Desenvolvimento inicial de variedades de cana-de-açúcar em latossolo do cerrado mato-grossense submetidas a níveis de compactação do solo

Abstract

The replacement of manual harvesting of sugar cane (Saccharum L.) by mechanized demands researches related to the development of genotypes that develop and produce well under conditions of greater soil compaction. Thus, the aim of the present study was to evaluate the effects of compaction on the initial growth and development of sugarcane varities with compaction levels in Dystrophic Red cerrado of Mato Grosso. The experiment was conducted in the experimental area at the Federal University of Mato Grosso, campus of Rondonópolis, in a greenhouse with a randomized block design consisting of 3X5 scheme factorial and corresponding to varieties and compaction levels respectively and four replicates, from September to december/2012. It was studied the varieties RB002504, RB867515 and RB931011 into five levels of soil compaction (1.0, 1.2, 1.4, 1.6 and 1.8 Mg m-3). The variables evaluated were: number of tillers, number of leaves, leaf area, fresh and dry weight of leaves, length and diameter of culms, fresh and dry mass of culms, plant height, root fresh weight, root dry weight, stomatal conductance, chlorophyll content and comsumption of water. For qualitative variables it was used the Turkey test for comparison of means and for quantitative variables regression analyzes, both until 5% probability. The increase of soil density influenced the early development of the three varieties of sugar cane studied. The variety RB002504 produces more tillers, leaves and greater leaf area and highlighting in the density 1.8 Mg m-3 in dry and fresh leaves. The variety RB867515 features larger diameter, root dry weight and stomatal conductance and variety RB931011 showed better results in variables: fresh and dry mass of stems, plant height, length and stalk diameter and chlorophyll content.