Cultivar, Nitrogen Rate, and Application Timing Effects on Irrigated Winter Malt Barley Nitrogen Uptake.

Barley (Hordeum vulgare L.) is the primary grain used for the production of malt. Malt barley typically carries a premium compared to feed barley, and the usability is directly related to grain nitrogen (N)/protein concentrations where excessive protein reduces the marketability. Despite greater yield potential, winter malt barley represents a smaller portion of production due to susceptibility to winterkill and diseases such as snow mold. The objective of this study was to compare three winter malt barley cultivars (i.e., Charles, Endeavor, and AB669) with various preplant fall applications (0 to 100 kg N ha^-1). Plant tissue samples were collected from a 0.9-m section of row early season to determine total N uptake. Early-season N uptake varied by cultivar and fall N application rate. Averaged across N rates, early-season nitrogen uptake of AB669 and Endeavor did not differ and were 43.8 kg N ha^-1 and 45.6 kg N ha^-1 where N uptake of Charles of 35.9 kg N ha^-1 was less than the other cultivars. Nitrogen rate response averaged across cultivar indicated an increase in N uptake (33.7 to 47.9 kg N ha^-1) from applications of 0 to 70 kg N ha^-1 where N uptake decreased at the 100 kg N ha^-1 rate (42.7 kg N ha^-1). The uptake of the 100 kg N ha^-1 rate was greater than the 0 kg N ha^-1 application, but less than the 70 kg N ha^-1 uptake and did not differ from the 35 kg N ha^-1 application. Results from the current study suggest that the maximum N uptake occurred at 70 kg N ha^-1. Final grain yield and protein data will be used with N-uptake data to evaluate the response of these cultivars to N application.