Temporal Changes in Cd Sorption and Plant Bioavailability in Compost-Amended Soils

Al Mamun, Shamim; Lehto, Niklas J.; Cavanagh, Jo; McDowell, Richard; Kellermann, Liv Anna; Robinson, Brett H. (2023). Temporal Changes in Cd Sorption and Plant Bioavailability in Compost-Amended Soils Soil Systems, 7(4), p. 107. MDPI 10.3390/soilsystems7040107

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The application of Cd-contaminated phosphate fertiliser has enriched concentrations of this non-essential element in many agricultural soils. Consequently, concentrations of the metal in some agricultural products exceed the Maximum Limit in foods. Composts can reduce the transfer of Cd from soil to plants; however, it is unclear how long this beneficial effect endures. We aimed to determine temporal changes of phytoavailable Cd in two market garden soils (an Allophanic Orthic Granular Soil and a Recent Silt Loam). Soils were amended with either municipal green waste compost or sawdust and animal waste compost at a rate of 2.5% w/w under three incubation regimes: at 19 °C, at 30 °C, and at 30 °C with additional N added as urea at 0.6 g urea/kg soil added over 1 year. Each replicate was sampled after 1, 5, 9, 13, 21, 31, and 49 weeks, and phytoavailable Cd was estimated through 0.05 M Ca(NO3)2 extraction. Seed potato (Solanum tuberosum), ‘Nadine’ variety, was grown in the Pukekohe Allophanic Orthic Granular Soil, freshly amended with municipal compost and the same soil aged for one year. The concentration of Cd in all samples was analysed using an ICP-OES (Inductively Coupled Plasma-Optical Emission Spectrometer). The C concentration in the soil—compost mixtures decreased over the year, with the greatest decreases occurring in the soils incubated at 30 °C with added N. Unexpectedly, the concentration of Ca(NO3)2-extractable Cd in the compost-amended soils did not increase over time and in some cases even decreased. This was confirmed through a pot experiment, which showed the Cd concentration in potato was reduced by 50% in both the freshly amended soil and the amended soil aged for one year. Cadmium immobilisation in soils might be due to both the sorption of Cd by organic matter and the occlusion of sorbed Cd by oxy-hydroxides of iron and aluminium. Over 49 weeks, soluble Cd does not increase as organic matter oxidises. The application of municipal compost to soil will reduce both plant Cd solubility and plant Cd uptake for at least one year in the soils tested.

Item Type:	Journal Article (Original Article)
Division/Institute:	School of Agricultural, Forest and Food Sciences HAFL School of Agricultural, Forest and Food Sciences HAFL > Agriculture School of Agricultural, Forest and Food Sciences HAFL > Agriculture > Soils and Geoinformation
Name:	Al Mamun, Shamim; Lehto, Niklas J.; Cavanagh, Jo; McDowell, Richard; Kellermann, Liv Anna and Robinson, Brett H.
ISSN:	2571-8789
Publisher:	MDPI
Language:	English
Submitter:	Liv Anna Kellermann
Date Deposited:	08 Dec 2023 10:29
Last Modified:	12 Dec 2023 14:32
Publisher DOI:	10.3390/soilsystems7040107
Uncontrolled Keywords:	Ca(NO3)2-extractable Cd; incubation; potato; organic amendment
ARBOR DOI:	10.24451/arbor.20585
URI:	https://arbor.bfh.ch/id/eprint/20585