Technical and economical evaluation of graminae cultivated single and in consortium with Brachiaria ruziziensis in the period of the harvest and second harvest in the Northwest of São Paulo

Abstract

Aiming at to establish the best technician-economic alternatives to compose the system of rotation of cultures in the period of harvest and second harvest, in no-till system (NTS), in implantation phase, in the São Paulo northwestern region, the objectives of this work for two years of study will be: a) to quantify the production of grains of the cultures of maize, sorghum and millet in harvests 2007/2008 and 2008/2009 and second harvest 2007 and 2008, b) nutritional evaluation of macro and micronutrients in the florescence stage, c) determine the tax of decomposition of the residual straw at the harvest of grains and the release of N, P and K, during the autumn and winter seasons of 2007, 2008 and 2009, d) to determine the impact of the fertilization in the production of grains and dry matter of the cultures at harvest and second harvest, e) to monitor the production and the quality of the forage consortium with maize, sorghum and millet in the summer (Santa Fé system) and in the autumn-winter produced in succession, f) to determine the residual effect of applied fertilization and g) to evaluate the optimum system of rotation in technician, economic and operational aspects. The assays will be installed in split-split-plot, with three repetitions. The main treatments will be the three graminea cultures, and the sub-treatments, exclusive and consortium culture, with and without fertilization. The comparison of the averages means variables will be done by analysis of variance at each time (harvest and second harvest), in factorial scheme 3 x 2 x 2 (three cultures, in two systems of handling: with and without consortium and two systems of fertilization: with and without seasoning). The comparison of the means will be done by the test of Duncan to the level of 0,05. In the B. ruziziensis trials (at autumn-winter season), it could be compared with the qualitative and quantitative production of the pasture in presence and absence of fertilization, over the residue of the cultures predecessors. This will allow by factorial analysis 2 x 3 (B. ruziziensis with and without seasoning and the effect of three residues of cultures predecessors). The comparison of the means will be done by the test of Duncan to the level of 0,05. At the end of the second year of study, it will be defined the more productive graminea in the harvest and second harvest, and the edge of economic profitability, aiming at the establishment of alternatives for the system of rotation in the region, based initially on the use of graminea generating a covering of resistant straw to the decomposition. The conditions of fertility of the soil at the end of the period also will be considered, under the different lead systems of handling. The rotations defined in the study had been planned considering the possible diversity in the time, together with conditions of logistic viability. (AU)