Agricultural pollution, which has a direct impact on the water, soil and air quality, is a common but increasingly
serious environmental problem nowadays. The misusage of fertilizer, high application fertilizer and low utilization rate,
are the major factors of the pollution. Therefore, the pollution caused by nitrate nitrogen has posed a very serious
problem to the ecological environment. Combined with the GIS technology, this paper takes Majiang County in Guizhou
province that is at southwest of China as a case, to carry out the research on the calculation of the nitrogen surplus in
paddy field and the dry land based on the farmland nutrient balance model using the fertilizer amount. This paper reveals
the spatial distribution characteristic of the nitrogen pollution, which can help to find a reasonable crop cultivation and
fertilization methods to increase the effective utilization fertilization and therefore reduce the pollution.
Based on Landsat MSS/TM images and CBERS-02 CCD data of Beitun Oasis in Ertix River Watershed in the years of
1972, 1989, 1999 and 2005, the landscape patterns for the past 30 years were analyzed. Using the GIS data collective
platform, we calculated the landscape pattern conversion probability matrix, landscape pattern index, and contribution
rates of major landscape components to characterize the impacts and responses of landscape pattern changes and
landscape ecological processes. The results indicate that in this region the areas of farmlands, urban & rural residential
lands and waters are increasing, the area of woodlands is decreasing, and that of grasslands is decreasing and then
increasing. In the desert landscape patterns, the areas of sandlands and Gobi deserts & bare lands are decreasing after
increasing, and those of saline or alkaline lands & marchlands are increasing obviously in the latter period. The features
of landscape ecological process of urban & rural residential lands are concentrated in spatial pattern, but for grasslands
and woodlands, those are fragmentized in spatial patterns. The landscape components convert very frequently, and the
landscape pattern is not stable. Woodlands ecosystem function reducing and soil salinization and alkalization result in a
negative influence on the local ecological system. It is essential to adjust the landscape patterns to rehabilitate and
construct the fragile ecological system of modern oasis landscape ecosystem in arid area and use water resources
reasonably, so that ecological environment and social economy is healthy and stable with sustainable development.
Grassland degradation in grassland ecosystems of China has been highly concerned in recent decades. Grassland growing is an important element for identification of grassland degradation. In this paper we intend to develop an applicable method for grassland growing monitoring in China using the EOS/MODIS data. Firstly the normalized difference of vegetation index (NDVI) can be calculated from April to October within grassland growing period in 2005 and 2006. In order to evaluate the grassland growing, vegetation index R was proposed, which was calculated from the NDVI value difference of the two years 2006 and 2005. According to the R value, five grades (from grade1 to grade5) were obtained: worse, slightly worse, balance, slightly better and better. Grassland region in China can be divided into a number of small sub-regions for determination of different regions and grassland types. Our results indicate that grassland growing was better in 2006 than in 2005. The grassland with balance, slight better and better growing accounted for 71.43% of the total grassland area, the area is 251.42 thousand KM<sup>2</sup>. The overall growing of 2006 is: Grade3>Grade4>Grade2>Grade5>Grade1.Valuation of the grassland growing is thus urgently required for better administration of the grassland ecosystem for sustainable development.
Drought is very severe in North China Plain, where winter wheat is one of the most important cropping systems. In this paper, we present an approach to map drought status of winter wheat in the plain for better farming management. The approach is based on the temperature-vegetation dryness index (TVDI) computed from the wet and dry edges of Ts-NDVI space. Using the MODIS data, we applied the approach to map drought status in North China Plain for the winter wheat growing period from March to May in 2006. Our results show that spatial variation of agricultural drought is very obvious in the region. Severe drought was observed in eastern Hebei, western Shandong, and northwestern Henan province respectively. The weather reports from China Meteorological Administration were used to validate our mapping results of the drought status. The highly accordance of our drought mapping results with the reported drought distribution from CMA confirms the applicability of TVDI approach in drought mapping in North China Plain.
