IMBIV   05474
INSTITUTO MULTIDISCIPLINARIO DE BIOLOGIA VEGETAL
Unidad Ejecutora - UE
artículos
Título:
Soil microbial communities under different soybean cropping systems: characterization of microbial population dynamics, soil microbial activity, microbial biomass, and fatty acid profiles
Autor/es:
MERILES, J. M.; VARGAS GIL. S.; CONFORTO, C.; FIGONI, G.; LOVERA, E.; MARCH. G. J.; GUZMÁN, C. A.
Revista:
SOIL & TILLAGE RESEARCH
Referencias:
Año: 2008
ISSN:
0167-1987
Resumen:
This work analyzes the direct effect of soil management practices on soil microbial communities, which
may affect soil productivity and sustainability. The experimental design consisted of two tillage
treatments: reduced tillage (RT) and zero tillage (ZT), and three crop rotation treatments: continuous
soybean (SS), cornsoybean (CS), and soybeancorn (SC). Soil samples were taken at soybean planting
and harvest. The following quantifications were performed: soil microbial populations by soil dilution
plate technique on selective and semi-selective culture media; microbial respiration and microbial
biomass by chloroform fumigation-extraction;microbial activity by fluorescein diacetate hydrolysis; and
fatty acid methyl ester (FAME) profiles. Soil chemical parameters were also quantified. Soil organic
matter content was significantly lower in RT and SS sequence crops, whereas soil pH and total N were
significantly higher in CS and SC sequence crops. Trichoderma and Gliocladium populations were lower
under RTSS and ZTSS treatments. Except in a few cases, soil microbial respiration, biomass and activity
were higher under zero tillage than under reduced tillage, both at planting and harvest sampling times.
Multivariate analyses of FAMEs clearly separated both RT and ZT management practices at each sampling
time; however, separation of sequence crops was less evident. In our experiments ZT treatment had
highest proportion of 10Me 16:0, an actinomycetes biomarker, and 16:1v9 and 18:1v7, two fatty acids
associated with organic matter content and substrate availability. In contrast, RT treatment had highest
content of branched biomarkers (i15:0 and i16:0) and of cy19:0, fatty acids associated with cell stasis
and/or stress. As cultural practices can influence soil microbial populations, it is important to analyze the
effect that they produce on biological parameters, with the aim of conserving soil richness over time.
Thus, in a soybean-based cropping system, appropriate crop management is necessary for a sustainable
productivity without reducing soil quality.Trichoderma and Gliocladium populations were lower
under RTSS and ZTSS treatments. Except in a few cases, soil microbial respiration, biomass and activity
were higher under zero tillage than under reduced tillage, both at planting and harvest sampling times.
Multivariate analyses of FAMEs clearly separated both RT and ZT management practices at each sampling
time; however, separation of sequence crops was less evident. In our experiments ZT treatment had
highest proportion of 10Me 16:0, an actinomycetes biomarker, and 16:1v9 and 18:1v7, two fatty acids
associated with organic matter content and substrate availability. In contrast, RT treatment had highest
content of branched biomarkers (i15:0 and i16:0) and of cy19:0, fatty acids associated with cell stasis
and/or stress. As cultural practices can influence soil microbial populations, it is important to analyze the
effect that they produce on biological parameters, with the aim of conserving soil richness over time.
Thus, in a soybean-based cropping system, appropriate crop management is necessary for a sustainable
productivity without reducing soil quality.v9 and 18:1v7, two fatty acids
associated with organic matter content and substrate availability. In contrast, RT treatment had highest
content of branched biomarkers (i15:0 and i16:0) and of cy19:0, fatty acids associated with cell stasis
and/or stress. As cultural practices can influence soil microbial populations, it is important to analyze the
effect that they produce on biological parameters, with the aim of conserving soil richness over time.
Thus, in a soybean-based cropping system, appropriate crop management is necessary for a sustainable
productivity without reducing soil quality.