Preliminary Study on Distribution Characteristics of Jatropha curcas and Selection of Its Suitable Habitat in Sichuan Province

In Sichuan Province, Jatropha curcas is mainly distributed within a narrow horizontal belt along dry-hot river valleys of the Jinsha River, the Anning River, the Yalong River and their main tributaries. J. curcas is usually distributed in scattered, clustered or patched pattern in the province. It was showed by investigation that the optimal habitat for J. curcas was below 1600m in Sichuan Province, with average distribution elevation between 500m and 1600m, and 1910m as the highest. It was indicated that there were no significant differences in plant height and basal diameter of the trees, the thousand-grain weight and the seed oil content sampled from trees growing on 3 typical vertical climate zones, i.e., on the Mount Erban zone, on the upper and the lower reaches of Panxi River. Neither there were not evident differences in sexually reproductive or vegetative growth of the plants that grew within elevation level within 500~1600m. The results showed that J. curcas plants grew better on dry red soil, mountainous coarse red soil and on the alluvial sandy soil than on the common mountainous red soil. However, there was no significant difference in the oil content of the seeds sampled from trees growing on different soil conditions. It was showed that deep soil (soil depth was from 50m to 120cm) was beneficial to growth of J. curcas. It was showed that J. curcas could grow well on varied slope aspects, though it grew better on sunny and semi-sunny slopes. The results also showed that J. curcas trees growing at the bottom of the slope, in the valley and on the river banks could grow and fruit better than those growing on the upper and middle parts of the slopes.