Drier-than-average conditions in many parts of the Midwest during the 2024 growing season presented challenges for farmers, including reduced crop yields and shifts in soil nutrient dynamics.
However, research from the University of Nebraska–Lincoln (UNL) reveals a silver lining: Dry conditions have resulted in higher-than-normal levels of residual soil nitrogen. With careful management, this leftover nitrogen can become a valuable resource for improving fertilizer efficiency in the upcoming planting season.
How Drought Conditions Create Residual Soil Nitrogen
Nitrogen is an essential nutrient for crops, but it needs water to be effectively absorbed by the soil. During a drought, the process slows down or stops completely, leaving nitrogen unused.
Over time, the surplus accumulates in the root zone, particularly when there is less leaching or denitrification caused by rain. The leftover nitrogen can then become a cost-saving resource for the next planting season.
Why Soil Sampling Matters
Soil sampling is an important tool for farmers aiming to maximize the residual nitrogen left after a dry growing season. Conducting these tests provides a clear understanding of how much nitrogen remains in the soil and helps farmers plan fertilizer applications more effectively.
The timing of soil sampling plays a role in its accuracy. While some farmers may opt for fall testing to get an early read on nitrogen levels, spring sampling is often more reliable. This method accounts for nitrogen shifts or losses that may occur over the winter, providing farmers with a more accurate assessment of the available nitrogen for crops.
Depth is another factor. Nitrogen can accumulate beyond the surface layers, particularly in drought-affected soils, so testing down to two or three feet ensures a comprehensive view of nutrient availability. This deeper sampling captures nitrate levels that might otherwise go unnoticed, allowing for more precise adjustments.
Once the results are available, farmers can use the data to adjust their fertilizer strategies. By factoring in the residual nitrogen already present in the soil, they can reduce unnecessary applications, lower costs, and minimize the risk of over-fertilizing, which could lead to environmental issues like groundwater contamination.
Making the Most of Residual Nitrogen
Using soil test data, farmers can refine their fertilizer strategies to make the most of residual nitrogen after a dry season. Reducing fertilizer applications at the start of the growing season helps avoid overapplication and keeps input costs in check. As crops develop, nutrients can be applied incrementally to match the plants’ needs at each growth stage, ensuring efficient use and minimizing waste.
Precision tools like variable rate applicators and nitrogen calculators further enhance the process by delivering nutrients exactly where they are needed. These technologies ensure even distribution across the field, reducing excess in some areas while preventing shortages in others. By combining strategic planning with precision technology, farmers can achieve better efficiency, healthier crops, and optimized yields.
Leverage Residual Soil Nitrogen for Cost-Effective Farming
When managed correctly, residual soil nitrogen is a valuable asset for farmers facing rising fertilizer costs and environmental pressures, enabling them to save money, support sustainable practices, and meet crop nutrient demands without excess. By prioritizing soil sampling and using data-driven strategies, you can start the season with a clear plan for success.
Contact your local John Deere dealer to learn more about tools and equipment to help you make the most of your soil’s nutrients.