Effects Of Common Grazing Methods On Production And Ecological Functions Of Mountain Meadow In Kanas Scenic Area In Summer

In this study,the mountain meadow in Kanas scenic area of Altai mountain in Xinjiang Uygur autonomous region is taken as the research object.based on the changes of the production and ecological functions of the mountain meadow ecosystem under different grazing methods,the trade-off or synergistic relationship between production and ecological functions is taken as the evaluation criterion.the goal of this study is to improve the synergy of various grassland ecosystem services and functions,evaluate the rationality of different grazing methods,and provide technical support and important approaches for sustainable grassland management countermeasures in Kanas scenic area.In this study,three grazing methods were set up:no grazing(no grazing in the whole growing season of the experimental area),horse grazing alone(with a stocking rate of 5 horses hm-2)and mixed grazing of horses and cattle(with a stocking rate of 5 horses hm-2+5 cattle hm-2).The area of the test plot was 4000m2,which was repeated 3 times.Before grazing,the weight of horses and cattle was weighed at about 300±25kg.The changes of grassland production function(aboveground biomass of forage grass,aboveground biomass of edible forage grass,grassland quality,etc.)and ecological function of grassland ecosystem(species diversity,ecological stoichiometry characteristics of plant community,soil respiration characteristics,soil carbon storage and litter ecological stoichiometry characteristics,etc.)under different grazing modes were studied,and the trade-off relationship between production and ecological function was analyzed.The main research results are as follows:(1)Compared with single grazing horses,mixed grazing horses have significantly reduced feed intake time,feed intake number and migration distance;However,under the same grazing mode(mixed grazing),the difference in feed intake time,feed intake number and migration distance between horses and cattle is small.(2)Compared with no grazing land,the height,coverage and aboveground biomass of single grazing land decreased,but the community density increased.The important values of perennial miscellaneous grasses and plants in one or two years increased,while the important values of other functional groups decreased.The community structure and composition changed obviously.Compared with single grazing plot,the height,density,coverage and aboveground biomass of mixed grazing plot decreased,the important values of perennial mixed grass and perennial rhizomatous grass increased,and the important values of other functional groups decreased.The species composition of perennial miscellaneous grasses has also changed.The mixed grazing of horses and cattle reduced the quality of pasture,the aboveground biomass of edible pasture and the production function of mountain meadow.Short-term single grazing can promote the above-ground biomass of edible forage grass and the grassland quality changes little,but with the extension of grazing time,the above-ground biomass and grassland quality of edible forage grass both decrease.(3)Mixed grazing resulted in the decrease of species richness index,species diversity index and evenness index of Kanas mountain meadow community,while the increase of ecological dominance.The contents of C,N and P in the mountain meadow community decreased,and the growth of the community changed from being restricted by N to being restricted by both N and P.The ecological function of the mountain meadow community was damaged.However,single grazing can increase the species richness index,species diversity index and evenness index of meadow community,thus reducing the ecological dominance,making the species distribution in the community more uniform and the dominant species less prominent.The contents of C,N and P in the mountain meadow community did not decrease significantly,and the growth of the community changed from being restricted by N to being restricted by P.(4)Most of the daily changes of soil respiration rate in non-grazing,single-grazing and mixed-grazing plots showed a single peak curve,with the maximum value at 14:00,16:00 or 18:00 and the minimum value at 8:00 or 22:00.The soil respiration rate and amplitude of non-grazing plot were higher than that of single grazing plot in each measuring period,and the soil respiration rate and amplitude of single grazing plot were higher than that of mixed grazing plot in each measuring period.Soil respiration rate was significantly correlated with soil temperature(0-5 cm)in mixed grazing plots at the early grazing stage(July)and the second grazing stage(August),and the temperature sensitive index(Q10)was relatively large.However,in the late grazing period(September),the soil respiration rate was significantly correlated with the soil temperature(0-5 cm),and the temperature sensitive index(Q10)was relatively large.(5)Mixed grazing resulted in a significant decline in soil C content and C:N,C:P in mountain meadow,and a downward trend in soil quality and fertility.At the same time,it also caused a significant decline in the C reserves in the 0-20 cm soil layer.Compared with no grazing plots,the C content and C:N,C:P in grazing plots decreased significantly.(6)Grazing mode will affect the trade-off between production and ecological function of the whole grassland ecosystem,and the more obvious it is with the increase of grazing pressure.The trade-off between production and ecological functions will have different reactions depending on grazing methods.