Copper fertilization of wheat on soils with marginal copper levels

Non-Peer ReviewedCopper (Cu) is the micronutrient most often deficient in Saskatchewan. Fertilizer placement is an important consideration, particularly in minimum tillage systems, because Cu is generally thought of as immobile in soil. Several new products and methods of application have become available since the last local research was completed in the mid-eighties. This study was conducted to identify relative effectiveness, as indicated by response of hard red spring wheat (Triticum aestivum L. cv. AC Barrie) to a variety of Cu fertilization strategies on mineral soils having low levels of available Cu. Field experiments at five Saskatchewan sites over three years compared the effect of Cu treatment on wheat yield, tissue and grain Cu concentration, thousand kernel weight and grain Cu accumulation. The ranking of Cu fertilization method from most to least effective, was: foliar Cu (sulphonate) at Feekes 6 or 10 > broadcast and incorporated Cu sulphate at 5.5 kg ha-1 or 11 kg ha-1 > broadcast Cu sulphate with no incorporation. Broadcast Cu oxysulphate was ineffective, particularly without incorporation. Seed placed Cu sulphate or oxysulphate were also ineffective. Where Cu deficiencies are confirmed, foliar application of Cu products are recommended for response of wheat within the year of application