Manage nutrients for winter wheat



August 31, 2021 - 8:47 AM

As August comes to an end, farmers begin a busy time of year, preparing for corn and soybean harvest, and planning for winter wheat planting. While everything seems to hit at once this time of year, there are things farmers can do now to help be prepared for the winter wheat growing season. Now is the time to starting preparing your nutrient management plan for your winter wheat acres.  

Many farmers become complacent with a “one size fits all” nutrient management plan, but in reality, no field is the same. Using a blanket fertilizer application on all your acres leaves room for wasting money by over-applying fertilizer, or risks under-applying fertilizer, and falling short of the yield potential of a field. The simplest way to avoid this from happening, is to apply the correct amount of nutrients to each field according to the field’s current nutrient levels, yield potential, and the uptake of the next crop

The first step in creating a nutrient management strategy can be taken now, before the busy harvest season hits. Taking soil samples in each field will enable you to identify the areas in the soil that need improvement. The most common issues in our soils are low pH and Nitrogen deficiencies. If soils are too acidic for optimal wheat growth (<6.0), then positive results can be seen from liming the field. Additionally, most fields are going to require nitrogen inputs, but the amount will vary for each field depending on soil type, expected yield, and existing nitrogen credits. Producers can also see yield improvements with small phosphorus applications.

Soil samples should be taken each year for N, P, and K content of the soil, or every 5 years at the minimum. The more regularly you get your fields sampled, the more often you will be able to change your applications to fit the field’s needs. Soil Samples can be handled through our extension offices, where we can lend our soil probes to collect your samples, as well as give you instructions on how to get the best samples from the field. We can also send your samples to the KSU soil lab to do all the testing. 

Once you get your soil test results back, you will be able to plan a fertilizer application. Your soil test results from the lab will include the amount of each nutrient you need to apply to reach optimum levels for wheat growth, but you can be even more specific with your nitrogen calculations. Using the equation by KSU, you can include your yield goal, soil texture, previous crop credits, and your results from the soil test to get a more accurate idea of the nitrogen needs of the field. The equation is as follows:

N Recommendation(lbs./acre) = (yield goal x 1.75) Soil texture adjustment- previous crop adjustment- previous year manure- profile nitrogen soil test. Different soil labs will use different methods to find the amount of each nutrient in the sample. This equation uses results found through the Kansas State soil Lab.

Now that you know the inputs needed for each yield to meet its yield potential, you can plan how you will apply these nutrients. Small amounts of your total nitrogen needs can be applied pre-planting as a starter, along with any phosphorus and potassium applications. 

These applications can either be made by broadcasting solid fertilizer and incorporating it into the soil through tillage, or left on the surface in no-till situations. In no-till situations there is the added risk of nutrient stratification, so different soil testing strategies should be used. Nutrients can also be applied via a band application by knifing liquid fertilizer into the soil profile. Another common application is applying fertilizer at planting using the drill. 

Come spring time is where you will see the greatest yield boost from fertilizing with nitrogen. Not only will you not risk losing your nitrogen to leaching or volatilization over the dormant season, you will also have time to judge the condition of the crop, and make any adjustments to your original plan.  

After you have considered the current condition of the crop, you can go ahead with applying the remaining nitrogen before your wheat hits the jointing stage in mid-March, where you will see the greatest opportunity for increased yields.

Producers who enjoy premiums for high-protein wheat at the market, can also choose to make later applications of excess nitrogen to promote a higher protein wheat crop.

While it might not always seem worth the while, taking the time to have your fields soil tested will give producers the best chance to fertilize a successful wheat crop. For more information on soil testing or questions about winter wheat production, call Chad Guthrie at your local extension office, or reach him directly at [email protected] and 1-620-223-3720.