[A comparative study on Amomum villosum cultivation under tropical wet seasonal rainforest and secondary forest at Xishuangbanna].

In order to protect rainforests, change the present Amomum villosum cultivation model, and explore the possibility of cultivating A. villosum under secondary forest, a comparative study was made on the growth and fruit yield of A. villosum cultivated under tropical wet seasonal rainforest and secondary forest at Xishuangbanna. The results showed that A. villosum cultivation had a significant effect on rainforest biomass and net productivity, but no effect on secondary forest. Under both rainforest and secondary forest, the order of plant density and biomass, from big to small, was vigorous plant, senescent plant, seedling, and shoot. The sum of shoot and seedlings was 3.95 and 1.66 times of senescent plant under rainforest and secondary forest, respectively, which meant that A. villosum could maintain population stability. Under rainforest, many of A. villosum seedlings were poorly growing old ones, and most of them could not grow and develop normally. The density and biomass of vigorous plant were not significantly different under rainforest and secondary forest, but those of shoot, seedling and senescent plant were significantly higher under secondary forest than under rainforest, suggesting that A. villosum rejuvenescence was faster under secondary forest. A. villosum fruit yield was 78.068 kg x hm(-2) in secondary forest, slightly higher than that in rainforest. It was worthwhile to notice that A. villosum yield was very low, its stem biomass ratio was very high (above 0.6), and the fruit biomass ratio was extremely low (about 0.01), which showed that the yield-increasing potency of A. villosum was great through improving biomass partition between fruit and stem. The biomass and canopy coverage of secondary forest was lower than those of rainforest, but the soil water content of secondary forest was similar to that of rainforest, which was favorable to the growth and development of A. villosum. The results presented above indicated that A. villosum could be cultivated in secondary forest.