Organic and chemical nitrogen in black sorghum grown with forage peanut as a cover crop. I. Nutricional value and dry matter pro duction

Abstract

A study was conducted on forage sor ghum (Sorghum almun) to evaluate the application of 0, 150, 225 and 300 kg ha-1of nitrogen from an organic fertilizer and 300 kg ha-1 N from Nutran® (ammoniun nitrate, 33.5% N) on dry matter (DM) production and forage nutritional value. Sorghum was planted in a plot of perennial peanut (Arachis pintoi CIAT 18744). Black sorghum and the perennial peanut were harvested every 54 days during a 312 day period. There was a quadratic response to the level of organic N application on DM and crude protein yield. Biomass production of sorghum fertilized with 300 kg ha-1 N from a chemical fertilizer (3.4 t DM) was similar to the DM (3.31 t) obtained with the application of 225 kg ha-1 N from an organic source. Even though CP content was higher in the Nutran® treatment, no differences were observed among treatments on NDF, ADF and IVDMD.