Productivity of cassava grown on Marandu grass straw managed through diferent grazing intensities

Resumo

For cassava farming, conventional soil preparation is traditionally used. However, in recent years, some producers have been showing interest in adopting no-tillage system. We evaluated the cassava yield in conventional tillage or no-tillage systems with marandu grass straw, as well as the straw decomposition and the physical and chemical soil attributes. A completely randomized design with five treatments and four replicates was used. The treatments were no-tillage (NT 0% - no-grazing pasture; NT 25%, NT 50%, NT 75% - grazing intensities to obtain an intake of 25%, 50% and 75% of forage mass, by animals) and conventional tillage (CT 50% - grazing intensity to obtain an intake of 50% of forage mass, before tillage). The soil tillage did not influence fresh and dry weight of cassava roots, with averages of 31.84 and 10.88 Mg ha^-1. After 448 days of cassava planting, straw decomposition did not differ between treatments, with an average value of 53%. The half-life time of straw was 221, 218, 263 and 321 days to treatments NT 0%, NT 25%, NT 50%, NT 75%, respectively. We observed that soil physical quality was improved in no-tillage treatment NT 50%, when compared to CT 50%. The residual straw of Marandu grass did not influence the cassava yield in no-tillage, when compared to conventional tillage. Part of the forage available in the pasture can be used for animal feed, before cassava planting.