Physical quality indicators and mechanical behavior of agricultural soils of Argentina

Mollisols of Santa Fe have different tilth and load support capacity. Despite the importance of these attributes to achieve a sustainable crop production, few information is available. The objectives of this study are i) to assess soil physical indicators related to plant growth and to soil mechanical behavior; and ii) to establish relationships to estimate the impact of soil loading on the soil quality to plant growth. The study was carried out on Argiudolls and Hapludolls of Santa Fe. Soil samples were collected to determine texture, organic matter content, bulk density, water retention curve, soil resistance to penetration, least limiting water range, critical bulk density for plant growth, compression index, pre-consolidation pressure and soil compressibility. Water retention curve and soil resistance to penetration were linearly and significantly related to clay and organic matter (R2 = 0.91 and R2 = 0.84). The pedotransfer functions of water retention curve and soil resistance to penetration allowed the estimation of the least limiting water range and critical bulk density for plant growth. A significant nonlinear relationship was found between critical bulk density for plant growth and clay content (R2 = 0.98). Compression index was significantly related to bulk density, water content, organic matter and clay plus silt content (R2 = 0.77). Pre-consolidation pressure was significantly related to organic matter, clay and water content (R2 = 0.77). Soil compressibility was significantly related to initial soil bulk density, clay and water content. A nonlinear and significantly pedotransfer function (R2 = 0.88) was developed to predict the maximum acceptable pressure to be applied during tillage operations by introducing critical bulk density for plant growth in the compression model. The developed pedotransfer function provides a useful tool to link the mechanical behavior and tilth of the soils studied.Fil: Imhoff, Silvia del Carmen. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; ArgentinaFil: Pires Da Silva, Alvaro. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; BrasilFil: Ghiberto, Pablo Javier. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Tormena, Cássio A.. Universidade Estadual de Maringá; BrasilFil: Pilatti, Miguel Angel. Universidad Nacional del Litoral. Facultad de Ciencias Agrarias; ArgentinaFil: Libardi, Paulo L.. Universidade do Sao Paulo. Escola Superior de Agricultura Luiz de Queiroz; Brasi

Variation of pre-consolidation pressure (σ) as function of water content (WCg) for two soil with similar clay content and different organic matter (OM) content.

<p>Variation of pre-consolidation pressure (σ) as function of water content (WCg) for two soil with similar clay content and different organic matter (OM) content.</p

Variation of the least limiting water range (LLWR) for two soils with similar clay content and different organic matter (OM) content.

<p>Variation of the least limiting water range (LLWR) for two soils with similar clay content and different organic matter (OM) content.</p

Least limiting water range (LLWR) for a soil with 17% clay and 2.8% organic matter (A horizon), and for a soil with 54% clay and 1.2% organic matter (B horizon).

<p>Least limiting water range (LLWR) for a soil with 17% clay and 2.8% organic matter (A horizon), and for a soil with 54% clay and 1.2% organic matter (B horizon).</p

Variation of pre-consolidation pressure (σ) as function of water content (WC_g) for two soil with similar organic matter (OM) content and different clay content.

<p>Variation of pre-consolidation pressure (σ) as function of water content (WC_g) for two soil with similar organic matter (OM) content and different clay content.</p

Variation of the compression index (CI) as a function of gravimetric water content (WC_g) for several combination of Clay+Silt content and organic matter content (OM).

<p>Variation of the compression index (CI) as a function of gravimetric water content (WC_g) for several combination of Clay+Silt content and organic matter content (OM).</p