Effects Of Abandonment Management On Soil C,N And Nutrient Content In Moso Bamboo Forest

Moso bamboo(Phyllostachys heterocycla var.pubescens),as an important forest resource in south China,has a great capability of carbon(C)sequestration and an important role of forestry in climate change.Thus,how to increase the C sequestration of bamboo forests to mitigate climate change had attracted people's attention.However,with the increase of labor cost and the decrease of bamboo price,many Moso bamboo forests have changed from intensive management to extensive management.However,most of the existing researches focus on the change of carbon sequestration capacity after extensive management or traditional management changes into intensive management,and there is still a lack of systematic research on how the conversion of intensive management to abadonment management affects soil carbon sequestration capacity of Moso bamboo forests ecosystems.Therefore,this experiment was conducted in Moso bamboo forest with similar site conditions in Lin'an and Yuhang,Hangzhou in Zhejiang Province.As sustainable management(SM:intensive management)as control,we investigated the variation characteristics of three duration of abandonment management(DM-I:abandonment management for 1-6 year;DM-II:abandonment management for 7-12 year;DM-III:abandonment management for 13-18year)with on soil C pools,N pools and nutrient content in Moso bamboo plantation,and the relationship among soil C pools,N pools,nutrient content and environment factors.The purpose of this study was to reveal the response of soil and vegetation carbon sequestration and the impact factor of the soil C pools and N pools in Moso bamboo forests after abandonment process.The main findings are as follows:(1)Compared with SM,the alkaline hydrolysable nitrogen(AN)was increased under abandonment management of Moso bamboo forests,there is no significance difference in surface soil,the AN was increased 117.54%in DM-II of subsurface soil.Abandonment management decreased soil available phosphorus(AP)with no difference significance.Abandonment management increased soil available potassium kalium(AK),the AK was increased 21.62%,2.05%in DM-I and DM-III in surface soil,but there is no significant difference in subsurface soil.By the analysis of structural equation modeling(SEM),soil bulk density(BD),p H and Moisture affect the soil nutrient content.(2)Compared with SM,the soil C sequestration in Moso bamboo forests under abandonment management significantly increased 3.73%,2.72%,4.53%,but there is no significance among different duration of abandonment management.In all,abandonment management can significantly improve the soil C sequestration in Moso bamboo forests.(3)Compared with SM,SOC increased under abandonment management,the surface SOC increased with increasing duration of abandonment management,DM-III significantly increased 18.08%in surface sol,DM-I significantly increased 9.13%in subsurface soil.The WSOC in DM-I of surface soil decreased 34.52%,and there is no significance difference in other abandonment management.MBC in surface soil under abandonment management increased with no significance difference,MBC in DM-II of subsurface soil increased 58.62%relatively.The invertase activity in surface soil gradually decreased compared with SM,DM-I and DM-II have significant difference with SM,also the invertase activity in subsurface soil increased gradually with no significant difference.By the analysis of SEM,soil BD have significant negative effect on SOC,soil MBC and invertase activity have significant positive effect on SOC.Duration of abandonment management have positive significant effect on SOC.(4)Compared with SM,the total nitrogen(TN)and microbial biomass nitrogen(MBN)have no significance difference in surface and subsurface soil.Soil WSON significantly decreased with increasing duration of abandonment management.WSON decreased 55.06%,47.10%,63.79%in surface soil,WSON decreased 51.72%,57.23%,63.43%in subsurface soil.In soil inorganic nitrogen,the NO₃^--N content in DM-III significantly decreased compared SM,the NH₄⁺-N content in DM-I and DM-II significantly increased compared with SM.By the analysis of SEM,soil p H and C/N ratio have significant negative effect on soil TN,soil MBN have significant effect on soil TN,duration of abandonment management have significantly positive effect on soil TN.