COMUNIDADES MICROBIANAS AFECTADAS POR CAPTAN EN SUELOS BAJO DIFERENTES PRÁCTICAS DE MANEJO

FLORENCIA M. BARBERO; ROMINA A. VERDENELLI; MARÍA F. DOMINCHIN; CAROLINA PÉREZ-BRANDAN; ANTONIO AOKI; SILVINA VARGAS GIL; JOSÉ M. MERILES

Ciencia del Suelo

ASOCIACIÓN ARGENTINA DE LA CIENCIA DEL SUELO

Lugar: Buenos Aires; Año: 2023 vol. 1

0326-3169

The application of fungicides has become a recurring method of modern agriculture.However, its frequent application could inhibit key processes in agroecosystems, particularlyin the soil. Captan is a broad-spectrum, organochlorine, non-systemic fungicide widely usedin agriculture. This study aimed to evaluate how different dosages of the fungicide captan3affect the microbiota of soil subjected to different types of management and with adegradation gradient associated with the soil organic matter (SOM) content. The trial wasconducted in a greenhouse and included soils with three types of management: pristineforest soil (L1), 2:1 rotation (soybean-corn) under no-tillage management (L2), and soybeanmonoculture under conventional tillage management (L3). The treatments were: control (0x),dosage 1.0 mg/kg soil (1x), and dosage 10 mg/kg soil (10x). Sampling was carried out 30days after the application of captan. Enzymatic activities related to C, N, and P cycles,phospholipid fatty acid profiles (PLFA), and a quantification method for ribosomal RNA genecopy numbers (16S and 18S) were evaluated to assess the impact of captan on the structureand activities of microbial communities. Our results showed increases in enzyme activitiesand biomass in L1 soils at 1x doses compared to the control, except for gram-negativebacteria that increased at 10x dosages. However, the application of 10x dosages producedlosses in activity and microbial biomass in the three types of soil. The lowest values of 16Sand 18S rRNA copies were registered in the treatments with fungicide. The 16S bacterialrRNA did not present differences between the treatments in the L3 soils. In conclusion, theL1 soil presented greater sensitivity in its response to captan compared to the L2 and L3soils under agricultural management.