Effects Of Different Grazing Patterns On Grassland Plant Communities And Soil Characteristics In Alxa Left Banner

To explore the impact of the current different grazing patterns on the Alxa Left Banner pastures,seven main pasture types,including Potaninia mongolica,Nitraria tangutorum,Haloxylon ammodendron,Reaumuria soongorica + Caragana tibetica,Salsola passerina,Reaumuria soongorica + Salsola passerina and Nitraria sphaerocarpa,were selected to study and analyze the effects of community characteristics,species diversity,forage nutrients,soil physical,chemical properties,soil organic carbon and total nitrogen storage under several grazing patterns,coverning non-grazing(the grazing prohibition started in 2003,2011,2016 is 2003 NG,2011NG,2016NG),grazing from 2016(2016FG)and long-term grazing(KG).Get the following results:1.Potaninia mongolica pastures: non-grazing increased the height,coverage,density and biomass of communities,and long-term grazing caused shrubs to be dwarfed.grazing from 2016 improved forage nutritional value,soil organic matter content,total nitrogen content and was beneficial to soil carbon and nitrogen,but reduced soil bulk density.2.Haloxylon ammodendron pastures: grazing from 2016 significantly increased the shrub height,herb height and biomass,forage nutritional value,while the non-grazing were the opposite.Different grazing patterns had not significant impact on soil nutrient content and moderate grazing can help maintain water and soil and increase water content.non-grazing accumulated organic carbon and total nitrogen reserves.3.Reaumuria soongorica + Caragana tibetica pastures: the change trend of shrub coverage,density and biomass were 2016FG>2003NG>KG.Both non-grazing and grazing from 2016 were conducive to plant growth,and grazing from 2016 were better,but the long-term non-grazing reduced the species diversity and forage quality.4.Reaumuria soongorica + Salsola passerina pastures: plants on grazing from 2016 plot growed better.Grazing plot shrubs had high crude protein content so plants had higher nutritional value.The long-term non-grazing was not conducive to maintaining high species diversity,but it was conducive to maintaining soil moisture and accumulating organic carbon reserves.5.Salsola passerina pastures: non-grazing significantly increased the height,coverage,density and biomass of communities,which promoted shrub restoration.Grazing promoted the herb growth.non-grazing increased the species diversity within a certain period of time,but that decreased with the extension of the enclosure time.Non-grazing was conducive to conserving water sources and increasing organic carbon reserves.Appropriate grazing from 2016 was conducive to increasing soil available phosphorus content.6.Nitraria tangutorum pastures: non-grazing promoted pasture restoration and growth,shrubs played a leading role,and grazing promoted herb growth.Non-grazing reduced the species richness and diversity index.Grazing from 2016 made the herb have the characteristics of high crude protein,high Ether extract,high crude ash and high fiber.In addition,grazing from 2016 was conducive to increasing soil water content,soil organic matter and total nitrogen,soil carbon and nitrogen reserves.7.Nitraria sphaerocarpa pastures: non-grazing plot started to prohibit grazing in 2011,which was beneficial to vegetation restoration;compared with long-term grazing plot,non-grazing plot had no significant impact on pasture quality and soil characteristics.The response of the plant communities and soil characteristics of the 7 main pastures in Alxa Left Banner to different grazing patterns is different,but in general,non-grazing was beneficial to vegetation restoration,and the pasture started grazing from 2016 was growing better.Long-term non-grazing reduced species diversity and forage quality,but moderate grazing is beneficial to maintaining high species diversity and forage quality.Non-grazing or grazing from 2016 was conducive to the retention of soil carbon and nitrogen.On the whole,we conclude that the combination pattern of non-grazing and grazing is scientific and rational to protect pastures and obtain economic benefits in Alxa Left Banner.