Biofertilizantes de rochas fosfatadas e potássicas com enxofre inoculado com Acidithiobacillus na adubação da uva (Vitis vinifera L.) em planossolo do vale do São Francisco

Abstract

The production of biofertilizers from rocks is a practical process that may reduce energy consumption and promote nutrients availability for plant growth, without environmental pollution. Nutrient content of P and K biofertilizers varied with the methodology of production and the materials used. Presently biofertilizers are known as manures that are produced using different organic by-products. The aim of this work was to evaluate the potential of the biofertilizers from rock phosphate (apatite) and potash rocks (biotite) plus addition of sulfur inoculated with Acidithiobacillus, compared with soluble chemical fertilizers on grape (cv. Italy) grown in the San Francisco Valley. A field experiment was carried in the District of Santa Maria da Boa Vista (PE) in a soil with low available P and K. Tree fertilizers sources were applied: PK biofertilizer, PK soluble fertilizers and PK powered rocks, at levels 50%, 100% and 150% of the recommended levels for irrigated the grapes, equivalent to simple superphosphate (SS) and potassium sulfate (K2SO4). A control treatment was added with no P and K applied (P0K0). The grape (cv. Italy) was grown spaced 3,50 x 2,50 m, with a total of 1404 plants (1.2 ha), cropped intensively until fruits harvest. In soil were determined: pH, P, S-SO4-2, K, Ca, Mg, and Fe; in leaves: P, S-SO4-2, K, Ca, Mg and Fe; in must: pH, P, S-SO4-2, K, Ca, Mg, e Fe; in grapes: SST (Brix0), ATT, SST/ATT, weight of berries, weight of clusters, size of clusters and fruits yield. The experiment was a factorial (3x3x3+1) conducted in randomized block design, with 4 replicates. The regression and analyses of variance and data were compared by Tukey-Kramer test (P=0.05), using the software Program SAS (2003), version 9.0. By the soil and plants results we conclude that the best fertilizers on grown the grape (cv. Italy) the chemical fertilizers in the 100% recommend; the biofertilizers, from phosphate and potash rocks, plus sulfur with Acidithiobacillus the may used as P and K sources in alternative to PK soluble fertilizers and 150% recommended levels for irrigated the grapes in the States of the Pernambuco.