Alternative sugarcane production for conservation of sandy soils: Sugarcane straw, intercropping and nitrogen

Abstract

The expansion of sugarcane cultivation in the Center-South region of Brazil has led to the use of, mainly, areas with low-yielding sandy soils. In this context, the objectives of this study were to evaluate the maintenance of the sugarcane straw, Brachiaria grass intercropping in sugarcane fields and nitrogen fertilization and on sandy soils in the state of Paraná. The field experiment was installed in the Paranavaí-PR city, at a unit of the Interuniversity Network for the Development of the Sugarcane Sector (RIDESA). The soil was classified as Latossolo Vermelho-amarelo distrófico. The treatments in the plant cane stage, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1) and monoculture or Brachiaria grass intercropping in sugarcane fields were arranged in a 4x2 factorial design. At plant cane harvest, the effect of unremoved straw was included as a new factor to be evaluated in the ratoon crops. The treatments in the ratoon crops were arranged in a 4x2x2 factorial design, consisting of four nitrogen rates (0, 50, 100 and 150 kg ha-1), monoculture or Brachiaria grass intercropping in sugarcane fields and the presence or removal sugarcane straw. The sugarcane straw on soil surface can increase the agronomic development of sugarcane and, the other hands, Brachiaria grass intercropping in sugarcane fields can reduce. Sugarcane was responsive to N rates and, in the highest rates, compensated the sugarcane straw absence and reduced Brachiaria grass intercropping competition.