A Dynamic Study On Land Degradation In JiLin Province Supported By RS-GIS-GPS Technique

Since last century, people have enlarged the land use intensity for the population suddenly growth and the urban construction land expansion. Soil erosion, land desertification, land salinification, the chemical fertilizer excessively using as well as unreasonably exploitation, all has created the land resource drop in quality. The unreasonable land utilization intensified the man land contradiction. Serious soil erosion, land degradation and the drought-flood disasters directly endangered human survival and development. The physiognomy of Jilin Province inclines from southeast to northwest, and the whole area is divided into four ecological zones accordingly, which named East Mountain Zone, East-middle Hill Zone, Middle Plain Zone and West Prairie Zone respectively. With fertile cultivated land, flourish forest and far-flung prairie, Jilin Province has become one of the most important grain-produced base, one of the six most productive wood regions, as well as one of the eight biggest pasturing areas. Influenced by natural factor and human factor, the land of Jilin Province became degraded, such as rainfalll erosion in the eastern, blackland degradation in the middle, desertification and salinification in the western, which limit the sustainable development of Jilin Province seriously. The former researches on land degradation of Jilin Province concentrated on some individual county or some certain region, and most researches either stressed land desertification and salinification, or stressed soil erosion. Therefore the integrated study on land degradation including desertification, salinification and rainfall erosion was few. Meanwhile the Land Use/Cover Change(LUCC) research on the whole Jilin province is nearly blank. Therefore, profited from the integrated research thoughts of the Global Change and those referrences to the other fields integration research results, considering the actual land degradation problems, guided by the integrated theory of the Regional Sustainable Development and the System Theory, The author accomplished A Dynamic Study on Land Degradation in JiLin Province Supported by RS-GIS-GPS Technique.In this paper the process and rule of LUCC were posted scientifically and the tendency of the land degradation were opened out, which would provide scientific basis for ecological environment restoration and land resource sustainable using decision-making, and would also promote the sustainable development of Jilin Province.Firstly, the land use/cover spatial database of Jilin Province in 1989 and 2000 was established under the support of RS and GIS technology, and then the LUCC analysis model and landscape ecological pattern analysis method to be used to carry on qualitative, quantitative analysis on LUCC dynamic change. The whole trend of LUCC of Jilin Province is four increasing and two decreasing, viz. farmland, the woodland, the habitation & industry-use land and unused land, which increased, in the meantime the grassland and water areas decreased. The research results show that woodland was the dominant pattern of land use in the Eastern, which occupied the entire area about 83%. Similarly, Farmland in the Middle, about 62%; Farmland and unused land in the Western, about 46% and 23% respectively. The highest extent of land-use change in the Eastern was unused land, which decreased 54.27%. Similarly, the grassland in the Middle, decreased 55.48%; the woodland in the Western, increased 50.50%. The intensity of land use is highest in the Middle and lowest in the Eastern. The index of the intensity of land use ascended from 233.76 to 240.84. The rate of farmland ascended from 37.27% to 38.62% while land-use rate descended from 93.85% to 93.61%. The land-use rate ascended in the Eastern and in the Middle, descended in the Western.From 1989 to 2000, the landscape fragmentation tended to rise, the index of patch fragment showed a quickly increasing tendency. With the further expansion of saline alkali land, saline alkali land patch bacame larger and larger and even to make a whole, therefore its patch fragment index fell down. The index of patch fragment and the index of diversity were highest in the Western and lowest in the Eastern, the index of dominance and CONTAG were reversed. The slope degree factor, the slope length factor and the vegetation factor were extracted supported by RS & GIS, the soil type factor, the rainfall erosion factor and the cultivation management factor were also acquired, and then the Universal Soil Loss Equation(USLE) was used to estimate the soil erosion change state of Jilin Province. The research result showed that the light-erosion area mainly distributed in the eastern mountainous area with high coverage of vegetation and in farmlands in interchannel valley, alluvial plain and river low terraces of middle part. The moderate-erosion areas centralize in eastern