Learning from progressive wheat growers: A case-study for the Wheat Yield Content in Kansas, US

Romulo Lollato1, Dorivar Ruiz Diaz1, Erick DeWolf2, Mary Knapp1, Dallas Peterson1, Allan Fritz1

1 Kansas State University, 2004 Throckmorton Center, Manhattan, Kansas, 66506, lollato@ksu.edu

2 Kansas State University, 4024 Throckmorton Center, Manhattan, Kansas, 66506


There is limited information on agronomic practices affecting wheat (Triticum aestivum L.) yield in intensively managed dryland systems despite the opportunity to narrow the existing yield gap (YG). We used a unique database of 100 intensively-managed field-years entered in the Kansas wheat yield contest during the 2010-2017 harvest seasons to i) quantify the YG, ii) describe wheat management, and iii) identify management opportunities and weather patterns associated with yield. We simulated wheat yield potential (Yw) using SSM-Wheat model for each field-year to estimate YG as the difference between Yw and actual yield (Ya), and used eleven statistical approaches to test the association of management practices and weather variables with Ya. Wheat Ya averaged 5.5 t/ha and simulated Yw averaged 6.4 t/ha, resulting in an YG of 0.9 t/ha (15% of Yw). High-yielding fields had lower maximum (Tmax) and minimum (Tmin) temperatures and greater cumulative solar radiation (RS) and precipitation during grain fill. Varieties susceptible to fungal diseases responded to foliar fungicide (0.8 to 1.4 t/ha) while resistant varieties did not. Seeding rate was negatively associated with Ya, as yield quantile 0.99 was 7.5 t/ha and decreased by 2.7 t/ha for every 100 seeds m-2 increase in seeding rate above 305 seeds m-2. In-furrow phosphorus fertilizer, previous crop, tillage practice, and nitrogen timing, were also associated with Ya. We conclude that fields entered in yield contests have closed the exploitable YG, and there are opportunities to improve Ya through improved management in regions with stagnant wheat yield.


The Australian Society of Agronomy is the professional body for agronomists in Australia. It has approximately 500 active members drawn from government, universities, research organisations and the private sector.

Photo Credits

David Marland Photography david_marland@hotmail.com Graham Centre for Agricultural Innovation, Charles Sturt University

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