Extração de ácido húmico, a partir de lodo de esgoto, na produção de alface
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2022-01-28
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Universidade Estadual Paulista (Unesp)
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Objetivou-se avaliar a viabilidade de extração de ácidos húmicos a partir de lodo de esgoto sanitário e seus efeitos sobre plantas de alface, em dois sistemas de cultivos (solo e hidroponia), comparados com o produto comercial. No experimento I foi realizada a extração de ácido húmico utilizando três tipos de materiais (lodo de esgoto estabilizado, compostado com bagaço de cana e in natura), empregando três metodologias para extração. Foram determinados os percentuais de carbono, hidrogênio e nitrogênio totais, razão isotópica de 13C/12C e 15N/14N e composição nutricional, todos realizados em triplicatas. No experimento II o delineamento experimental foi em blocos casualizados, esquema fatorial 2 x 6, sendo duas fontes (ácido húmico extraído a partir de lodo de esgoto e ácido húmico comercial) e seis concentrações (0, 0,5, 1,5, 3,0, 4,5 e 6,0 mM de C L-1), com quatro repetições e três plantas por parcela. As plantas de alface foram avaliadas por meio das seguintes variáveis: diâmetro do caule e da planta, comprimento do caule, altura da planta e números de folhas, massa fresca e seca da parte aérea, análise química de nutrientes da parte aérea, volume radicular, índice indireto de clorofila (SPAD) e pigmentos fotossintéticos. Os dados foram submetidos à análise de variância e as médias comparadas pelo teste de Tukey a p ≤ 1% e 5% de probabilidade e para o experimento II quando os dados foram significativos, foi realizado o estudo de regressão para as concentrações.
The objective was to evaluate the feasibility of extracting humic acids from sewage sludge and its effects on lettuce plants, in two cropping systems (soil and hydroponics), compared with the commercial product. In experiment I, the extraction of humic acid was carried out using three types of materials (stabilized sewage sludge, composted with sugarcane bagasse and in natura), using three methodologies for extraction. The percentages of total carbon, hydrogen and nitrogen, isotopic ratio of 13C/12C and 15N/14N and nutritional composition were determined, all performed in triplicate. In experiment II, the experimental design was in randomized blocks, factorial scheme 2 x 6, with two sources (humic acid extracted from sewage sludge and commercial humic acid) and six concentrations (0, 0.5, 1.5, 3 .0, 4.5 and 6.0 mM of C L-1), with four replications and three plants per plot. Lettuce plants were evaluated using the following variables: stem and plant diameter, stem length, plant height and number of leaves, shoot fresh and dry mass, chemical analysis of shoot nutrients, root volume, indirect chlorophyll index (SPAD) and photosynthetic pigments. The data were submitted to analysis of variance and the means were compared by the Tukey test ap ≤ 1% and 5% of probability and for experiment II when the data were significant, the regression study was carried out for the concentrations.
The objective was to evaluate the feasibility of extracting humic acids from sewage sludge and its effects on lettuce plants, in two cropping systems (soil and hydroponics), compared with the commercial product. In experiment I, the extraction of humic acid was carried out using three types of materials (stabilized sewage sludge, composted with sugarcane bagasse and in natura), using three methodologies for extraction. The percentages of total carbon, hydrogen and nitrogen, isotopic ratio of 13C/12C and 15N/14N and nutritional composition were determined, all performed in triplicate. In experiment II, the experimental design was in randomized blocks, factorial scheme 2 x 6, with two sources (humic acid extracted from sewage sludge and commercial humic acid) and six concentrations (0, 0.5, 1.5, 3 .0, 4.5 and 6.0 mM of C L-1), with four replications and three plants per plot. Lettuce plants were evaluated using the following variables: stem and plant diameter, stem length, plant height and number of leaves, shoot fresh and dry mass, chemical analysis of shoot nutrients, root volume, indirect chlorophyll index (SPAD) and photosynthetic pigments. The data were submitted to analysis of variance and the means were compared by the Tukey test ap ≤ 1% and 5% of probability and for experiment II when the data were significant, the regression study was carried out for the concentrations.
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Substâncias Húmicas, Lodo de Esgoto, Extração de Ácido Húmico, Alface, Humic Substances, Sewage Sludge, Humic Acid Extraction, Lettuce