Water availability of a sandy soil and its impacts on the physiology, productivity and quality of the cotton under crop rotation system with different carbon accumulation potentials in the soil

• Grant number: 23/03112-6
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: September 01, 2023
• End date: August 31, 2026
• Field of knowledge: Agronomical Sciences - Agronomy - Crop Science
• Principal Investigator: Fábio Rafael Echer
• Grantee: Gustavo Ricardo Aguiar Silva
• Host Institution: Faculdade de Ciências Agrárias. Universidade do Oeste Paulista (UNOESTE). Campus de Presidente Prudente. Presidente Prudente , SP, Brazil
• Associated research grant(s): 24/20169-4 - Beltwide Cotton Conferences, AR.EXT

Abstract

Sandy soils are distributed all over the world, but only 4% is used for agriculture. In these soils, the no-sowing system is a way to enable agricultural production, especially in regions subject to water deficits. The objective of this work will be to evaluate the effect of different cover crops on soil water conservation, physiological aspects of cotton and cotton fiber productivity and quality. The experiment will be conducted at the Experimental Farm of Unoeste (51°40230"W, with an altitude of 401m) in sandy soil in the 2023/2024, 2024/2025 and seasons. The experimental design used will be in randomized blocks with five replications. The treatments will be crop rotation systems installed in 2015: Fallow (no cover crop), Single Grass (SG), Grass+Grass (G+G) (two grasses in intercropping), Grass +legume (G+L) (one grass and one legume in intercrop) and MIX (three mixtures of cover crops). The species used in the rotation systems in the off-seasons will be: Fallow: without cultivation; Single grass: Ruzigrass; Grass+grass: Ruzigrass + Millet; Grass+leguminous: Millet + Black Mucuna; MIX: Millet+Mucuna preta+ ruzigrass. The sowing of cover crops and owes will be carried out in May and October 2023 and 2024, respectively. After desiccation of the cover crops will be quantified the dry matter mass production of the area and root part which will be dried and will have their dry matter mass determined, will be ground and will have the levels of C and N determined. At 30, 60, 90 and 120 DAE of the cotton, the leaf area index (LAI) and the efficiency of radiation use will be evaluated. In addition, three plants per plot will be collected to evaluate the dry matter accumulation of the man. The water potential and stomatic conductance will be evaluated between the periods of 30 to 50, 50 to 70 DAE and 70 to 90 DAE of the umdo. The water content in the soil will be evaluated using the continuous monitoring technique "Time Domain Reflectometry" (TDR) installed at the beginning of the cultivation of the cotton. On occasion, the physiological maturity of cotton will be determined the components of cotton production (number of weeds and average weight of weeds), productivity and fiber quality. In May 2025, after cotton harvest, the soil will be randomly collected to determine soil density, TOC contents and physical fractionation. In addition, after harvest, soil will be collected for differentiation of aggregates. The data will be submitted to analysis of variance and regression and for the significant effects the means compared by the Tukey test (p <0.05), using the statistical program SISVAR (Ferreira, 2000), and the graphs plotted in the Sigma Plot® software. (AU)