Estimativa do potencial de fornecimento de nitrogênio de leguminosas forrageiras de clima tropical. IV. Região de Pindamonhangaba

The present field work was conducted during three years at the Estacao Experimental de Zootecnia de Pindamonhangaba, do Instituto de Zootecnia State of Sao Paulo, Brazil. It was evaluated the nitrogen fixation through forage legumes: perennial soybean - Neonotania wightii (Arnott) Lackey, galaxia - Galactia striata (Jacq.) Urb. and centro - Centrosema pubescens Benth, single or m mixture with Setaria sphacelara Stapf. cv. Kazungula. These species and associations were fertilized with three levels of nitrogen: 0, 150 and 300 kg per hectare per year. Setaria responded to nitrogen fertilization until 150 kg N/hectare/year incrising 48.5% the dry matter productions of protein. The forage legumes, perennial soybean, galaxia and centro increased 9.44, 11.49 and 11.46% the dry matter production of setaria exclusive and without N. The apparent nitrogen transference of perennial soybean, galaxia e centro to the associated setaria was 28.9, 59.6 and 6.5 kg/hectare/year, respectively.