Effects Of Under-forest Economic Model Of Pinus Massoniana On Soil Active Carbon And Soil Respiration In Changting

Soil carbon pool is the largest carbon pool of terrestrial ecosystems,which has a direct impact on the carbon balance of terrestrial ecosystem.,and also had a profound impact on soil quality.This thesis regard Changting County in southern red soil erosion area as the research area,choose the Pinus massoniana as the upper tree species,under-forest economic model selected the four species:Myrica rubra,Camellia oleifera,Sapindus mukorossi,Gardenia jasminoides,Chicken breeding Model and Pinus massoniana?as a control?as the research object.Through field monitoring and laboratory analysis,researching the SOC,DOC,MBC and the effect of soil respiration of different under-economic model.This paper draws the following conclusion:?1?By analyzing the SOC content of 0-100cm soil layer in different model,SOC content is at a low level of 7 g·kg^-1,and which was generally decreased with the increase of the soil depth.With the increase of the soil depth,the difference of SOC between adjacent soil layer is smaller.Myrica rubra model has the highest content of SOC in 0-10cm layer,and followed by Camellia oleifera,Chicken breeding,Sapindus mukorossi,Gardenia jasminoides and Pinus massoniana.?2?The reserves of organic carbon of Pinus massoniana model is the lowest in six models,in 0-100cm is only 7.87t·hm^-2,and 0?20cm soil accounted for 46%.Compared with Pinus massoniana,the soil carbon reserves of Myrica rubra,Camellia oleifera,Sapindus mukorossi,Gardenia jasminoidesand Chicken breeding Model are all increased,0-20 cm of 0-100 cm soil carbon ratio between 59.91%-62.91%.?3?There are some differences in MBC content in different soil layer?0-20cm?.The maximum MBC content in 0-10cm and 10-20cm layer is Myrica rubra model.Followed by Camellia oleifera,Chicken breeding,Sapindus mukorossi,Gardenia jasminoides and Pinus massoniana.The content of MBC of different under-forest economic model have obvious seasonal change,which showed a trend of the double peak phenomenon.The content of MBC achieve the peak in May and October,the lowest content of MBC appears in December.?4?Different model significantly increased the DOC content.The content of Soil soluble organic carbon in the vertical direction gradually decreased with the depth of soil layer,and mainly concentrated in 0?20 cm soil layer.There are also some differences among different models,and Pinus massoniana model is the lowest,and the content of 0-10cm and 10-20cm DOC is the almost same.The DOC of 0-10cm and 10-20 cm of Myrica rubra model are higher than other models.?5?The content of soil soluble organic carbon has obvious seasonal variation,which is the highest in spring,followed by winter and summer,and the lowest is autumn.The content of SOC at 0-10 cm is generally higher than 10-20 cm in the vertical direction,but in the summer,due to the leaching of rainwater,the content of 0-10cm and 10-20cm SOC have not absolutely difference,even lower than 10-20cm.?6?The air temperature,soil temperature and soil respiration rate in six model have a same dynamic change rule,which is single-peak curve.But the different model have different respiratory rate and the peak time.The soil respiration of different model in 4 days of January,April,July and October are all appeared a single peak curve.The rising trend begin at 7:00,respiration rate increased with the rising of temperature,achieve the peak at 14:00-16:00.Then with temperatures dropping,the respiratory rate began to fall,and reach the lowest point at 2:00-6:00.?7?The seasonal dynamics of soil respiration rate presents a similar regular.soil The respiration rate in different model have obvious seasonal change.And the regular is:summer>spring>autumn>winter.There is little difference in soil respiration rate between different model in winter.