Soil tillage erosion estimated by using magnetism of soils—a case study from Bulgaria

Abstract

A detailed field and laboratory study on small 0.84-ha test site of agricultural land near Sofia (Bulgaria) has been carried out in order to test the applicability of magnetic methods in soil erosion estimation in the particular case of strongly magnetic parent material. Field measurements of magnetic susceptibility were carried out with grid size of 6 m, resulting in 258 data points. Bulk soil material was gathered from 78 grid points. Natural, non-disturbed soil section was sampled near the agricultural field for reference profile of complete undisturbed soil. Surface susceptibility measurements reveal well-defined maxima down slope which, however, cannot be assigned directly to a certain depth interval, corresponding with susceptibilities along the non-disturbed soil profile. This is caused by the high magnetic susceptibility of the lithogenic coarse-grained magnetic fraction. Non-uniqueness is resolved by using magnetic susceptibility of coarse (1 mm > d > 63 μm) and fine (d < 63 μm) mechanical fractions and the parameter Δχ = 100*(χ (coarse) -χ (fine))/χ (bulk) (%). It shows increased values in the C-horizon of undisturbed soil profile, which corresponds to a certain part of the studied area. After the application of an empirical model to predict the values of magnetic parameter after tillage homogenization and removal of soil material from the surface, the amount of soil loss is estimated.

Using magnetic susceptibility mapping for assessing soil degradation due to water erosion

“…These findings correspond to similar studies previously published (Jordanova et al 2010(Jordanova et al , 2014Jakšík et al 2015). Frequency dependent susceptibility (χ fd ), or difference in magnetic susceptibility (Δχ) suggested by Jordanova et al (2011) as a suitable factor for assessing the presence of ultrafine crystalline iron minerals in humic horizons (i.e. suitable conditions for natural crystallization of goethite and hematite), was not evaluated in this study because of statistically insignificant results previously published for this area (Jakšík et al 2015).…”

“…Royall (2001) made use of mineral magnetic measurements to investigate soil erosion and sediment delivery in a small agricultural catchment in a limestone terrain. By using magnetic susceptibility, the rate of soil erosion can be estimated for a given period of agricultural land use ( Jordanova et al 2011( Jordanova et al , 2014. There is a wide range of other applications of magnetic properties for assessing soils, such as for hydric soil delineation (de Jong 2002;Grimley et al 2004) or soil pollution assessment (e.g.…”

Relación entre propiedades físicas y la susceptibilidad magnética en dos suelos del Valle del Cauca

“…Uniform mineralogy is typical for both surface soils and samples from different depths in nondisturbed soil profile (Jordanova et al, 2011). This supports the hypothesis that, within the studied area, the observed magnetic differences comes from variations in soil movement and redistribution of the ferromagnetic carriers due to tillage operations.…”

A Review of Geophysical Methods for Soil Structure Characterization

“…This kind of well‐developed soil structure facilitates fluxes of water and oxygen through the soil and makes these fluids available to plants, thereby, helping plant growth, promoting nutrient recycling and recharge of groundwater (Beven & Germann, ; Maximilian et al, ; Rabot et al, ). In contrast, a poor soil structure is one that restricts water infiltration and gas exchange, thereby, resulting in water runoff, soil erosion, and unfavorable anoxic conditions that limit plant growth and may trigger greenhouse gas emissions by anaerobic bacterial respiration (Berisso et al, ; Chen et al, ; Jordanova et al, ; Nawaz et al, ).…”