Substratos formulados a base de biochar de lodo de esgoto: atributos físico-hídricos e eficiência agronômica para mudas de eucalipto
Resumo
With the growth of the world population and increasing urbanization and
economic development, there will be an increase in the generation of solid
waste and consequently, larger quantities of sludge from sanitary sewage
treatment plants (LETES) will be generated. Currently, studies focused on the
use of LETE biochar as a component of substrates for seedling development
have been conducted, but there is a great lack of information about its use in
the production of seedlings from different crops, such as eucalyptus, for
example. In this sense, the present study aims to evaluate the efficiency of LETE
biochar as a substrate in the production of eucalyptus seedlings. The study was
conducted with aerobic and anaerobic LETES from the sewage treatment plants
of Rio Grande/RS and Passo Fundo/RS, respectively. The substrates were
formulated from aerobic and anaerobic LETE biochar added to a "base" mixture
(vermiculite, carbonized rice husk, and organic compost). Chemical and
physico-hydraulic characterization of the substrates was then performed, along
with the agronomic performance evaluation for eucalyptus cultivation. It was
observed that biochar resulted in an increase in both wet and dry density and a
decrease in total porosity. Regarding chemical characterization, LETE biochar
influences the availability of macronutrients and micronutrients, some more
significantly than others. Formulations containing 50% or more LETE biochar
were those that showed Dickson Quality Index equivalent to or higher than
commercial substrates. The results of this study reinforce the viability of using
anaerobic and aerobic LETE biochar-based substrates as an efficient and safe
foundation for developing plant growth media.