| The quality of arable land is the key to guarantee food security. In China, a large population with relatively little arable land has always been a challenge of development and national security. In the meanwhile, the qualities of most arable lands are generally low, which has already became a new obstacle which China has to tackle. Land consolidation has achieved remarkable achievements in increasing the number and improving the quality of arable land. To carry out researches on key technology of land consolidation project would benefit the enhancement of land consolidation, realize the strategy of “improvement of crop productivity and agricultural technology”, as well as reinforce the multiple objectives of quantitative, qualitative and ecological reconstruction of arable land.Research progress and relative basic theories were systematically reviewed, furthermore, the definition of arable land quality was redefined. By analyzing the characteristics of arable land quality, we considered arable land quality as a composition of natural, engineering, and management elements. Based on the factors agricultural land gradation, the feasibility of quality upgrade was pointed out by analyzing the effects of land consolidation projects on influencing factors of arable land quality. Based on a summary of the obstacle factors of arable land quality upgrade, methods and construction technology aiming at ameliorating the effective thickness of il, the profile form of soil body, the soil obstacle layer and the texture of surface soil were proposed to enhance the present land consolidation project system. Through analyzing the designing and procedure of land consolidation project, integrating approaches of arable land quality upgrade were proposed according to the present designing system. According to the idea of controllable designing of arable land quality upgrade, the investigation technology of arable land quality monitoring were studied in order to amend the lag of basic agricultural land gradation data. For the purpose of accurately evaluating the effects of land consolidation on arable land quality, the revaluation method based on agricultural land gradation has been developed to evaluate the arable land quality in study area. On the basis of pre-evaluation method of the potential of gradation factors, a model for calculating realizable potential of arable land quality was proposed. According to the how well land consolidation projects can improve these gradation factors, project-type zoning technology was studied based on the combination of potential indexes. Furthermore, the procedures of setting the target of arable land upgrade in different investment conditions and default target grades were studied. Finally, the key technology of land consolidation project designing, which integrate technologies mentioned above were proposed based on the achievements of agricultural land gradation.To take Land consolidation project of Zhongjiang County in Sichuan Province as an example, 38 sampling points were laid for further empirical study. Updating investigations on five gradation factors including effective soil thickness, soil profile form, slope, rocky outcrops, guarantee rate of irrigation and drainage condition were carried out. The quality of arable lands in study area were revaluated based on the updating investigation. The results compare new arable land quality grade with original grade shows that national natural grades in 12 evaluation units were one grade lower, and the national utilization grades in 2 evaluation units were two grade lower. The realizable potential of arable land quality upgrade was calculated by area weighting. The average realizable potential of national natural grade is 0.84 grade, the average realizable potential of utilization natural grade is 0.62 grade, and the average realizable potential of arable land class level is 0.72. Finally, three type of engineering zone were classified based on project of increasing effective thickness of soil layer and project of irrigation. |
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