Recovery Effects Of Closed Fencing On Forages And Soil Nutrients In Typical Steppe

Recently, steppe degradation in Inner Mongolia is very serious. And closed fencing as an economical and effective method for degraded steppe ecological restoration is widely used in the steppe restoration and governance. In order to further study the recovery effects of closed fencing on forages and soil nutrients, correctly evaluate the effects of closed fencing and make the corresponding policy of closed fencing, the total nitrogen and total phosphorus of soil and grass and the protein of forage and grass mass were compaired in this paper by using the method of field investigation and laboratory analysis combined in typical steppe of Xilinhot City. And the correlations between the soil and grass nutrients, grass protein and chlorophyll, the protein quantity of the main grass and that of the grass group in closed fence and grazing were also analyzed. The main results were as followed:1. The total nitrogen and total phosphorus of soil and grass within the fence were both significantly higher than that out of the fence. And this explained the grazing had some effects on maintaining the soil fertility and grass nutrients.2. The nitrogen and phosphorus content of Leymus chinensis and Stipa krylovii showed the same trend, both increased with the increase of soil nitrogen and phosphorus content. However, there was significantly positive correlation in the Leymus chinensis and Stipa krylovii phosphorus and soil phosphorus, and this correlation within the fence was higher than out of the fence. The results showed that banning grazing was beneficial to promoting the absorption and utilization of soil nutrients in grass.3. There was significantly positive correlation in the protein and chlorophyll content of Leymus chinensis and Stipa krylovii, and thus the protein content could be estimated by the chlorophyll content. Moreover, the estimation value of them in no-grazing was more accurate than that in grazing.4. The protein content of grass group was increased with the protein content of Leymus chinensis and Stipa krylovii, and had obvious the positive correlation with them. Meanwhile, the correlation coefficient in no grazing conditon was larger than that in grazing. This indicated that it was feasible to use the protein content of Leymus chinensis and Stipa krylovii to estimate the total protein content of grass group in typical steppe.