INVESTIGADORES
WALL Luis Gabriel
artículos
Título:
Analysis of organic fractions as indicators of soil quality under natural and cultivated systems
Autor/es:
DUVAL M; GALANTINI J; IGLESIAS J; CANELO S; MARTÍNEZ JM; WALL LG
Revista:
SOIL & TILLAGE RESEARCH
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2013 vol. 131 p. 11 - 19
ISSN:
0167-1987
Resumen:
Soil organic matter (SOM) or carbon (SOC) is the most important component of the soil and it is
composed of fractions with different lability. Particulate organic carbon (POC) and carbohydrates (CH),
among others, are the most sensitive to changes in crops and soil management practices. The purpose of
this study was to analyze different soil parameters aimed for the evaluation of management practices
effects under widely different soil and climatic conditions. Soils were located along a West?East transect
in the most productive region of the Argentinean pampas: [West] Bengolea and Monte Buey (Co´ rdoba),
Pergamino (Buenos Aires) and Viale (Entre Rios) [East]. Three treatments were defined according to land
use: ??Good agricultural practices?? (GAP): sustainable agricultural management under no-till; ??Poor
agricultural practices?? (PAP): non-sustainable agricultural management under no-till; ??Natural
environment?? (NE): rangelands long as reference situation. Samples were taken at 0?10 and 10?
20 cm depths. SOC was determined in different particle size fractions: 105?2000 mm (coarse particulate
organic carbon, POCc), 53?105 mm (fine particulate organic carbon, POCf), and 53 mm (mineral-
associated organic carbon, MOC). Total (CHt) and soluble (CHs) carbohydrate contents were also
determined. The SOC level in NE was decreasing from the East (27.3 g kg1 in Viale) to the West
(13.3 g kg1 in Bengolea), following the rainfall and texture gradient among sites. The POCc/SOC and
POCc + POCf/SOC ratios in the NE showed differences among sites, suggesting different dynamic
depending on the environmental characteristics at the different locations. The SOC levels in the upper
layer of agricultural soils were 16?44% lower than natural ones. Carbon stocks were estimated for an
equivalent mass of soil (950 and 2350 Mg ha1) in order to consider differences in bulk densities among
different treatments. Mean values were significantly different (p < 0.001) for the different management
practices: NE (26.6 Mg ha1) > GAP (20.1 Mg ha1) > PAP (16.3 Mg ha1). In general, labile organic
fractions showed differential sensitivity. Fractions with an intermediate dynamic, as POCf (53?100 mm)
and CHt, seem to be better indicators to detect the short- and medium-term management effects than
more dynamic fractions.