摘要
为研究径流中的养分与植被覆盖的相互关系,通过人工降雨实验,采集流经油松林下枯落物层的地表径流水样,分析枯落物层对地表径流中化学元素及变化趋势的影响。结果表明:不同枯落物覆盖度对径流中总氮浓度的影响较大,随着枯落物覆盖度的增加,径流中总氮含量降低,随降雨时间大致成抛物线形变化,中间出现了一个平稳的过程,表现出增大-平稳-降低-稳定的变化过程。全磷含量极低,随枯落物覆盖度增加有微弱的增加趋势,一方面由于枯落物的覆盖减弱了径流与土壤层的相互作用,减少了土壤层对磷元素的吸附、固定和持留作用;另一方面径流对枯落物中磷元素的冲刷和淋溶,使得径流中的总磷含量随着枯落物覆盖度的增加而增加,而由于磷元素极易被土壤吸附和固定,所以径流中总磷浓度很低,增加趋势并不大,同时随着降雨历时的增加,总磷浓度的变化也不明显,减小的趋势十分微弱。全钾含量随枯落物覆盖度的增加而增加,随降雨时间成显著的线性降低的趋势,线性关系明显,原因是一方面径流量对钾有稀释作用,无枯落物覆盖更容易形成地表径流;另一方面也与枯落物为钾源有关,地表径流对枯落物中钾元素的冲刷也使得枯落物覆盖度高的林地地表径流中钾元素浓度高。同时,由于枯落物层的存在,增加了雨水的入渗,也降低了径流流速,加剧了径流与表层土壤的相互作用,相互作用的结果加速了土壤中的钾元素向径流释放。
In order to discuss the relationship between nutrients in runoff and vegetation cover, through artificial rainfall experiment and collecting surface runoff samples flowing through pine forest litter layer, the effect of litter layer on the chemical elements and trends in surface runoff was analyzed in the study. The results indicated that litter coverage had great effects on total nitrogen concentration in runoff. With litter coverage increasing total nitrogen content decreased in the runoff. It was in a parabolic change with rainfall duration increasing and a smooth process appeared in the middle time. Total nitrogen content presented a trend of increase-balance-decrease stability. The total phosphorus content was very low. It slightly increased with the litter coverage increasing. On the one hand, the coverage of litter weakened the interactions between runoff and soil layer and also weakened the adsorption, fixed and retention effects of soil layer on phosphorus element. On the other hand, this was because erosion and leaching of runoff on phosphorus made the total phosphorus content increasing with the increase of the litter coverage. And also because phosphorus elements can easily be adsorbed and fixed by soil, the total phosphorus concentration in runoff was very low and the increasing tendency was not large. Meanwhile, with rainfall duration increasing, the total phosphorus concentration did not change obviously and decreasing trend was small. Total potassium content increased with litter coverage increasing. It presented a trend of significant linear decrease with rainfall time increasing. Because on the one hand, runoff had a dilution effect on potassium, so without litter cover, it was easier to form surface runoff. On the other hand, the erosion of runoff on potassium also made potassium concentration higher in runoff where litter coverage was high. At the same time, the litter increased the infiltration of rainwater, reduced runoff velocity and raised the interaction between runoff and top soil, which accelerated the release of potassium into the runoff.
出处
《生态环境学报》
CSCD
北大核心
2012年第11期1800-1803,共4页
Ecology and Environmental Sciences
基金
“十二五”国家科技支撑计划项目(2011BAD38B05)
林业公益性行业科研项目(201104005)
