Fertilidade do solo, nutrição, fisiologia e produção do maracujazeiro amarelo sob irrigação e adubação organomineral

Abstract

Yellow passion fruit is a crop of socioeconomic importance in the medium and small properties of the Serra da Ibiapaba. The cultivation of the fruit in this region is usually performed in soils of low fertility, especially in phosphorus, that also goes under water limitation for irrigation. Based on that, the objective of this study was to evaluate the soil fertility and the vegetative growth of yellow passion fruit ‗Sol do Cerrado‘ submitted to different irrigation depths, phosphate and organic fertilization. The experiment was carried out in the municipality of Tianguá - CE. The treatments were organized in a subdivided plot using a 2×(3 × 5) design, where the main plot corresponded to the irrigation depths (100 and 70% ETc) and the subplots corresponded to the combinations between sources of organic matter (with and without, using bovine manure and poultry litter) and phosphorus doses (0, 40, 80, 120, 160 of P2O5 kg ha-1). The treatments were distributed in four randomized blocks and the subplots consisted of three plants. The organic inputs were provided in order to raise the level of soil organic matter to 4%. Phosphorus doses were obtained from simple superphosphate (18% P2O5, 12% S, 20% Ca), that were applied 50% during the preparation of pits and 50% at the beginning of the flowering stage. The following soil properties were evaluated: phosphorus, potassium, magnesium, calcium, organic matter, aluminum, acidity, cation exchange capacity and sum of bases. The growth in height, stem diameter, period for pruning of the main stem and reproductive branches of the plants were evaluated. Data were submitted to analysis of variance. The means of the treatments under organic fertilization and irrigation depths were compared by the Tukey test at 5% probability and the phosphorus doses by polynomial regression, using the software SAS (2011). Phosphorus and poultry litter contributed to the increase of phosphorus and potassium content, and cation exchange capacity of the soil. The reduction of the irrigation depth, from 100 to 70% of the evapotranspiration of the crop, did not compromise the emission of the productive branches. Phosphate fertilization and poultry litter stimulated the growth of the yellow passion fruit plants.