Densidade de plantio na produtividade do sorgo sacarino

Abstract

Sorghum emerged as an important alternative to be used in the sugar cane harvest for the generation of biomass in ethanol production. An important factor to be considered and studied for the good development of the crop is the density of planting, the spacing between rows and the density of planting can directly influence the productivity of the crop. Therefore, the choice of the appropriate plant arrangement is an important management practice to optimize yield of sorghum, as it directly affects the interception of solar radiation, in competition for water and nutrients, which are determinants of productivity. In view of the above, the objective of this work was to evaluate the biomass productivity of sorghum as a function of different spacings between lines and plant population. The experiment was carried out at the Curu Valley Experimental Farm, Pentecoste-CE, the sorghum genotypes used (BRS 506, SF- 15 and 7C30) were submitted to spacing between 50; 60; 70 and 80 cm, and between the plants of 8; 12 and 16 cm. The experimental design was a randomized block design, with four replications in a factorial scheme (3x4x3), three genotypes, four spacing between rows and three spacings between plants. The plants were harvested at 110 DAS for genotypes BRS 506 and 7C30 and at 130 DAS for genotype SF 15, where the variables fresh and dry matter of the parts were separately analyzed, leaves (MFF and MSF), stalks (MFC and MSC) and total dry matter mass (MST) which was determined with the sum of the dry matter mass of the parts. It was observed that the MFF and MFC variables presented better means for the BRS 506 genotype with 2.38 and 53.99 t ha-1. When the variables were analyzed in the factor between lines, it was always presented with better averages in the spacing between the lines of 50 cm, justified by the greater amount of plants in the hectare, with a compensation. It was concluded that the BRS 506 sorghum genotype had better biomass indexes and was recommended for planting in the northeastern semi-arid region, adopting 50 cm spacing and 8 cm plant spacing, with a population of 240,000 plants per hectare.