Decomposition Of Picea Jezoensis Twig And The Function Of Soil Fauna In Changbai Mountains

The litter decomposition plays a crucial role in regulating the buildup the forestsoil organic matter, releasing of nutrients for plant growth, and influencing the carboncycling. Soil fauna play an significant role in litter decomposition processes throughbreakdown of litter, digestion and stimulation of microbial activities. Terrestrialecosystem consists of the aboveground and the belowground portion, which influencethe function of the ecosystem.We use two different standard litterbags,2mm and0.01mm, to assay thedecomposition rate (picea jezoensis) and measure the impact of soil fauna communitystructure and diversity characteristics in decomposing of twig. During theexperimental period, a total of435, belonging to18groups were found in2mmlitterbag in the upper coniferous forest. The dominant groups were Mesostigmata,Oribatida, accounting for65.74%of the total individual density. There were199individual,17groups in the lower coniferous forest. The dominant taxas wereMesostigmata, Oribatida, Pseudachorutidae, accounting for69.35%of the the totalindividual density.The experiment revealed the decomposition rate of Picea jezoensis twig in warmseason was higher than that in cold season, which was obvious in mesh diameter of2mm. In the same forest, the decomposition rate in diameter of2mm litterbags washigher than that in diameter of0.01mm litterbags without soil fauna, which explainedthat the presence of soil fauna accelerate twig decomposition. In the early stage(2011.10~2012.10), the decomposition rate in diameter of2mm litterbags hadreached35%~38%, and33%~35%in diameter of0.01mm litterbags. Decompositionrate in lower coniferous forest is higher than that in the upper coniferous forest.The study on twig decomposition in two sizes of litterbag showed that soil faunaplay a facilitation role in general, but it vary in different decomposition stage, such asfrom October2011to April2012, soil fauna played a inhibition effect, rest of thedecomposition stage played a facilitating role. Study on contrast of different periodsof soil fauna found in two habitats contributes to the twig decomposition rate of soilfauna maximum period appeared April2012to October2012. The dominant taxa ofsoil fauna involved in twig decomposition is Isotomidae,Pseudachorutidae,Oribatida,Prostigmata, Mesostigmata.