The Effect Of Nitrogen Release Of Litter Decomposition On Soil Nitrogen Forms In Broad-Leaved Korean Pine Mixed Forest Gap

Based on Broad-leaved Korean Pine mixed forest gaps(according to the order of area from largest to smallest, the forest gaps all were nines that numberd1-9) in XiaoXing’anling Mountains,3,4,5,6,7and9sample were to measure litter standing crop and litter nitrogen,1,2and8sample were to measure decomposition rate by using Pinus koraiensis, Tilia and Betula costata litter leaf, the characteristic of soil(0～10cm) ammonium nitrogen (NH4+-N), nitrate nitrogen (NO3--N), total soluble nitrogen (TSN), soluble organic nitrogen (SON), microbial biomass nitrogen (BMN) and total nitrogen (TN) were also analyzed to research under the litter leaf and during litter leaf decomposition period. The results were as follow:1. According to the proportion of coniferous and broad leaved tree species of plant, The Broad-leaved Korean Pine mixed forest stand of Liangshui national nature reserve were divided into55～82%:18～45%(type A) and35～39%:59～65%(B type). The litter standing crop and nitrogen storage of type A reached the peak in May and September, the litter standing crop was listed in the decreasing order of H, F, L; nitrogen storage increased from L to Hlayer; the released nitrogen from litter decomposition was easily of enrichment in F and H layer.In type B, the litter standing crop order listed in the decreasing order of L, F, H;both litter standing crops and its nitrogen storage in each layer reached the peak in May and Ooctober; nitrogen storage decreased from L to H layer; nitrogen was easily transformed between all litter layers, nitrogen transformed from litter layer into the soil was more than type B.2. The litter standing crop of4,6and9samples forest gap reached the peak in May and September, the nitrogen storage in forest gap was smller than which in closed forest; nitrogen storage increased from L to H layer and enrichment in F and H layer.while ones of3,5and7samples were in May and Ooctober, nitrogen storage decreased and transformed in F and H layer. The litter nitrogen of forest gap and closed forest were listed in the decreasing order of H, F,L3. During the litter decomposition period, the residue in closed forest was lower than froest gap, the weight loss and weight loss ratio were higher than froest gap,but not significant difference, the model of litter decomposition rate was exponential (R>0.961,P<0.01).The annual decomposition rate of Pinus koraiensis, Tilia and Betula costata litter leaf in forest gap was higher than its closed forest, and were listed in the decreasing order of Betula costata, Tilia and Pinus koraiensis;8,2and1samples as well. The time of50%and95%decomposition were listed in the decreasing order of1,2and8samples. During the study period, the nitrogen of Pinus koraiensis and Tilia were enrichment, while was enrichment-release of Betula costata.The BMN in forest gap was smaller than that in closed forest in May. While in other months,there was various between forest gap and closed forest, but the difference was complex.4. The positive correlation between the litter standing crops (in L layer, F layer and H layer) and nitrogen in S layer, respectively; between nitrogen in H layer and nitrogen in S layer, respectively; between the litter standing crops (in L layer and F layer) and nitrogen in H layer, respectively, reached significant level.The correlation between BMN and forest gap aera was negative in May, respectively;the nitrogen of Betula costata has positive correlation with soil NH4+and NO3-, negative correlation with soil DON. The correlation between nitrogen of F layer and soil NO3-, DON, BMN, respectively; between nitrogen of H layer and soil BMN, respectively;between the litter standing crops (in L layer and F layer) and soil NO3-,TN, respectively; between nitrogen return as well as release rate(LF and FH) and soil NH4+, NO3-,DON, respectively,reached significant level.