Soil microbial biomass and enzyme activity in six Brazilian oxisols under cropland and native vegetation

Wanderley José De Melo,Antônio Sérgio Ferraudo,Valeria Peruca De Melo,Liandra Maria Abaker Bertipaglia,Ademir Sérgio Ferreira Araujo,Gabriel Mauricio Peruca De Melo

doi:10.1590/1678-4499.20200242

Wanderley José De Melo, Antônio Sérgio Ferraudo + Show 4 more

Open Access

https://doi.org/10.1590/1678-4499.20200242

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Abstract

ABSTRACT Oxisols are important soils that have been converted from native vegetation to croplands, and can affect soil biological properties such as microbial biomass and enzyme activity. Thus, the aim of this study was to evaluate the changes on soil microbial biomass and enzyme activity when native vegetation (NV) was converted to cropland (CL), such as maize or sugarcane in six oxisols from Sao Paulo state, Brazil. Soil microbial biomass C (MBC) and N (MBN), and the activity of arylsulphatase, dehydrogenase and fluorescein diacetate hydrolysis (FDA) were assessed in samples collected at 0-0.20 m. In general, MBC was higher under NV than CL (about + 40%), while MBN and FDA did not show a consistent pattern between NV and CL. All soils showed higher values of arylsulfatase (increased from 101 to 717%) and dehydrogenase (increased 15 to 220%) under NV than CL. In conclusion, soil microbial biomass C is usually higher under native vegetation than cropland. Arylsulphatase and dehydrogenase were the attributes that presented better differentiation between native and cropped soils.

Highlights

Oxisols are soils found almost exclusively in tropical areas from South America and Africa, being important to agriculture (Buol and Eswaran 1999)
Soil samples were selected according a survey of soils from São Paulo state, Brazil: red-yellow oxisol (RYO), red oxisol (RO), acriferric red oxisol (ARO), yellow oxisol (YO), acricferri1 yellow oxisol (AYO), and dark red oxisol (DRO)
Red-yellow oxisol and DRO soils were cropped with maize over the past 5 years using the no-tillage cropping system, while RO, ARO, YO and acriferric yellow oxisol (AYO) were cropped with sugarcane

Summary

Introduction

Oxisols are soils found almost exclusively in tropical areas from South America and Africa, being important to agriculture (Buol and Eswaran 1999). In Brazil, these soils cover about 100 million hectares, being described as highly weathered, and acidic, containing small amounts of plant nutrients (Gomes et al 2019). Liming and chemical fertilization can make these soils suitable for agriculture. About 70 million hectares of Brazilian oxisols have been converted to cropland (Balota et al 2015). Important for food production, the conversion from native soils to cropland decreases soil C storage as native vegetation is removed and replaced by crops which support lower soil C content and plant biomass (Fujisaki et al 2015). There is a decrease in the soil biological processes (Gmach et al 2020)

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