Influence Of Gap On Litter Decomposition And Nutrient Dynamics In Typical Mixed Broadleaved-Korean Pine Forest In Xiaoxing’an Mountains

The litter leaf is recognized as the critical pathways of material circulation and energy flow in forest ecosystems, and it is an important part of ecological functions of ecosystem. The research was carried out in the forest litter fall of the broadleaved-Korean pine mixed forest, the station as Liang Shui national Nature Reserve during October2006to November2009. By comparing the litter decomposition rate, regularity of nutrient release of decomposition in the process, the effect of gap on litter decomposition of broadleaved-Korean pine had been studied.The litter decomposition rate of gap and nongap were different because that the gap played an important role to interfere forest ecological change. By the decomposition of three years, the litter retention rate of Betula costata, Tilia amurensis, Pinus koraiensis and Broadleaved-Korean pine mixed leaf were35.15%(53.31%in nongap)38.34%(50.89%),40.64%(47.19%),36.94%(39.46%). Decomposition rate of the overall performance was:the gap<the none gap; Olson model was used to estimate the litter decomposition of time needed for the50%and95%and the litter decay of K value. The experimental fitting correlation coefficient R all reached very significant level and the effect was very good. The time sequence of litter decomposition needed for the50%and95%:Broad-leaved Korean pine mixed leaf> Tilia amurensis> Betula costata> Pinus koraiensis, decomposition time needed for50%of gap and nongap is1.996-3.762a(2.624-4.793a) decomposition time needed for95%is8.629-15.686a(11.354-20.660a), decomposition time needed for95%is5-6times of50%; k value of the maple birch leaf and mixed leaf decomposition is significantly higher than the nongap(P>0.05), and decomposition coefficient of linden and Korean pine were greater than the none gap, but not significant difference. This experiment showed that gap will speed up the litter decomposition rate.In this study, litter of the gap and the nongap decomposition after3years, to change trend of C, N, P, K in the gap and none gap is no significant difference by release or adsorption concentration after decomposition of the3years. During decomposition the elements C, P, and K in leaf litter released continuously, and the release pattern of C followed linear function while that of P and K followed a function of higher degree Element N presented different levels of accumulation, but had no clear pattern. C/N ratio of the release rate were significantly negatively correlated (P<0.05), The results indicated that Carbon, and C/N ratio could be regarded as good indexes to judge the litter decomposition rate.