The Study on Range Condition and Evaluation System of Different Degradation Grassland in the Area of Jinqiang River, TianZhu County
|School||Gansu Agricultural University|
|Keywords||degraded grassland Community Characteristics soil nutrition soil urease weight TianZhu County|
In this study, the alpine meadow grassland of Jinqiang River region in Tianzhu County was studied using analytic hierarchy process(AHP) method to determine the 10 indicators weight of species diversity, total digestible nutrient(sTDN), soil organic matter, and the other 8terms. for the soil - grass health evaluation system, which was re--tested with some data of 5 cites. the above system could be used to quantitative evaluation of the grassland areas .1、After the weather analysis of Jinqiang river region, the temperature and precipitation rate had not much change in the research area, therefore, the productivity of grassland degradation due mainly to over-exploitation by man-made cause. From 1980 to 2006 period, the local annual average temperature raised much, with an average temperature of 0.3℃per year; The accumulated temperature of more than O℃was not obvious, but the fluctuations was about 5.9%, and the growth rate was about 2.8℃per year; precipitation averaged 408.3±52.4mm, reached the peak in 1988; the past 30 years, K value (grassland moisture index)average d 2.778±0.475,which declined 0.003 per year, but the environment of Jinqiang river region was still bellowed to the type of cold temperature and humid temperate with coniferous forests in the comprehensive and sequential of grassland.2、Nature grassland was the product of drought conditions. In Jinqiang river region , precipitation was basically the same in more than 20 years. Except the normal inter-annual fluctuations, the precipitation did not show more obvious trend of changes. Average annual temperature in this area had an increase of about 0.1℃per year , At the same time humidity dropped. However, grass production decreased obviously. All of this could basically explain the fact that human factors caused overgrazing of livestock sped up grassland degradation.3、Sampling investigation and nutritional analysis were carried out to compare community characteristics among samples, and to analysis differences in economic characteristics with Grassland forge—rank System and TDN. The orders of Variety and abundance of populations were as follows: moderately degraded (16), mild degradation (14), non-degraded (12), severe degradation (11), extreme degradation (9). The orders of Variety and abundance of populations about Polygonum were as follows: non-degraded sample (0.801), mild degradation (0.278), moderately degraded (0.126), whereas in severe degradation and extreme degradation of samples were 0. Grasses showed mild grasses in favor of the use of an important increase in value. Analysis the quality of forage grass with Grassland forage—rank System, the all plots were first order .Valuation from the natural level of productivity, no degradation, light degradation, severe degradation of grassland was 4, and severe grazing , extreme grazing and 5, 6 ,respectively.4、There is also deference in level of grassland soil nutrition in different degraded degree grassland; all the five plots were in neutral ph,but have the trend of increasing; In all the plots ,the organic matter decreased gradually with the expansion of deteriorate degree, Soil Available Nitrogen showed a change of low-high-low , Soil Available Potassium showed the trend of high-low-high, and Soil Available Phosphorus declined gradually. Soil urease reflect biologic activity, the variation of soil urease was deteriorate extremely degeneration > medium degree degeneration> light degree degeneration> heavy degree degeneration.5、To estimate soil-grass system, indicators weight of grassland was 0.6, indicators weight of soil was 0.4. You can value by the index as below: comprehensive score = variety of species×0.1319 + TND×0.0868 +coverage×0.2231 +advantage superiority of toxin grass×0.1582 +OM×0.1784+pH×0.0680+Available N×0.0622+Available p×0.0305+Available K×0.0305+soil urease×0.0305.According to health value, partition standard were excellent between 1～0.9, good between 0.9～0.8, middle between 0.8～0.7, bad between 0.7～0.6.The results of comprehensive evaluation of different degeneration degree plots showed: grassland health evaluation of slight degeneration was fine, undegeneration and medium degeneration were good, heavy degree degeneration was normal,deteriorate extremely degeneration was bad; moderate utilization of grassland was beneficial to grassland health development, On the contrary, excessive utilization of grassland was not good for grassland health.