mountain basin and middle hill, where were mainly 8-15°(slope) farmlands. The intensity-errosion areas centralized in eastern Low Mountain and the middle mountain chapada. On eastern part around the mountainous basin distributed fragmentarily.The soil erosion area of Jilin Province in 1989 was 15 228.0km~2, accounted for the entire province area 8.00%. and 19 795.7km~2 in 2000, which accounted for 10.40%. The soil erosion rate and the change rate of soil erosion was highest in the middle while lowest in the western. Speaking of the regions,Liaoyuan soil erosion rate was highest, and Jilin, Changchun, Tonghua followed. It deteriorated in some extent in different soil erosion area. The main reason that caused soil erosion deteriorated was the farmlands increasing, the gressland reducing. On the other hand, the trees cuts and renewal was also an important reason.High spatial resolution remote sensing image data such as TM/ETM, MSS has the limiting factor, which is lower time resolution, higher material construction cost and narrower scanning range. But MODIS data has the superiority, such as broad sight, quick gaining, continuous observation and lower cost. So the MODIS data to was used to monitor the alkaline desertification. The result indicated that, the total alkaline desertification area of the western Jilin Province was 1 496 240hm~2, accounted for 31.9%. Among them, the heavy alkaline desertification area was 149 660hm , accounted for alkaline desertification total area 10%, the moderate alkaline desertification area is 432 740 hm~2, accounted for 28.9%, the light alkaline desertification area was 913 840hm~2, accounted for 61.1%. The alkaline desertification land mainly distributed in Daan, Qian'an, Tongyu, Zhenlai, Changling. This result compared to the researches based on TM/ETM remote sensing data, which indicated the two has a higher uniformity. So MODIS data has a higher confidence level in carrying on quantitative investigation.Based on land use/land cover interpretation in 1989 and 2000, the Markov Model was used to forecast desertification tendency in the western Jilin. The result indicated that, till 2011 the sand land area will reduce from 215 400 hm~2 in 2000 to 214 700 hm~2, salt alkaloid area will increase from 772 400 hm~2 to 905 600 hm~2. Till 2022, the sand land area and salt alkaloid area will respectively reach 213 300 hm~2 and 1 042 800 hm~2, which mean that the sand land area proportion will reduce, but the salt alkaloid area proportion will elevate steadily.The reason caused land desertification and ecological environment deterioration in western Jilin was either natural factors or human factors. The natural actors were foundation, while human factors were inducement and primary.The Canonical Correlation Analysis result indicated that, the average perperson water resources, the population density and organic content in soil were main driving force for saline alkali land increase, while the average perperson water resources, evaporation-precipitation rate and organic content in soil were main driving factors for sand land increase. To controlled the expansion of alkaline desertification, people must take some countermeasures, such as population growth controlling, tradition agriculture cultivation and water used custom changing as well as saline alkali land treatment and improvement.Jilin Province Tongyu County was taken as an example to assess its agricultural sustainable development ecology safety, in which 25 index was selected to set up the assessment system, including the index of ecological environment pressure, of the ecological environment state and of the ecological environment responses. The index weight was determined by mean square component estimation. The findings indicated that, the ecology security rank of Tongyu County was at the drop stage from 1985 tol998. This were caused by both natural and human factors. Since 1998, because of the environmental awareness enhancement and ecology renovated project execution, the local ecological environment started to change better. Therefore, the agricultural ecology security rank had rised. In the recent 20 years, the Tongyu county agriculture ecology safety descended. The security rank was in between III -V level, and secures state dropped from sensitive condition to risk condition. The ecology safe construction main countermeasures are farmland protection, pollution reduction as well as the full utilization of limited water resources.The features and innovations of the thesis were that, the dynamic research on land degradation in Jilin Province was accomplished in different angle and scale, in which some models was used under the integrated multidisciplinary theory and methods, and the tendency of the land degradation was promulgated. This production can be used as a reference for region land resource management & reasonable use, the ecological environment protection and the social economy sustainable development.