Atributos químicos do solo, crescimento e estado nutricional de cajueiro adubado com farinha de ossos e tratado com hidrogel.

Abstract

The recent renovation of cashew orchards (Anacardium occidentale L.) has contributed to the development of cashew trees in the northeastern region of Brazil. However, there have been many difficulties in the management of the implantation of the crop, due to several factors such as edaphoclimatic, with soil naturally poor in organic matter and water stress caused by irregular rainfall. In this way, the objective was to evaluate the growth, soil chemical attributes, nutritional status and cashew gas exchange as a function of fertilization with bone flour and hydrogel concentrations. An experiment was carried out in a 2 × 5 factorial scheme with two concentrations of the polymer (0 and 5 g L-1

per plant) in the municipality of Boa Saúde-RN, and five doses of bone flour (0, 250, 500, 750 and 1000 g per plant) and four replicates with three plants per plot. Growth was evaluated every two months for 360 days after transplanting (DAT) by measuring plant height, stem diameter and number of leaves per plant. The chemical characteristics of the soil and leaf mineral composition were performed with representative samples, collected at 360 DAT. At 340 DAT the physiological, photochemical and chlorophyll readings were performed on the plants. Data were submitted to analysis of variance and regression when significant. There was influence of bone flour doses on the growth variables. The estimated mean dose of 493 g of bone flour per plant in the absence of hydrogel favors the accumulation of P, Ca and Mg leaf, while higher doses tend to reduce. However, if combined with hydrogel, higher doses of bone flour (up to 1000 g per plant) tend to maximize the content of these macronutrients in the early dwarf cashew leaves. The estimated values of internal CO2 concentration and stomatal conductance differed statistically between treatments, and no differences were observed in the other variables of gas exchange. It is concluded with this work that there are changes in the biometric, nutritional and physiological variables of precocious dwarf cashew when submitted to fertilization with bone flour and hydrogel application.