SULFUR AND BORON-MAGNESIUM-ZINC COMPOUND FERTILIZER CONTRIBUTE TO THE REPRODUCTIVE GROWTH OF JATROPHA CURCAS L.

Abstract

Jatropha curcas L., a native tree to Mexico and Central America, is cultivated in many counties of China as a source for biodiesel. The effects of different fertilizers on the growth of Jatropha curcas L. were studied under soil conditions of low nitrogen (N), phosphorus (P), potassium (K) and boron (B) in soil. Compared with 16N-16P-16K compound fertilizer, both sulfur (S) and a B-management (Mg)-zinc (Zn) compound fertilizer both increased the oil concentration of the seed, and promoted the reproductive growth. Only the fertilizer S increased the seed yield and the Acid value of the oil, while the B-Mg-Zn compound fertilizer declined the Acid value of the oil and induced the differentiation of female flowers. Boron-Mg-Zn compound fertilizer induced a smaller increase in the oil concentration of Jatropha curcas seed than fertilizer S and the largest increase in growth rate of trees. Moreover, Jatropha curcas showed a higher requirement of S for the reproductive phase than for its vegetative growth. Jatropha curcas may belong to the species with restricted B mobility, and B fertilizer should be sprayed as a foliar fertilizer. However, further research on the S nutrition of Jatropha curcas is required.