Decomposition characteristics of leaf litter of Pinus massoniana and Schima superba in the acid rain region of Chongqing, China
The Masson pine (Pinus massoniana) forests grow widely in south China, and are seriously damaged by the long-term acid rain. It is expected that an intercropping with broadleaved tree species, such as Schima superba which can grow well under the canopy of Masson pine forests, can improve the health condition of Masson pine trees damaged by acid rain by accelerating the nutrition cycling of forest ecosystems. In order to assess the possible improving effect of intercropping with Schima superba, a field study of litter decomposition was carried out at Tieshanping forest Farm of Chingqing, a region with severe acid rain and forest damage, to compare the decomposition rate of Masson pine needle litter with that of the broad-leaf litter of Schima superba, and to see if the decomposition rate of Pinus massoniana needle litter can be increased by mixing them with the broad-leaf litter of Schima superba. It was found that the decomposition rate of leaf litter of both tree species was very low because of the severe soil acidification, with the annual decomposition coefficient of 0.345 0 and 0.413 2 for Pinus massoninana and Schima superba respectively. The decomposition rates in Tieshanping amounted to only about half of that reported in the forests of Fuzhou City in Fujian Province (with the annul decomposition coefficient of 0.651 2 and 0.813 3). It needs 2.0 and 1.68 years for a 50%decomposition of the litter of Pinus massoninana and Schima superba, and 8.64 and 7.26 years for a 95%decomposition of them. It was also found that the decomposition rate of Pinus massoniana needles was not increased when it was mixed with the broad-leaf litter of Schima superba, probably because of the decomposer quantity reduction and the change of decomposer composition caused by severe soil acidification. It seems from this study that the intercropping of Schima superba can no more play the role of improving the health condition of Masson pine forests damaged by acid rain. Moreover, it was reported that the fast growth of Schima superba can lead to more soil acidification. Thus, Schima superba should not be suggested as a suitable tree species to be intercropped into the Masson pine forests for improving the health condition of Masson pines growing in the region with severe soil acidification.
国家科技期刊平台
NSTL
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维普
