Search

In recent years, cadmium (Cd) contamination in agricultural soils and its subsequent transfer to crops is one of the high-priority environmental and public health issues of global concern, especially in densely populated developing countries like Bangladesh. However, no effective strategy has been introduced or implemented yet to manage Cd-contaminated soils in order to sustain agricultural production with no human health risks. In this study, agricultural soil samples were collected from 60 locations of 10 upazilas from Tangail district to assess the extent of soil Cd contamination. The Cd concentration ranged from 0.83 to 4.08 mg kg -1 with a mean of 2.17 mg kg -1 in topsoil (0-15 cm), and from 0.67 to 3.74 mg kg -1 with a mean of 2.10 mg kg -1 in subsoil (16-30 cm). The values of contamination factor (CF) indicated that all the sampling locations were found to be highly contaminated with Cd. Pot trials with the application of different doses of biochar and vermicompost in Cd-contaminated soil (0.8 mg kg -1 Cd) revealed that integrated application of biochar (5 t ha -1 ) and vermicompost (5 t ha -1 ) was the best treatment that significantly (p < 0.05) reduced plant Cd concentration (72%) and increased the biomass of experimental crop, Red amaranth (Amaranthus cruentus). This combined treatment also significantly reduced the uptake of Cr (37%) when co-contamination was present. The study suggests the application of biochar (5 t ha -1 ) in combination with vermicompost (5 t ha -1 ) to reduce human health risk and increase crop production when the soil is loamy sand in texture., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V. part of Springer Nature.)

Repeated applications of Cd-rich phosphate fertilizers have resulted in elevated concentrations of this toxic element in some New Zealand soils. Exceedance of the food safety standard for Cd (0.1 mg kg fresh weight) has been reported for potato ( L.). Composts may efficiently sorb Cd in soil and therefore reduce its phytoavailability, leading to reduced uptake by plants. We aimed to determine the potential of various composts, shredded corn stover, and lime at two different rates to reduce the transfer of Cd from a soil (containing 1.45 mg kg Cd) to potato (var. 'Nadine'). In the control, the peeled tubers, skins, leaves, and stems had Cd concentrations of 0.04, 0.09, 0.26, and 0.53 mg kg dry weight, respectively. There was a 71% reduction in tuber Cd concentrations in potatoes grown in soil amended with 5% (w/w) shredded corn stover, although it significantly decreased potato biomass. Potatoes grown in soil amended with pig manure compost, mushroom compost, sawdust-animal waste compost, and municipal compost at rates of either 2.5 or 5% (w/w) reduced tuber Cd concentrations by 58 to 66%, 46 to 63%, 52 to 53%, and 29 to 49%, respectively. Lime (1.3%) application in soil reduced tuber Cd concentrations by 50%. Composts significantly increased tuber biomass. Further work is warranted to identify the key components of composts that result in reduced Cd uptake by plants., (Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.)

Cadmium (Cd) is a non-essential trace element that accumulates in agricultural soils through the application of Cd-rich phosphate fertiliser. Vegetables can accumulate Cd to concentrations that sometimes exceed food safety standards. We investigated the potential of low-cost soil amendments to reduce Cd uptake by spinach (Spinacia oleracea L.), lettuce (Lactuca sativa L.) and onion (Allium cepa L.). Batch sorption experiments revealed the relative sorption of Cd by biosolids, charcoal, lignite, sawdust, two types of compost, bentonite and zeolite. Lignite and compost had the greatest ability to sorb Cd and were subsequently selected for pot trials, which elucidated their effect on Cd uptake by onions, spinach and lettuce in two market garden soils with native Cd concentrations of 1.45 mg/kg and 0.47 mg/kg. The addition of 2.5% (dry w/w) municipal compost reduced the Cd concentration in onions, spinach and lettuce by up to 60% in both soils. The addition of lignite gave variable results, which depended on the soil type and rate of addition. This Cd immobilisation was offset by soil acidification caused by the lignite. The results indicate that municipal compost is a low-cost soil conditioner that is effective in reducing plant Cd uptake., (Copyright © 2016 Elsevier Ltd. All rights reserved.)