Aeration conditions of a clayey oxisol under long-term no-tillage
Abstract
The hypothesis of this study was that the absence of soil tillage in long-term
no-tillage (NT) systems can be detrimental to soil aeration. The objective was to
assess the aeration condition of an Oxisol (Rhodic Ferrasol), very clayey texture
(750 g kg-1 of clay; 200 g kg-1 of sand), after 30 years of cultivation under NT. The
physical property soil air permeability (Ka) is sensitive to changes in the soil pore
system. Aside from Ka, the air-filled porosity (!a) and indices of pore continuity (K1
and N), derived from the relationship between Ka and !a, were used as indices of
soil aeration. From the soil layers 0.0-0.1 and 0.1-0.2 m, 240 undisturbed samples
were collected along a transect perpendicular to the crop rows, at three sampling
positions: corn plant row (CR); center of the interrow (INT); and the equidistant
point between CR and INT (PE). The properties Ka and !a were determined at soil
matric potentials (Ym) of -2, -4, -6, -10, -30, and -50 kPa. Soil bulk density (BD) was
also determined. The results confirmed the hypothesis. In the 0.0-0.1 m layer, Ka,
K1, N and !a were significantly greater and BD significantly lower in CR than at the
other sampling positions. At a Ym of -10 kPa, the Ka of CR was 6.9 and 8.4 times
higher than in PE and INT, respectively, in the 0.0-0.1 m layer. The properties Ka,
K1 and N were sensitive enough to detect changes in the pore system and their differences between the sampling positions demonstrated the importance of the
spatial location for soil sampling. Tilling the crop rows provides better soil aeration
under NT.
Journal Title/Title of Proceedings
Revista Brasileira de Ciencia do Solo
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Version
Publisher PDF
Volume/Issue Number
38:3
Page Numbers
990‐999