Published on Monday, February 18, 2019
Many farmers perform fall operations at the conclusion of harvest to spread out their workload and/or properly prepare their fields for the next growing season. Given the challenges of the 2018 harvest season in some areas, many farmers' main focus was to complete harvest, which meant that traditional fall operations may have been left undone. This could leave many farmers with questions regarding how to react to the unfinished business.
Two tasks that many did not complete this past fall are anhydrous ammonia application and herbicide burndown. The good news? There are options for both of these tasks that can be executed this year with positive results. Some farmers may even discover that a new way is a better way! This article will focus on anhydrous ammonia application while a future article will discuss spring herbicide burndown options.
Anhydrous ammonia applications in the spring?
Given the warm, wet December weather, it may be beneficial that fall anhydrous applications did not occur. However, many farmers may be wondering how they should apply their typical fall anhydrous application in the spring. When anhydrous ammonia is injected into the soil, it will diffuse out in a circular pattern, creating a band. The diameter of the band will be impacted by soil type and soil moisture. When ammonia (NH3) is injected into the soil, it attaches to a hydrogen ion from water to form ammonium (NH4+).
This positively-charged ion allows ammonium to attach to negativelycharged soils particles (clay and organic matter) and limits its movement. Therefore, soils with adequate moisture will reduce the anhydrous band diameter. In very dry soils, the band will expand to a greater distance. Soil texture and organic matter can also impact the size of your anhydrous band. Coarse-textured soils will likely have a larger band. There is a danger of injury to young roots from this anhydrous band. Band size is why depth of application in the spring is important, especially as the application timing gets closer to planting.
My advice to farmers who are applying anhydrous ammonia close to their planting date (i.e. within 7 days) is to move their application deeper (8 in. if possible) to keep that band away from the immediate vicinity of germinating seeds and the seminal root system. From a timing perspective, I recommend farmers apply anhydrous ammonia more than three days prior to planting. In situations where this can’t be accomplished, my experience has taught me that the depth of application and soil moisture are more important factors than timing.
Here are some other management practices to consider when applying anhydrous ammonia in the spring:
• Do not make applications when soils are too wet, causing smearing and a lack of closing. This can lead to upward migration of the ammonia gas, putting it closer to the seed.
• If possible, split your nitrogen application. Full rates at planting can create a larger risk of injury. Sidedressing anhydrous ammonia is an extra pass across the field, but so is replanting.
• Try to apply at a slight angle to reduce intersection with the row if possible.
• The use of a nitrogen stabilizer in the spring with anhydrous ammonia can still be beneficial depending on your drainage and soil types. Heavier clay soils and/or soils with limited drainage have greater potential to benefit from the use of a stabilizer.
• Use this opportunity to try a reduced rate strip on your farm to learn if spring and/or split applications of nitrogen may allow a reduction in your overall nitrogen use rates. This inconvenience could be a great opportunity to learn.
If you have additional questions about this topic or other “unfinished business” from the fall, reach out to your local Beck’s agronomist, seed advisor or dealer. Stay tuned for a future article regarding spring herbicide burndown options.
Author: Jim Schwartz
Categories: CropTalk, 2019