GROWTH AND DEVELOPMENT OF COTTON CULTIVATED AFTER Urochloa spp.

Abstract

No-tillage systems (NTSs) are generally known for their beneficial effects, whether on soil attributes or the yield of the target crop. For instance, research has explored the benefits of growing target crops, such as soybean or cotton, on soil previously occupied by a cover crop. However, fewer studies have investigated the potential negative implications of NTSs. Since, certain cover crops can release exudates harmful to other plants, there is a need to fill this knowledge gap. To this end, this study used four experiments to investigate the effects of two species of Urochloa on cotton germination, plant emergence, and biomass production. In the first two experiments, cotton germination was evaluated by placing seeds on paper rolls moistened with different concentrations of root washings of Urochloa plants cultivated for 45 days in tubes kept in a greenhouse, and desiccated with or without glyphosate. In the other two experiments, the emergence and biomass production of cotton were evaluated, which was sown in pots where two species of Urochloa were previously grown and subsequently desiccated or not with glyphosate, and managed in three ways: a) the entire plant of Urochloa spp. was kept in the pot (shoots and roots in the soil), b) only the aerial parts of Urochloa spp. were kept on the soil surface, and c) only the roots of Urochloa spp. were kept in the soil. Cotton seed germination was negatively affected by Urochloa spp. root washings. Both the emergence percentage and emergence speed index of the cotton plants were negatively affected when only the leaves of Urochloa spp. were kept in the soil with and without glyphosate desiccation. No adverse effect of the treatments (pre-cultivation and management of Urochloa spp.) on the production of cotton shoot and root biomass was observed.