Produtividade do milho em sucessão a plantas de cobertura de solo

Abstract

The system of direct sowing is based on the absence of soil rotation, its permanent cover and crop rotation. Among these aspects, the use of hedge plants contributes to the production of residues in areas of grain production. However, information on corn grown in succession to cover crops is scarce for the Amazon. The objective of this work was to evaluate the effects of soil cover plants on maize productivity in a no tillage system in the southwest region of Amazonas. The study was carried out in two successive trials, in the agricultural years 2017/2018 and 2018/2019, in the experimental area of the Federal Institute of Education, Science and Technology of Amazonas - IFAM, in the municipality of Eirunepé-AM, using five species of brachiaria (Brachiaria decumbens L.), brachiaria (Brachiaria ruziziensis L.) and calopogonium (Calopogoníum mucunoides Desv.) in the soil. Also used were treatments with native vegetation and fallow in the clean, in two agricultural years. Subsequently, sowed the corn, hybrid AG 1051 throughout the growing area. The experiment was a randomized block with four replicates, totaling 28 plots. The density and dry matter of cover plants and weeds, macronutrient content, RNE-neighborhood effect index, remaining dry matter decomposition, half-life time, and productivity components were evaluated. The accumulation of dry matter of the cover plants did not differ among them, only for native vegetation. In the two years, the hedge plants accumulated larger amounts of nitrogen, potassium and calcium; and lower amounts of phosphorus, magnesium and sulfur. All treatments with weed plants influenced the suppression of weeds, especially Brachiaria ruziziensis, with a value of 98% relative neighboring index. The decomposition rate of the remaining dry matter was similar in the evaluated two years. The grasses had lower losses of dry matter remaining, consequently, longer life. On the other hand, the legumes presented greater losses of dry matter remaining, thus shorter half-life. Canavalia ensiformis was superior in 83% of the variables that compose the productivity. Cover plants Canavalia ensiformis and Calopogonium mucunoides promoted higher grain yield increases in relation to the other treatments.