Residual effects of surface applications of organic matter and calcium salts on the subsoil of a red-brown earth

Abstract

Summary. The effects of surface soil applications of organic matter and calcium salts on the subsoil (200–280 mm) of a red-brown earth (Natrixeralf) were investigated in a field experiment. The calcium treatments included gypsum, lime or nil-calcium added to the surface soil. To these calcium treatments, organic matter or nil-organic matter was added. Three years after final applications of organic matter and calcium salts to the surface soil, the physical and chemical properties of the subsoil were measured. The bulk physical measurements of the subsoil (penetrometer resistance, bulk density, macroporosity and plastic limit) were not significantly influenced by the treatments. The electrical conductivity of the subsoil was greater in the gypsum-treated soil than in the lime- or nil-calcium-treated soils. Subsoil pH values were lower in the gypsum-treated soil than in the lime- or the nil-calcium-treated soil. Dispersion (spontaneous and mechanical) of the clay subsoil decreased with gypsum-treated surface soil. In treatments where both organic matter and gypsum were added to the surface soil, the subsoil showed an increased concentration of exchangeable calcium and decreased spontaneous dispersion of the clay.

When does organic carbon induce aggregate stability in vertosols?

“…Bennett et al (2014) observed increased soil function and vegetative growth 12 years after the application of gypsum and lime on a red sodosol, and concluded that the initial addition of Ca 2+ to the soil increased soil function and stability. We believe our data indicate that the presence of large amounts of TOC may increase the availability of Ca 2+ in the soil and therefore contributes to microaggregate stability (Chorom and Rengasamy, 1997;Vance et al, 1998). The likely explanation for this is the influence of TOC in raising CEC and lowering pH in the soil (Bennett et al, 2014).…”

Soil carbon dynamics in saline and sodic soils: a review

“…The addition of organic matter in conjunction with gypsum has also been successful in reducing adverse soil properties associated with sodic soils and in decreasing the ESP. Vance et al. (1998) found that addition of organic matter and gypsum to a surface soil decreased spontaneous dispersion and EC more than gypsum alone.…”

Impact of Some Soil Amendments on Properties and Roductivity of Salt Affected Soils at Kafr El-Sheikh Governorate

“…The application of compost accelerated sodium leaching and reduced EC, which increased water-holding capacity and soil aggregate stability (Tejada et al, 2006). Decreased soil dispersion and reduced EC more effectively than those attained when amending soils with gypsum solely (Vance et al 1998), beside of improving the chemical properties (EC, pH and SAR) of the saline sodic soil to the desired levels (Ghulam et al 2011).while the dispersion of clays from soils was increased when Ca/Mg ratios in the percolating solutions were below unity with an SAR1:5 >3. (Bardhan et al, 2007) while the productivity of soil was higher when Ca/Mg ratio on the soil exchange complex was 3.2:1 (Ansari et al, 2010).…”