A long‐term no‐tillage system can increase enzymatic activity and maintain bacterial richness in paddy fields
Filipe Selau Carlos, Naihana Schäffer, Élio Marcolin, Rodrigo Schmitt Fernandes, Roberta Fogliatto Mariot, Michael Mazzurana, Luiz Fernando Würdig Roesch, Bruno Levandoski, Flavio Anastácio de Oliveira Camargo
Abstract
Abstract Soil management systems cause many changes in the microenvironment that directly affect activity and diversity of microorganisms. In lowlands, there is a gap in relation to the adoption of no‐tillage (zero‐tillage) and the impact it has on soil under cultivation of irrigated rice. This study, an in‐field experiment, evaluated the microbial enzymatic activity and diversity in an Entisol cultivated with rice under different managements for 22 years. The experiment started in the 1994/95 growing season, and the treatments were no‐tillage, conventional, and pregerminated management systems. After 22 years, the data obtained on most of the evaluation dates indicated that no‐tillage increased microbial biomass carbon (+45%), microbial biomass nitrogen (+54%), and basal respiration (+54%). No‐tillage compared to management under soil tillage (pregerminated and conventional tillage) increased the activity of β‐glucosidase (+43%), acid phosphatase (+68%), diacetate fluorescein (+34%), and urease (+96%). The enzyme activity was correlated with the soil organic carbon content and particulate fraction. Despite the relatively high enzyme activity with no‐tillage, bacterial richness was maintained in this soil management system. The Proteobacteria phylum has a greater abundance in the NT (43.2%) in relation to the CT (32.3%). Bacteroidetes phylum has a lower abundance in the NT (10.0%) in relation to the CT (15.2%). The Verrucomicrobia phylum has a greater abundance in NT (8.9%) in relation to CT (4.9%). The results suggest that no‐tillage is an important management tool in the recovery of irrigated rice areas whose soil has undergone microbiological degradation.