Effects Of Conversion From Evergreen Broad-leaved Forests To Moso Bamboo Forests And White Tea On Soil Carbon Pools

Forest soil carbon pool is the principal part of the terrestrial ecosystem.The SOC could be changed greatly by disturbance including lots of forest managements from human beings,so carbon accumulation and release will happen in the short term.Meanwhile,it is a sensitive index to reflect the dynamics of soil carbon pool and always has become one of the powerful bases for sustainable forest managements.In the research,soil samples were collected from adjacent white tea(WT)and Moso bamboo(Phyllostachys heterocyla)forests(MBF)10a and 40 a and compared with the natural evergreen broad-leaved forests(EBF),respectively,then determined including characteristics of soil basic nutrients and different forms of SOC(water soluble organic carbon(WSOC),light fraction organic carbon(LFOC)and heavy fraction organic carbon(HFOC),SOC in aggregates with different particle sizes,humus carbon(HC)fractions and phytolith carbon(PhytOC).The effects of conversion from EBF to MBF and WT on soil carbon pools have been elucidated in a systematic and comprehensive way,the main results are as follows:(1)Converting EBF to MBF and WT,the variation of soil fertility and SOC pool mainly occurred in the surface soil(0-10cm).The WSOC,LFOC,HFOC,HC and PhytOC contents showed a decreasing trend with the increase of soil depth in different forests.Compared with the EBF,the content of SOC,alkaline hydrolysis nitrogen(AN),available phosphorus(AP)and available potassium(AK)decreased significantly,and soil pH increased slightly.All kinds of soil fertility were deficient on different forests.(2)Conversion EBF to MBF and WT decreased the WSOC contents,and 40 aWT was significantly lower than the EBF(p< 0.05).Compared with the EBF,the WSOC contents of 10 a MBF and 40 a MBF were reduced by 10.7% and 12.2%,respectively.(3)Conversion EBF to MBF and WT decreased the HFOC contents.In terms of HFOC contents,10 aMBF was distinctly lower than EBF(p<0.05),40 aMBF decreased by 13.3% in comparison with the EBF.10 aWT was obviously higher than that of 40 a WT(p<0.05).In terms of LFOC contents,converting EBF to WT,it increasedclearly,especially,40 aWT increased much more than that of the 10aWT(p<0.05);but MBF was lower significantly than that of EBF(p<0.05),and 40 a MBF<10a MBF.(4)Converting EBF to MBF and WT decreased the SOC contents in 2~0.25 mm soil aggregate.The SOC ratios of aggregates in different forest lands were as follows: 2~0.25 mm >0.25~0.053 mm >(0.25~0.053mm).The SOC contents ofMBF and 40 aWT in 2~0.25 mm aggregate were significantly lower than that of EBF(p<0.05),and 10aWT>40aWT,but 40 aMBF was distinctly higher than that of 10aMBF(p<0.05).(5)The contents of HC inclusive of fulvic acid carbon(FAC),humic acid carbon(HAC)and humin acid carbon(HMC)in different forest lands showed that: FAC> HMC > HAC.Compared with the EBF,the soil HC contents of WT and MBF decreased in 0-10 cm,and thatMBF and 40 aWT declined significantly(p<0.05);HAC and FAC contents in different lands indicated that: EBF>10aWT>40aMBF>10aMBF>40aWT.(6)Conversion EBF to MBF and WT increased the soil PhytOC contents.The soil PhytOC contents in different lands showed that: 40aMBF>10aMBF>40aWT>10aWT>EBF.