Saline-sodic soil and organic matter addition in the cultivation of the colored cotton 'BRS Topázio'

Abstract

The prevailing climate of the semiarid region in the northeastern region of Brazil along with inadequate irrigation management, have caused the formation of halomorphic soils, which have hampered agricultural production and environmental sustainability of this region. Therefore, this study aimed to evaluate the emergence and initial growth of the cotton cultivar 'BRS Topázio' cultivated in soil with different levels of exchangeable sodium percentage (ESP) and concentrations of organic matter (OM) in a greenhouse from April to June 2014. The experiment was set in a randomized block design in a 5 × 4 factorial scheme, with three replicates, and the treatments consisted of five ESP levels (13.6, 22.4, 30.1, 39.0, and 48.0) and four OM concentrations (0, 5, 10, and 15% based on soil volume). Soils with an ESP ranging from 13.6 to 48.0 did not interfere with the emergence and number of leaves of cotton at 10 days after seeding (DAS). At 44 DAS, in the period preceding the flowering stage, ESPs ranging from 27 to 30 promoted greater plant height, stem diameter, and fresh and dry matter of shoot. Increasing OM increased the emergence percentage and emergence speed index and, at 44 DAS, increased plant height, stem diameter, and shoot fresh and dry matter. Increasing OM mitigated the effect of the exchangeable sodium up to an ESP of 30 on the number of leaves, plant height, stem diameter, and leaf area at 10 DAS, and up to mean ESPs of 28.5 and 34.0 for the number of leaves and leaf area, respectively, at 44 DAS.