Phosphorus deficiency is a common problem with corn planted into a rotation following canola.
In its early stages, corn relies on mycorrhizae to help with the majority of phosphorus uptake. The trouble with corn following canola is that canola and other crucifer plants are not hosts for micorrhizae, so the beneficial fungi populations must be re-established.
Despite this “corn after canola syndrome,” crop insurance data in Manitoba shows canola is the most common predecessor to corn.
Minimizing this early phosphorus deficiency and its impact on yield at the end of the season is one of the priorities for Magda Rogalsky of the University of Manitoba in her research looking at P management in corn.
In this Corn School West episode, she explains how she’s seeing promising results from applying starter P with the corn when planting into canola residue. The idea is that the starter fertilizer is helping the corn compensate for not having micorrhizae to help with P uptake.
She’s comparing how corn performs in canola versus soybean residue (unlike canola, soybeans are micorrhizal) using five different treatments: a check with no starter P and two different rates of both MAP and MESZn fertilizer side-banded at planting (see side bar.)
“We can see a huge difference between the no-P check and where the starter phosphorus was added, especially in the canola plots,” explains Rogalsky.