南小河沟流域不同措施处理下的水土流失规律

以南小河沟流域长期定位试验场为研究对象,研究了10种不同措施处理下水土流失规律。结果表明,泥沙流失量与径流量变化规律并不一致。一般坡度越大,侵蚀量的增量越大。由于坡度越大,需要坡长越长才能和坡度较小的的坡面受水面积相等,这时即使因为坡度加大,入渗率减少,但实际入渗水量也有较大增加,即坡面水流的径流量并不会随着坡度的加大而无限的加大,20°为径流量临界坡度;采用水平阶整地的油松沙棘混交林地,植被覆盖度达到65%,水土流失治理效果显著,平均含沙量2.377kg/m3,比裸地减少了57.77%以上;平均径流量0.121m3,比裸地减少了19.74%以上;以生物措施为主进行水土保持治理的杨家沟小流域与原始生态环境下的董庄沟小流域相比较,2012年侵蚀模数减少了2 589.95t/(km2·a)。

Law of Soil and Water Loss Under Different Measures in South Xiaohegou Watershed

A study with 10 treatments was conducted in the long-term observation station of the South Xiaohegou watershed to investigate the law of soil and water loss under different surface treatments. Results show that soil loss was not consistent with runoff processes, but affected by slope. The soil loss incremental rate generally increased with increasing slope degree. However, when slope increased, slope length for collecting the same amount of water as at the smaller slope increased, which could lead to a reduction in water infiltration into soil, but the total infiltration increased. Therefore, runoff amount did not show a proportional increase with slope increase when slope was greater than 20°which was determined as the threshold. The study also shows that a mixed plantation of Chinese pine tree with sea-buckthorn at a coverage of 65% could significantly reduce soil and water loss, with a sediment concentration of 2.377 kg/m³ which was 57.77% lower than soil loss on the bare land. The averaged runoff of 0.121 m³ under the plantation was 19.74% lower than the bare land. In 2012, soil erosion index for the Yangjiagou watershed where biological control practices for soil and water conservation had been applied was 2 589.95 t/km² lower than the Dongzhuanggou watershed which remained in the natural conditions without any human disturbance.