Nitrogen application timing the key to achieving protein
2020 has dropped a lot onto the world of farming. COVID-19, increased pressure on commodity pricing, demand/supply chain concerns, strong bread demand, and overall strong pricing for wheat has created some increased demand for spring wheat seed. If you are growing spring wheat for the first time in a few years, there are a few things you should pay close attention to. First, spring wheat yields have improved – significantly. Second, the demand for protein from flour millers is becoming increasingly important to pay attention to. A few years ago you could grow a spring wheat crop and if you had slightly low protein, you would just miss out on the premium. Today, many grain elevators are actually discounting for having low protein. Why? In short, there is plenty of competitively priced wheat available in the world for the low protein market, creating pricing pressure. This makes it more important to ensure that you target acceptable protein levels in spring wheat for your market.
So, how do we get strong protein in spring wheat?
In short, we have to pay attention to the same details that we have preached in the Hard Red Winter Wheat Crop, with slightly different quantities of N at each timing.
First, enough total fertility based on expected yield is very important. Older varieties of spring wheat had a tough time breaking the 60 bu/acre yield plateau. New varieties have no problem moving well beyond that – we have seen as high 100 bu/acre plus yields. Enough base fertility to achieve yield and protein is key. If you used 100 units of nitrogen for your 60 bushel crop, you can’t expect 100 units of nitrogen in an 80 plus bushel crop to give both yield and protein. More total fertility can often be the first answer.
Second, split application of nitrogen is equally important. Most growers will do a “split application” of fertilizer on spring wheat, but it mainly consists of a pre-plant application and a post emergence application (tillering timing). In order to target protein, we need to focus on making N available at heading time and targeting that second application at, or closer to GS32.
Your Hard Red Winter Spring crop has two jobs to do. Make grain kernels (= YIELD), and produce adequate protein levels (= GRADE). These two jobs need to be accomplished separately. For HRSW this process has led most producers to executing a two to three-part fertility program. Cash crop rotation should plan to receive a minimum of 120N in total, as an average. Amounts higher than 120 have certainly produced impressive yield results in past. And, adjustments can successfully be made to lower the rates when to consider application methods efficiency or residual soil nitrogen.
“Kickstart or Pre-plant” – not unlike any other wheat crop, the Kickstart application is intended to break the wheat out of the ground quickly and feed that young plant. In the early part of the spring growing season, soils are cooler and nutrients are slower to mineralize for plants to access. This can be a simple starter fertilizer, or you may try applying up to 30-50% of your total N requirement here. Every operation approaches this timing differently depending on resources available.
“Yield Maker” – at Zadok’s 32, second node of the plant pushes up the stem above the soil surface, the plant will start into rapid growth. The internode length has been determined and the grain head is forming. The crop will be ready to receive the next portion of fertilizer. The nutrients will be used in supply the energy required to feed the high demands of above ground growth and head formation. If you use enough total N for your expected yield, you may achieve protein with this 2 pass system. If the crop looks “strong”, consider moving to a third, “protein push” application.
“Protein Push” – there are basically four common ways to do this job… (the final 20% of nitrogen needs).
- Add an extra 30N in a protected for to your “Yield Maker” application, you can save to cost of an extra application, but it is possible that the weather will allow the N to release too soon/late.
- 30N as UAN liquid fertilizer application with streamer nozzles just prior to the flag leaf emerging, try to apply on a cloudy day, perhaps consider diluting 1:1 with water.
- Include addition of a safe form of Liquified Low Buriate Urea at 2gal per acre with T3 fungicide application. This will save a cost of application pass, but testing is still being done to confirm if any yield penalties could occur.
- Apply 30N via hardened granular nitrogen fertilizer applied with a calibrated high-clearance spinner unit. Apply at full flag leaf stage. This will follow same tracks as sprayer. The granular product should provide the least risk of burn to the flag leaf. (Amidas looks to be a good product to suit this application.)
Sulpher is another essential component in wheat fertility program. As a general statement, it has been found that wheat requirements for S are 1:10 of nitrogen. The choice of form and application method will vary depending on equipment and product preference. In a perfect world, S could be applied in all three of the application passes. In most cases, the S will be applied with the Kickstart pass. We have seen some anecdotal reports that S is important in creation of protein in HRS too. We are hoping to see more research with S include in the Protein Push applications in future.
There has not been mention of potassium or phosphorous in the approach, but they certainly can not be forgotten. Be sure to do soil test and ensure proper crop removal requirements are met.
This staggered nutrient application plan will allow to best follow the 4R nutrient approach and provide best probability of high yields a strong protein.