Humic acids from vermicompost positively influence the nutrient uptake in mangosteen seedlings1

ABSTRACT The application of growth promoting substances, such as humic acids, during the formation of fruit seedlings can benefit growth and increase the plant nutrient uptake and translocation. This study aimed to evaluate the effect of the application of humic acid doses (0 mg L-1, 2 mg L-1, 20 mg L-1, 40 mg L-1 and 200 mg L-1) extracted from vermicompost of sugarcane filter cake on the nutrient uptake of seminal mangosteen (Garcinia mangostana L.) seedlings. The experimental design was completely randomized, with 7 replicates for each treatment. The application of humic acids promoted curvilinear increments with quadratic rates for N, P, K, Ca, Mg and S contents from shoots and roots, as well as quadratic increments in the Zn and Mn uptake by shoots. The application of humic acids increased the chlorophyll a and chlorophyll b contents and reduced the carotenoid content. Overall, the regression analysis demonstrated that a dose of 150 mg L-1 is capable of providing the most adequate nutrient uptake by plants, and should be recommended for the production of mangosteen seedlings. Humic acids from vermicompost can provide a better nutrition in mangosteen seedlings at the nursery stage.