“Hot Streaks” Improve Fertility Program
We are gearing up for planting here at Peterson Farms. I’ve been looking at new things to try this spring to improve our planting accuracy and our fertility program. Over the winter you should have been reviewing last year and evaluating your system. How was your crop? Did you have any fertility issues? If so were they related to the year’s drier soils with less uptake? Or were they deficient due to higher populations and not feeding the crop?
Last year’s growing season was very different than what we’ve experienced in recent years. Nitrogen management was different due to the warmer soils and reduced rainfall. In 2012, we could produce 180bu corn on 120lbs of Nitrogen due to better mobilization from the soil. In 2011, with the wet early season we had, it took 180lbs of N to reach 120bu/ac.
Nitrogen management really comes down to timing; the timing of the application is almost more important than the actual rate used. With increased early rainfall in our heavier soils, denitrification becomes a major issue losing the N to the atmosphere. Our lighter soils normally have the opposite problem losing N to leaching. Timing is critical in both of these scenarios if we can apply the N as close to plant uptake as possible.
Large losses are easy to see, but how do we know if we’ve lost 15-30lbs of N in our fields? The field may show symptoms by becoming not as green, but it is not always visual enough to catch. That’s why putting a “hot streak” of Nitrogen – 300lbs or more – in a strip, creating a non-deficient check, to compare against is a good idea. Nitrogen loss is a problem we can address to fix yield after symptoms have been noticed.
Hot streaks also work for some of our other nutrients. Most of our soils have an abundance of Potassium, with soil test levels in the 300-600ppm range. NDSU recommends a K application for any soils testing less than 240ppm. Are we accessing all of this K though? Last year we noticed more K deficiencies than in the past with the drier soils we had. Corn plants need soil moisture to take up K and this was an issue in a large part of our region in 2012. Potassium uptake is greatest in corn after V6 and is very rapid. This is a critical time for determining yield, and if a K deficiency is shown (necrosis or yellowing on the outer edges of the leaves) yield has already been lost. Applying a hot streak of K is another good check to verify your system is working and you are not leaving bushels in the field. We noticed more stalk integrity issues in 2012, especially in the low rainfall areas. I would attribute some of this to a K deficiency.
Hot streaks do not need to be applied in all your fields. Pick out some representative locations on your farm that give an overall indication, by soil type and drainage, of how your fertility program is working for you this summer.
