Topsoil Properties as Affected by Tillage Systems in the Rolling Pampa Region of Argentina

Abstract

Improved topsoil structural quality is expected under no‐till farming, but soil physical constraints can develop under continuous no‐till. Our objectives were: to evaluate the properties of loam, silty loam, and silty clay loam soils under various management practices on a regional scale; to clarify the relationship between soil organic matter pools and soil physical properties; and to find a minimum set of topsoil properties to characterize trends established by tillage. Thirty‐nine loam, silty loam, and silty clay loam soils were sampled from cropped fields managed using conventional tillage (CT) and no‐till (NT) as well as six undisturbed soils (uncropped). The A horizon thickness did not differ among soil textural groups and was 4 cm thicker in uncropped soils. Total and particulate organic C were significantly affected by management (uncropped > CT = NT, P < 0.001). Soil structural instability of uncropped soils (0.317 mm) differed from CT soils (0.723 mm) but not from NT soils (0.573 mm). Soil structural instability was negatively related to total and particulate organic C, and no relation was found with the resistant organic C pool. Water infiltration rate was the only topsoil property affected by a significant texture × management interaction. Lower infiltration rates in NT silty soils were caused by platy structural forms with horizontal pores. Soil penetration resistance (0–5 cm) was 0.77 MPa higher in NT than in CT soils. A minimum set of topsoil properties to evaluate tillage management includes structural instability, total or particulate organic C, infiltration rate, and penetration resistance.

Topsoil compaction and recovery in integrated no-tilled crop–livestock systems of Argentina

“…Linear slope was lower in the 0-5 cm than in the 5-20 cm soil layer, with greater differences in the Argiudoll. The response of soil PR to WC in topsoil was not as high as expected, which agrees with results found by other authors (Franzluebbers and Stuedemann, 2008;Álvarez et al, 2009). This weak response of PR was ascribed to the damping effect of the organic matter (OM) accumulated over several years on the surface in systems under no-till management (Wander and Bollero, 1999;Álvarez et al, 2009).…”

“…A main risk of integrated crop-livestock systems is the generation of shallow soil compaction, especially in those under no-till management due to absence of mechanical disturbance (Díaz-Zorita et al, 2002;Strudley et al, 2008;Álvarez et al, 2009). A question that still remains regarding this management is the capacity of soils under no tillage to naturally reverse the soil compaction produced by this farming system.…”

Spatiotemporal Dynamics of Soil Penetration Resistance of Recultivated Soil

“…To assess the condition of the soil body, the soil penetration resistance index is applied (Bölenius et al, 2006;Medvedev, 2009;Alvarez et al, 2009). This emulates the living conditions of soil inhabitants (Lipiec, Tarkiewicz, 1990;Vanags еt al., 2004;Godefroid, Koedam, 2004;Langmaack et al, 2002).…”

Seasonal changes in soil physical properties under long-term no-tillage

“…Soil disturbance from seeding operations can result in "localized tillage" of the soil surface under NT (da Silva et al, 1997 and thus impact soil physical quality. Usually it has been considered that stabilization of soil properties is reached after about five years of continuous NT (VandenBygaart et al, 1999;Rhoton, 2000;Alvarez et al, 2009). However, short-term changes in soil physical properties may be driven by different factors such as agricultural machinery, soil type, topography, climate and crop selection (Strudley et al, 2008).…”