Production and composition of anatomical fractions of four sorghum hybrids under nitrogen dosages

Resumo

The objective of this study was to evaluate the production and composition of anatomical fractions of four forage sorghum hybrids under three N (nitrogen) dosages. The experimental design was in randomized blocks in a factorial scheme 4x3 (four sorghum hybrids and three N dosages). The sorghum hybrids were the following: 1F 305, 0369 267, 0369 255 and BR 700, and N dosages were 0, 60 and 120 kg/ha. It was determined the NMP (natural matter production), DM (dry matter contents), DMP (dry matter production), TDMP (total dry matter production), regrowth percentage and composition of the anatomical fractions of the plants. In the first and second cuts the N dosage of 120 kg/ha had greatest NMP and DMP. DM contents were influenced by both hybrids and N dosages in the first cut, but not in the second one. The hybrid 0369 255 and N dosage of 120kg/ha had the highest TDMP. The hybrid 1F 305 differed from the others in relation to the proportion of leaves in the first cut. In the second cut the hybrids 1F 305 and BR 700 had the highest proportion of leaves. In both cuts, the N dosage of 120kg/ha had the highest proportion of leaves. Overall, the hybrid 0369 255 fertilized with 120kg/ha of N is the best combination for obtaining high yields of forage-type sorghum.