Uso de biochar de eucalipto na produção de cana-de-açúcar

Abstract

Biochar has been proposed as a promising alternative for the final disposal of solid waste, as it increases carbon supply and improves soil quality. Thus, the studies aimed at evaluating biochar as a substrate and soil conditioner for the production of sugarcane. Hence, two experiments were set up: the first in a greenhouse with a completely randomized design, under a 5 x 4 factorial scheme, consisting of five levels of biochar (0, 25; 50; 75; and 100% v / v to replace the conventional substrate) and four particle sizes (<1, 2, 4, and 9 mm), with nine replications. The second in the field, with a randomized block design, under a 2 x 5 factorial scheme, corresponding to the biochar + NPK and biochar treatments without fertility correction and five doses of biochar (0, 10, 20, 30, and 40 Mg ha-1 ), carried out by two cutting (harvest) cycles. In the first experiment, the following seedling characteristics were evaluated: the average sprouting time, sprouting speed, growth by height, leaf number, leaf length and width + 2 and dry mass of shoot and roots. In the second experiment, the chemical attributes of the soil were evaluated at 60 (2017), 360 (2018), and 720 (2019) days after the application of the biochar to the soil, and the growth of plants was evaluated at 45, 60, 75, 105, 145, 180, 220, 250, and 290 days after planting, through the number of leaves, plant height, leaf length and width + 2. The first and second harvests were carried out at 330 and 360 days, respectively, and the stem length, diameter, number and mass, were measured to estimate productivity. The granulometry under 1 mm provided the best growth and development of sugarcane seedlings. In the soil, the addition of doses of biochar decreased pH and increased the levels of phosphorus, calcium, potential acidity, carbon and total nitrogen of the soil. For the cultivation of sugarcane for two consecutive years, the application of 36 Mg ha-1 of biochar without complementary fertilization with NPK was sufficient to obtain productivity comparable to the treatments that received the complement with NPK in the first and second cycles.