浅析万昌镇土地利用现状及相关问题的探讨

万昌镇位于永吉县西北部,距县城口前镇50公里,土地肥沃,水利资源丰富,是吉林省水稻主要产区。近年来,由于招商引资,修路、建桥、开矿,建立各种园区等,征用了大面积土地,致使全镇的土地利用结构发生了变化,特别是耕地面积逐年减少,严重的影响粮食产量和粮食生产安全,影响了农村经济快速发展。下面就全镇土地利用有关问题进行分析和探讨。

Landform Instability and Land-use Dynamics in Tropical High Mountains, Central Mexico

This investigation is an analysis of the influence of landform instability on the distribution of land-use dynamics in a hydrographical basin, located in the Mexican Volcanic Belt mountain range (central Mexico), currently affected by substantial changes in land use and deforestation. A landform map was produced, in addition to seven attribute maps - altimetry, drainage density, slope, relief energy, potential erosion, geology and tectonics - which were considered as factors for determining landform instability through Multi-criteria Evaluation Analysis. Likewise, the direction and rhythm of land-use dynamics were analyzed in four dates - between 1976 and 2000 - and cross tabulations were made between them, in order to analyze the trends and processes of land-use dynamics. Afterwards, the databases obtained were cross tabulated with the landform variables to derive areas, percentages and correlation indices. In the study area, high-instability landforms are associated with most ancient volcanic and sedimentary landforms, where high altitude, drainage density, slope and potential to develop gravitational and fluvial processes are the major factors favouring a land-use pattern, dominated by the conservation of extensive forest land, abandonment of human land use and regeneration of disturbed areas. In contrast, low-instability landforms correspond to alluvial plains and lava hills covered by pyroclasts, where low potential erosion to develop fluvial processes, added to water and soil availability and accessibility, have favoured a land-use pattern dominated by the expansion of agroforestry plantations and human settlements, showing a marked trend towards either intensification or permanence of the current land use and with little abandonment and regeneration.

Research on the Influence of Land Use Changing on Non-point Source Pollution in Heihe River Basin

Based on the exploring of SWAT model suitability in Hei River Basin, this paper analyze quantitatively and compare non-point source pollution loads occurred under different land use scene. At last, the following conclusion can be attained： （1） Land use change exerts tremendous influence on non-point source pollution. Since forest land can save water and reduce soil loss, which decreases greatly the source of non-point source pollution; （2） Strengthening land management and promoting reasonable land use, especially the over 15 degree slope farmland, will be the effective measure to control non-point source pollution and protect the quality of water in the Hei River basin; （3） The best land use situation in Hei River basin should be like the following modes： complying with national water source protection policy, gradual evacuation of river basin population, returning all the sloping farmland which is above 15 degree to forest land, allowing the existence of few farming land below 15 slope degree on the premise that the drinking water quality standard is reached, no unused land, good vegetation covering situation. At then, total nitrogen load is 13.25 kg, total phosphate load is 3.29 kg, which means it will not contaminate

Land Use Change Effects on Discharge and Sediment Yield of Song Cau Catchment in Northern Vietnam

The purpose of this paper is to implement ＂Soil and Water Assessment Tool （SWAT）＂ model to examine the effects of land use change scenarios; associated with crop rotations and special cultivation techniques most susceptible to erosion; exert on runoff discharge and sediment yield from Song Cau catchment in Northern Viet Nam. All scenarios＇ simulations resulted in a decrease of soil losses and sediment yield comparing to the current land use status. SWAT successfully predicted soil losses from different HRUs that caused significant sediment yield, and it predicted explicitly the consequences of non-structural mitigation measures against erosion.

Research Progress in National Land Use Planning and Implementation Guarantee System

Land use plan serves as a leading role in land resource management, necessitating a powerful implementation guarantee system. The research concluded researches on guarantee system for land use plan from law, administration, econo- my, society and technology. Finally, existing problems and suggestions were pro- posed.

Effects of future land use change on the regional climate in China

Land use and land cover change(LUCC)is one of the important human forcing on climate.However,it is difficult to infer how LUCC will affect climate in the future from the effects of previous LUCC on regional climates in the past.Thus,based on the land cover data recommended by the Coupled Model Intercomparison Project Phase 5(CMIP5),a regional climate model(Reg CM4)was used to investigate the climate effects of future land use change over China.Two 15-year simulations(2036–2050),one with the current land use data and the other with future land cover scenario(2050)were conducted.It is noted that future LUCC in China is mainly characterized by the transition from the grassland to the forest.Results suggest that the magnitudes and ranges of the changes in temperature and precipitation caused by future LUCC show evident seasonality,which are more prominent in summer and autumn.Significant response of climate to future LUCC mainly happens in Northeast China,North China,the Hetao Area,Eastern Qinghai-Tibetan Plateau and South China.Further investigation shows that future LUCC can also produce significant impacts on the atmospheric circulation.LUCC results in abnormal southwesterly wind over extensive areas from the Indian peninsula to the coasts of the South China Sea and South China through the Bay of Bengal.Furthermore,Indian tropical southwest monsoons and South Sea southwest monsoons will both be strong,and the abnormal water vapor convergence from the South China Sea and the Indian Ocean will result in more precipitation in South China.