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Methods For Environemental Risk Control Of Intensive Agricultural Land Use At Landscape Scale

Posted on:2016-04-04Degree:DoctorType:Dissertation
Country:ChinaCandidate:H Q LiFull Text:PDF
GTID:1109330467491318Subject:Land Resource Management
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Highly intensive agricultural land use has caused many environmental problems, such as water quality degradation and soil erosion. Facing the increase of agricultural environmental problems, how to maintaining stable economic growth along with environmental improvement has been a significant challenge to agricultural sustainability in the future. The study took place in Jinjing Town where located in the primary grain-producing areas in China. Base on the theory of landscape ecology, land use effects and environmental risk control, we built three different alternative scenarios using a normative landscape scenario method and CA-Markov chain model, and presented the land use environmental risk from economical, social and environmental aspects. Combination with farm behaviors analysis, we proposed some effective approaches for environmental risk control of high intensive agricultural land use from multiple perspectives. The main conclusions as following:(1) Normative landscape scenario method was introduced to the field of agricultural landscape pattern design and new countryside construction planning. Comparing of land use effects among different alternative scenarios using normative landscape scenario method and trend extrapolation method, the results suggested that normative landscape scenario was plausible, recognizable, resilient, and inspired. This method is not only a suitable method in land use optimization, agricultural alternative scenarios, and new countryside construction planning, but also can provide available policy choices for policymakers.(2) Eighteen catchments were delineated in Jinjing watershed and corresponding water sampling sites were placed on the mainstream and tributaries by DEM, land cover map and GPS. Four water quality pollutions which include nitrate nitrogen (NO3-N), ammoniacal nitrogen (NH4+-), total nitrogen (TN), and total phosphorus (TP) were monitored from2009to2010continually. Based the pollution concentration data, water quality dynamic was analyzed at both spatial and temporal scales, excessive nitrogen has become an important risk factor in the Jinjing watershed. Three different buffer areas along the river were drawn to analyze the correlation between landscape pattern and water quality pollutions by Pearson’s correlation coefficient analysis and the result showed catchment was the suitable study unit size. Using the principal component analysis, four landscape types paddy land, forest, tea garden and residential area were chosen as main landscape analysis parameters, and calculated landscape pattern index of each catchment. Finally, a stepwise multiple regression analysis was employed to model the relationship between landscape characteristics and water quality pollution of N03--N、NH4+-N、TN for each season. The results demonstrated that both landscape composition and configuration affect water quality and can help environmental managers to understand the relationships between landscapes and water quality. It is meaningful to predict the water quality and provide landscape ecological approaches for agricultural land use environmental control in the future.(3) Scenario1emphasized on maximizing agricultural production and scenario2emphasized on improving water quality were build using a normative landscape scenario method, meanwhile, scenario3emphasized on new countryside construction was modeled using life cycle theory and CA-Markov chain model. Contrasted with the baseline year2010, the land use effects of each alternative scenario were calculated in terms of a range of environmental benefits, economic values, ecosystem service values, biodiversity, and farmer perceptions analysis. The results suggest that scenario1has a largest increase in agricultural production and the highest economic value. Scenario2improves water quality effectively and presents good ecological functioning and biodiversity. Scenario3promotes rural development with a stable ecological and ecological environment on the background of population and residential area increase dramatically. According to the analysis of farm perception and behavior, farmers are likely to prefer scenario1because it increases economic returns. However, this scenario may contradict the farmers’ perception of an appealing landscape, a friendly environment, and a beautiful rural landscape, which can be achieved in scenario2.Three future alternatives with special goals were designed by experimental simulations and empirical analysis. Therefore, they are feasible, operative and plausible, could exist in the future. The study may provide available choices on future agricultural and countryside development, environmental risk control and land use pattern for policymakers.(4) By reviewing future landscape scenarios and analyzing farmer perceptions, an series of approaches on landscape pattern optimization, farm perceptions and behaviors guiding, agricultural and land policy regulation were proposed to control environmental risk of agricultural land use. Landscape pattern control approaches include landscape pattern optimization on spatial aspect and landscape unit design. Farm perceptions and behaviors control approaches include two aspects. One is guiding farm’s decision behaviors, treatments of domestic wastewater and solid waste, and household breeding, the other is changing farmer’s cultivation perceptions and environmental awareness. Agricultural and land use policy approaches include a array of production prices, alternative influences of agricultural subsidies and ecosystem service payments, agricultural services, and related agricultural and land use regulations.
Keywords/Search Tags:Normative landscape scenario, agricultural landscape, land use, farmer behavior, environmental risk
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