Application of aquifer delineation using hydro-geophysical techniques was conducted in De Aar, the eastern part of the Karoo region, Northern, South Africa. This study is aimed at demonstrating the use of hydrogeophycal techniques in delineating aquifer systems into unconfined and confined to estimate areas and zones likely to control ground-water recharge. An integrated hydrogeophysical approach using vertical electrical resistivity sounding (VES) and ground telluric methods was applied to delineate subsurface structures. Six VES surveys and seven profile surveys were measured using a Wenner array configuration and ground telluric method respectively. VES data was processed using IPI2win software and used to produce a 2D inference of the subsurface electrical resistivity model. The telluric passive surveys were processed through an automated in-built algorithm to generate 2D profile maps while the electric potential difference curve was interpreted with the lithological cross section constructed 2D conceptual model. The VES results showed four significant layers of low (0.9-8.1 Ωm), moderate (22.4-125 Ωm), and high 68-177 Ωm) electrical resistivity values which are suggestive of the different lithological formations. Additionally, the subsurface model from ground telluric methods supported shallow groundwater potential boreholes with the inference of fewer groundwater accumulations below 50 m. These hydrogeophysics results were compared to the drill chip lithological results and both suggested a double-layer aquifer system, which may therefore suggest that recharge estimation needs to be carried out in two different aquifers. The study therefore successfully demonstrated the use of geophysics techniques in delineating aquifer systems, thereby enhancing the identification of potential recharge areas.

The aquifer delineation using a hydrogeophysical survey was carried out in De Aar, a small town in the eastern part of the Karoo supergroup, Northern Cape, South Africa. In this re-gion, the current approach for estimating recharge, water allocation plans, and water monitoring does not consider the existence of different types of aquifers. Instead, it assumes there is one aquifer system and therefore the area might have one value of recharge. This study aimed to delineate aquifers into unconfined and confined aquifers for estimating recharge and demonstrate the use of geophysics techniques in delineating aquifer systems. Six VES stations and seven profile lines were measured using a Wenner array configuration and ground magnetotelluric method, respectively. VES data was processed using IPI2win software while electric potential difference curve was in-terpreted together with lithological data. Four significant layers of low (0.9-8.1 Ωm), moderate (22.4-125 Ωm), and high 68-177 Ωm) resistivity values were delineated suggestive of the different lithological formations. The subsurface profile mapping using ground magentotelluric methods did not suggest groundwater accumulations below 50 m, instead supported shallow groundwater potentials boreholes. These results have provided a double layer aquifer system thereby suggesting that recharge estimation need to be carried out in two different aquifer systems to enhance water allocation plans, and water monitoring in groundwater-dependent areas similar to prevailing conditions in the current study area.

Plants are affected by soil environments to the same extent they affect soil functioning through interactions between environmental and genetic factors. Here, five plant species (broad bean, pea, cabbage, fennel, and olive) grown under controlled pot conditions were tested for their ability to differently stimulate the degradation of standard litter. Litter, soil C and N contents and soil microbial abundance were measured. The architecture and morphological traits of roots systems were also evaluated by using specific open-source software (SmartRoot). Soil chemical and microbiological characteristics were significantly influenced by the plant species. Variations in soil C/N dynamics were correlated with the diversity of root traits among species. Early-stage decomposition of the standard litter changed on the basis of the plant species. The results indicated that key soil processes are governed by interactions between plant roots, soil C and N, and the microbial metabolism that stimulate decomposition reactions. This, in turn, can have marked effects on soil chemical and microbiological fertility, both fundamental for sustaining crops, and can promote the development of new approaches for optimizing soil C and N cycling, managing nutrient transport, and sustaining and improving net primary production.