Optimizing Wheat Harvest Cutting Height for Harvest Efficiency and Soil and Water Conservation

Winter wheat (Triticum aestivum L.) productivity is frequently limited by water availability and degraded by wind erosion. Managers of harvest operations must balance soil and water‐conservation benefits of maintaining sufficient stubble height with the risk of losing grain yield due to unharvested spikes below the combine cutting height. This study calculated the relationship between expected harvest losses and conservation of soil and water at various combine cutting heights. Mature wheat spike height frequency distributions for 5 yr were collected for different tillage and residue‐cover levels. Wind‐velocity profiles were measured for different stem frequencies and heights at three sites with harvested wheat stubble. Potential evaporation of water was calculated by PENFLUX, a Penman‐type energy balance model. Potential soil loss was computed from the relative friction velocity (RFV). Stem heights were generally normally distributed, regardless of year or treatment. Quantifying RFVs at the soil surface and relative evaporation rates showed that combine cutting heights