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The vertical distribution of Cd, Cr, Cu, Pb, and Zn and their mobility (except Cr) were investigated in ten agricultural soil cores, collected near non-ferrous metal mines and smelters along Jishui River, in Jiangxi Province, China. The surface soils near mines and smelters were contaminated by Cd, Cu, Pb, and Zn, with concentrations higher than the guideline values of China. For most polluted sites, heavy metals were mainly retained in the surface soil (0-20 cm), and the contents of them became constant in deeper soil. In all soil cores, the mean content of Cr was lower than the guideline value of China. Correlation results between studied heavy metals and soil properties showed that heavy metal contents throughout the soil profile was mostly influenced by organic matter (OM), pH, and clay content. Particularly soil OM can significantly impact on transport of soil heavy metals. There were positive correlations of OM content with all studied heavy metals, and the correlations with Cr, Cu, Pb, and Zn were significant or very significant. Heavy metal mobility in the studied region were assessed using a mobility index (MI) and mobility order was Cd ) Pb > Cu % Zn.

Abstract:To ease food insecurities in northern Canada, some remote communities started gardening initiatives to gain more access to locally grown foods. Bush beans (Phaseolus vulgaris L.) and potatoes (Solanum tuberosum L.) were assessed for N, P, K, Mg, and Ca concentrations of foliage as indicators of plant nutrition in a calcareous silty loam soil of northern Ontario James Bay lowlands. Crops were grown in sole cropping and intercropping configurations, with comparisons made between an open field and an agroforestry site enclosed with willow (Salix spp.) trees. Foliage chemical analysis of the sites revealed an abundance of Ca, adequacies for Mg and N, and deficiencies in P and K. Intercropping bean and potato did not show significant crop-crop facilitation for nutrients. The agroforestry site showed to be a superior management practice for the James Bay lowland region, specifically for P. The agroforestry site had significantly greater P for bean plant (p = 0.024) and potato foliage (p = 0.002) compared to the open site. It is suspected that the presence of willows improve plant available P to bean and potatoes by tree root-crop root interactions and microclimate enhancements.

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