KEYWORDS: Vegetation, Remote sensing, Soil science, Geographic information systems, Agriculture, Volume rendering, Environmental hazards, Data modeling, Data integration, Information technology
The Crisscross Region of Wind-drift Sand Regions along the Great Wall and Loess Plateau locates in southern Ordos Plateau and northern Chinese Loess Plateau, where wind erosion and water erosion coexist and specified environmental and socio-economic factors, especially human activities induce serious land degradation. However, there are only a few studies provide an overall assessment consequences. Integrated land quality assessment considering impacts of soil, topography, vegetation, environmental hazards, social-economic factors and land managements are imperative to the regional sustainable land managements. A pilot study was made in Hengshan County (Shanxi Province) with the objective of developing comprehensive land quality evaluation model integrating data from farmers' survey and Remote Sensing. Surveys were carried out in 107 households of study area in 2003 and 2004 to get farmers' perceptions of land quality and to collect correlative information. It was found out that farmers evaluated land quality by slope, water availability, soil texture, yields, amount of fertilizer, crop performance, sandy erosion degree and water erosion degree. Scientists' indicators which emphasize on getting information by RS technology were introduced to reflecting above indicators information for the sake of developing a rapid, efficient and local-fitted land quality assessment model including social-economic, environmental and anthropogenic factors. Data from satellite and surveys were integrated with socio-economic statistic data using geographical information system (GIS) and three indexes, namely Production Press Index (PPI), Land State Index (LSI) and Farmer Behavior Index (FBI) were proposed to measure different aspects of land quality. A model was further derived from the three indexes to explore the overall land quality of the study area. Results suggest that local land prevalently had a poor quality. This paper shows that whilst the model was competent for its work in the study area and evaluation results would supply beneficial information for management decisions.
This paper analyzed land use change in Bashang area of Hebei province, with 1992 and 2002 TM (ETM). Based on GIS and statistical methods, the intensity, state index of land use change and transfer matrix were used to study spatio-temporal land use change in the region. The results showed that the area of arable land decreased greatly, also the area of wetland decreased. The other way round, the area of grassland, forest land and building land increased. As a whole, the intensity of forest land change was higher, but others were lower. From the transfer matrix, most of the arable land changed into grassland and forest land, some to building land. The grassland and forest land was mainly transferred from unused land, except for arable land. The building land mostly came from arable land. The wetland was used for grass and forest area. It was showed that the eco-environment degraded, and the land use change was an important driving force of eco-environment change in the study area. Unfeasible land use pattern and land reclamation by human beings resulted in soil loss and sandy land increase.
In this article, the information development techniques and methods of characteristic spatial and spectral dimensions applied to distinguish separability of the similar spectrums and the relationship with soil physical and chemical characteristic in the conjoind field of the desert foreland and the Loess Plateau of China. The soillines parameters were primarily proved up the relations with soil orginal matter and soil water content,and had better availability to the markedly different soils; Canonical Discriminant can efficaciously distinguished the soils which were similar each other in the spectral and chemic-physical characteristic.The two principal components were extracted from PCA. Thereinto the soil water and whole Fe3+/Fe2+ contributed to Fac1 and accounted for 72%;Fac2 for 27%. Further,a unitary quadratic equation was modelestablished with the Fac1 as causal variable and soil water content as independent variable based on the above-mentioned results.
This paper analyzed major characteristics of land use changes in the Beijing-around region, based on TM(ETM) in 1991 and 2002. On the basis of that, we studied the differences in districts of land use change on county area scale, using intensity, state and trend parameters of land use change. In addition, we investigated the effects of land use change on eco-environment in this region. We found that the area of arable land decreased greatly, with a gradually increasing trend from southeast to northwest from 1991 to 2002. On the other hand, the area of forested land and grassland increased, especially in the northwestern area. The total area of sandy land increased, with a gradually decreasing trend from east to west. Land use change was characterized by low intensity, and the area of net change in each kind type of land use was much more for the most counties in the studied region. From south and north to middle and east to west, the intensity of land use change increased gradually. The degree of single-direction interchange between different land use types decreased gradually from west to east. In recent 10 yr, quality and productivity of land was decreased increasingly in this region. But with the construction of various forest zones by reversing arable land to grassland and forest land, the descent dust amount per yr in Beijing suburban decreased with increase of the area of grassland and forestry land in the Beijing-around region.
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