No abstract

RESUMO Objetivou-se avaliar a viabilidade econômica da implantação do mogno-africano no município de Cristalina-GO através de indicadores econômicos. A área corresponde a 6 hectares no município de Cristalina, Goiás. As mudas de mogno-africano, foram plantadas no espaçamento de 3 x 2 metros, em ciclo de uma rotação com idade de corte para 21 anos. Para esse estudo utilizou-se os seguintes indicadores econômicos: Índice Benefício Custo (IBC), Valor Presente Líquido (VPL) e aplicação do Payback econômico do capital investido. Com base nos resultados desses parâmetros, pode-se obter um VPL de R$ 1.570.492,20 um B/C de 2,73, e um tempo de retorno para o capital investido pelo payback verificado no sétimo ano. Sendo assim, a implantação do mogno-africano apresentou ser economicamente viável, indicando ser uma boa opção de investimento.

Objective to evaluate the initial growth of seedlings of cultivated in different substrata baru. The experiment was conducted in a greenhouse at the State University of Goiás, Ipameri, in plastic bags with a capacity of 8 dm-3. The experimental design was completely randomized design with four treatments and five replications. The treatments were comprised of formulated the basis of substrates: cerrado soil (S1); cerrado soil + cow manure in the ratio 2:1 tanned (S2); cerrado soil with saturation by bases corrected to 60 % (S3); and composts of forest (S4). The seedlings were conducted for 90 days, during which the following variables were evaluated-answers: height, diameter of the collect, number of leaflets, leaf area, dry weight of shoot, root, and total IQD. The data were subjected to analysis of variance and tukey test. Seedlings grown in S4 (composts forest) presented the highest average in height, diameter of the collect, and dry mass of leaves, stem, root and total, followed by the S3 (cerrado soil saturation of bases with 60 %), which also showed growing seedlings in height, diameter, and dry mass. Seedlings grown in S2 did not differ from those grown with the S1. The greatest seedling growth observed in the S4 and S3 can be related to the higher level of fertility of these substrates. The use of substrate formulated with composts forest provides seedlings of baru with higher quality to the field.

African mahogany (Khaya senegalensis A. Juss) has been an important option to supply the increasing demand for noble forest products for the Brazilian furniture industry. In the present study, the objective was to evaluate the initial development of mahogany plants in response to different doses of zinc. The experiment was carried out inside a greenhouse, in the experimental area of the State University of Goiás, Ipameri Campus, in 7 dm 3 plastic containers, and using soil samples, identified as Dystrophic Red-Yellow Latosol (Oxisol), as substrate. The experimental design was completely randomized, with five treatments and five replications, totaling 25 experimental units. The treatments consisted of five Zn concentrations: 0, 2.5, 5, 10 and 20 mg dm -3 , obtained by zinc sulfate fertilizer. At 150 days, the measurements of the plant height, the root crown diameter, dry matter mass of leaves, stem, root and total were evaluated. The tested increasing zinc doses did not promote increased plant growth. African mahogany presented low zinc requirement in the early stages of development for the studied edaphoclimatic condition, and no application of zinc via fertilizers was required. This fact may resulting from the natural concentration of 0.2 mg dm -3 of Zn in the used soil, which was enough to supply the nutritional demand of the plants in the first five months of development.

The objectives of this study were: to evaluate the leaching potential of B in a Latossolo Vermelho-Amarelo (Oxisol) as a function of sources and doses of this micronutrient; among the sources tested (boric acid, ulexite and the commercial source H2 Boro), to determine the one with the lowest leaching potential; to evaluate leaching losses at different doses in each soil layer evaluated; and to identify chemical and physical variables of soils that influence B leaching. For that, two experiments were conducted in a greenhouse. The first one tested B leaching in the soil, with the three sources under study and five doses of B (0; 12; 24; 36; and 48 kg ha-1), whereas the second experiment evaluated the influence of soil physical and chemical attributes on B leaching using soils randomly collected in 22 localities in southeastern Goiás, Brazil. Regardless of the dose applied, ulexite led to the lowest soluble B content in the profile of the analyzed soils and also in the leachate. Boric acid was the only source that showed a different behavior in relation to B content in the different soil layers and in the leachate. In the soil layer from 21 to 30 cm, ulexite is the source with the lowest soluble B content. The behaviors of the more soluble sources, in this case boric acid and H2 Boro (H2 Agrosciences - Monoethanolamine borate), regardless of the dose, are very similar, being highly leachable in the profile of the Oxisol used. Soils with clayey texture and higher values of H+Al and CEC were able to retain higher B contents in the upper portion their profiles (layers from 0 to 10 cm and 11 to 20 cm), but soils with sandy texture and higher values of sum of bases showed greater B losses by leaching.