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The Driving Forces, Effects And Sustainable Appraisal Of Land Use Changes In The High Input Agricultural Region

Posted on:2004-10-29Degree:DoctorType:Dissertation
Country:ChinaCandidate:X B KongFull Text:PDF
GTID:1116360092496395Subject:Soil science
Abstract/Summary:PDF Full Text Request
Changes in Land use and land cover (LUCC) are the challenge to the sustainable land management(SLM),and the SLM is the key to solve these sustainable development problems.Combining the LUCC study with the SLM study is the innovation of separate studies.Quzhou county in Hebei province is located in the middle of Huang-huai-Hai plain. It is a typical agricultural region with higher input and higher yield. So Quzhou county was chosen as a case study area for researching the driving forces and effects of land use changes, evaluating the sustainability of land use changes, and identifying the methods of sustainable land use.The land use map was taken as the basis map. With GIS, GPS supporting, all of the data collected, including statistics data, farmers input and output data, soil fertility data, water depth and quality data, etc. were put on the land use map. By comparing the temporal and spatial changes of these data, there were following conclusions out coming:(l)The change of cultivated land shows this tendency: rapid increasing period, rapid decreasing period, slow decreasing period, stable period, The driving force of cultivated land change are population change, climate change, technical change, the economic development and the national policies.(2) the results of the fluctuation of the crop structure shows that the wheat sowing is stable, but the corn and the cotton sowing fluctuates all the way each other. Farmers arrange the crop sowing portion depending on the price of input material and the price of products.(3)Farmers have the different land use aim, which come through the food oriented, the food and profit oriented and profit oriented.At the first phase, the farmers have no other means to satisfy food demanding, farmers had to increase the sown area, by reclaiming the margin arable land.At the second phase. Farmers demand not only the food security but also the profit.they managed to arrange the labour forces, input and farmland use direction wisely. At the third phase.the farmers take the profit as the only goal, they put farmland into using in the most profitable crop, even transform farmland into construction land, if the chance coming.According to our analysis, the farmers in Quzhou are in the second phase, which means they already have enough food and put much more inputs for earning high yield and high income.(4)The ground water table was getting down, caused by precipitation decreasing, no river water coming due to the upstream reservoir, complete drainage in rainy season and irrigation using groundwater.(5) The organic matter, total nitrogen, available phosphorus content were different between different land use types in 1980 and 1999, the order of these nutrients content in different land use types was irrigated land>rained farmland>grassland in 1980; the order of these nutrients content in different land use types in 1999 was vegetable land >irrigated land> rained farmland; The changes of organic matter, total nitrogen, available phosphorus content were different between different land use types from 1980 to 1999, the order of these nutrients content change was vegetable land>irrigated land> rained farmland>grassland.The groundwater depth is the key to control the salt content of soil. With the ground water table falling down, the salt content of soil decreased. So the saline soil could be cultivated as farmland. Finally the soil fertility was gradually increased with the chemical fertilizer inputing.(6)There were the evidence of nitrate accumulation in the groundwater pesticide and high weigh metals accumulation in the surface soil, with the more utilization of fertilzer and pesticide. But, it is not reached the critical standard.(7)With the improvement of soil quality, the crop yield increased rapidly and the income of the farmers also increased too at the same time.(8)The most limited factor to the sustainable land use is the water resource, due to the increase of the crop yield and the crop sowing area, So it is important for sustainable land use to...
Keywords/Search Tags:Land use change and its driving forces, effects of land use, sustainable land use appraisal, intensive agricultural region
PDF Full Text Request
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