Efeito do sistema de corte na produção de cana-de-açúcar e em propriedades físicas de solo de tabuleiro no Espírito Santo

Abstract

A long term experiment with sugar cane (RB 739735) was installed at Linhares, Espírito Santo State, in order to evaluate the technical and edaphic aspects of two systems of sugar cane harvesting: the first with previous burning of the sugar cane (Burned Cane) and the second with spreading of straw on soil surface (Green Cane). The experiment was installed on a Yellow Podzolic soil and the experimental design was completely randomized with six repetitions. After six years of cropping, a process of soil degradation was observed in the Burned Cane system, with decreasing of aggregate mean diameter and increase of soil bulk density at 0-5 cm deth. Differences of total porosity and poros distribution as a consequence of harvesting system were not detected. The soil water infiltration was greater in the areas under Green Cane harvesting system, but the same results were not observed when the saturated hydraulic conductivity was measured using the method of the steady state permeameters. The earthworm population (Megascolicidae), annual balance, was significantly greatest at the Green Cane system. However, there were no differences between earthworm population in the differents periods of the year. There were no differences in the quality of sugar s cane juice and stem, for the periods of days after harvesting. The harvest efficiency in the Green Cane system was equivalent, in average, to 40% of the Burned Cane. The time necessary to control the weeds at the Green Cane system was 80% lower than in the Burned Cane system. On the other hand, this economy was equivalent to the cost of spreading of straw on the soil surface. The additional volume of undesirable material, in the transportation container, for the Green Cane system, was equivalent to 4,6 ton/ha, consequently diminishing the load density during the transport. The study of cost and lucrativity points out that the improving of harvesting efficiency, in addition to a possible greater productivity of Green Cane system, are the main aim to be acquired in order to make Green Cane system a more attractive business option to farmers.