Potencial de plantas de cobertura no manejo das infestantes em plantio de milho (Zea mays L.)

Abstract

The cultivation of cover crops has been a practice for a long time, as they increase the organic matter in the soil, aid in nutrient cycling and biologically fix nitrogen. Thus, it is important to evaluate the performance of cover species: black velvet bean (Mucuna pruriens L. DC. var. utilis), brachiaria (Brachiaria ruziziensis R.Germ. & Evrard), cowpea (Vigna unguiculata L.) and pig bean (Canavalia ensiformis DC.) in the management of corn weeds under local conditions. For this, the field experiment was organized in randomized blocks, with five treatments (four cover and control species) and four blocks, containing 20 experimental units, in two cultivation cycles. Before the implementation of the experiment, the phytosociology of the area was carried out, as well as the 60DAS and 90 DAS. Biometric parameters of corn were measured at intervals of 15 DAS and between the penultimate and last collection with an interval of 35 days. The leaves opposite and below the ear, at the beginning of dolling were collected for foliar analysis of N, P and K. As for cover species, biomass, dry mass and percentage of cover were obtained at intervals of 15 DAS, the foliar analyzes of N, P and K were carried out using material from the collections of 60 DAS and 75 DAS. There was suppression of weeds by cover crops in corn cultivation. The introduction of ground cover plants between the rows of maize cultivation increased the chemical properties of the soil (T, t, SB, V%, m% and Al3+). Maize productivity was not influenced by the cultivation of cover crops. Cover crops caused an increase in the total dry mass of corn plants. The cover crops, from 60 DAS, showed high increases in dry mass, especially for C. ensiformis and B. ruziziensis. C. ensiformis and B. ruziziensis presented the highest percentages of soil cover in the studied agrosystem. In all treatments, the concentrations of P and K in leaves of maize plants were ideal. Cover crops showed adequate leaf N concentrations during both cropping cycles.