| Agricultural land consolidation (ALC) as an approach to change the land use conditions, which funded by national investment and local government provide some matching funds. After the implementation of ALC, the area of cultivated land has increased, the quality of cultivated land was improved, and ALC not only promoted the regional development, but also plays a key role in easing of land use conflicts and guarantees the food security. There are many researches about effects of ALC on social and economic benefits. ALC brought those benefits to farmers, but large-scale implementation of the agricultural land consolidation project (ALCP) within the geospatial farmland will destroy the natural balance of ecosystems, and the cropland ecosystem (CE) has a greater resistance to maintain the balance. The CE is centered on crops, has human interact with biological and ecological environment. It not only has the basic functions of energy flow, material circulation and information exchange, but also provides production, economic, security, supply and ecological functions for human. Therefore, this thesis studied effect of ALC on cropland ecosystem functions (CEF), referenced to guide the regional planning and strengthen assessment of ecological impact.First, the paper studied the implementation of ALCP based on China’s current status and analysis of CEF, sort out the effect process of ALCP on the ecosystem and its functions and recovery. Second, we found out the mechanism of the effect of ALC on the multifunction and basic functions of the ecosystem. Third, the paper use set pair analysis and variable fuzzy sets method to study the effects of ALC of individual provinces on CEF from the province-scale of ecosystem multifunction. Forth, from projects-scale, we calculated the eco-flows including the emergy and exergy of effect on the eco-system, these flows are basic function flows, and then studied the influence time of the ALC. Last, the paper compared the cumulative effects in time series, to simulate the relationship function of the effects of ALC on CEF by Logistic growth Model. By exploring these five aspects of the main conclusions are as follows:(1) The ALC in china is still in the development stage. During the year of 2006-2010, the ALC investment accounted for 11.32% of total investment of agriculture, and it is increased year by year. The ALC significantly promoted the development of rural economy. There are 2.7 million hm2 of the new cultivated land after ALC from 2006-2010, built irrigation and drainage ditches for 6.70×106km, completed field road for 5.90×106km. The ALC improved production conditions, promoted social stability and improving living conditions in rural areas, but changed the landscape pattern of cropland and affected ecological environment.(2) The ALCP had ecological impact on soil, water, biological environment of cropland. Agricultural land consolidation affected production, economic, security, supply and ecological functions, etc. of CEF, also had an effect on ecosystem basic functions at the micro scale, that are energy, material, and information flow etc. Large-scale ALC will have some cumulative temporal and spatial effects on CEF.(3) Agricultural land consolidation affected multifunction of cropland ecosystem, and those effects had obvious geographical differences between functions. The most prominent features are the positive effects on the economic function and negative effects of ecological function on a national scale. The ALC significantly improved production function of the major grain producing provinces, promoted economic function in the coastal provinces etc., protected the security functions of Xinjiang and other places, greatly improved the supply function of Liaoning, Jiangsu, Shandong province, etc., but played a negative role on influencing the ecological function of the southern provinces and central provinces.(4) As a case study on the ALCP of Fengxiang County, Shaanxi Province, the results are the ALCP had a long time effects on the eco-flow of CE; after the first year of implementation of the ALCP, the exergy of the eco-flow effects is 7.17 PJ, the emergy is 21.02EJ; the CE take 4 years to achieve a relatively ecosystem balance calculated by the emergy method, according the exergy method, the CE naturally restore the ecosystem balance need 29 years, the net cash flow and net ecological value turned positive three years after the project began.(5) The cumulative effects of large-scale agricultural land consolidation on CEF is much higher than the simple sum of the effects of the project, so this cumulative effect is synergistic effects and its trend presented Logistic retarded growth. During five years after the implementation of the ALCP, the difference value between cumulative effects and sum effects reached the maximum value, and then five years later growth speed will be receded. However, this tiny recede trend reveals ALC is changing the dynamic balance of cropland ecosystem stability, and it is very natural and normal. |
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