Use of biochar in the composition of organic substrates for the production of papaya seedlings

Abstract

The technical aspects that involve the production of seedlings should be well studied to reduce the mistakes made in this phase. The present work aimed to evaluate biomass production, gas exchange and nutrient accumulation in papaya seedlings grown on substrates from organic residues, with or without the addition of green coconut shell biochar. The work was conducted in a greenhouse at the Federal University of Ceará, in Fortaleza, CE, Brazil. The experimental design adopted was completely randomized, consisting of eight treatments and four repetitions, with ten plants per repetition. The eight treatments comprised the substrates: composting sewage sludge, composting green coconut shell, composting carnauba bagana, commercial substrate Turfa Fértil®, composting sludge + biochar, composting green coconut shell + biochar, composting bagana + biochar and commercial substrate + biochar. Biometric analyzes, gas exchange and accumulation of mineral elements were performed. Papaya seedlings showed higher quality when they were grown with sewage sludge, sludge + biochar and bagana + biochar, while the commercial substrate was not efficient, leading to a lower result for all variables. The addition of biochar was beneficial in all treatments in which it was used.