| In recent years, along with the rapid economic development and the accelerated process of urbanization, the contradiction between people and land has become increasingly prominent, and the demand of land for construction is increasing every year. The protection of arable land red line and stick to 1800000000 Mu is the basic goal of our country. So how to coordinate and support for the demand of economic development and infrastructure construction land, is the problem in front of workers of land science. Corresponding to it is with the rural farmers’ income increasing, many farmers have moved from the countryside to the city, which makes a lot of rural homestead idle, resulting in a waste of land resources. According to the Ministry of land and resources issued the "urban and rural construction land" policy, the rural homestead reclamation is an important way to solve the shortage of land conflicts. Chongqing positively responds to the national policy in recent years, and the area of land reclamation is larger. In 2008 to 2013 in Chongqing City, rural construction land reclamation projects had 6314, and the area of land reclamation was 24740 hectares, and achieved certain results, but also appeared a series of problems, such as the only pay attention to the new farmland index, the reclamation after the land does not manage protection, that leads to the poor quality of cultivated land after reclamation, inefficient use of land and appeared fallow again. At home and abroad on the rural homestead reclamation research mainly concentrated in the potential evaluation about rural residential reclamation, benefit analysis, current situation, problems and measures of land reclamation, reclamation soil quality and land reclamation planning design and other aspects, but there is less research on the reclamation land use. So the research on the land reclamation of cultivated land use pattern has ascertain practical significance to increase crop yield, improve the reclamation of cultivated land use efficiency, realize the farmers’ income increasing, enhanced cultivated land protection.Based on investigation of the present situation of land reclamation of cultivated land use in Chongqing city, this study analysis and compares the economic efficiency and the utilization rate of light energy of each mode, and makes a field experiment in Tongliang County Water Town by selecting six kinds of good planting patterns (i.e. CP1 dish-green beans, CP2 rape/corn, CP3 lima bean-corn, CP4 potato/ watermelon, CP5 potato/corn, CP6 Asparagus-corn). Then researching the influence of six kinds of planting patterns on soil quality, economic benefit and ecological benefit, and synthetically evaluates the six planting patterns by using the gray correlation degree analysis method. The research has drawn the following conclusions:1. Investigation of rural homestead reclamation of arable land use status of Chongqing cityWe discover by investigating the land use pattern of reclamation of rural homestead in Chongqing Three Gorges Reservoir area, Wulong mountain area and west area, the vegetable pattern has the highest net income for the western region of the regional land reclamation, and its net income is 101850 yuan/ hectare; Artemisia annual’net income is the lowest in Wanzhou of the Three Gorges Reservoir area, and its net income is only 10500 yuan/hectare; Light utilization rate of corn/sweet potato pattern is the highest in Three Gorges Reservoir area, and its light energy utilization rate is 1.04%; The lowest is flue-cured tobacco in mountainous area of Wulong, its light energy utilization rate is only 0.1%.2. Effects of different reclamation of arable land use patterns on soil quality(1)Effects of different reclamation of arable land use patterns on soil physical propertiesAfter the test, soil and planting density of each model was lower than before, and the difference was significant, in which bulk density of CP3 (Hu Dou-corn) was the lowest and CP4 (potato/watermelon) was the highest. The soil water content and soil porosity of all matters has increased then the before, but the difference between the model did not reach the significant level. At the end of the experiment, the planting soil gravel content decreased, and the difference is significant, the smallest model of gravel content is CP3 (Hu Dou-corn). Different planting patterns on soil aggregate effect on >5mm and 2-5mm particle size had significant difference after the experiment, and soil aggregate percentage and mean weight diameter was increased, and CP3 (Hu Dou-corn) both were the highest. So six planting patterns can improve soil structure and increase the stability of aggregates, but CP3 (Hu Dou-corn) had the best effect.(2)Effects of different reclamation of arable land use patterns on soil chemical indexThe end of the experiment, in addition to soil pH value, total nitrogen and total potassium had no significant effect, the effect of other chemical properties were significant. The soil pH value of various planting patterns were decreased than before the test, and the highest mode was CP3 (Hu Dou-corn) and the minimum was CP4 (potato/watermelon). After the test the content of soil organic of CP1 (dish-green beans), CP2 (rape/maize), CP3 (lima bean-corn) and CP5 (potato/corn) was increased, but the others’was decreased. The highest content was CP2 (rape/corn) and the least was CP4 (potato/watermelon). In the Soil total nutrients, soil total nitrogen content were increased in addition to test CP4 (potato/watermelon) and CP6 (lettuce-corn), and CP3 (lima bean-corn)’was the highest and the content of CP4 (potato/ watermelon) was the lowest; Total phosphorus content of all patterns were decreased and the content of total potassium was increased, and the content of CP2 (rape/ maize) was the highest.In the soil available nutrients, nitrogen content were increased than before the test, and CP3 (lima bean-corn)’was the highest; the content of available was decreased in addition to CP2 (rape/corn), and CP4 (potato/watermelon)’was the lowest; the content of available potassium were increased in addition to CP4 (potato/watermelon), and CP3 (lima bean-corn)’was the highest. Synthetically compared the effect of soil chemical properties of various planting patterns can obtain, the effect of improving soil nutrient of CP4 (potato/watermelon) was the worst, but CP2 (rape/corn) and CP3 (Hu Dou-corn) can improve soil nutrient.3. Analysis of the benefits of different modes of land reclamationIn six planting patterns, CP1 (dish-green beans)’economic yield was the highest, and it was 31838.10 kg/hectare, and CP3 (lima bean-corn)’economic yield was the lowest, and it was only 7401.60 kg/hectare. CP6 (Asparagus-corn) has the highest biological yield and it was 30498.58 kg/hectare. The lowest was CP4 (potato/ watermelon) and it was 14810.74 kg/hectare. CP1 (dish-green beans)’total revenue, cost, net income and the ratio of output to input were the highest, and its net income was 64778.92 yuan/hectare. The total revenue, net income and the ratio of output to input of CP2 (rape/corn) was the lowest, and its net income is 5779.53 yuan/hectare, only is 8.92% of the former, and the cost of CP3 (Hu Dou-corn) is the lowest. The light energy utilization rate of CP5 (potato/maize) was the largest which reached 1.57%, and CP4 (potato/watermelon) was the lowest which only 0.13%. CP5 (potato/maize)’ output and net capacity were was the highest, and its net capacity was 316189.75 MJ/hectare, and CP2 (rape/maize)’ investment was the highest, and the ratio of output to input of CP6 (Asparagus-corn) was the largest, and all the energy index of CP1 (dish-green beans) was the smallest, and its net capacity was 9611.48 MJ/hectare which was only 3.04% of the former.4. Comprehensive evaluation different land use model of the reclamation of arableThis study selected ten indicators to evaluate the six planting patterns from the physical and chemical properties of soil, economic benefits and ecological benefits using the gray correlation analysis method, and obtained CP5 (potato/ maize)’ association both was the largest of all the assignment of weight and weight assignment according to the importance of each index, and it was the optimal model, so we can make the appropriate promotion in land reclamation of arable land planting; while CP4 (potato/watermelon) correlation degree is the smallest and it was the degradation model. |
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