Nutrient Management
Managing P and K with High Removal, Low Crop Prices, and Increasing Fertilizer Prices
Antonio Mallarino, professor emeritus, Agronomy, Iowa State University
Wednesday, 10:50 AM – 11:40 AM in Bishop C
Wednesday, 12:50 PM – 1:40 PM in Bishop C
The presentation will address producers concerns about cost-effective ways to optimize P and K management with currently high crop yield and removal with harvest when crop prices are low while fertilizer prices are increasing by providing practical options.
Strategies to Minimize Dissolved P Losses in No-Till
Antonio Mallarino, professor emeritus, Agronomy, Iowa State University
Wednesday, 1:50 PM – 2:40 PM in Bishop C
No-till management is a good and low-cost conservation practice to reduce soil and sediment-bound P from fields. However, the proportion of dissolved P in runoff or tile drainage increase potentially affecting freshwater quality and impairing the Gulf of Mexico further. The presentation will provide crop, soil, and fertilizer management strategies to alleviate this drawback of no-till management.
Meet N-Fertilizer Needs in 2026
Sotirios Archontoulis, professor, Agronomy, Iowa State University; and Mitchell Baum, technical project specialist, Agronomy, Iowa State University
Wednesday, 1:50 PM – 2:40 PM in Skinner A
Wednesday, 4:10 PM – 5:00 PM in Bishop AB
Since 2022, the Iowa Nitrogen Initiative has conducted over 1,000 on-farm nitrogen rate trials with over 200 farmers across the state of Iowa. Dive into the agronomic science behind what we’ve learned about forecasting the economic optimum N rate and how you can make data driven decisions to save money and meet crop needs.
Manure: A Complete, But Uncertain Fertilizer
Daniel Andersen, associate professor and extension specialist, Agricultural and Biosystems Engineering, Iowa State University
Thursday, 9:00 AM – 9:50 AM in Skinner A
Thursday, 11:20 AM – 12:10 PM in Skinner A
Manure continues to serve as a full-package nutrient source, but questions about its predictability, availability, and alignment with crop needs are growing. This session will examine how we assess, value, and apply manure in crop systems. We’ll explore whether long-standing tools, like PMR 1003, and the P-Index are still enough or if today’s nutrient availability, timing, and emissions questions demand deeper insights.
Sulfur in Corn and Soybean: What We Know and are Learning from the Iowa SulfURNET
Larousse Dorissant, postdoctoral research associate, Agronomy, Iowa State University; and Richard Roth, assistant professor and extension nitrogen specialist, Agronomy, Iowa State University
Thursday, 9:00 AM – 9:50 AM in Skinner B
Thursday, 10:20 AM – 11:10 AM in Skinner B
Sulfur has become an increasingly important nutrient for corn and soybean production in the Midwest. This presentation will provide a practical overview of the sulfur cycle, sources, sampling, and management strategies farmers can use to make informed decisions. Updates from the Iowa SulfURNET (Sulfur Utilization Research Network) will also be shared to highlight the latest research findings from across the state.
From Field Sample to Farm Decision: Making Sense of Nitrogen Tests
Richard Roth, assistant professor and extension nitrogen specialist, Agronomy, Iowa State University
Thursday, 2:20 PM – 3:10 PM in Bishop AB
Thursday, 3:20 – 4:10 PM in Bishop AB
Nitrogen testing can provide valuable insights, but only if you know how to sample correctly, understand what the lab is measuring, and apply the results on your farm. This session will cover common tests such as the fall stalk nitrate test, late-spring nitrate test, preplant nitrate test, and potentially mineralizable nitrogen test. Participants will walk away with practical guidance on how to interpret results and turn them into confident, profitable nitrogen management decisions.