Bacterial Indicator of Agricultural Management for Soil
under NoTill Crop Production
Eva L M Figuerola 1, Leandro D Guerrero 1, Silvina M Rosa 1, Leandro Simonetti 1,Mat??
as E Duval 2,
Juan A Galantini 2, Jose?
C Bedano 3, Luis G Wall 4, Leonardo Erijman 1,5 *
1Instituto de Investigaciones en Ingenier??
tica y Biolog??
a Molecular (INGEBICONICET) Vuelta de Obligado 2490, Buenos Aires, Argentina,2CERZOSCONICET
Departamento de Agronom??
a, Universidad Nacional del Sur, Bah??
a Blanca, Argentina,3Departamento de Geolog??
a, Universidad Nacional de R??
o Cuarto, R??
rdoba, Argentina,4Departamento de Ciencia y Tecnolog??
a, Universidad Nacional de Quilmes, Roque Sa?
a 352, Bernal, Argentina,5Facultad de Ciencias Exactas
y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabello?
n 2, Buenos Aires, Argentina
The rise in the world demand for food poses a challenge to our ability to sustain soil fertility and sustainability The
increasing use of notill agriculture, adopted in many areas of the world as an alternative to conventional farming, may
contribute to reduce the erosion of soils and the increase in the soil carbon pool However, the advantages of notill
agriculture are jeopardized when its use is linked to the expansion of crop monoculture The aim of this study was to survey
bacterial communities to find indicators of soil quality related to contrasting agriculture management in soils under notill
farming Four sites in production agriculture, with different soil properties, situated across a westeast transect in the most
productive region in the Argentinean pampas, were taken as the basis for replication Working definitions of Good notill
Agricultural Practices (GAP) and Poor notill Agricultural Practices (PAP) were adopted for two distinct scenarios in terms of
crop rotation, fertilization, agrochemicals use and pest control Noncultivated soils nearby the agricultural sites were taken
as additional control treatments Tagencoded pyrosequencing was used to deeply sample the 16S rRNA gene from bacteria
residing in soils corresponding to the three treatments at the four locations Although bacterial communities as a whole
appeared to be structured chiefly by a marked biogeographic provincialism, the distribution of a few taxa was shaped as
well by environmental conditions related to agricultural management practices A statistically supported approach was used
to define candidates for managementindicator organisms, subsequently validated using quantitative PCR We suggest that
the ratio between the normalized abundance of a selected group of bacteria within the GP1 group of the phylum
Acidobacteria and the genusRubellimicrobiumof the Alphaproteobacteria may serve as a potential managementindicator
to discriminate between sustainablevs nonsustainable agricultural practices in the Pampa region
Citation:Figuerola ELM, Guerrero LD, Rosa SM, Simonetti L, Duval ME, et al (2012) Bacterial Indicator of Agricultural Management for Soil under NoTill Crop
Production PLoS ONE 7(11): e51075 doi:101371/journalpone0051075
Editor:Hauke Smidt, Wageningen University, The Netherlands
ReceivedJune 12, 2012;AcceptedOctober 30, 2012;PublishedNovember 30, 2012
Copyright:2012 Figuerola et al This is an openaccess article distributed under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Funding:The authors are members of the BIOSPAS consortium (http://wwwbiospasorg/en) ELMF, JCB, LGW and LE are members of Consejo Nacional de
ficas y Te?
cnicas (CONICET), Argentina JAG is member of Comisio?
n de Investigaciones Cient??
ficas of Buenos Aires Province, Argentina (CIC)
MD and SR received fellowships from ANPCyT, Argentina LDG and LS were fellows of CONICET The funders had no role in study design, data collection and
analysis, decision to publish, or preparation of the manuscript
Competing Interests:The authors have declared that no competing interests exist
* Email: [email protected]
These authors contributed equally to this work
Sowing crop into notill soil is a farming method that has
initially been developed as an alternative to conventional tillage
practices, with the aims of using less fossil fuels, reducing the
erosion of soils, and increasing the soil carbon pool  Soil
structure can be significantly modified through reducedtill
management practices  Soil aggregates are less subjected to
dry and wet cycles in notilled soil, compared to conventionaltilled
soil, due to the protection exerted by