosphorus in the contructed buffer zone with four vegetation combination treatments. The result showed that the order of reduction effects on the runoff and total phosphorus concentration inr four treatents was herb > herb +shrub > shrub. The highest runoff reduction rate was 86.93% in the herb buffer, and the corresponding reductions in total phosphorus were 95.20% and 80.69% respectively in the higher and lower phosphorus concentration input simulation.The reduction effect on total phosphorus raised with the increase of the buffer width of four different treatments.The reduction effects were better in the upper half section of the buffer zones. The reductions in total phosphorus were higher in the simulated higher phosphorus concentration input. The total reduction amounts of phosphorus in the four buffer treatments were 27.70 g, 28.02 g, 28.06 g and 26.94 g, respectively. The results provide a scientific demonstration and theoretical basis for the construction of the riparian buffer zone in the upper reaches of Jiulong River.