| Selecting Shiqing Cun Nanping Zhen, Nanchuan District of Chongqing City, a typical rocky desertification village as the research area, which has five representative kinds of land-use patterns, i.e., slope farmland, woodland and grassland, honeysuckle land, while comparing their ecological benefits, economic benefits, social benefits and the comprehensive benefit. several evaluation indexes are selected as the evaluation factors, with the multi-objective grey relation projection method, based on its value, the projection value is greater, the better benefits. In addition, the reasons of differences of benefit are analysised.The composition fertilizer benefit, consolidation benefits and water conservation benefit, which is the most important for rocky desertification, form the ecological benefit, and the number of total indicators is 21. Economic benefits are mainly fromed by 3 aspects of the 5 landuse, namely the input、the output and the contribution rate of the agricultural output value,and the evaluation indexes are material input per unit area, the economic benefit of unit area, the net income per unit area per unit area, the rate of return on investment, unit area output input ratio. Social benefit is mainly consist of helping rural residents get rid of poverty, promoting social progress, safeguarding social stability and unity. Correspondingly, pure income per unit area per unit area, economic benefits, the rate of return on investment, land productivity, labor productivity, increase the employment situation of rural infrastructure construction, the improvement of agricultural science and technology achievements, the application situation and the health of rural residents in different land use patterns on income contribution rate are selected as the indicators.The results showed that:(1) In terms of ecological benefits, woodland> honeysuckle land> grassland> cultivated land> slope farmland. The capacity of consolidated soil is that woodland> grassland > honeysuckle land>cultivated land> slope farmland.the capability of soil nutrient preserving is woodland>honeysuckle land> grassland> cultivated land> slope farmland. The gap between Honeysuckle land and woodland is not sharp, and both projection values are high, while the others are weak. Water conservation capacity is grassland> wood land>honeysuckle land>cultivated land> slope farmland. Therefore, in the rocky desertification process, taking the ecological restoration into consideration merely, the conversion of cropland to forest project should be vigorously popularized, developed root system of plants should be planted, timely fallowed,and set up the fallow mechanism, while the traditional farming should be limited.(2) As far as economic and social benefits is concerned, honeysuckle land> woodland > cultivated land> grassland> slope farmland. Planting honeysuckle at Karst mountain area has important significance, because it can ease the economic backwardness and alleviate the contradiction between people and land to some degree. In addition, it may maintaine regional stability and unity, promote regional social progress.(3) In terms of the causes, the difference between capacity of overland flow and soil anti erosion the reason. Due to the vegetation cover and infiltration, they have different production capacities, and the physical properties of surface soil and lead to different anti erosion ability. because of low runoff ability and a strong anti erosion ability, the woodland has strongest consolidation; compared with the honeysuckle and traditional farmland, without the influence of human activity,the grassland has good ecological system, so it has better consolidation; compared with the other two kinds of traditional farmland, honeysuckle has less damage to the surface of soil erosion, the soil erosion is weaker; because of the larger slope and phenomenon of downslope tillage, the loss of soil of slope farmland is the strongest.(4) Different land use have different nutrient preserving capabilities and soil fertility which has relevant to the intensity of soil erosion and the anti erosion properties of soil fertility elements, in other words, it has relationship to the strength of soil fertility dissolution. Woodland has lowest runoff coefficient, so the soil and water loss is smaller. Cultivated land and slope land has larger vegetation coverage, but with the biger runoff intensity, which is resulted form human activities, in the end,they has stronger fertilizer retention capacity. Downslope tillage contribute s to soil erosion,while the ratio of the study area downslope tillage is higher, and the bedrock fracturerate is high, the soil erosion is serious. In addition, the steep over 10 degrees in the area is larger, which has significance to exacerbate the loss of soil fertility. Compared with the cultivated land, the advantage of planting honeysuckle is that human activities has less damage to the surface, reducing the loss of soil fertility level, correspondingly, contrast to the slope land, without the influence of human activity on soil fertility for a long time, grassland has great significance to avoid soil fertility getting loss caused by human activity.(5) The water storage capacity of different land use types is mainly affected by litter, soil physical properties, permeability effect. Litter size, structure, and texture have an important influence on litter water storage. And the infiltration capacity of soil is mainly composed of soil physical properties. Grassland has larger litter content, it has soft texture, with stronger litter water storage capacity, but combinated with effects of soil physical properties, water storage capacity of forest land is the strongest. The other 3 land use patterns, affected by human activities, water holding capacity of litter and soil water storage capacity are worse. |
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