Statewide Iowa (RI) – With the corn and soybean harvest winding down, many farmers are turning their attention to fertilizer. Richard Roth, a nutrient management specialist with Iowa State University Extension, says the primary motivation for farmers to apply fertilizer in the fall is to spread out the workload. Spring rainfall and muddy fields can narrow the window for applying fertilizer and planting seeds. To prevent nutrients from washing into streams and rivers, Roth says timing is key.
Roth recommends farmers monitor the Iowa Environmental Mesonet’s soil temperature maps.
When the soil is warm and moist, microbes convert ammonium into nitrate, and without living roots to absorb nitrate, it can easily move with water and accumulate downstream. Between 25-50% of the total anhydrous ammonia fertilizer applied to fields across Iowa occurs in the fall, often to save time around spring planting.
KIWA Staff Photo
