Litter And Effect On Soil Physical And Chemical Properties In Pinus Tabulaeformis Plantation At Different Ages

The decomposition of forest litters was an important process of nutrient cycling in forest ecosystems and played important role in soil organic matter formation and nutrients released. The nutrition elements released from decomposition in forest litters was an important material sources to vegetation grow. At the same time, Litter layers was main part to keep water and soil. The annual litterfall, pools of litter layers, decomposition rate of forest litters, water holding capacity, the content of main nutrients in litter layers, the physical and chemical properties of forest soil in different plots and the impact of litter on changes of physical and chemistry in Pinus tabulaeformis plantation at different ages in Xiaolong Mountain were studied in the paper. Main results were as follows:(1)The annual litterfall and pools of litter layers was increased with ages, the annual litterfall was rang from 1.957 t?hm-2 to 4.236 t·hm-2, pools of litter layers was rang from 12.232 t?hm-2 to 18.788 t?hm-2, annual litterfall of 30a pinus tabulaeformis plantation had the maximal amount up to 4.236t?hm-2,but the pools of litter layers of 23a pinus tabulaeformis plantation had maximal amount up to 18.788 t?hm-2. the annual litterfall of pinus tabulaeformis plantation was less than secondary forest, but pools of litter layers was more than secondary forest.(2)The decomposition rate of litter was increased with ages. The litter decomposition rate of 7a pinus tabulaeformis plantation was 0.160t·hm-2·a, The litter decomposition rate of 30a pinus tabulaeformis plantation was 0.240t·hm-2·a; the average decomposition rate of litter layers was 33.6% compared with secondary forest. The characteristics of litter quality was different obviously between two trees, To change the type of vegetation has great impact on the material circulation in ecosystem.(3)The content of N ,P ,K in litter layers of pinus tabulaeformis plantation were ranging from 8.56～11.40g·kg-1,0.45～0.63 g·kg-1,0.74～1.23 g·kg-1, respectively. The average reserve of total N, P, K in litter layers were 158.36㎏·hm-2,8.44㎏·hm-2,15.92㎏·hm-2, respectively. The content of N, P in 30a pinus tabulaeformis has maximal amount, but the content of K was less than others. The average reserve of total N, K was 1.31 and 2.99 times than secondary forest, but the average reserve of total P was less than secondary forest.(4)Both water content and saturate water-holding capacity was increased with ages and ranged from 38.98% to 59.22%, 246.95% to 300.33%,respectively,and could be described statistically, the water content and saturate water-holding capacity of 30a pinus tabulaeformis plantation had the maximal amount up to 59.22%,300.33%.The average water content of pinus tabulaeformis plantation was less slightly than secondary forest, but saturate water-holding was more less than secondary forest (p<0.001).(5) The physical and chemical properties were improved with ages, the content of soil organic matter was ranging from 17.5 to 21.0g·kg-1, the content of soil total N ranging from 0.92 to 1.45 g·kg-1, the content of soil total K was ranging from 15.3 to 21.0g·kg-1,the content of soil total P was ranging from 0.35 to 0.50 g·kg-1, pH was ranging from 6.50 to 7.08, field capacity was ranging from 18.08% to 22.81%, soil bulk density was ranging from 1.06 to 1.19g·cm-3.The content of soil organic matter, soil total N, total P, field capacity was less than secondary forest, but the content of soil total K was almost equal to secondary forest and bulk density was more than secondary forest. It was obvious that soil fertility of secondary forest was better than pinus tabulaeformis plantation.(6)The soil factors of soil organic matter, total N, total P, total K, pH, field capacity showed positive correlation with annual litterfall, reserve of litter and decomposition rate, but the factor of soil bulk density showed negative correlation with those factors of forest litter.