摘要
在自然降水条件下,连续14年对半干旱黄土丘陵沟壑区坡耕地及其4种退耕类型径流、侵蚀进行观测实验。结果表明:坡耕地退耕显著减少地表径流和土壤侵蚀,退耕类型之间径流量和侵蚀量存在显著差异,其大小次序为:农耕坡地>牧草地>乔木林地>自然草地>灌木林地。地表径流和侵蚀具有明显的季节分布特征,减流、减沙效应主要发生于7月和8月。牧草地累积减流、减沙效应随年度增加逐步下降,乔木林地的累积减流效应逐渐下降而减沙效应则逐步增加,灌木林地累积减流、减沙效应持续提高,自然草地则为先增长后降低的过程。14年观测结果表明:累积减流、减沙效应次序为:灌木林地>自然草地>乔木林地>牧草地。牧草地和乔木林地在短期具有较好的减流、减沙效应,而灌木林地和自然草地具有较好稳定持久的水土保持功能。
To control the soil and water losses is one of the general objectives of the Cropland Conversion Program (CCP). Therefore, there is a growing need to assess and improve the feasibility of soil and water conservation between cropland and conversion options in semiarid hilly loess plateau during the long-term period. The experiment was comparatively investigated upon runoff and soil erosion rate of conversion options under natural rainfall. The data were collected on nine runoff plots of 50 m^2 and six 100 m^2 plots over a period of 14-year. Significant differences occur between the conversion options in assessment of the water and soil conservation effects and efficiencies. On the basis of runoff during 14 years, the following ranking from the most to the least favorable was made for water and soil conservation effects: shrubland > wild grassland > woodland > pastureland. The runoff reduction mainly occur in July and August. The percentage of reduction runoff in July and August versus total reduction runoff in pastureland, shrubland, woodland and wild grassland is 49%, 73%, 58% and 73%, respectively, that of reduction erosion is 75%. The reduction ratio of cumulative runoff in woodland and pastureland gradually decreased from 43%, 52% during 1~2-year, 30% during 8 years and to 12%, 21% during the 14 years, respectively. Inversely, those in shrubland and wild grassland increased from 43%, 41% during 1~2 year, 61%, 59% during 8 years and to 66%, 44% during the 14 years. It may be concluded that theuse of purple alfalfa (Medicago sativa) and Chinese pine (Pinus tabulaeformis), in some cases, can produce much better conservation results such as in the short-term other than in the longer term.
出处
《水土保持学报》
CSCD
北大核心
2004年第4期37-41,共5页
Journal of Soil and Water Conservation
基金
国家重点基金项目(90102018)
国家"十五"科技攻关项目(2001BA606A-03)资助
