INFLUENCE OF CUTTING HEIGHT OF PLANTS IN AGRONOMIC CHARACTERISTICS AND NUTRITIVE VALUE OF SILAGES OF CORN AND DIFFERENT TYPES OF SORGHUM

Abstract

The objective of this work was to evaluate the agronomic characteristics, the bromatologic composition, and digestibility of silages of different types of sorghum and cultivars of maize submitted to two cutting heights of the plants (0,1 m and 0,5 m). Four groups of cultivars were employed. These groups were formed by two cultivars of grain sorghum, two cultivars of sorghum double intention, two cultivars of forage sorghum, and two cultivars of corn. The experiment was conducted under the randomized block design in 4 x 2 factorial scheme, i.e. four cultivars and two cutting heights, with three replicates. The following characteristics were evaluated: dry matter yield (DM), participation of culm (CMS), leaf (FMS) and panicles or spikes attributes (PEMS) in the DM, density of plants, fall ill plants and slopes, days for the harvest, height of plants, crude protein (CP), neuter detergent fiber (NDF), acid detergent fiber (ADF), and degradability “in situ” after 24 hours (DEG). Significant effects only were found for cutting heights for the culm participation in DM and ADF characteristic, being that the rise of the height of cut of 0,1 m for 0,5 m reduced the values of CMS (32,5% for 29,9%) and of ADF(25,9% for 23,2%), not influencing, however, the NDF and the degradability of DM “in situ” after 24 hours. The cultivars of corn had gotten lesser values of CMS that cultivars of forage sorghum and similar to the other types of sorghum, in two cutting heights. The cultivars of corn and forage sorghum stood out for presenting greater dry matter yield, respectively 14,4 ton.ha-1 and 13,3 ton.ha-1. The corn cultivars conferred greater nutritive value to silages due to the lower percentages of fiber and greater percentage of rumen-degraded dry matter.

Keywords

• cultivars: degradability: forage: Sorghum bicolor: Zea mays