Influência do biocarvão na fertilidade do substrato, emergência e crescimento inicial de mudas de mamão e melão.

Abstract

The use of organic residues from agricultural activities in the form of biochar can be a viable alternative both in the process of managing the generated biomass and in recycling the nutrients contained in these residues. In order to produce good quality seedlings, taking into account the composition and availability of substrates in the region, the aim of this study was to evaluate the influence of the application of different doses of biochar, produced from poultry litter as a conditioner for substrate for the production of fruit seedlings. The work took place in a protected environment and in a laboratory, both belonging to the Federal University of Campina Grande - UFCG. The experiment went through two stages: the first consisted of soil incubation and its chemical characterization, and the second consisted of two experiments, the first with melon and the second with papaya, both carried out in a protected environment. For each experiment, the statistical design used was completely randomized in a 6 x 2 factorial scheme, consisting of 6 doses of biochar (4, 8, 12, 16 and 20 t ha-1 and the control) and two varieties of each crop with 4 repetitions, totaling 48 experimental units. Then, evaluate the plant height, stem diameter, number of leaves and leaf area variables, as well as the respective absolute growth rates. The fresh and dry phytomass of the aerial part and root system and the Dickson Quality Index were also analyzed. The data were submitted to the variance homogeneity test (Cochran and Bartlett), and the verification of the normality of the residues (Shapiro-Wilk) and, in case they did not meet the requirements, they were transformed. Once the assumptions of the analysis of variance were met, the data were followed for analysis of variance by the F test at 1 and 5% probability. When a significant effect was verified, the polynomial regression analysis for biochar doses and the comparison between means for varieties were carried out using the Student's T test, using the SISVAR statistical software. It is concluded that the use of biochar from poultry litter did not affect the emergence percentage of melon and papaya seeds; however, it favored its chemical characteristics, as well as providing a satisfactory growth of melon and papaya seedlings, with the doses of 8 and 12 t ha-1 being the ones that provided the best results.