The Effect of Seeding Rate and Nitrogen Fertilization on Barley Yield and Yield Components in a Cool Maritime Climate

Soil and climatic conditions in Newfoundland are on the margins of agricultural capability, and almost all feed grain is imported. The overall objective of this work was to develop guidelines for the production of barley in Newfoundland, with the goal of establishing modern cropping recommendations. We conducted a 4-year study near St. Johnʹs to examine the effect of seeding rate and topdress ammonium nitrate (N) fertilization rate on Chapais six-row barley (Hordeum vulgare L.) yield components and grain yield. Increasing seeding rate from 200 to 380 seeds m-2 did not alter grain yield in any year. Increasing topdress fertilization from 0 to 60 kg N ha-1 increased spike density m-2 at harvest, resulting in linear increases in grain yield in all years. Highest N rates had greatest lodging in two years. Based on our results, agronomic recommendations for eastern Newfoundland now include barley seeding rates of 250 ± 50 seeds m-2, with topdress applications up to at least 30 kg N ha-1.