Efeito da umidade do solo e carga aplicada pela roda compactadora no ambiente solo-semente em sistema de plantio direto na cultura da soja

• Autor(a) principal: Modolo, Alcir José
• Data de Publicação: 2006
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/630
• topic: Micromorfologia; Plantio direto; Máquinas agrícolas; Solos; Compactação; Micromorphology; Direct planting system; Agricultural machinery; Soil compactation; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA::MAQUINAS E IMPLEMENTOS AGRICOLAS

The soil s physical conditioning around the seeds is important to the initial cultivation development and to assure an adequate plant population. An appropriate soil-seed contact is required to a rapid emergence and a good effectiveness of cultivation. The present work aimed to study the effects of the combination between the soil water contents of the soil and the loads applied by the press wheel of seed drills on the soil-seed contact in a system of direct planting cultivated with soybean. The experiment was made as subdivided design, where units had three soil water contents (U1, U2 e U3) corresponding to 0.27, 0.31 and 0.36 kg kg-1, and in the sub-units, the four load levels applied by the press wheel (C1, C2, C3 e C4), corresponding to 0, 50, 90 and 140 N, respectively, in random blocks deign, with four repetitions. Before the experiment installation, physical attributes of the experimental area were determined: textural analysis, soil water content, soil density, particles density, total porosity and the mechanical soil resistance. After planting, the emergence speed index, the aggregate average diameter in the planted line, the percentage of fines (< 2.0 mm), the minimum, medium and maximum soil density in the seed area, the minimum, medium and maximum soil density profile, and the mechanical soil resistance to the penetration in the planted line. According to the results, the present work allowed conclude that: the loads applied by the press wheel increased the soil density in the vertical planting level beneath the planting depth, when compared with values obtained before the planting; the combination between the loads applied by the press wheel and the soil water contents did not influence the < 2.0 mm percentage and the minimum, medium and maximum soil densities in the seed area; the best plant emergence speed index occurred whit soil water contents of 0.33 kg kg-1 and loads of 86.21 N; using the computerized tomography of non-deformed soil samples, it was possible to quantify minimum, medium and maximum soil density profile, allowing the detailed densities characterization from surface down to the studied depth; the maximum load of 140 N applied by the press wheel on the seed caused a superficial crust of the soil, delaying the plants emergence; soybean planting should not occur without soil compactation around the seed.