【摘要】 <正> 三川河流域地处我国黄土高原东部,属黄河一级支流。流域面积4161km~2,覆盖吕梁地区的方山、离石、中阳和柳林四个县。流域内黄土丘陵沟壑区占39％,土石山区占61％。全流域共有水土流失面积2767.2km~2,占总面积的66.5％。治理前,流域年平均土壤侵蚀模数为7024t/km~2,其中黄土丘陵沟壑区的年土壤侵蚀模数高达1.56万t/km~2。严重的水土流失每年带走大量适宜植物生长的表土,导致土壤贫瘠,土地生产能力下降,环境恶化,生态严重失调。重点治理前的1982年,流域内人均产粮259kg,人均收入仅69元。1983年三川河流域确定为全国八个水土保持更多还原

【Abstract】 After 10 years of comprehensive harnessment of soil loss, the degree of comprehensive harnessment in Sanchuanhe river basin reached 57. 6%, the overall static ratio of output to input was 2. 60, the investment return period was 12. 67 years;the dynamic ratio of output to input was 1. 69, the investment return period was 14. 85 years, the internal rate of return was 19. 94%. Among various measures of harnessment, the investment return period of machine-built terraces was the shortest, while the internal rate of return and ratio of output to input of economic forest were the highest. In the Sanchuanhe river basin, high grade machine-built terraces are the foundmental measures to upgrade farm production and to solve the problem of eating of farmers; Vigorously developing economic forest is the crux to increase the income of the mass and to Improve the level of life; Building protection forest and planting grass by retreating from farmland have important effects in reducing soil erosion arid improving local bio-nenvironment.更多还原