Canola Takes Up More Cadmium and Phosphorus from Soil Than Spring Wheat

Abstract

Different sources of phosphorus (P) fertilizer (triple superphosphate and phosphate rocks) with different concentrations of cadmium (Cd) as an impurity were applied in different amounts to plots in a field experiment to produce soil with different concentrations of Cd. The plots were sown to canola (rape, Brassica napus L.) and spring wheat (Triticum aestivum L.). For each amount of Cd applied, the concentration of Cd in canola grain was about three times that in wheat grain. The concentration of P in canola grain was consistently about double that in wheat grain. Canola used all sources of P more effectively than wheat to produce dried shoots and grain.

Keywords:

• cadmium
• phosphorus
• canola
• spring wheat
• triple superphosphate
• phosphate rock

ACKNOWLEDGMENTS

Frank O'Donnell provided technical assistance, as did the staff of Esperance Downs Research Station. The Chemistry Centre (WA) measured the concentration of elements in plant tissue and grain. The Western Australian Department of Agriculture provided funds.

Notes

^ACanola, rape, Brassica napus L. cv. “Karoo;” wheat, Triticum aestivum L. cv. “Camm”.

^BTSP, triple superphosphate; NCPR, North Carolina phosphate rock; QPR, Queensland phosphate rock. Ratios of Cd:P in each source were (mg Cd/kg P applied): current TSP (20 mg/kg P); previous TSP (160.7 mg/kg P); previous NCPR (437 mg/kg P), and previous QPR (389 mg/kg P).

^CRR, relative response, calculated for each P source by dividing the slope (B) coefficient for each species by the B coefficient for wheat; by definition, RR for wheat is 1.00.

^ACanola, rape, Brassica napus L. cv. ‘Karoo’; wheat, Triticum aestivum L. cv. ‘Camm’.

^BTSP, triple superphosphate; NCPR, North Carolina phosphate rock; QPR, Queensland phosphate rock.

^CRR, relative response, calculated for each P source, by dividing the slope (B) coefficient for each species by the B coefficient for wheat; by definition, RR for wheat is 1.00.

^ACanola, rape, Brassica napus L. cv. ‘Karoo’; wheat, Triticum aestivum L. cv. ‘Camm.’

^BTSP, triple superphosphate; NCPR, North Carolina phosphate rock; QPR, Queensland phosphate rock.

^CRR, relative response, calculated for each P source by dividing bc for each species by bc for wheat; by definition, for each P source, the RR of wheat is 1.00.