Seeding Rate Influence on Rainfed Maize Grain Yield and Components in the Western Corn Belt

CORE IDEAS: Maize seeding over 20,000 kernels ha–¹ seldom increased yield in water‐limited western Nebraska. Increased seeding rate increased the number of ears m–², which was compensated for by other yield components to reduce or maintain grain yield in western Nebraska. Primary yield components had greater effect than secondary yield components in water‐limted western Nebraska, compared with other studies under well‐watered conditions. Grain yield components were analyzed to determine the influence of seeding rate on maize (Zea mays L.) yield under rainfed conditions in the Western Corn Belt. The objectives were to compare maize yield and yield components at four seeding rates in Brule, Ogallala, and North Platte, NE, in 2012 and 2013. Research was conducted by planting multiple maize hybrids at 20,000 to 57,000 kernels ha⁻¹. Grain yield, ears m⁻², rows ear⁻¹, kernels ear⁻¹, kernels row⁻¹, 100‐kernel weight, and bulk grain density were determined. Path and regression correlation analyses was used to understand yield determination with seeding rates, and determine yield component relative importance. Seeding rates >20,000 kernels ha⁻¹ only increased maize yield in one environment, whereas decreasing yield by approximately 1 Mg ha⁻¹ in three environments. In the hot, dry 2012 growing season, ears m⁻², kernels ear⁻¹, and 100‐kernel weight had positive direct effects on yield for sites with silt loam and loam soil textures, but only the kernels ear⁻¹ for the sandy soil site. In the higher rainfall environments of 2013, positive direct effect of ears m⁻² with yield were present, but in the lower rainfall site, ears m⁻² had negative direct effect with yield. Based on the magnitude of the direct effects, the yield component ears m⁻² was most important for yield determination followed by the kernels ear⁻¹, and lastly kernel weight. Maize should be planted at 20,000 kernels ha⁻¹ in the Western Corn Belt to optimize grain yield and the number of ears m⁻² produced.