Fertilidade do solo e ajuste de equações de volume em plantios de clones de Eucalyptus urophyla x Eucalyptus grandis no Nordeste Paraense.

Abstract

The process of forest degradation results in a set of environmental problems such as the extinction of many species of fauna and flora, climate change, soil erosion and siltation of waterways. Thus, reforestation plantings contribute to reducing deforestation of native forests. Objective of this study was to evaluate the fertility of the soil and their interactions with the development volumetric Eucalyptus sp. and comparisons among soil chemical properties of Eucalyptus sp. with an ecosystem of native forest in the northeastern state of Para. To achieve this goal will be addressed in two chapters (Cap 2 and Cap 3), namely: Cap 2 - Influence of soil fertility in volumetric growth of clones of Eucalyptus grandis x Eucalyptus urophylla. and Cap 3 - Assessment of fertility soil under vegetation with clones of Eucalyptus sp. and native forest. The study was conducted in operational areas of the company Vale Florestar SA, located in the municipality of Dom Eliseu belonging to the middle region of the northeastern state of Pará. In Cap 2, the experiment was implemented in a completely randomized in two eucalyptus clones (Clone 1 - Cl and Clone 2 - C2), with ten replicates per experimental area. Data collected dendrometric and edaphic attributes, which were submitted to multivariate principal component analysis, in which it was observed that the Cl, the soil chemical attributes respondents were more variable pH H2O. pH KC1, Ca, V% m %, H + Al. SB and Al, and C2 were as follows; K, Ca, H + Al, SB, T%, also the Pearson linear correlation and principal component analysis showed no interactions between the chemical attributes and soil attributes dendrometric. In Cap 3, the experiment was implemented in a completely randomized in three systems of land use (with eucalyptus clones: Clone 1 - Cl; Clone 2 - C2 and native forest - FN) for the years 2007, 2009, 2010 and 2011, with ten replicates per experimental area, featuring treatments in factorial scheme 3x4, in which the evaluation period and the system of land use influenced the chemical characteristics studied thus soil fertility was better in the native forest ecosystem with However, the C2 expressed a similar values.

The Amazon region has experienced strong environmental pressures due to deforestation for cattle pasture and logging disordered. However, planting areas with species ofEucalyptus can reduce pressure on native forests. Under the management of these forest species, the understanding of soil fertility can facilitate information relevant to the management applied, íocusing development to increase volume of eucalyptus clones. The objective of the research was to adjust a regression model to estimate the volume of standing trees of two clones of Eucalyptus sp and compare them with soil fertility, aiming to identify the chemical attributes that may be limiting the development oí plants. The experiment was implemented in a completely randomized in two eucalyptus clones (Clone 1 - Cl and Clone 2 - C2), with ten replicates pei experimental area. Data collected dendrometric and edaphic attributes, which were submitted to multivariate principal component analysis. He settled 20 experimental plots of 900 m" each. The data collections were carried out in 2010. Among the tested models presented the best goodness offit was the model of Schumacher-Hall 2 {LnVr = -9,66709104 + 1,59114016 x Ln DAP + 1,15131955 Ln HT). In clone 1. the chemical soil respondents were more variable pH H20, pH KC1, Ca, V% m% H+Al, SB and Al. While in the clone 2 were as follows: K, Ca, H+Al, SB, T%. The Pearson linear correlation and principal component analysis showed no interactions hetween soil chemical properties and attributes dendrometric.

One way to quantify the impacts of reforestation with Eucalyptus is comparatively evaluate the chemical properties of soil with native forest. The objective ofthis research is to evaluate the fertility of the soil under vegetation with clones of Eucalyptus grandis x Eucalyptus urophylla and native forest, in order to compare the chemical attributes as a means of environmental sustainability indicators. The study was conducted in operational areas of the company Vale Florestar SA, located in the municipality of Dom Eliseu belonging to the middle region of the northeastern state of Pará. The experiment was implemented in a completely randomized in three treatments (with eucalyptus clones : Clone 1 - Cl; Clone 2 - C2 and native forest - NF) for the years 2007, 2009, 2010 and 2011, with ten replicates per experimental area, featuring treatments in factorial scheme 3x4. 30 plots were installed, with 900 m2 each. The evaluation period and the ground cover influenced the chemical properties studied. In general, fertility was better in the ecosystem with native forest, however, the clone expressed a similar values.