摘要
生物土壤结皮对提高黄土区土壤抗冲刷与抗侵蚀能力起着重要作用,充分认识和了解其作用机理对治理该区土壤侵蚀具有重要意义。该文采用原状土冲刷槽的实验方法,于2008年9月对陕北黄土区不同类型生物土壤结皮冲刷过程中的径流含沙量、冲刷总量及抗冲指数进行了研究,结果表明:①苔藓比例是衡量生物土壤结皮抗冲能力的重要指标,土壤冲刷总量与苔藓比例呈负相关,生物土壤结皮崩解时间与其呈正相关。②生物土壤结皮冲刷过程中,径流含沙量随冲刷时间逐渐增加,在生物土壤结皮完全崩解后,径流含沙量开始减少。③土壤抗冲指数(冲走1g土所需时间)与时间呈显著二次多项式的关系,即随着时间增加,生物土壤结皮逐渐崩解,土壤抗冲指数随之降低。④生物土壤结皮的盖度与土壤冲刷侵蚀量呈负相关,即盖度越高,侵蚀量越低;在坡度与冲刷强度相同条件下,无结皮土壤径流含沙量是全覆盖结皮土壤的35倍。⑤坡度与生物土壤结皮径流含沙量呈正相关,且在陡坡条件下,生物土壤结皮抗冲刷和抗侵蚀能力更为明显,因此,提高生物土壤结皮盖度、增加生物土壤结皮苔藓含量是提高黄土区土壤抗冲刷能力的有效方法之一。
Microbiotic soil crust plays a key role in improving the soil anti-scourability in loess area and a full understanding of its mechanism is important in soil erosion conservation in this region. In this study, the authors used scouring experiment to study anti-scourability index of different types of microbiotic soil crust by measuring sediment concentration in surface run-off in the loess area of northern Shaanxi Province, northwestern China. The results showed that： 1 ） the moss content in microbiotic soil crust was an important anti-scourability factor and had a negative correlation with sediment concentration, while a positive correlation with the time of microbiotic soil crust collapsing. 2） During the process of scouring, sediment concentration increased with scouring time, and decreased after microbiotic soil crust collapsed. 3） Anti-scourability had quadratic relationship with scouring time. As the microbiotic soil crust collapsed with time, anti-scourability decreased. 4） The coverage of microbiotic soil crust had a negative correlation with sediment concentration, i.e. the higher the coverage was, the lower the soil erosion was. The erosion rate for soil without crust covering was 35 times of that with a fully covered surface. 5） Slope had a positive correlation with sediment concentration. The role of anti-scourability of microbiotic soil crust was especially distinct for a steep slope. In conclusion, increasing the coverage and lichen rate of microbiotic soil crust is an effective way to improve soil anti-scourability in the loess area.
出处
《北京林业大学学报》
CAS
CSCD
北大核心
2009年第5期96-101,共6页
Journal of Beijing Forestry University
基金
“十一五”国家科技支撑计划项目(2006BAD03A03)
关键词
生物土壤结皮
抗冲性
黄土区
microbiotic soil crust
anti-scourability
loess area
