Calagem e o crescimento inicial de pitaia vermelha (Hylocereus polyrhizus) propagada por sementes

Abstract

The red pitaya (Hylocereus polyrhizus) is an epiphyte cactacea that has aroused great interest in the years due to its exotic appearance, peculiar flavor and nutraceutical qualities, in addition to the very attractive market price for rural producers. However, there are still few studies on the management carried out in the culture of pitaya. Liming is a relevant management, which should be studied since most of the Brazilian soils present an acid reaction, compromising the production of most crops. Thus, the objective of this work was to study the effects of liming on the chemical characteristics of the soil, on the morphological processes and nutritional status of red pitaya, propagated from seeds. The experiment was conducted in a protected environment and in the field, with the pots distributed according to the statistical design in randomized blocks, with five treatments (doses of limestone 0; 0.6; 1.2; 1.8; 2.5 t ha -1) and four repetitions. Each plot of the experiment consisted of two pots, for a total of 40 experimental units, one plant per pot. Throughout the period, experiments were carried out when evaluating the vegetative growth of the studied species in relation to biometric parameters. The study of contents and accumulation of nutrients in the aerial part of the plant was also carried out at the end of the experiment. The data were prepared for analysis of variance by the F test and regression analysis. Liming to increase pH and base saturation, as well as reducing aluminum saturation and adjusting the availability of nutrients. PH values between 5.5 and 6.0 and base saturation (V%) between 40 and 50% are considered adequate for the good initial development of the red pitaya. The biometric variables cladode diameter (DC), cladode thickness (EC), length of the root system (CSR), dry mass of the cladode (MSC) and dry mass of the root system (MSSR), increased positively, maximum values between the doses 1.0 t ha-1 and 1.5 t ha-1, this being the ideal range recommended to achieve the greatest growth of the plants. As for the nutrient content in the aerial part, the levels of N, P and Mg increased and Zn and Mn decreased in the plants, finding the following bands that feed the largest vegetative increments: phosphorus 9.4 - 10.0 g kg-1; magnesium 5.3 - 6.0 g kg-1; nitrogen 5.3 - 6.0 g kg-1; zinc 187.0 - 218.2 mg kg-1; manganese 162.0 - 177.0 mg kg-1. Liming contributed to the accumulation of macronutrients N, P, K, Ca and Mg and micronutrients Cu, Mn and Zn in the cladodes.