Biomassa seca como combustível para incêndios em áreas cultivadas com cana-de-açúcar (Saccharum officinarum L. officinarum L.)

Abstract

Brazil is the world's largest producer of sugarcane and in the state of Minas Gerais its cultivationhas an expansion prognosis. Vegetation fires cause disasters around the world, causing damage tohealth and the environment, as well as economic and social damage. In Minas Gerais there isrecurrence of these events from July to September. The research aimed to characterize the fuels ofpostharvest straw in sugarcane plantation after the first and second cuts/harvests. The study area islocated in the municipalities of Uberaba and Conquista. For sampling, 6 areas were selectedwithout record of flames since planting. In each of them, 10 samples were collected using 1m2 jig.A sealer was used to classify the fuels according to the diameter ranges, being fine fuel that of 0 to0.7 cm in diameter, which corresponds to 1 h of fire timelag; and coarse fuel measuring from 0.71to 2.5 cm, corresponding to 10h of timelag. After weighing, a sub-sample of about 200g of thestraw was separated and dry to calculate the percentage humidity of the fuel. The results wereanalysed by descriptive statistics and boxplot distribution. The average values of the coarse fuels(246.50g) and the thin (269.53g) have greater uniformity in the first cut, but this average isdistanced in the second cut (fine 2,130.20g and 96.60g thick). The first cut straw presented anaverage humidity of 21.5%, standard deviation of 6.45% and 75% of the data are shown to bemoisture below 25%, this puts these fuels below the extinction humidity of 30%, according to thespecific literature, which makes them available for burning. Thus, it is concluded that sugarcanestraw is a type of predominantly fine and dead fuel, available for burning during a forest fire,burned or prescribed burning. The first cut after straw has 2.70 T∙ha-1 of fine fuels, whichrepresents 52.23% of the total fuels and 43,124.8 MJ/ha of fire load. When the second cut remains,there are 21.3 T∙ha-1 of fine fuels, which makes up 96.6% of the total fuels deposited in the soil,representing 340,832 MJ/ha.