Dale R. Clark, Ph. D.
Director of Research for Northern Seed
We have been getting a lot of questions around protein in cereal crops. I’ll touch on why protein is important to the milling industry and the key agronomic drivers of high protein. You can improve your protein levels with a few simple steps.
Higher protein in hard red winter and hard red spring wheat usually mean a stronger wheat for the baking industry. The Hard Red Winter protein basis (that point at which there is no discount or premium) is usually around the 12.5% level and this can change depending on the level of the current harvest, especially in the Central Plains states. For hard red spring (also called DNS or Dark Northern Spring) the protein basis is 14%. The premium and discounts applied to HRS vary each year, depending on the protein level in the previous year’s crop.
Nitrogen is the primary nutrient needed to produce higher levels of protein in a cereal crop, and Sulfur is the next most essential nutrient. For HRS it takes about 3 lbs of available N for every bushel produced to maintain the 14% protein level. The anticipated yield at planting time and the soil available N will determine the amount of N that is needed to be applied. For Sulfur, about 20-25 lbs of Sulfur should be applied in the form of Ammonium Sulfate. Elemental Sulfur can also be applied, but it takes about one year for this to break down into the available form, so if you use this form, you need to plan ahead. Another important aspect when trying to push protein content is when to apply the fertilizer. During heading through flowering is a good time to add N. The head size has already been determined and the N will build protein. You can use 28-0-0 or 32-0-0, but when using these products at more than 1 or 2 gallons per acre, you will need to use streamer bars or streamer nozzles. Do not flat fan high rates or you will experience sever leaf burn. Also, this should be timed ahead of a moisture event as the N needs to come into the plant through the roots. Other products such as Utilize, N-Demand, or CoRon could be flat fanned and some of the N in these products are also in the leaf of a plant. If interested in one of these products consult your crop advisor for more information.
Varieties with the ability to make protein are probably the most important part of the equation. Plant breeders from both private and public institutions are constantly trying to improve their varieties for yield, disease resistance and other agronomic traits. While improving these traits they must always be vigilant to maintain the genetics that are necessary to produce the proper grain protein. In our test plots, WB 9669 has performed very well. In 3 years of testing, it has averaged almost 2 points higher protein than the plot average. Cereal Quality Labs, maintained by public and private institutions, continually test the new lines for not only the percent protein of the new lines, but also for the functionality of that protein for making bread. The other important groups are the soil scientists and agronomic advisers that continually monitor the various soil profiles and make fertilizer recommendations to the grower.
Crop rotation can play a big part in protein levels of cereal crops. Crops such as Canola will pull a lot of sulfur out of the soil so one needs to add that back. Legumes can fix nitrogen through the symbiotic relationship if inoculants are applied with the seed at the time of planting. Much of this N is left for the next crop and would be available for producing protein. It is important to have a good soil test prior to planting to determine how much N is available from last year’s crop.
The legumes may provide a source of free nitrogen, but the plant and the seed still need a certain level of N to produce not only the grain nitrogen but the growing plant. Legume crops seem to make the soils more mellow, increasing the water holding capacity of the crop, which not only will increase yield, but also stop some of the leaching of the N in times of excessive water. Proteins are made up of Amino Acids, Amino Acids contain N, and some contain S. So if you don’t have enough N and S, then proteins cannot be produced.