Nitrogen Timing
How many meals do you have in a day? Today’s top dietitians say to maximize our body’s efficiency, we should be eating 6 or more times per day. Have you ever tried that? It is proven that if you do this, you will experience a higher energy level throughout the day, and will notice an efficiency in building lean muscle (with a moderate exercise routine) and a decrease in wasted calories (fat).
In many cases, we have been conditioned by our farming community to apply 100% of our nitrogen needs in one pass at one time. Sometimes, this one pass is in October when the days are still long and soil temperatures are in the mid 50’s. Did you know that the N holding capacity in an average Iowa or Illinois loam do not exceed 125 lbs of N per acre? Very similar to our body, the soil can only utilize so much at one time, without turning the extra into waste (or loss).
As I have learned in the past 15 years of studying soils and fertility, the easy road is not always the right road when it comes to applying nutrients like nitrogen. Some farmers say it’s a pain in the neck to plan on a second or a third pass across a field… “when one will do”… or will it?
Corn on Corn: The most obvious thing I’ve seen in my career when it comes to corn on corn production is that you must have the ability and the commitment to split apply nitrogen. There are many, many other factors, but if you are willing to take on the task of producing continuous or multiple years of corn, you must have a sidedress system in place. In many cases, 3 layers of nitrogen are necessary to make sure the corn has enough nitrogen at the right time. I pay very close attention to V4, V10-12, and R1-R6.
1st Year Corn: I don’t believe there is a “credit” for nitrogen toward your corn after soybeans. I think there is a combination of effects involving seed to soil contact, planter mechanics, residue and C:N rations that are more at play. I do believe that in a 50/50 corn/soybean rotation, 3+ applications of nitrogen are less critical than in corn on corn environments. However, if you are looking to maximize yields in your system, you need to think about the physiological needs of the corn plant throughout the season just the same as in a corn on corn environment.
Tools to use: Make sure that you are working with an agronomist willing and able to help you make decisions throughout the year. Late spring nitrate tests (LSNT) are a very common practice that most are familiar with. However, tissue testing and stalk nitrate tests are other tools that can be used to fine-tune any nitrogen program. I will be the first to admit, nitrogen management is a slippery animal, and there is no cookie cutter approach. Watch the rainfall, watch your soil temperatures, use the tools in your toolbox, and ask for help from a trusted source when necessary!