Land use/cover change (LUCC) has significant impacts on regional environment. Land surface temperature (LST) is an
important indicator for assessment of regional environment especially in big cities where urban heat island is very
obvious. In this study, remote sensing and geographic information systems (GIS) were used to detect LUCC for
assessment of its impacts on spatial variation of LST in Urumqi, a big city in northwestern China. Two Landsat
TM/ETM+ images respectively in 1987 and 2002 were examined for LUCC detection. LST and NDVI were computed
from the images for different land use/cover types. Impacts of LUCC on regional environment can be assessment
through LST difference during the period. Our results showed that land use/cover changes were very obvious in Urumqi
between 1987 and 2002 due to rapid expansion of the city. Urban/built-up land increased by almost twice in the period,
while the barren land, the forestland and water area declined. The increase of urban/built-up land was mainly from the
barren land. Spatial distribution of LST in the city has been highly altered as a result of urban expansion. The
urban/built-up area had LST increase by 4.48% during the period. The LST difference between built-up land and other
land use/cover types also significantly increased between 1978 and 2002, with high LST increase area corresponding to
the urban expansion regions. Moreover, changes of vegetation also had shaped many impacts on spatial variation of LST
in the city. We found that NDVI has a negative correlation with LST among the land use/cover types. This probably is
due to the ecological function of vegetation in cooling down the surface from high evapotranspiration. The study
demonstrated that combination of remote sensing and GIS provided an efficient way to examine LUCC for assessment of
its impacts on regional environment in big cities.
Sangong waddi basin in the north piedmont of Tianshan Mountains is a typical inland arid ecosystem in China. Desert environment especially land cover and land use in the basin changes dramatically in recent decades under the anthropogenic impacts. In order to develop an approach to highlight the environmental changes, we present a case study in the paper to examine the effects of different vegetation indices to the spatial changes of desert environment in the basin using Moderate-resolution Imaging Spectroradiometer (MODIS) data. First we compute the different vegetation indices including Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) for the basin from MODIS data and then compare their applicability to indicate the seasonal changes and spatial variation of vegetation in the basin. The results show that when the two vegetation index EVI and NDVI were used at the same time in monitoring the desert vegetation situation, Smaller the difference value between their values were, less the human activities interfere. The vegetation gradient variation of the desert vegetation is distinct in the basin. Therefore EVI can be used to highlight vegetation growth over the alluvial fans while NDVI is suitable to monitor vegetation growth in the hilly regions. With this finding, we further develop an approach to examine the desert environment changes in the basin. Based on the examination, several policy recommendations have been proposed in the study for better administration and utilization of arid land resources in the basin.
Several sandstorms invading the capital of China in recent years cause many concerns to the issues of grassland ecosystem degradation in arid and semiarid grassland region of north China. Actually the degradation can be viewed as the decrease of primary productivity in the grassland. This provides the possibility to monitoring the degradation using satellite remote sensing technology. In the study we present our experiences in conducting the monitoring of grassland ecosystem degradation in north China. Using the EOS/MODIS data, we develop an applicable method for the monitoring on the basis of net primary productivity (NPP). We assume that there is always a turf without degradation in the area of the same hydrothermal condition and type of grassland. We then use the NPP of the turf to determine the level of degradation in this area. The grassland region in north China can be divided into a number of small sub-regions for the determination and the division of sub-regions can be done according to the types of grassland. As far as every sub-region is concerned, we take the max NPP as the base line to determine the degradation of other pixels in the sub-region. The degradation can be graded into five levels: serious degradation, high degradation, medium degradation, light degradation and non-degradation. Finally we apply the method to analyze the spatial characteristics of grassland degradation in north China in the year 2005. The results show that the situation of grassland degradation in north China is very serious. 95.57% of the grassland in north China has suffered from deterioration to various levels, among which serious degradation, high degradation, medium degradation and light degradation account for 41.06%, 33.52%, 11.72% and 9.28% of the total, respectively.