Understanding the mineral nutrient value of wheat residue

Authors: Adams, Curtis; Rogers, Christopher; MARSHALL, JULIET - University Of Idaho; HATZENBUEHLER, PATRICK - University Of Idaho; WALSH, OLGA - University Of Idaho; THURGOOD, GARRETT - University Of Idaho; DARI, BISWANATH - North Carolina A&t State University; LOOMIS, GRANT - University Of Idaho; Tarkalson, David

Submitted to: Crops and Soils
Publication Type: Trade Journal
Publication Acceptance Date: 9/27/2024
Publication Date: 10/25/2024
Citation: Adams, C.B., Rogers, C.W., Marshall, J., Hatzenbuehler, P., Walsh, O., Thurgood, G., Dari, B., Loomis, G., Tarkalson, D.D. 2024. Understanding the mineral nutrient value of wheat residue. Crops and Soils. WERA-103. https://doi.org/10.1002/crso.20409.
DOI: https://doi.org/10.1002/crso.20409

Interpretive Summary: Wheat is produced primarily for the grain, but wheat residue is a secondary byproduct that is increasingly harvested and sold. However, many of the benefits of keeping residue in the cropping system are often not well understood or are undervalued by producers, including recycling of mineral nutrients contained in the material. We conducted research to provide wheat producers with better information on the amount and economic value of mineral nutrients in residue. We found that there is a substantial pool of mineral nutrients contained in wheat residue, which is particularly concentrated in K. But there are also non-trivial amounts of N, secondary macronutrients, and micronutrients that can have high replacement costs. The total residue biomass content of these nutrients is linearly related to the amount of residue produced, so the consequence of harvesting residue, in terms of nutrient removal from the system, becomes greater as the productivity and yield increase. Using the data we collected, we developed tools to easily estimate the amount of nutrients contained in residue as a function of grain yield. Within the article, we describe how to use these tools. We also more fully discuss our residue nutrient results. Finally, we present economic analysis that illustrates the fertilizer replacement cost of nutrients in residue, should the residue be harvested.

Technical Abstract: There is a substantial pool of mineral nutrients contained in wheat residue, concentrated in K, which has substantial economic value. Given this value, it is important for wheat producers to weigh the relative benefits of residue harvest, which gives immediate but marginal revenue gains, and residue retention, which has multifaceted benefits that include substantial savings on future nutrient costs. Persistent removal of nutrients from agronomic systems through residue harvest affects soil nutrient availability in the short- and long-term, and the timing and magnitude of these changes will depend on the cropping system and soil.