Levantamento da fertilidade dos solos do grupo luiz jatobá, alagoas, ultivadas com cana-de-açúcar (Saccharum officinarum)

Abstract

The recommendation of liming and fertilization for sugarcane crop is based on chemical analyses of soils collected at depths of 0 to 20 and 20 to 40 cm, for most sugarcane producing regions in northeastern Brazil. With this, a work was conducted with the objective of identifying the main limiting nutrients of the various soil fertility samples of the Luiz Jatobá Plant, cultivated with sugarcane. For this, determinations of pH, calcium, magnesium, aluminum, H+Al, phosphorus, potassium, organic matter and relative frequency analyses based on classes of very low, low, medium, high and very high according to the variable studied will be made. PH were determined in water, routable cations (Ca2+, Mg2+ and Al3+) with solution of KCl 1 mol L-1 and Na+ and K+ were extracted with solution HCl 0.05 mol L-1 and H2SO4 0.0125 mol L-1 – Extractor Mehlich-1. Extractable acidity (H+Al) with calcium acetate solution 0.5 mol L-1 to pH 7.0 and were determined by titration with NaOH, phosphorus available with Mehlich-1 were determined colorimetrically with ascorbic acid with reducer. And, the organic carbon determined by the colorimetry process. The influence of the increase or decrease of pH, under the inclination of the curve generated by the equation, results in increased or decreased base saturation, where the lower the slope of the curve, the greater the base saturation. Regarding the soil layers under study, there was a difference in nutrient content, with the major deficiency found in the layer 20 to 40 cm. For phosphorus content, both layers are low in nutrient content. However, for the potassium content, 84.9% of the analyzed soils were generally presented, below the critical level. In this case, measures can be adopted, aiming in short and medium term the correction of limiting elements, in order to obtain the increase in sugarcane productivity.

Keywords: soil fertility analysis, fertilization, sugarcane.