Alterações microbiológicas em um solo de tabuleiros costeiros sob diferentes sistemas de produção de milho integrado com Urochloa spp.

Abstract

Microorganisms are agents that play important roles in the soil, such as decomposing organic matter and cycling nutrients. Despite this importance, there are few studies that evaluate the effect of different grain production systems in the functioning and structure of the soil microbial community in the Coastal Tablelands region. Therefore, this work aimed to evaluate how grain production systems affect the functioning and structure of the soil microbial community and their relationship with soil quality. For this purpose, soil samples were collected from 5 treatments: No-tillage corn monoculture (MM), corn planting intercropped with Urochloa decumbens/Soybean (M+Ud/S), corn intercropping with Urochloa decumbens (M+Ud ), pasture with Urochloa decumbens (M+Ud/Ud/Ud) and pasture with Urochloa ruziziensis (M+Ur/Ur/Ur), both with 30 months. Through these samples, the Soil Quality (SQ) (soil organic matter, soil density, aggregate stability, mechanical resistance to penetration and average diameter of aggregates) were evaluated, Biomass and Microbial Activity (BAM) (basal respiration, carbon from microbial biomass and the activity of the enzymes acid phosphatase, β-glycosidase, arylsulfatase and fluorescein diacetate hydrolysis) and the Microbial Community Structure (ECM) which was determined by the method EL-FAME and microbial groups were identified: Arbuscular Mycorrhizal Fungi (AMF), Saprophytic Fungi (FUN), Gram-Positive Bacteria (BGP), Gram-Negative Bacteria (BGN) and Actinomycetes (ACT). Our results showed that grain production systems affect BAM and ECM differently, with increases in enzymes and basal soil respiration in treatments M+Ud, M+Ud/Ud/Ud and M+Ur/ Ur/Ur, on the other hand, increases in microbial biomass carbon were observed in the MM and M+Ud/S systems. Regarding ECM, the M+Ud/Ud/Ud and M+Ur/Ur/Ur systems provided greater increases for the microbial groups FMA, FUN and BGN while the treatments M+Ud, M+Ud/S and o MM promoted greater abundance of BGP and ACT. BAM and ECM had no relationship with QS. Based on the results found here, it was found that the use of Urochloa species and their longer continuous permanence time in grain production systems provides changes in BAM and ECM in the soils of the Coastal Tableland. Keywords: Soil Quality; Conservationist Agriculture; Microbiological Indicators.