No‐till Induced Increase in Organic Carbon Reduces Maximum Bulk Density of Soils

Abstract

Compaction can be a problem in some no‐till (NT) soils, but accumulation of soil organic C (SOC) with time may reduce the soil's susceptibility to compaction. Relationships between SOC and soil maximum bulk density (BDmax), equivalent to maximum soil compactibility, have not been well documented, particularly in NT systems. We assessed near‐surface BDmax using the Proctor test under long‐term (>19 yr) moldboard plow (MP), conventional tillage (CT), reduced tillage (RT), and NT conditions in the central Great Plains and determined its relationships with SOC, particle size distribution, and Atterberg consistency limits. The experiments were located on silt loam soils at Hays and Tribune, KS, and loam soils at Akron, CO, and Sidney, NE. The near‐surface BDmax of the MP soil was higher than that of the NT soil by 13% at Sidney, while the near‐surface BDmax of the CT was higher than that of the NT soil by about 6% at Akron, Hays, and Tribune. Critical water content (CWC) for BDmax in the NT soil was higher than in the CT and MP soils except at Tribune. The BDmax decreased with increase in CWC (r = ‐0.91). The soil liquid limit was higher for NT than for MP by 82% at Sidney, and it was higher than for CT by 14, 9, and 31% at Akron, Hays, and Tribune, respectively. The SOC concentration in NT soil was higher than in MP by 60% at Akron and 76% at Sidney, and it was higher than in CT soil by 82% at Hays. The BDmax decreased (r = −0.64) and the CWC increased (r = 0.60) with an increase in SOC concentration. Across all soils, SOC concentration was a sensitive predictor of BDmax and CWC. This regional study showed that NT management‐induced increase in SOC improves the soil's ability to resist compaction.

Temporary effect of chiseling on the compaction of a Rhodic Hapludox under no-tillage

“…These results are similar to those found by araújo et al (2004), who stated a reduction in structural soil quality after chiseling, increasing the resistance to penetration, i.e., affecting the soil structure negatively. The higher resilience of soils under nT may be due to reduced soil tillage favoring the accumulation of straw and organic matter (om) in the surface layers (Blanco-canqui et al, 2009(Blanco-canqui et al, , 2010.…”

“…The Bdref can be obtained through the proctor test Blanco-canqui et al, 2009) or through the uniaxial compression test that has, as reference, a pressure of 200 kpa (håkansson, 1990; lipiec et al, 1991; silva et al, 1997). The proctor test may overestimate the dc, as it results in higher Bdref values than those obtained through the uniaxial compression test (håkansson, 1990; håkansson & lipiec, 2000).…”

Atributos físicos e carbono orgânico em latossolo vermelho sob diferentes sistemas de uso e manejo

“…A vulnerabilidade do solo à compactação pode ser modificada pelos sistemas de uso e manejo do solo (Blanco-Canqui et al, 2009) via modificações nos teores de COS e, por consequência, na capacidade de suporte de carga dos solos. Estudos recentes indicam que o aumento no teor de COS amplia a capacidade de suporte de carga dos solos, bem como a resiliência do solo às cargas aplicadas (Braida et al, 2010).…”

North American Soil Degradation: Processes, Practices, and Mitigating Strategies

“…Also, despite the numerically lower erodible fraction for soil managed with conservation tillage compared with CT, Van Pelt et al [65] concluded that the protective mantle of crop residue is crucial to preventing erosion in the North American Central Great Plains. Conservation tillage also reduces soil compaction by increasing root growth and SOC [66], soil erosion by increasing surface residue cover [67], fuel costs for tillage, and potential global warming by increasing soil C sequestration [68] by conserving more soil water and increasing crop yields [29,44,47]. Although successful conservation tillage may require higher N fertilization because of enhanced N immobilization due to increased surface residue accumulation [69], benefits for mitigating soil degradation by increasing SOC and reducing soil compaction and erosion outweigh limitations.…”