Comparative Study On Land Consolidation Planning And Benefit Analysis Of Chongqing

Land consolidation is an effective measure to increase arable area, improve land quality, and enhance the land use. Thereby, it mitigates the land demand, improves agricultural production conditions and ecological environment, and assures the food safety and priming of economy. In recent years, a series of land consolidation standards and technical specifications has appeared. Whereas, due to the different conditions of nature and social economy, the land consolidation planning must consider the need of product development, the willing of farmer and the domain specificity of region of interest for the optimal state of the economical, social and ecological benefit.Land leveling project, agricultural hydraulic engineering, and farm road engineering among purple rock and karst region, suburb and exurb region are compared in this paper. Besides, it also descusses their difference of economical, social, ecological and comprehensive benefit. Thus, some characteristics of the land consolidation planning with different cultural, social economy conditions could be deduced to offer theoretical foundation for southwestern hilly and mountainous regions. The main results of the paper were followed:(1) Thickness of purple soil ranges from 0.20 to 0.60m and the purple rock can weather into soil in some years, so the thickness must be larger than 0.6m after the land consolidation. The place with lean soil can add the thickness of purple soil by blasting the rock which can weather intio soil, rather than by covering soil. By contraries, the soil thickness of karst terrain ranges from 0.10 to 0.40m and the soilforming process is very slowly, so the thickness need reach 0.40～0.50m after the land consolidation by covering soil and the land with much bare rock and gravel should be exploited for horizontal expansion. The raised path throuth fields of purple soil regions are mainly made of soil, while those are mainly made of stone stock in karst terrain. The engineering work load and invest of land leveling project of karst terrain are higher than the purple soil regions.The terrace type of dryland in suburb choose bench terrace made with crosswalll, but exurb choose sloping terrace made with crosswall and soil. Suburb exploit uneven ground and the land with much bare rock and gravel into gardenplot or dryland, as to improve the land yield capacity. The crosswall need be supported in gardenplot of suburb for the conservation of soil and water. While the gardenplot of exurb need not any land leveling project. Accordingly, the engineering work load and invest of land leveling project of karst terrain are higher than the purple soil regions.(2) Improving the density and size of escape canal is very important to cope with the drainage in purple soil ranges, while it is very important to improve the density and capacity of water-storage facility in karst terrain, due to the soil texture and the speed of infiltration. In addition, karst channel can be mucked out and utilized to improve the drainage capacity.Generally, the agricultural water requirement in suburb is less than that in exurb region, but the more intensivism is in demand to form highly efficient agriculture that provides greater and better yields. So, the water conservancy works, abstraction works and drainage works must be supported well in suburb. While the water conservancy works and drainage works must be supported well in suburb, due to the plant production is the most important industry.(3) Clear roadway of byway ranges from 3.0 to 4.5 m and build drainage to increase the stability of foundation and subgrade. The road surface which made from clay-bound macadam is 0.20-0.30m higher than original ground in purple soil ranges, while the road surface which made from concrete is 0.30-0.50m higher than original ground in karst terrain ranges. The thickness of subgrade made from slabstone ranges from 0.10 to 0.15m in purple soil ranges, while that made from slabstone and clay-bound macadam ranges from 0.10 to 0.15m, 0.10 to 0.15m, respectively. The drainages beside byway in purple rock region make from rag, and those make from sett in karst terrain ranges.The protection of slope must be payed attention to, such as build shelter forest, planting grass to lighten the pavement erosion.Clear roadway of byway ranges from 4.0 to 4.5m in suburb region, while that ranges from 3.0 to 3.5m in exurb region. The thickness of byway subgrade made from slabstone ranges from 0.15 to 0.20m in suburb region, while that ranges from 0.10 to 0.15m in exurb region. The thickness of byway road surface which made from concrete is 0.20-0.30m in suburb, while the thickness of road surface which made from clay-bound macadam is 0.10-0.15m in exurb. The arterial road thickness of yield road is 1.2-2.2m, the branch road thickness is 1.0-1.5m in suburb, while arterial road thickness of yield road ranges from 0.8 to 1.0m, and the branch road thickness ranges from 0.6 to 0.8m in suburb.(4) The economic, social, ecological and comprehensive benefit of bashan and yuchi land consolidation are outstanding. The economic benefit of bashan(NFV₁=34.20, NPV₂=-18.16, FIRR=5.31%)is better than yuchi (NPV₁=21.13, NPV₂=-14.07, FIRR=5.20%). The social benefit of bashan(0.895) is worse than yuchi(1.080); The ecological benefit of Bashan (0.939) is worse than Yuchi (1.096). The comprehend benefit value of Bashan (85.61) is smaller than Yuchi (83.05).The economic, social, ecological and comprehensive benefit of yuzhui and yujia land consolidation are outstanding. The economic benefit of bashan(NPV₁=30.90, NPV₂=-15.76, FIRR=5.32%)is better than yuchi (NPV₁=23.62, NPV₂=-10.30, FIRR=5.39%). The social benefit of bashan(0.999) is better than yuchi(0.972); The ecological benefit of Bashan (1.026) is better than Yuchi (0.979). The comprehend benefit value of Bashan (87.01) is larger than Yuchi (85.17).The benefit value of land grading of bench terrace made from dry rag is 81.80, while that of bench terrace made from grouted rubble is 89.48. So, the comprehend benefit of bench terrace made from dry rag is better than that made from grouted rubble.