While some parts of the province have welcomed recent and persistent precipitation, many areas have had fields underwater. This moisture stress can starve plants of oxygen, causing them to yellow, but it can also cause more issues in terms of the soil nutrients.

"When our soils get saturated (with water) when they're warm like this, in less than 24 hours the microbes in the soil consume all the oxygen, and then the root zone turns anaerobic. That's why the plants turn yellow," explains Manitoba Agriculture crop nutrition specialist John Heard. "Under those anaerobic conditions, then the microbes start prying the oxygen off our nitrate form of nitrogen, and that nitrogen is lost as a gas, lost to the plant."

This is denitrification, which Heard says accounts for a lot of the losses we see from excess moisture, rather than a loss of nutrients due to soil leaching.

As advanced as cereal crops are now, Heard says there's not a lot of intervention that can help in terms of recovering yield losses caused by nitrogen losses, but he says there's still hope for corn crops.

"Corn has taken up a fraction of the nitrogen it will need to grow a crop," he says. "As the corn recovers from the excess water, there are times that we can go in there, and we can sidedress nitrogen. Many people do that as a plan, but those that have already invested their money in nitrogen early can do an assessment to see if they need to come in to top up what was potentially lost."

Heard says we can also sometimes see sulphur deficiencies in corn and wheat as a result of the sulphur being washed below the root zone. He says this can also cause crop yellowing.

According to Heard, producers can do a simple 12-inch soil test to estimate how much nitrogen is in the soil and how much is needed.