Suprimento de nitrogênio, estado nutricional, produção e qualidade da borracha de árvores de Hevea brasiliensis.

We aimed to study the effect of N fertilization on leaf composition, yield and quality of rubber of trees of Hevea brasiliensis Muell. Arg. and how the responses relate to plant N status at the previous growing season. The experiment was carried out in a commercial rubber plantation, located in the municipality of Barbosa, São Paulo State, with 12-year-old trees and first tapping. The treatments corresponded to fertilization with N at the recommended rate (50 kg ha-1) and excessive rates (100 and 200 kg ha-1); a control without application of the nutrient was also included. Tree nutritional status, yield and quality of rubber were evaluated. The results revealed a decreasing linear effect of N on yield. The highest N rate also affected latex quality, as revealed by a decreasing in the values of parameters associated with mechanical strength. There was an increase in leaf concentration of N, P and K, while Ca was reduced. Our results, therefore, suggest that leaf analysis could be a complementary tool for adjusting N fertilization of rubber trees and contribute to reduce the likelihood of detrimental effects of nutritional imbalance on trees performance and rubber quality. [ABSTRACT FROM AUTHOR]