Effects Of Different Grassland Utilization On Litter Decomposition Of Three Dominant Plants In Typical Steppe

In the context of global change and human disturbance,the study on plant litter decomposition in grassland ecosystems is the key to understand ecosystem functional processes and develop sustainable management measures for rational use of grassland resources.In the Xilingol steppe area of Inner Mongolia,we studied litter decomposition processes of three dominant plant species in temperate typical steppe grasslands under different land use.We got following results:(1)The effect of different grassland utilization treatment on litter decomposition: under the displacement treatment,the litter decomposition rate of Leymus chinensis was significantly different among the three grassland use types(P<0.05),the order for decomposition rate is grazing> mowing> enclosing;After the litters were displaced,the weight loss rate of Cleistogenes squarrosa litter wassignificantly higher than Stipa krylovii in grazing and mowing plots(P<0.05).In the in-situ treatment,the cellulose ofCleistogenes squarrosa litter in mowing plot was significantly higher than that in the enclosed plot(P<0.05).(2)Differences in litter substrate composition among plant species:in enclosed plots,the litter hemicellulose content was significantly higher in Cleistogenes squarrosa than Stipa krylovii and Leymus chinensis litter(P<0.05).In grazing plots,The hemicellulose content was significantly in Stipa krylovii and Cleistogenes squarrosa higher than Leymus chinensis litter(P<0.05);The initial cellulose content of Stipa krylovii litter in enclosed and grazing plots was significantly higher than that of Leymus chinensis and Cleistogenes squarrosa litter(P<0.05);under all the three treatment,the lignin content of Stipa krylovii was significantly higher than Leymus chinensis and Cleistogenes squarrosa(P<0.05).In the in-situ treatment,in the enclosing plots and grazing plots,the loss rate of the hemicellulose content in the Cleistogenes squarrosa litter was significantly higher than that in the Leymus chinensis and Stipa krylovii litter(P<0.05).After the litter was displaced in mowing plot,the loss rate of hemicellulose in Cleistogenes squarrosa was also significantly higher than that in the Leymus chinensis and Stipa krylovii litter(P<0.05).In the mowing plot,the loss rate of in cellulose ofCleistogenes squarrosa litter was the highest(P<0.05).(3)Litter decomposition did not show significant changes,between in-situ and displacement the difference may show with the decomposition time.Grazing generally promotes litter decomposition,but its effects differ among plant species.The litter with higher quality has the greater decomposition rate.