Thinking about switching up your nitrogen & fungicide routine? Van Wall Agronomist Todd Farver is back with another episode of our 2021 Seed to Grain Series, powered by Solutions 360! In Part 4, we’re focusing on the benefits of applying in-season nitrogen, and we’ll dive into a Q&A about fungicide.
Before we even think about the different methods of nitrogen application, it’s important to consider what your need will actually be. Here’s a general rule of thumb to keep in mind: it takes 1 pound of nitrogen to yield 1 bushel of corn. On the simplest level, this means you can easily calculate your nitrogen need based on your yield goals (and previous yield history). If you have a field that averages 250 bushels/acre, plan on needing 250 pounds of available nitrogen to maintain the yield.
In case you missed it, the key word in that last sentence was available nitrogen. There are multiple ways that nitrogen can be ‘lost’ in the soil, or become unavailable to a growing plant. Leaching, denitrification, and volatilization are the 3 most common ways in which available nitrogen can be lost, and there are few ways for us to prevent them (or estimate their extent).
To sum up the importance of estimating your nitrogen need, it’s not just about a rule of thumb or choosing a rate. Because nitrogen can be lost during and after application from variables outside of our control, it can be difficult to truly estimate how much nitrogen is available to your corn crop at any one point in time.
This is where the ‘spoonfeeding’ method comes into play. By spreading out nitrogen applications, we reduce the risk associated with relying on just one pass to carry us through till harvest. For example, if we apply in the fall and poor weather conditions cause us to lose 10% of our available nitrogen, then we’ll have to accept that our yield will be below average. But, if we were able to come back and apply a second or third time throughout the growing season, we could better accommodate for those losses and get the crop back on track.
Not only do we know how much nitrogen goes into every bushel of corn raised, we also know when our crop will need it most. A corn plant will take up half of its total nitrogen need between the V8 and VT stages. This time frame could be comprised of only 30 days, so it’s critical that we have enough nitrogen available for our crop to be successful. However, the stages of V8 to VT don’t occur until well into the growing season. So how can we be sure that we’ll have enough nitrogen available to last?
You guessed it – spoonfeeding makes another appearance. Because it’s nearly impossible to predict nitrogen availability with a high degree of accuracy, being able to adjust our application timing and rates in-season allows us to spread risk across the entire growing season. Think of it as putting your eggs into two or three baskets instead of one. This method can also save you money on fertilizer cost, as it can help prevent overapplication. In years like this, when dry conditions have been widespread across much of the state, spoonfeeding gives you the opportunity to assess crop prices and adjust your input cost accordingly.
Regardless of your chosen method of nitrogen application, it’s important to remember the 4 R’s. Make sure to use the right source depending on the timing of your application to get the most effectiveness. For example, if you are relying solely on fall-applied nitrogen, use only ammonium sources with a nitrification inhibitor to avoid leaching. The right rate is based not only on your yield goals, but also the soil type and expected weather pattern. The right time and right place are largely dependent on your crop plan for the year. Both can change depending on whether you choose to split-apply or do a one-time pass. Nitrogen is key to raising a good corn crop, so it’s important to use it correctly for not only the health of the plants, but also your bottom line.
With the weather conditions that we experienced this year, Van Wall Agronomist Todd Farver received lots of questions about fungicide. Here are his tips & considerations for fungicide both this year and beyond.
Should I spray my soybeans with fungicide this year? To me, soybeans are an easy answer: yes! Applying fungicide at R3 can potentially increase yields by 3-8 bushels per acre. I always recommend applying fungicide on soybeans because it almost always pays to apply. With prices the way they are currently, it won’t take much of a yield bump to see the payback.
What about my corn crop? Fungicide in corn gets a bit more complicated. Seed companies have done lots of research on fungicide responsiveness, and found that certain hybrids will give you a tremendous yield bump if applied at the proper time. In the past, the standard timing for fungicide application was at brown silk. Now, some companies are suggesting application between V12 and VT will give you the best bump. Make sure to read the label and talk with your chemical and seed sales reps to ensure you choose the proper fungicide for your program.
My area has been dry this year. Do I still need to worry about disease pressure? Before making any decisions about fungicide, it’s always best to scout your crop and see how much pressure you’re up against. Because it has been drier across a large portion of Iowa this year, disease pressure will likely be on the lower side, so you may be able to skip fungicide. But, every crop is different – so hit the field before choosing anything!
How real is the ‘stay-green effect’? The biggest downside to spraying fungicide is the stay-green effect – and it IS real. Because your plants will take longer to dry down in the field, you may need to factor in additional drying costs post-harvest. Penciling this out will be the most effective way to choose whether fungicide will pay back in the end.
At the end of the day, the decision of whether to apply fungicide needs to be made on a field-by-field and hybrid-by-hybrid basis. While applying at a less-than-optimal time will still give you the benefit of yield protection, you likely won’t see a yield bump. The timing of application is a decision that has to be made quickly, so be sure to scout your fields as frequently as possible leading up to flowering.
Be sure to follow us on social media and subscribe to our YouTube channel to be notified when Part 5 of the 2021 Seed to Grain Series is live! You can also reach out to Agronomist Todd Farver directly for questions about your crop this year.