Evaluating winter malting barley grain yield with fractional green canopy cover

摘要

Abstract Because of growth in the craft brewing industry, farmers in the eastern United States are planting winter malting barley (Hordeum vulgare L.) to meet demands for locally sourced grain. However, given that barley is a relatively new crop in this region, basic agronomic information relating to stand assessment is needed. This is particularly relevant in this region, as climatic variability from extreme temperature fluctuations during the winter and spring can reduce a barley stand, creating the need for farmers to estimate grain yield potential. The objective of the research was to evaluate the relationship between spring stem counts, fractional green canopy cover (FGCC), and normalized difference vegetation index (NDVI) and barley grain yield. Trials were established at five site‐years in Ohio, where seeding rate treatments of 0.75, 1.0, 1.5, 2.0 and 2.5 million seeds acre−1 were used to simulate a range of poor to excellent plant stands. All barley stand assessment methods were conducted in the spring at the Feekes 5 growth stage. Stem counts were correlated with FGCC and NDVI measurements (r = .76 and .74, respectively). Stem counts (R2 = .67) and FGCC (R2 = .65) measurements accounted for the greatest variability in barley grain yield. Specifically, FGCC ≤5% corresponded to yield between 27 and 39 bu acre−1, whereas 5 to 10% corresponded to yield between 60 and 89 bu acre−1. Fractional green canopy cover should be considered as a stand and yield assessment tool, as it reduces labor compared with stem counting techniques.