Uso de biochar na composição de substratos para produção de mudas de espécies florestais

Abstract

Biochar is an organic waste from the wood industry potentially suitable for composing substrates used in the production of forest seedlings, because it is rich in carbon and has physicochemical characteristics capable of reducing the leaching of nutrients, promote greater water retention, contribute to the increase of porosity and aeration of the soil. Thus, the objective of this work is to evaluate the effect of the addition of biochar in the composition of substrates to produce seedlings of native forest species of the Caatinga of Tabebuia aurea, Handroanthus impetiginosus e Pityrocarpa moniliformis. The experiment was conducted in a completely randomized design, consisting of eight treatments and four repetitions each. The mixture of the substrate was constituted in the proportions: sand (25%) + coconut fiber (50%) + expanded vermiculite (25%); sand (25%) + coconut fiber (30%) + expanded vermiculite (25%) + biochar (20%); sand (25%) + coconut fiber (20%) + expanded vermiculite (25%) + biochar (30%); sand (25%) + expanded vermiculite (25%) + biochar (50%); commercial substrate Tropstrato® (100%); commercial substrate Tropstrato® (80%) + biochar (20%); commercial substrate Tropstrato® (70%) + biochar (30%); commercial substrate Tropstrato® (50%) + biochar (50%). The variables evaluated were emergency percentage, emergence speed index, growth rate diameter the neck, height of the aerial part, height of the aerial/diameter the neck ratio, number of leaves, root system dry mass, shoot dry mass, total dry mass, shoot dry mass/root system ratio and Dickson Quality Score. There was no significant difference for percentage of emergence and emergence speed index. for the three species studied in the different substrates used. The addition of 30% of biochar to the commercial substrate is a viable alternative to produce of T. aurea seedlings, while the addition of 20% of biochar to the commercial substrate was ideal to produce seedlings of H. impetiginosus and P. moniliformis. The use of biochar in the substrate composition is a viable and environmentally sustainable alternative to produce native forest seedlings in the Caatinga.