| Soil and water loss has become a worldwide problem and as the most universal geological hazard it is called peristaltic disaster.There always exists soil and water loss at different degree in both developing countries and developed countries.At present 97%of crop production still depends on soil.Any crop planted in the land lossing fertilizer,water and soil won't have a good harvest.It is a very important issue for small watershed comprehensive management to provent water and soil erosion,rationallydevelop and use land and water resources,develop ecological economy and sustainable agriculture in these areas of natural resources destruction and,serious water and soil erosion.In this study,field investigation and laboratory analysis were combined to investigate systematically soil and water conservation measures in Yuzigou small watershed of kaixian county and analysis the ecological benefit,economic benefit,social benefit and evaluate the comprehensive benefit.This study shows successful experiences of soil and water conservation comprehensive management and possesses guiding significance for scientific policy making for the government.The results show that:(1) soil and water conservation treatment measures can control soil and water loss,the quantity of surface runoff and soil loss is much less than waste grassland.The index of runoff is rubble transforming slope into terrace(0.46m~3/100m~2)＜forest for soil and water conservation(0.66m~3/100m~2)＜soil conservation farming(1.25m~3/100m~2)＜economic fruit forest(1.51m~3/100m~2)＜nudation land (2.99m~3/100m~2);the index of soil loss is rubble transforming slope into terrace(0.18 kg/100m~2)＜forest for soil and water conservation(0.53kg/100m~2)＜economic fruit forest(2.25kg/100m~2)＜soil conservation farming(3.13kg/100m~2)＜nudation land(6.51kg/100m~2).The effect is different as the dissimilar measures, rubble transforming slope into terrace is prominent,while forest for soil and water conservation,soil conservation farming,economic fruit forest is not perfect ay all,but all of their effect are all better than the waste grassland.(2) The effect of soil improving is different.Compared with the waste grassland,all kinds of soil and water conservation treatment measures can effectively improve soil nutrient,increase soil fertility;increase the content of big soil pore to promote the infiltration rate.Rubble transforming slope into terrace and forest for soil and water conservation have a remarkable effect on physical properties improving.And rubble transforming slope into terrace also has a remarkable effect on improvement of soil fertility.(3) The economic benefit is different in diverse soil and water conservation treatment measures.The index of the net benefits is rubble transforming slope into terrace(10106.1yuan/hm~2)＞soil conservation farming(7896.9 yuan/hm~2)＞economic fruit forest(7141.05 yuan/hm~2)＞forest for soil and water conservation(2230.05 yuan/hm~2);the index of the outout-input ratio is rubble transforming slope into terrace(2.05)＞soil conservation farming(1.77)＞economic fruit forest(1.68)＞forest for soil and water conservation(1.42),so the rule of the net benefit and the outout-input ratio show the same trend.(4) The index of the comprehensive benefit is rubble transforming slope into terrace(2.160)＞forest for soil and water conservation(1.501)＞economic fruit forest(1.371)＞soil conservation farming (1.298)＞nudation land(0.327).Compared with the comprehensive benefit of waste grassland,that of rubble transforming slope into terrace,economic fruit forest,soil conservation farming,forest for soil and water conservation are 6.61,4.59,4.19,3.97 times of it.(5) According to benefit analysis of diverse soil and water conservation treatment measures,different measures have different advantages.If only small watershed comprehensive management is suited to local conditions and develop complementary measures,the management can be effective and improve the sustainable development soil and water conservation agriculture. |
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