Chromium (III) and its effects on soil microbial activities and phytoremediation potentials of Arachis hypogea and Vigna unguiculata

Abstract

The aim of this research was to evaluate the impact of chromium (III) nitrate on soil microbial activities and growth performance and phytoremediation potentials of two staple leguminous crops, namely cowpea (Vigna unguiculata) and groundnut (Arachis hypogea). Pristine sandy loam soil samples were polluted with nitrate salts of chromium (III) at four different levels (50, 100, 200 and 400 mg/kg) in triplicates. There was a significant (P < 0.05) retarding effect of this metal on the study parameters. A consistent decrease in the total bacterial count in response to increase in dosage of the metal salt was observed. Chromium was also observed to significantly (P<0.05) affect the microbial metabolism as indicated by the decline in microbial respiration shown by the lowering of CO 2 evolution in the test samples. There was a reduction in the general growth performance of the two test plants treated with different levels of chromium when compared with the control. Phytoaccumulation experiment showed that only cowpea roots accumulated the pollutant from the 400 mg/kg treated soil, with no metal salt presence in aerial parts of the plants. This chromium-removal potential demonstrated by cowpea makes it a better candidate than groundnut for the phytoremediation of chromium-contaminated soils.

Heavy metal tolerance and accumulation in the Brassica species (Brassica chinensis var. parachinensis and Brassica rapa L.): A pot experiment

“…This delay in germination time suggests the possibility of secondary induced dormancy in response to metal concentrations [ 60 ]. These current findings are consistent with those of Eze et al [ 61 ], who similarly observed delayed germination in Cr-treated soils, with concentrations of up to 400 mg/kg compared to the control treatment, indicating that germination time increased with higher levels of metal contamination in soils.

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Temporal Stability of Soil Microbial Properties in Responses to Long-Term Application of Compost Obtained from Tannery Sludge

“…Thus, the higher pH and accumulation of Cr in soil under the highest rate of compost can contribute to decrease incorporation of C by microbes. Indeed, Cr presents an inhibitory effect on C incorporation by microbes and this effect is concentration-dependent [29]. On the other hand, soil pH is an important driver that affects the efficiency of accumulating C into microbial biomass [25].…”

“…Several soil properties influence the soil respiration, being moisture, temperature, and organic C content, which are the most important soil factors [23]. In particular, soil temperature and moisture are important factors influencing microbial activity acting on organic C [29,30]. The respiratory quotient also varied according to treatments over time (Figure 2D).…”

Modeling the Carbon Sequestration Potential of Multifunctional Agroforestry-Based Phytoremediation (MAP) Systems in Chinandega, Nicaragua

“…Of the species that were identified at Picacho and El Ensayo, the following 28 complied with the selection criteria and thus can be considered appropriate for multifunctional agroforestry/phytoremediation systems in Chinandega: Amaranthus Spinosus [31], Anacardium occidentale [32], Arachis hypogaea [33], Arachis pintoi [34], Azadirachta indica [35], Brachiaria ruziziensis [36], Byrsonima crassifolia [37], Ceiba pentandra [38], Chrysopogon zizanioides [38],…”