利用3S技术动态监测天山草地农业产量及其成因分析

NEW APPROACH TO GRASS-YIELD ESTIMATION AND ECO-ENVIRONMENT FORMATION ANALYSIS BY USING 3-S METHODS IN TIANSHAN AREA, XINJIANG

在新疆阜康县大量“天地”资料观测基础上 ,利用 3S(RS、GIS和 GPS)技术和生态系统分析方法 ,对新疆天山草地农业资源进行了系统的动态监测和大面积估产研究。结果表明 ,该县草地和森林面积 1 998年比 1 988年分别下降了 1 7.5%和 51 .0 % ,而农业用地面积和沙漠危害面积却分别增加了 57.8%和 2 1 .2 % ,实现了利用 3S技术系统准确监测新疆阜康县草地农业资源动态变化 ,其大面积草地遥感估产精度达到 75.8%以上。最后 ,建立了新型 PPR估产模型 ,其估产精度达到 81 .76%以上 ,并给出了理论生态成因解释与定量分析结果等。

As is known, the future of grass yield resource development and management of the grassland is up to the exploration and scientific management of the grassland. To this end, the present paper aims at a discussion on the possibility and potential to increase the grass yield of the northern Tianshan grassland by using a new approach known as 3S(RS GIS GPS) system. First of all, we have made systematic observation of the four types of grasslands in northern side of Tianshan, for their respective green herbage yields and ecological data from 1976 to 1998. And then we have analyzed the yield formation, variation period and ecological effects in the above said grassland types by means of three biological spectrum methods. The results show that the formation and variation periodicity of grassland yields are by large influenced by the fluctuation of eco climatic factors. As we observe, the variation period is repeated by 4 years and the periods of yields are in general conformity by 1/4 period delay as compared to that in climatic change. According to our observation results, the key ecological factors to the grassland yields are soil water content and the precipitation factors among all the climatic factors in the arid regions. Secondly, based on the grassland yield data gained from the remote sensing data of the satellites and space shuttles, the farming resources on the grassland are monitored by using RS, GIS and GPS in Fukang, Xinjiang in 1988-1998, which have shown that the total area of grasslands and forests in 1998 had been reduced by 17.5% and 51% as compared to those in 1988, but the farmland and desert area in 1998 had increased by 57.8% and 21.2% as compared with 1988. The estimated yield accuracy given by the above mentioned 3S system was over 75.8%. The use of the 3S system can also extend to inventory, evaluation and monitoring of the grassland resources and incorporation of the remote sensing data to support and improve the decision making processes on the use, development and utilization of their resource area. And, last of all, the estimating yield models are established by using the new Projection Pursuit Regression (PPR) method in different grassland types, the accuracy was above 81.76 % and ecological effects on the natural grassland yield can quantitatively been explained in the area. Thus, the purpose of using 3S (RS GIS GPS) system to improve the scientific management and exploitation of the grassland agricultural resources in arid grassland ecosystem has satisfactorily been achieved.