Abstract
Cadmium (Cd), a potentially toxic heavy metal for humans and animals, accumulates in the liver and kidneys of older animals grazing New Zealand and Australian pastoral soils. Phosphorus (P) fertiliser is the major input of Cd into these farming systems. A study was conducted to evaluate the effects, over 10 years, of annual application (30 kg P ha−1 yr−1) of four forms of P fertilisers having different solubilities and Cd contents [41, 32, 10 and 5 μg Cd g−1 for North Carolina phosphate rock (NCPR), single superphosphate (SSP), diammonium phosphate (DAP) made from low Cd phosphate rocks and Jordan phosphate rock (JPR) respectively] on soil and herbage Cd concentrations. Ten years of fertiliser application caused a marked increase in surface soil Cd concentrations. Total soil Cd was significantly higher in SSP and NCPR treatments compared to control (no P fertiliser), JPR and DAP treatments in the 0–30 and 30–75 mm soil depths. Plant-available Cd (0.01 M CaCl2 extractable Cd) was higher in SSP treatments than in control and other fertiliser treatments. Chemical analysis of herbage samples showed that there was no significant difference in Cd concentration in pasture grasses between treatments in the second year of the trial but in the eighth and tenth year, plots fertilised with SSP and NCPR had significantly higher Cd in pasture grasses in most of the seasonal cuts compared to control, JPR and DAP. Cadmium recovery by both grasses and clover was less than 5% of Cd applied in fertiliser. Clover Cd concentration and yield were much lower than those for grass and therefore its contribution to pasture Cd uptake was very low (< 7%). A strong seasonal effect on grass Cd concentration, which is inversely related to pasture growth rate, was observed in all three sampling years — Cd concentration was highest during autumn and lowest in spring. Total Cd contents of the fertilisers and their rate of dissolution rather than soil pH [pH (H2O) at 30–75 mm depth of 5.39, 5.20, 5.11 and 5.36 for NCPR, SSP, DAP and JPR treatments respectively]influenced soil and herbage Cd. These results showed that the use of P fertilisers with low Cd contents will reduce herbage Cd levels and has the potential of reducing Cd levels in grazing animals and their products.
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Andrews P, Town R M, Hedley M J and Loganathan P (1996) Measurement of plant-available cadmium in New Zealand soils. Aust J Soil Res 34: 441–452.
Bramley R G V (1990) Cadmium in New Zealand agriculture. NZ J Agric Res 33: 505–519
Cook P J and Freney R J (1988) Sources of cadmium in agriculture. In: Simpson J and Surnow B (eds) Proceedings of the National Symposium on Cadmium Accumulations in Australian Agriculture. Australian Government Publishing Service. Canberra pp 4–19
He Q B and Singh B R (1993) Effect of organic matter on the distribution, extractability and uptake of cadmium in soils. J Soil Sci 44: 641–650
Jackson A P and Alloway B J (1992) The transfer of cadmium from agricultural soils to the human food chain. In: Adriano D C (ed) Biogeochemistry of Trace Metals, Lewis Publishers, London pp 109–158
Lee J, Rounce J R, Mackay A D and Grace N D (1996) Accumulation of cadmium with time in Romney sheep grazing ryegrass/white clover pasture: Effect of cadmium from pasture and soil intake. Aust J Agric Res 47: 877–894
Loganathan P, Mackay A D, Lee J and Hedley M J (1995) Cadmium distribution in grazed hill pastures as influenced by 20 years of phosphate fertiliser application and sheep grazing. Aust J Soil Res 33: 859–871
Manoharan V, Loganathan P and Tillman R W (1995) Effects of long-term application of phosphate fertilisers on soil acidity under pasture In: R. A. Date, N. S. Grundon and G.E. Rayment (eds) Plant-Soil Interactions at Low pH: Principles and Management. Kluwer Academic Publishers, The Netherlands pp 85–91
McGrath S P (1987) Long-term metal transfers following applications of sewage sludge. In: Coughtrey P J, Martin MH and Unsworth MH (eds) Pollutant Transport and Fate in Ecosystems. British Ecological Society Publication No 6. Blackwell Scientific Publications, Oxford pp 301–317
Roberts A H C, Longhurst R D and Brown M W (1994) Cadmium status of soils, plants and grazing animals in New Zealand. NZ J Agric Res 37: 119–129
Rothbaum H P, Gogual R L, Johnston A E and Mattingly G E H (1986) Cadmium accumulation in soils from long continued applications of superphosphate. J Soil Sci 37: 99–107
Syers J K, Mackay A D, Brown M W and Currie L D (1986) Chemical and physical characteristics of phosphate rock materials of varying reactivity J Sci Food Agric 37: 1057–1064
Tiller K G (1988) Cadmium accumulation in the soil-plant system: an overview in relation to possible transfers to agricultural products. In: J Simpson and B Surnow (eds) Proceedings of the National Symposium on Cadmium Accumulations in Australian Agriculture. Australian Government Publishing Service, Canberra pp 20–47
Whitten M G and Ritchie G S P (1991) Calcium chloride extractable cadmium as an estimate of cadmium uptake by subterranean clover. Aust J Soil Res 29: 215–221
Williams C H and David D J (1973) The effect of superphosphate on the cadmium content of soils and plants. Aust J Soil Res 11: 43–56
Williams C H and David D J (1977) Some effects of the distribution of cadmium and phosphate in the root zone on the cadmium content of plants. Aust J Soil Res 15: 59–68
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Loganathan, P., Hedley, M.J., Gregg, P.E.H. et al. Effect of phosphate fertiliser type on the accumulation and plant availability of cadmium in grassland soils. Nutr Cycl Agroecosyst 46, 169–178 (1996). https://doi.org/10.1007/BF00420551
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DOI: https://doi.org/10.1007/BF00420551