Manejo da correção da acidez do solo no consórcio milho-braquiária

• Autor(a) principal: Silva, Paulo Igor Barbosa e
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1193
• topic: Milho-braquiária; Fertilidade dos solos; Características químicas dos solos; Calcário; Corn with brachiaria; Soil Fertility; Soil chemical characteristics; Limestone; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

One of the challenges of intercropping corn with brachiaria in degraded areas in Brazil is low soil fertility. This study was conducted to seek alternatives in rebuilding the fertility of such soils. We evaluated: the effects of limestone doses on soil chemical characteristics at different depths; the strategy and form of application of different doses; mulching; application of agricultural gypsum; and cultivation systems, in a dystrophic, Humic Red-Yellow Latosol. Lime doses were 0.00; 0.25; 0.50, 1.00; 1.50; and 2.00 times the limestone requirement (7.00 t ha-1, TNP = 105%) estimated to neutralize Al3+ and increase Ca2+ + Mg2+ contents. Evaluations included lime doses, with or without incorporation, application of gypsum, and soil mulching. In year 2, a plot that had been previously left to fallow, and split applications of limestone were included, in addition to the treatments of year 1. Increased limestone doses resulted in higher grain productivity and higher concentrations of N, P, K, Ca, and Mg in the corn leaves. As to treatment effects on brachiaria intercropped with corn, increased limestone doses reduced brachiaria yield. However, in brachiaria grown as a monocrop, higher limestone doses resulted in higher brachiaria dry matter yield and higher N, P, K, Ca, and Mg contents in year 2. In year 1, higher limestone doses increased pH in water, and Ca2+ and Mg2+ contents, and decreased the soil s exchangeable acidity (Al3+) and potential acidity (H+Al) contents. Those contents decreased with soil depth. In year 2 those contents depended on the trait evaluated and the soil layer under consideration. Limestone incorporation, mulching, and gypsum application improved soil chemical characteristics, resulting in higher corn grain productivity. However, the effects of limestone applications, either as a single dose or as split doses depend on the crop previously grown and dose applied.