When it comes to producing malting barley, fertility management is a balancing act. Making grade requires growers to walk a fine line between yield and protein – if they miss the mark, they’re growing feed barley.
Fine tuning nitrogen rates is the biggest fertility challenge malt barley growers face, says Jack Payne, Farmers Edge operations coordinator based in Olds, Alberta. “With nitrogen you get higher yield, but you also get higher protein and that’s not good. You want more starch in the kernels rather than protein because the starch gives you fermentation. Higher protein can shut you out of the malt market.”
Payne says the goal for growers is to hit the sweet spot – fertility levels that allow strong yields and optimum protein. Soil tests help hit the target. “The first thing you need to know is how much nitrogen you have in your soil,” adds Payne. “Without that information you’re shooting blind.”
Start with a soil test
A fall soil test will indicate both macro and micronutrient levels. Growers can then work with their agronomist to develop a balanced program that delivers sufficient nitrogen, phosphorus and potassium, and address any micronutrient concerns.
Setting a yield target is key to establishing the right nitrogen rate, says Payne. He notes that soil moisture also plays a strong role in setting that target. Typically, when you have high yield you get low protein in the grain – the perfect combination. But when it comes to nitrogen the inverse is also true. “If you are shooting for a 100-bushel yield and you only have enough moisture for 60 bushels, the crop will use that extra nitrogen to produce higher protein in your grain.”
That’s why assessing moisture availability is so important, says Payne. “If you're looking at Southern Alberta on dry land where there's no irrigation, for example, an 80 or 90-bushel yield might be tops. So you have to adjust your fertility program for the yield in your area. There is no one recipe for fertilizer that will work everywhere.”
Think variable rate when applying fertilizer
When he talks to growers, Payne recommends they take a look at variable rate fertilizer application and understand how it can help make malt. Creating management zones in a field combined with regular soil testing allows for targeted nutrient application and can produce a significant return on investment.
“I’ve seen fields where there's five different zones based on soil type, topography and yield potential. I've also seen up to 60 pounds difference in the soil test nitrogen in those different zones. If you take the average nitrogen soil test across the field and apply a flat fertilizer rate, only 40 percent of the field is getting the right rate,” says Payne. “The other 60 percent is either too high or too low. In a large portion of the field you’re losing yield or increasing your high protein risk.”
Nitrogen application timing is another consideration. Payne notes that nitrogen taken up by the plant after stem elongation impacts protein more than yield. “Barley really uses most of the nitrogen up front, early in the growing season, to build yield. When we top dress nitrogen later in the season the plant tends to use it to increase protein levels.” Payne recommends growers avoid slow release nitrogen products when growing malt because soil moisture and weather conditions can create release later in the season and that can also cause protein problems.