By Scout Nelson
The recent dry weather and an unusually mild winter have accelerated the need for early nutrient management decisions among farmers.
In a Strategic Farming session titled "Let's talk crops," Ryan Miller, an Extension educator for crops, led a discussion with Dan Kaiser, an Extension nutrient management specialist, and Jeff Vetsch, a researcher at the Southern Research and Outreach Center.
They explored critical questions on when and how to apply fertilizer to achieve the best returns amidst current price fluctuations and cost considerations.
Given the current field conditions, the timing for applying essential nutrients such as phosphorus, potassium, and lime is ripe if they were not applied last fall. However, the lack of rainfall poses a risk as fertilizers could remain on the soil surface without dissolving, potentially leading to loss.
The discussion also covered the use of anhydrous ammonia with nitrification inhibitors, especially beneficial in south central Minnesota, to reduce nitrogen loss. Concerns were raised about the application of urea, particularly without immediate incorporation into the soil due to the risk of volatility losses.
Experts delved into the complexities of nitrogen management, highlighting the use of variable rate technologies and soil tests like the preplant nitrate test (PPNT) and the pre-sidedress nitrate test (PSNT) to refine fertilizer application strategies.
The conversation underscored the intricate relationship between nitrogen application rates, crop yield levels, and soil characteristics, emphasizing the goal of optimizing production while minimizing environmental impact.
The role of enhanced efficiency fertilizers, such as ESN (polymer-coated urea), and the use of nitrification and urease inhibitors in protecting against nitrogen losses were also discussed.
The panel addressed the impact of tillage practices on nitrogen application, the benefits and limitations of deep banding nutrients in strip-till systems, and the environmental considerations of broadcasting phosphorus and potassium without incorporation.
Cover crops like cereal rye were noted for their nitrate scavenging ability, though their contribution to nitrogen release for the subsequent cash crop remains uncertain in Minnesota's context.
The variability of soil potassium levels throughout the cropping season, influenced by crop demand and leaching, was another point of interest. Experts advised trusting soil test results despite seasonal fluctuations and dismissed the necessity of considering potassium base saturation in decision-making.
The session concluded with practical advice for implementing variable rate technologies and in-season sensing tools for nitrogen management, highlighting the importance of flexibility and responsiveness to changing conditions in nutrient management strategies.
Photo Credit -university-of-minnesota
Categories: Minnesota, Crops