Desempenho agronômico e qualidade nutricional de silagens de sorgo biomassa, sacarino e forrageiro em região semiárida

Abstract

his work was carried out in order to evaluate the agronomic performance and nutritional silages quality of biomass, saccharin and forage sorghum grown under rainfed agriculture in the semi-arid region of Minas Gerais. The research was developed in the 2014/2015 and 2015/2016 crops in Nova Porteirinha and Mamonas county, in which BRS 716 and CMSXS 7016 biomass sorghums, BRS 506 and BRS 511 saccharin sorghums and BRS 655 and Volumax forage sorghums were evaluated. The experimental design was in a randomized block with three replicates. The occurrence of droughts and the temporal and spatial irregularity of the precipitation influenced the productivity of all sorghum genotypes. The BRS 716 and CMSXS 7016 genotypes presented the highest Yields of green matter (GM) and dry matter (DM) in both places and crops. In 2014/2015 crop, the GM yield was 81.74 t ha-1 (BRS 716) and 73.02 t ha -1 (CMSXS 7016) in Nova Porteirinha; and 44.73 t ha -1(BRS 716) and 45.50 t ha-1 (CMSXS 7016) in Mamonas. In the 2015/2016 crop, the DM yield was 40.97 t ha (BRS 716) and 46.55 t ha (CMSXS 7016) in Nova Porteirinha, and 39.74 t ha-1 (BRS 716) and 36.91 t ha-1 (CMSXS 7016) in Mamonas. The biomass genotypes showed greater water use efficiency (WUE) in the 2014/2015 crop in Poth places. In Nova Porteirinha, the BRS 716 genotype presented an average value of 82.51 kg DM ha-1 mm-1, whereas, in Mamonas, the CMSXS 7016 genotype had an average value of 43.91 kg DM ha-1 mm-1. In the 2015/2016 crop, BRS 716 and CMSXS 7016 genotypes showed higher WUE in Nova Porteirinha, with mean values of 17.18 and 21.84 kg DM ha-1 mm-1, Respectively. In Mamonas, there was no significant difference in the WUE between the genotypes analyzed in the 2015/2016 crop. There was no significant difference in the interaction crops, places and genotypes, of the chemical- bromatological variables: MM (10.85%), CP (7.91%), NFC (24.50%), NDF (56.91%), NDFap (55.15%), AFD (32.72%), cellulose (3.93%), hemicellulose (23,95%) and dry matter digestibility (79.13%). The BRS 716 and CMSXS 7016 genotypes obtained the highest digestible dry matter (DDM) production in both Tocations and crops. In the 2014/2015 crop, the DDM production was 20.60 t ha-1 (BRS 716) and 18,07 t ha-1 (CMSXS 7016) in Nova Porteirinha; and 13.45 t ha--1 (BRS 716) and 13.59 t ha-1 (CMSXS 7016) in Mamonas. In 2015/2016 crop, DDM production was 5.82 t ha-1 (BRS 716) and 7.17 t ha-1(CMSXS 7016) in Nova Porteirinha and 9.17 t ha' (BRS 716) and 7.99 t ha-1 (CMSXS 7016) in Mamonas.