Eugene J. Gawalko

A prediction model for estimating the cadmium content of durum wheat from soil chemistry

A non-linear prediction model for the Cd content of durum wheat grain has been developed based on the 0.1 M Na4P2O7-extractable Cd and organic carbon in the <2 mm fraction of the soil ploughed horizon. The extraction is selective for metals held as metal–organic complexes in the soil, and will also extract more loosely held metal. The prediction model explains 74% of the variability of the durum grain data (N=34), and confirms the importance of the metal-organically held Cd, organic carbon and pH in influencing the uptake of Cd by durum wheat in Canadian Prairie soils.

CADMIUM, COPPER, IRON, MANGANESE, SELENIUM, AND ZINC IN CANADIAN SPRING WHEAT

Surveys of the average quality of different grades of the various classes of Canadian grains and oilseeds harvested each growing season are a major endeavor of the Grain Research Laboratory. With increasing interest in trace element levels in various cereal and oilseed crops, as part of the 1996, 1997 and 1998 Harvest Surveys, Western Canadian hard red spring wheat crops were characterized for cadmium, copper, iron, manganese, selenium and zinc. Samples were selected from producer submitted harvest survey samples received from crop districts in Manitoba, Saskatchewan and Alberta for the 1996, 1997 and 1998 crops. The methodology, including sample preparation, instrumentation and quality assurance, is described for each element. Data generated from the three crop years was evaluated with temporal and spatial variability studies. Year-to-year variations in grain chemistry are small for Cd, Mn, Se and Zn, but Cu and Fe contents show 12% and 9% decreases respectively over the three years. The overall variability for the plant-essential trace elements, Cu, Fe, Mn and Zn, is low in comparison with Cd and Se. It is demonstrated that the spatial variation in crop chemistry across the Canadian Prairie wheat producing region is greater than the year to year variations, and that soil properties are major factors controlling Cd and Se levels in grain.

Macro-relationships between regional-scale field pea (Pisum sativum) selenium chemistry and environmental factors in western Canada

Garrett, R. G., Gawalko, E., Wang, N., Richter, A. and Warkentin, T. D. 2013. Macro-relationships between regional-scale field pea (Pisum sativum) selenium chemistry and environmental factors in western Canada. Can. J. Plant Sci. 93: 1059-1071. A baseline study of cultivar, temporal (2004-2006) and spatial variability in field pea (Pisum sativum) selenium (Se) concentration was undertaken in western Canada based on six common cultivars (295 samples) grown in 35 variety trials. Selenium was determined by atomic absorption spectroscopy following a HNO3 digestion. Non-significant differences in pea Se concentration occurred due to cultivar and temporal variability. Trial site soil organic C, pH, cation exchange capacity, soil texture estimates, and classifications were recovered from Agriculture and Agri-Food Canadas Canadian Soil Information System database. Twenty-five percent of the pea Se variability was due to soil edaphic factors, particularly organic C and pH, this increased to 39% with inclusion of great soil group classification. The remaining variability was due to growing season weather conditions, with hotter drier summers leading to higher Se concentrations. Naturally Se biofortified pulses are available to be targeted to selenium deficient populations.