Effects Of Overgrazing And Burning On Vegetation And Soil Of Shrubby Grassland Of Rocky Mountain

The shrubby grasslang of rocky mountain was becoming degradation,the results was synthetic action by the environment factors and human factors.But in certain condition,the human factor plays the leading role,the human factors were some productive activities,such as burning and overgrazing,they were direct effect growth of plant, types of vegetation,species composition,standing crops,soil and successsion.But correlational research had not seen in the public reports of the literature. To explore the influence of the degradation and karst environment relationship of the shrubby grasslang of rocky mountain. Find out the main environment proplem about degradation,the shrubby grasslang of rocky mountain located MaShan county goat field in MaShan county QiaoLi town in guangxi. The effect of burning and overgrazing on vegeatation types, standing crop and soil of shrubby grassland of rocky mountain.The main results were shown as follows:(1)The vegetation characteristics of herb grass、the water content of vegetation and the number of specise of grass was negatively correlated with growth rate of grassland. The vegetation characteristics of shrub grass、the standing crop of grass vegetation、standing dead litter and litter was positively correlated with growth rate of grassland. The burning group was the largest than overgrazing groups and contrast groups. The overgrazing group was biger than contrast groups.The standing crop of overgrazing group average be871.06g/m2,the standing crop of burning group average be683.47g/m2,the standing crop of contrast average be1492.00g/m2. The average coverage of overgrazing be50.4%, the average coverage of burning be73.4%,the average coverage of contrast be83.2%.The average height of herbaceous plant be38.4cm in overgrazing group. The average height of herbaceous plant be41.6cm in burning group. The average height of herbaceous plant be55.2cm in contrast group. The average species of vegetation be16.2N/m2in overgrazing group. The average species of vegetation be14.3N/m2in burning group. The average species of vegetation be12.4N/m2in contrast group. The shrubby grassland of rock mountain comperhensive grade evaluation. The pasture from ovegrazing groups can evaluation for "three-level,third-class",the pasture from burning groups can evaluation for "three-level,third-class",the pasture from contrast groups can evaluation for "one-level,third-class".(2)The forage nutrition composition of different test groups was not signigficant difference (P>0.05),curde protein content was7.5%,curde fat content was4.45%,crude fiber content was43.0%,nitrogen free extract content was37.5%,curde ash content was7.15%. The dry matter feed intake of black goat in different test groups was not signigficant difference (P>0.05), overgrazing group be938.92g/d, burning group be890.85g/d, contrast group be1492.00g/d. The dried goat droppings quality of black goat in different test groups was not signigficant difference (P>0.05).The dried goat droppings quality be311.34g/d in contrast group. The dried goat droppings quality be307.01g/d in overgrazing group. The dried goat droppings quality be295.84g/d.The dry matter apparent digestibiltiy was not significant difference in three groups grassland.Different groups of forage nutrtion composition digestibility of apparent was not significant difference (P>0.05).The dry matter apparent digestibility rate was66%,the crude protein apparent digestibility rate was74%,the crude fat apparent digestibility rate was76%, the crude fiber apparent digestibility rate was51%,the nitrogen free extract apparent digestibility rate was85%.The protein intake of overgrazing group had the largest average each goats53.04g/d. The protein intake of contrast group had average each goats51.12g/d. The protein intake of burning group had average each goats50.34g/d.Them groups protein level basic meet the goat growth nutritidn need each goats4g/d. After the comprehensive evaluation to different groups of grassland about carrying capacity,the contrast group can carrying5.63goats each hectare,burning group can carrying4.7goats each hectare,ovetgrazing group can carrying4.15goats each hectare.(3) The water content of soil was the highest on the foot of mountain,and water content of hillside was higher than water conten of the top of a hill. The soil chemical properties of organic matter,total nitrogen,available nitrogen,total phosphorus.total potassium trend was similar. The contrast group was the highest,overgrazing was second higher,burning was the lowest.The organic matter,total nitrogen, available nitrogen,total phosphorus in soil nutrients along with dephts turn to descending. The treatment group had no significant difference between soil nutrients in5-10cm. The PH value trend for burning group first,overgrazing second and contrast group last. Therefore, the trend was that pH value from surface soil was higher than the pH value from lower soil. The soil comprehensive fertility index in overgrazing group surface soil was0.624.It belong to fourth fertiltiy, The IFI in burning group surface soil was0.53.It belong to fifth fertility.The IFI in contrast group surface soil was0.846.It belong to second fertility.