Desenvolvimento inicial do milho adubado com fontes de fertilizantes fosfatados

Abstract

The tropical regions frequently present edaphic problems that interfere with agricultural production, among them, the low availability of P stands out, which is one of the essential elements for plants. When applied to the soil, the culture absorbs the fertilizers, but they can also increase absorption and favor the leaching of other nutrients. To obtain great productivity it is essential to apply this nutrient via fertilization. In this sense, the objective was, in leaching columns, to quantify the absorption of macronutrients, the content of these in the leached solution after 15 and 30 days of cultivation and to evaluate the initial development of the corn, according to the modes of application and sources of phosphate fertilizers with and without sulfur. The experiment was conducted in a greenhouse, using samples of Red-Yellow Latosol, conditioned in PVC cylinders. The completely randomized was the experimental design used, with four sources of P and two modes of application, in a 4x2 factorial scheme, with an additional treatment as control, without the application of phosphorus, totaling 36 plots. The treatments, except for the additional, received successively the following amounts of fertilization: 940 kg ha-1 of superficial SSP; 308 kg ha1 of superficial MAP; 308 + 40 kg ha-1 of MAP + superficial Sulfugran; 308 + 2000 kg ha-1 of MAP + superficial Plaster; 940 kg ha-1 of incorporated SSP; 308 kg ha-1 of incorporated MAP; 308 + 40 kg ha-1 of MAP + incorporated Sulfurgran; 308 + 2000 kg ha-1 of MAP + incorporated Plaster. Samples of the leached solution were collected at 15 and 30 days of corn cultivation for the analysis of macronutrients, pH and electrical conductivity and at 30 days, chlorophyll content, electron flow, stem diameter and plant height were quantified. The plants were chopped to quantify the mass of green matter, the drying was done and the mass of dry matter was quantified, which was ground to perform the analysis of macronutrients in the aerial part. The statistical program R (R Development Core Team) was used to analyze the data, the analysis of variance (Anova) and the F test were performed. The corn culture responded to the application of fertilizers containing phosphorus and sulfur, standing out in relation to the control treatment. The application of superficial plaster provided greater leaching of nutrients. The MAP source, even without the addition of sulfur, favored the leaching of nutrients.