A Mathematical Equation to Calculate Linear Distance of Cyclic Horizons in Vertisols

Abstract

Deep and wide shrinkage cracks and slickensides are developed in Vertisols due to the presence of shrink‐swell minerals like smectites. As a result of swelling of these minerals, vertical and horizontal shear stress pushes the clay mass upward forming parabolic thrust cones as cyclic horizons. A mathematical equation has been proposed for measuring the linear distance of these cyclic horizons taking into account the depth of occurrence of slickensides. This equation is an improvised, but useful, method to identify locations of microdepressions and microknolls required for better management of Vertisols.

Vertisols of tropical Indian environments: Pedology and edaphology

“…These values can easily be obtained by soil survey and mapping. The accuracy of the equation proposed by Bhattacharyya et al (1999b) is between 81 and 86% in vertisols in arid to semi-arid climates. The equation provides a new method of locating micro-depressions and micro-knolls in an effort to better manage vertisols for agricultural and non-agricultural purposes.…”

“…Vertisols that are not cultivated are associated with native vegetation, such as grasslands and savannahs (Probert et al, 1987). Vertisols can tilt large trees (Bhattacharyya et al, 1999b). Not surprisingly, few, if any, commercial forests are found on vertisols (Buol et al, 1978), but mixed pine and deciduous forests are reported in selected regions of east Texas.…”

“…Prior knowledge about the highs and lows of the cyclic pedons may help the stakeholders plan their programmes and avoid mishaps. In view of the need for a method to determine LD, a mathematical equation has been proposed to measure the LD of the cyclic horizons, taking into account the depth of occurrence of slickensides (Bhattacharyya et al, 1999b). A standard parabolic equation represented by (y 2 = 4ax) was considered, where a is the focus of the parabola.…”

“…When the profile is examined away from the centre of the cyclic horizon, the value of a cannot be obtained, and calculation of LD becomes difficult. Thus, Bhattacharyya et al (1999b) proposed the following equation.…”

Soil Classification Following the US Taxonomy: An Indian Commentary

“…Vertisols are deep, dark colored, clayey, and smectitic soils that exhibit cracks and slickensides (Table 1). Earlier studies suggested that the slow and steady process of haplodization induced by argillipedoturbation (Hole, 1961) inhibit the process of horizonation (Simonson, 1961) and favors the development of Vertisols with characteristic cyclic horizons (Bhattacharyya et al, 1999b). Extensive pedological research in the last decade on Indian Vertisols, however, does not support the earlier concept of Vertisol formation because of the active operation of the clay illuviation process (Satyavathi et al, 2005; Pal et al, 2009, 2010), which is a more dominant pedogenic process than the argillipedoturbation.…”