How Long Can Winter Wheat Wait for Nitrogen Applications?
Cristie Preston, Ph.D.
Agriculture has always been an integral part of Dr. Cristie Preston’s life. She grew up in southwest Virginia and had interest in crop and animal agriculture since an early age. Once she began college, she initially chose to study animal science but switched to soil science. Dr. Preston attributes her decision partly to an influential professor who told her, “You can’t understand animals until you understand what they eat.” She received a Bachelor of Science degree in animal science and a Master of Science degree in crop and soil environmental science from Virginia Tech. Dr. Preston holds a Ph.D. in agronomy, focusing on soil fertility from Kansas State University. While completing her advanced degrees, Dr. Preston conducted more than six years of field and lab research. Dr. Preston has experience in laboratory research measuring volatility loss from urea-based fertilizers. Her field research has focused on phosphorus availability and the interactions with tillage and placement. She also has extensive experience in working with large data sets and analysis. Her main priority is helping growers to identify yield-limiting factors and fix those issues as cost efficiently as possible.
A wet early spring can always make it challenging for farmers looking to apply nitrogen to winter wheat. Following winter dormancy, wheat begins to “green-up” as temperatures become warmer. To maximize yields, many farmers apply nitrogen at this growth stage to match nitrogen uptake. With the chances of yet another wet spring, how much time do farmers have to make nitrogen applications before yields are affected?
An update to a previous article from Oklahoma State University shows that farmers may have longer to make applications than previously expected. Results show that pre-plant applications of nitrogen may be cheaper, but in-season applications tend to result in higher yield. In-season applications, if made before the end of March (approximately Feekes 6-7), can still result in the highest yields. The closer nitrogen is available to peak uptake levels, the greater chance for maximizing yields.