INBA 12521
INSTITUTO DE INVESTIGACIONES EN BIOCIENCIAS AGRICOLAS Y AMBIENTALES
Unidad Ejecutora - UE
artículos
Título:
Changes in topsoil bulk density after grazing crop residues under no-till farming
Autor/es:
FERNÁNDEZ, P. L.; ÁLVAREZ, C. R.; SCHINDLER, V.; TABOADA M. A.
Revista:
GEODERMA
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Año: 2010
ISSN:
0016-7061
Resumen:
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The grazing of crop residues during the winter
in integrated crop-livestock systems can either increase soil bulk density (BD)
by compaction or decrease BD by swelling, as a function of soil water content
(GW) during grazing. A field experiment was conducted from 2005 to 2008 to
evaluate the BD response to grazing in a no-till silty loam soil (Typic
Argiudoll) of the Pampas region of Argentina. Soil BD (core method), GW
data and the calculated air volume (AV) were obtained from the 0-50 mm and 50-100 mm layers at different
sampling times from ungrazed and grazed treatments. Over most of the study
period (2006 through 2008) soil BD showed little impact from grazing, with
minimal temporal variation (1.32 - 1.46 Mg m-3). This stable
behavior was ascribed to low rainfall and relatively low GW values at the time
when soil was trampled by livestock and routinely traffic by machinery. Soil BD
in the upper (0-50 mm)
layer was significantly (p < 0.001) lower at the beginning of the study
(2005 to early 2006), when the rainfall was higher (as was soil GW) during transit
periods. Lower BD was not due to soil swelling but to air that was trapped by
kneading in response to transit of livestock and machinery. Fitted straight
lines indicated that this process became particularly prominent when GW > 330 g kg-1 in the ungrazed treatment and GW > 240 g kg-1 in
the grazed treatments. Grazing accentuated the soil kneading process that
promoted air entrapment. Study results suggest that winter grazing of crop
residues caused no deterioration
of topsoil porosity in the no-tilled silty loamy soil[M1] .
[M1]Asi coincide con las conclusiones del trabajo
