Sorghum Nitrogen Timing for Oklahoma Growers

Sorghum can take a hard year, but nitrogen timing can decide whether fertilizer turns into grain or gets lost before the crop can use it. In this episode of Red Dirt and Round Bales, Dave Deken visits with Raedan Sharry Ph.D. of Oklahoma State University about delayed nitrogen management in Oklahoma sorghum. They discuss when holding nitrogen back can improve efficiency, why rainfall after application matters, and why yield potential should guide every fertility decision. Key takeaways: Delayed nitrogen can help high-yield sorghum fields put more nitrogen into grain. Lower-yield or late-planted sorghum may benefit more from early nitrogen, especially when tillering matters. Nitrogen needs to be available to the roots, not just applied to the field. Rainfall after application is critical, especially with surface-applied urea. Urea, UAN, and ammonium nitrate carry different loss risks depending on timing and conditions. Timestamped rundown 00:00–00:10 — Dave Deken opens the episode with a look at agriculture and rural life in Oklahoma.00:13–01:10 — The episode sets up sorghum as a dependable Southern Great Plains crop that handles heat and dry conditions better than many crops, while still needing good fertility management.01:10–01:55 — Dave introduces delayed nitrogen management and explains the basic idea: instead of applying all nitrogen before planting, growers may hold some back and apply it closer to when the sorghum plant can use it.01:55–02:37 — The episode explains that delayed nitrogen is not a blanket recommendation. High-yield fields may benefit, while lower-yield or late-planted fields may need nitrogen earlier.02:37–03:26 — Raedan Sharry Ph.D. explains that delayed nitrogen can help move more nitrogen into grain yield in higher-yield situations, but lower-yield sorghum may need nitrogen up front for tillering. He also notes that nitrogen should be coming into the plant by about 63 days after planting, based on OSU data.03:26–04:06 — Dave emphasizes that applied nitrogen is only useful if it becomes available to the plant, which often depends on rainfall moving fertilizer into the root zone.04:06–04:48 — Sharry explains nitrogen use efficiency: later applications can help reduce losses to biomass, leaching, volatilization, or the environment when yield potential is strong.04:48–05:22 — Dave shifts to nitrogen source, noting that urea, UAN, and ammonium nitrate behave differently when left on the soil surface.05:22–06:18 — Sharry discusses volatilization risk with urea and UAN, the lower volatilization concern with ammonium nitrate, and why rainfall within roughly 14 days is important. He warns that urea losses can increase quickly after about five days without rainfall.06:18–07:23 — Dave closes by reinforcing the main lesson: delayed nitrogen is useful in the right field, season, and timing, but poor stands, drought, late planting, or low yield potential may make waiting less valuable. Red Dirt And Round Bales website