| We explored the response of total carbon, dissolved organic carbon (DOC) and mass loss for Pinus massoniana(P.Massoniana). Toona ciliate(T.Ciliate), Cinnamomum camphor a (C.Camphora). Phoebe zhennan(P. Zhennan) to forest gap disturbance in Pinus massoniana plantation ecosystem, which directed by nesxnatural forest management thoughts. We selected 42-year-old Pinus massoniana plantations with seven different gap sizes (G1:100 m2, G2:225 m2, G3:400 m2. G4:625 m2. G5:900 m2, G6: 1225 m2, G7:1600 m2) in the study, using the litterbags method. Discussed the effects of decomposition time, gap sizes and soil fauna on total carbon release rate, DOC release rate and mass loss rate for four leaf litter. The result shows that:(1) Compared with closed canopy(US). small(G1:100 m-) and large size(G7:1600 m2) of forest gaps, medium sized forest gaps(G3-G5:400-900 m2) promoted the total carbon release rate. DOC release rate and mass loss rate for leaf litter.(2) The differences of total carbon content, DOC content, total carbon release rate, DOC release rate and mass loss rate between gap center and gap edge were not significant. In addition, total carbon release rate, DOC release rate through soil fauna had significant difference between gap center and gap edge a small number of forest gaps, but there was no obvious change rule.(3)Decomposition time had significant effects on total carbon release rate. DOC release rate and mass loss rate, after 1 year's decomposition, the average total carbon release rate, DOC release rate and mass loss rate four species was 53.36%? 67.19% and 88.78%, accounted for 66.51%?73.77% and 91.61% of two years, which was Significantly hieher than 26.86%?23.88% and 8.13% in the second vear.(4)variation trend of leat litter k value for tour species was Ciliate(T./16)>C. Camphora(0.789)> P. Massoniana (0.686)> P. Zhennan (0.508),50% and 95% decomposition time of each plants was T.Ciliate(0.44 and 1.78 a)<C. Camphora(0.89 and 3.90 a)<P. Massoniana (1.05 and 4.43 a)<P. Zhennan (1.36 and 6.05 a), total carbon release rate, DOC release rate of 1 year for T.Ciliate and 2 year for other three splants were T.Ciliate(90.58% and 98.35%), C.Camphora(94.02% and 98.88%), P. Massoniana (85.87% and 98.44%), P. Zhennan (84.84% and 93.36%),(5)Mass loss rate, total carbon release rate and DOC release rate through soil fauna were P. Massoniana (8.43%,11.17% and 3.83%), C.Camphora(6.76%,5.13% and 5.24%). What is more, mass loss rate, total carbon release rate and DOC release rate through soil fauna in G2-G6 were significantly higher than them in G1?G7 and closed canopy.Decomposition process of leaf litter in seven different sized gaps of seven period has respective characteristic in Pinus massoniana plantation. the mass loss rate, total carbon release rate and DOC release rate of medium sized forest gaps(G3-G5:400-900 m2) are significantly higher than other gap sizes and closed canopy. the decomposition prossion of four leaf litter is not only had important effects by tempreture and water content, but only significantly effected by soil fauna. In addition, the mass loss rate, total carbon release rate and DOC release rate for four plants in the first year are significantly higher than the second year. When we reconstruct the low-function forest, we can take advantage of small and medium sized gaps and introduce native broad-leaf tree specie T.Ciliate and C.Camphora to accelerate nutrient cycling and maintain the soil fertility of Pinus massoniana plantation. |
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