Avaliação do risco de anoxia para o cultivo do eucalipto no Rio Grande do Sul utilizando-se levantamento de solos

Abstract

Eucalyptus is very sensitive to oxygen deficiency. The identification of soil attributes that can indicate conditions for anoxy and thus restrict the growth of the culture becomes essential for planning soil management, and plant breeding. Therefore, this study was conducted in the forest site Cerro Coroado were eucalypt plants had problems with anoxy, reflected by its low productivity, in the County of Cachoeira do Sul, State of Rio Grande do Sul. The work aimed at elaborating, decoding, and interpreting a semi-detailed soil survey for Eucalyptus forests in the State of Rio Grande do Sul. The following soil attributes: effective depth of solum, presence of mottling, gley status, presence of cohesive behavior, gravel and stone content, and land slope and shape were subject of particular attention. The interpretative map for the risk of anoxy for Eucalyptus was elaborated by using information gathered from the semi-detailed soil survey, creating five risk classes. These classes were associated with observed mortality rates of Eucalyptus. The highest mortality rates of Eucalyptus occurred in the soil classes classified as having high to very high anoxic risk. This classification can be used to guide the management practices for the cultivation of Eucalyptus. The interpretation of soils map information for the anoxy risk was compatible with the direct measure of the anoxic effects on the Eucalyptus trees.