Litter decomposition in a subtropical plantation in Qianyanzhou,China |
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Authors: | Shiguo Xu Yunfen Liu Yingguang Cui Zhiyong Pei |
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Institution: | (1) Shandong Normal University, No. 88, East Wenhua Road, Jinan, 250014, China;(2) Institute of Geographical Sciences and Natural Resources Research, The Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing, 100101, China;(3) The Second High School of Binzhou, Binzhou, 256621, Shandong, China;(4) The Administrative Center for China’s Agenda 21, Beijing, 100038, China; |
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Abstract: | A long-term (20 months) bulk litter decomposition experiment was conducted in a subtropical plantation in southern China in
order to test the hypothesis that stable isotope discrimination occurs during litter decomposition and that litter decomposition
increases concentrations of nutrients and organic matter in soil. This was achieved by a litter bag technique. Carbon (C),
nitrogen (N) and phosphorus (P) concentrations in the remaining litter as well as δ13C and δ15N during the experimental period were measured. Meanwhile, organic C, alkali-soluble N and available P concentrations were
determined in the soils beneath litter bags and in the soils at the control plots. The dry mass remaining (as % of the initial
mass) during litter decomposition exponentially declined (y = 0.9362 e−0.0365x
, R
2 = 0.93, P < 0.0001), but total C in the remaining litter did not decrease significantly with decomposition process during a 20-month
period. By comparison, total N in the remaining litter significantly increased from 5.8 ± 1.7 g kg−1 dw litter in the first month to 10.1 ± 1.4 g kg−1 dw litter in the 20th month. During the decomposition, δ13C values of the remaining litter showed an insignificant enrichment, while δ15N signatures exhibited a different pattern. It significantly depleted 15N (y = −0.66x + 0.82, R
2 = 0.57, P < 0.0001) during the initial 7 months while showing 15N enrichments in the remaining 13 months (y = 0.10x − 4.23, R
2 = 0.32, P < 0.0001). Statistically, litter decomposition has little impact on concentrations of soil organic C and alkali-soluble N
and available P in the top soil. This indicates that nutrient return to the topsoil through litter decomposition is limited
and that C cycling decoupled from N cycling during decomposition in this subtropical plantation in southern China. |
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