Biochemical activity in Brazilian Cerrado soils is differentially affected by perennial and annual crops

Abstract

Organic matter mineralization depends on how microbiota access nutrients, substrates and soil fertilization. This study shows influence of perennial (sugarcane) and annual (soybean and corn) crops on the activity of enzymes participating in the carbon, nitrogen and phosphorus cycles and proposes using hydrolases as bioindicators of soil quality. Samples were collected, during dry season and rainfall, in six different plots where sugarcane, soybean, corn and native Cerrado soils could be found at the same location. We evaluated chemical properties and activity of α-and β-glucosidase, acid phosphatase, protease and glycine aminopeptidase from 48 samples collected at 0-10 cm depth. Sample of monoculture soils showed low organic matter content, total organic carbon, total nitrogen and microbial biomass carbon. Native Cerrado soils had major activities of α-and β-glucosidase, acid phosphatase and glycine aminopeptidase while sugarcane areas showed minor values. Despite native vegetation replacement decreasing biodiversity and reducing soil biochemical activity, annual crops stimulate microbial activity in this environment and maintain nutrient cycling. Soil hydrolase activities can be used as bioindicators of these ecosystems.

Fostering water resource governance and conservation in the Brazilian Cerrado biome

“…When the native Cerrado vegetation is converted to shallow‐rooted, nonpermanent croplands, changes in the interaction between water and soil occur (Cabral, da Rocha, Gash, Freitas, & Ligo, ). Land conversion modified soil pH, bulk density and available P and K for croplands (Zago et al, ), while pollution of some rivers and streams by pesticides exceeds the Brazilian and European Union (EU) water quality limits (Hunke, Mueller, Schröder, & Zeilhofer, ). In Brazil, the use of fertilizers doubled from 80 to 160 kg/ha between 1992 and 2012 (IBGE, ) and the application of pesticides added 3.5 kg of petrochemicals per hectare, making Brazil the largest agricultural user of chemical fertilizers and pesticides per capita and per area (Wittmann et al, ).…”

Chemical attributes of Brazilian Cerrado soil under different management systems

“…Nunes et al (2011) evaluated management systems and organic matter contents in Oxisol of the Cerrado biome with a soybean-corn succession, and found that the least cultivated systems had lower MO levels than the pasture production systems. Santana et al (2016) and Zago et al (2018) highlight that land use and management system exert a profound influence on nutrient supply, since it directly affects the soil microbiota, influencing the decomposition of MO and mineralization of nutrients to the soil. However, the systems studied differed from the natural Cerrado on several of the chemical properties studied, corroborating the findings of Carneiro et al (2009).…”

“…Soil properties in the native Cerrado area are defined by the vegetation and deposition of organic matter, while soil exploration by the roots increases its structural quality, nutrient availability and creates a microclimate in the region (Silva Júnior et al, 2012;Abreu et al, 2016;Zago et al, 2018). Roots also protect the soil against direct exposure to sunlight and the impact of rainwater, which can disaggregate the soil and carry its nutrients by runoff.…”

“…Thus, there is a search for different productive forms, in which the agricultural system is rethought, tending to approach an agro-ecosystem as close to the natural environment (Altieri et al, 2017;Zago et al, 2018). The crop-livestock-forest integration system seeks to bring current productive models closer to ecosystem relationships, reducing environmental impacts and enhancing ecological processes that positively influence agricultural production, such as nutrient, hydrological and carbon cycling.…”

Does Crop-Livestock-Forest Systems Contribute to Soil Quality in Brazilian Savannas?

“…The transformations coming from anthropic action alter composition and amount of organic matter of the soil and directly affect its physical and chemical properties. These transformations imply perturbations and directly influence the microorganisms, microbial processes and nutrient cycling in the soil (Zago et al, 2018).…”