Impact of Long-term Phosphate Application and Level of Fertilizer Cd on Crops and Soils

Public concern regarding the transfer of cadmium (Cd) from fertilizer phosphorus (P) products to soils, and uptake by crops, has increased interest in evaluating the true impact of fertilization practices on food nutrient content. The objectives of the study are:1) determine the cumulative impact of applying fertilizer P, varying in Cd concentration, on grain yield and micronutrient concentration, total soil Cd, phyto-available Cd, and grain Cd concentration, on a range of soil types; 2) determine the impact of soil characteristics on availability of native soil Cd and Cd added with P fertilizer, and; 3) determine the effectiveness of several soil testing methods in predicting availability of native and applied Cd across a range of soil types and environmental conditions.

Field studies were initiated at seven sites across western Canada using a 4-year crop rotation of durum wheat, flax, durum wheat, and flax (may be replaced with soybean). Phosphorus application increased the grain yield of durum wheat at two of the seven locations in 2002, and two locations with flax in 2003. Soil and grain samples are being evaluated for concentration of Cd and other nutrients. Greenhouse studies are also ongoing to establish the speciation and phyto-availability of the Cd from the various P fertilizer sources on the soils from the seven locations. MB-16