Agronomic Evaluation of Sweet Sorghum in Semiarid Region: Cultivar and Spacing Effects

The objective of this study was to evaluate the agronomic characteristics of two sweet sorghum varieties for row spacing in the semiarid region of the State of Ceará, Brazil. Hence, an experiment was carried out on the Experimental Farm of the Federal University of Ceará, in two agricultural cycles (2015 and 2016), in sandy loam Planosol during the rainy season. Two sweet sorghum varieties (BRS 506 and SF 15), cultivated at 50, 60, 70, and 80 cm row spacing, were evaluated at different times after sowing (30, 45, 60, 75, and 90 days), in a randomized block design repeated four times in the arrangement of subdivided plots (2 × 4 × 5). The BRS 506 variety had higher mean number of leaves and leaf angle +3 in the two cycles evaluated. The highest mean plant height was observed at 90 DAS (328.11 cm). The stalk diameter at 15.59 mm was greatest with 70 cm spacing between rows. The chlorophyll content of the leaves may be influenced by stress factors, such as water and mineral deficiency, primarily nitrogen. The best results for chlorophyll occurred in the first cycle, in which the greatest mean was observed at 75 days, while in the second cycle, a year that presented low precipitation (water stress), the greatest means were observed at 30 days. Taking into consideration our results, BRS 506 variety is recommended for cultivation in semiarid northeastern Brazil, presenting good agronomic characteristics, when sown with 70 cm spacing between the rows.