Decomposition Of Litter And Yak Dung And Its Effect On Soil Characteristics

Litter and yak dung are two major ways to return nutrients to grassland ecosystem in the Qinghai-Tibet Plateau,which are important links to maintain grassland ecosystem material flow and energy cycle.In nature,yak dung is often covered on litter and mixed with litter to decompose,but little is known of the effects of yak dung and litter mixed to decompose.This experiment started in October,2018 and ended in October,2019 for a period of one year.Elymus nutans,Agropyron cristatum,Cirsium setosum,and Gentiana macrophylla were selected as experimental materials.The litterbag method and stack method were used to study the decomposition of litter and yak dung and its effect on soil characteristics.The main results obtained from the study were as follows:(1)The litter decomposition was affected by the initial nitrogen content,lignin content,and lignin / nitrogen ratio of the litter.Cirsium setosum and Gentiana macrophylla decomposed faster,and Elymus nutans and Agropyron cristatum decomposed slower.(2)The decomposition rate of yak dung in summer was faster than that in winter.The release of nitrogen and phosphorus in yak dung was also faster in summer than in winter.By the end of the experiment,dung decomposed by 47.34%.(3)The decomposition of yak dung and litter could increase the content of DOC,DON,DOP,TN,TP,MBC and MBN in the soil.(4)Yak dung could accelerate the mass loss of litter and the release of nitrogen and phosphorus of litter.(5)The co-decomposition of yak dung and litters showed significant antagonistic effect on soil pH and significant synergistic effect on the content of DON,DOP,MBC,MBN in the soil.It mainly showed significant synergistic effect on soil TN and additive effect on soil TP.It showed antagonism effect or synergistic effect on soil DOC,depended on sampling times.