Response to side-banded phosphorus and zinc fertilizer for corn grown after canola or soybean in southern Manitoba

A two-year crop rotation study in southern Manitoba assessed the effects of starter fertilizer on grain corn (Zea mays L.) production when corn followed canola (Brassica napus L.) versus soybean (Glycine max L. Merr.). Treatments included a control (no starter) and two rates of phosphorus (P) (30 and 60 kg P2O5 ha-1) as monoammonium phosphate (MAP, 11-52-0) or MicroEssentials® SZ (MESZn, 12-40-0-10-1) side-banded at planting. The preceding crop did not have any influence on mycorrhizal colonization of corn roots at V4 corn growth stage. However, side-banded fertilizer increased early-season biomass by as much as 111% compared to the unfertilized control, with the largest increases occurring where corn followed canola. Phosphorus concentration and uptake in early-season biomass increased as the P rate increased. Zinc (Zn) concentrations in early-season biomass were greatest for the unfertilized control and MESZn treatments, while Zn uptake was significantly greater with the application of starter fertilizer compared to the unfertilized control. Starter P advanced silking date by 2 to 7 days relative to the unfertilized control. At maturity, starter P reduced grain moisture by 21 to 27 g kg-1 in corn, only after canola. The high rate of MAP increased grain yield by an average of 770 kg ha-1 compared to the unfertilized control, regardless of the preceding crop. The negative influence of the preceding canola crop on early-season growth and mid-season development of corn can be managed with starter fertilization, to provide adequate P and Zn to the corn crop and maintain successful production in Manitoba.