Carbon And Nitrogen Storage Of Bambusa Emeiensis And Alnus Cremastogyne Forest Eco-system In Rainy Zone Of West China

The forest ecosystem which is the main part of the terrestrial ecosystems, not only plays an important role in maintaining regional ecological stability, but also have can’t be underestimated contribution to the global carbon balance progress. There are many differences includes tree species composition, forest age structure and their location as well as management in forest ecosystem which give rise to diversities in some aspects for example the size of carbon storage, nutrient cycling as well as effect in the progress of global carbon cycle of forest ecosystem. To estimate the amount, composition and distribution of carbon storage in different forest ecosystem accurately is help to ascertain "carbon missing", in-depth understand carbon cycle principle, cope with global climate change. In forest ecosystem nitrogen reserves and its distribution pattern have a significant impact on carbon storage and distribution. To understand nitrogen storage and its distribution pattern in different vegetation types is helpful for further in-depth understanding the function nitrogen have and mechanism nitrogen influent carbon cycle in forest ecosystem carbon cycle. In this paper, we adopted the method which combine collected in the field and analyze in laboratory to study the carbon and nitrogen storage, distribution and soil labile carbon characteristics of Bambusa emeiensis and Alnus cremastogyne artificial vegetation type in Rainy Zone of West China. We came to the conclusion as follows:(1) The vegetation layer biomass and the amount of carbon storage of Bambusa emeiensis groves was higher than Alnus cremastogyne plantation. The vegetation layer biomass and the amount of carbon storage of Bambusa emeiensis plantation were184.82t·hm-2and96.07t·hm-2and that of Alnus cremastogyne plantation were100.34t·hm-2and50.36t·hm-2.The tree layer biomass was the biggest portion in two kinds of forest ecosystems. The tree layer biomass was106.51t·hm-2which was57.63%of the overall in Bambusa emeiensis groves, at the same time, the tree layer biomass of Alnus cremastogyne groves was66.91t·hm-2that was66.68%of the overall. (2) The carbon and nitrogen storage of tree layer were main portion of vegetation layer and in carbon and nitrogen content decreases with increasing depth in two kinds of forest ecosystem. Carbon and nitrogen content of different soil layer and the amount of carbon and nitrogen storage of soil in Alnus cremastogyne groves were higher than that of Bambusa emeiensis plantation. Carbon and nitrogen storage of soil in Alnus cremastogyne plantation were81.30TC·hm-2and10.70TN·hm-2and those in Bambusa emeiensis plantation were71.10TC·hm-2and10.30TN·hm-2.The soil carbon storage from0cm to40cm in Alnus cremastogyne plantation and Bambusa emeiensis plantation were62.40%and71.17%of the overall.(3) The carbon and nitrogen storage of Alnus cremastogyne ecosystem was130.65TC·hm-2and that of Bambusa emeiensis ecosystem was167.16TC·hm-2.The carbon storage exist in soil layer in Alnus cremastogyne ecosystem was61.75%of total; the vegetation layer carbon storage was mainly portion of carbon storage of Bambusa emeiensis ecosystem. The litter layer carbon storage was the least part in two forest ecosystems, all less than5%. The nitrogen storage of different layer in two plantations, from big to small, are pattern Soil layer>Vegetation layer>Litter layer, nitrogen storage of vegetation layer in Alnus cremastogyne ecosystem and Bambusa emeiensis account for97.10%and93.18%of the entire ecosystem nitrogen storage.(4) In Alnus cremastogyne groves and Bambusa emeiensis groves SMBC content from0cm to40cm changes in the range of0.08～0.65g·kg-1and0.14～0.44g·kg-1.The variation of SMBC content between different soil layers in Alnus cremastogyne groves bigger than that of Bambusa emeiensis groves. In Alnus cremastogyne groves and Bambusa emeiensis groves SMBN content changes in the range of18.42～141.78mg·kg-1and25.00～102.74mg·kg-1. The C/N<20:1in two plantations indicates that the lack of C is restrictive factor for plant growth in these ecosystem.(5) The WSOC content of0～10cm and20～40cm in Alnus cremastogyne plantation were higher than these in Bambusa emeiensis groves about10.5%and 3.5%. The WSOC content decrease with depth increasing in two plantation types but the rate of change is different, indicates that the distribution of WSOC in the soil profile was strongly influenced by vegetation type and its composition.(6) In two kinds of plantation types, ROC and POC content distribution in the soil profile have the same variation pattern and ROC and POC content in Alnus cremastogyne plantation is higher than that in Bambusa emeiensis groves in all soil layer. The result show that the effects of vegetation on the soil surface of labile carbon component is significant,but sub-soil is not very obvious. Alnus cremastogyne upgrade the labile carbon content greater than Bambusa emeiensis.Base on above Finding, there are great difference in C and N storage and distribution, Bambusa emeiensis is good for the vegetation layer carbon accumulation. To increase the function to absorb CO2of Bambusa emeiensis, we should protect the vegetation from destroying. The Bambusa emeiensis is more conducive to the accumulation of carbon and nitrogen. In two kinds of plantation carbon and nitrogen storage in soil layer is the largest proportion of ecosystem carbon and nitrogen storage, meanwhile, production activities on soil disturbance occurs mainly in the shallow layer. Therefore, in the management process, to minimize the human disturbance, which is important to increase the amount of carbon and nitrogen storage of forest ecosystem.