Revista Brasileira de Ciências Ambientais (Sep 2024)
Does the compost barn system bedding as a source of organic fertilizer cause toxicity in soil invertebrates?
Abstract
Modernizing dairy cattle farming techniques promotes a gradual shift from traditional pasture-based systems to confinement with higher investments in animal comfort and welfare, such as the compost barn system (CBS). In this method, animals generate composted waste in the barn itself, on the bedding where they are housed, which is of high fertilizing potential, and whose subsequent application to soils can affect the functionality of edaphic organisms. The study aimed to evaluate the toxicity on edaphic organisms (Folsomia candidaand Eisenia andrei) of increasing doses of CB bedding applied to two soils with different textural characteristics. Ecotoxicological tests were standardized following the recommendations of ISO 11268-1 and 11268-2 for earthworms, and ISO 11267 for springtails. The experimental design was completely randomized with five replications, with the treatments being CB bedding doses (0, 6, 12, 18, 24, and 30 t of waste ha-1). Data were subjected to normality (Shapiro-Wilk) and variance homogeneity (Levene) tests, followed by analysis of variance (ANOVA) and post-hoc comparisons using the Dunnett test (p<0.05). Still, no significant difference was found between treatments. The tested doses of CB bedding as organic fertilizer showed no acute or chronic toxicity in the two organisms studied (E. andrei and F. candida) in both soils Oxisol and Entisol Quartzipsamments. The proportional increase in dose promoted the growth of earthworm body mass and stimulated reproduction, as found in springtails. Thus, it is concluded that doses of up to 30 t ha-1 of CB bedding do not have acute and chronic toxicity effects on earthworms and springtails in Oxisol and Entisol Quartzipsamments. The greater sensitivity of chronic assays with these organisms shows a positive impact of the applied doses, promoting increased reproduction of these organisms.
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