Wheat mineral nutrient uptake, harvest indices, and grain density from a regional perspective

Authors: Adams, Curtis; Rogers, Christopher; MARSHALL, JULIET - 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

Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/7/2025
Publication Date: 4/28/2025
Citation: Adams, C.B., Rogers, C.W., Marshall, J., Walsh, O., Thurgood, G., Dari, B., Loomis, G. 2025. Wheat mineral nutrient uptake, harvest indices, and grain density from a regional perspective. Agronomy Journal. 117(3).Article e070066. https://doi.org/10.1002/agj2.70066.
DOI: https://doi.org/10.1002/agj2.70066

Interpretive Summary: Wheat takes up essential mineral nutrients from soil and fertilizer to support its growth, but we have limited understanding of nutrient uptake at broad scales, accounting not only for basic crop nutrient demands, but also for differences in uptake across environments and production settings. This is needed to better manage and model nutrients in wheat systems. In this project, we provided data and analysis characterizing wheat nutrient uptake in grain and the whole crop at a regional scale (Idaho, USA). We developed tools to estimate wheat nutrient uptakes that can be reasonably applied to most wheat production settings. Additional analysis of nutrient harvest indices (the fraction of each nutrient in grain relative to total uptake) provided information on internal nutrient dynamics of wheat and insights for ongoing improvement of grain yield and nutritional value in relation to mineral nutrient uptake and partitioning within the plant.

Technical Abstract: Research is lacking on wheat mineral nutrient uptake at broad scales, accounting for environmental variation, which is needed to effectively manage and model nutrient dynamics of wheat systems. Therefore, our primary objectives were to: 1) provide analysis and estimation tools characterizing wheat nutrient (N, P, K, Mg, Ca, S, Mn, Fe, Zn, Cu) uptake in grain and the whole crop at farm and regional scales; and 2) evaluate nutrient harvest indices (NutHIs)—nutrients deposited in grain relative to total aboveground uptake—as an indicator of crop nutrient relations/economies. There were clear linear relationships between grain yield and nutrient uptakes in grain and the whole crop. Functions describing the nature and error of these relationships are presented, along with more flexible estimation approaches. Median NutHIs approximated averages synthesized from recent studies and generally exceeded those from older studies, consistent with evidence that NutHIs have increased with wheat improvement. The NutHIs, except ZnHI, were generally positively associated with grain harvest index (HI) and not related to yield. Given that grain mineral density, an indicator of nutritional value, has declined over time, making ongoing progress in simultaneously improving grain yield and mineral density may depend on selection for increased crop nutrient uptake and partitioning to grain. This study also provided corroborative evidence that the wheat classes do not differ in grain mineral density. In summary, this research provides valuable data and tools useful for sustainable nutrient management and provides insights into the nutrient economy and nutritional value of modern wheat.