Planting Date and Nitrogen Rate Effects on Spring Malting Barley

Planting date ( D ) and N fertilizer have been shown to significantly increase spring malting barley ( Hordeum vulgare L.) grain yield and protein when grown under dryland production systems where water is limiting. This study was conducted to determine D and N rate effects on grain yield, grain protein, kernel plumpness and yield components of spring malting barley grown under a production system that minimized crop water stress. Between 1984 and 1988, ‘Klages’ barley was planted at 2‐wk intervals between 15 April and 19 May (expressed as days from 1 January) at Powell, WY on a Garland clay loam (fine, mixed, mesic, Typic Haplargid). Ammonium nitrate was applied at rates of 0, 67, 134, and 202 kg N ha −1 . Early planting increased kernel weight 14% and kernel density 16% compared to late planting; spike density was not affected. Increasing N from 0 to 202 kg N ha −1 increased spike density 39% and kernel density 63%; kernel weight was not affected. Grain yield decreased from 4.7 to 4.0 Mg ha −1 with later planting date and increased from 3.4 to 4.9 Mg ha −1 as N rate increased from 0 to 202 kg N ha −1 [Grain yield (Mg ha −1 ) = 6.92 − 0.027( D ) + 0.007(N); R 2 = 0.89 ** , significant at P = 0.011. Grain protein was unaffected by D and increased from 102 to 121 g kg −1 as N rate increased from 0 to 202 kg N ha −1 [Grain protein (g kg −1 ) = 127 − 0.194(0) + 0.095(N); R 2 = 0.96 ** ]. Kernel plumpness decreased from 97 to 95% with delayed D and was unaffected by N rate [Kernel plumpness (%) = 106 − 0.076( D ) − 0.005(N); R 2 = 0.80 ** ]. Spring barley grain yield and kernel plumpness response to D and N rate for furrow irrigated cropping was similar to responses for dryland cropping. However, contrary to dryland results, grain protein was not affected by D when grown with minimum water stress.