A Soil Physical Assessment Over Three Successive Burned and Unburned Sugarcane Annual Harvests

A field experiment was carried out to evaluate changes in soil physical properties over three successive years of sugarcane cultivation under burned (BH) and unburned (UH) cultivation systems. Soil samplings were collected after sugarcane planting, after the plant-cane harvest (H1) and after the first ratoon harvest (H2) in areas subjected to BH and UH. The degree of compactness (DC), macroporosity (MaP), soil penetration resistance (SPR), total organic carbon, field water content ( θ ) and water content at field capacity ( θ FC ) were measured. Moreover, the amount of surface straw was measured after H1 and H2. Soil physical quality was considerably reduced after H1 regardless of the harvest systems. Annual successive harvests increased DC by 10%, reducing MaP by about 50% and increasing SPR. The negative effects of the successive harvests were slightly greater at BH because of the lowest amount of sugarcane straw on the soil surface, which considerably reduced θ . It can be concluded that successive harvests reduce the soil physical quality in burned and unburned harvest systems after the first harvest, but the negative effect is more prominent in areas with straw burning.