Experiments measuring effects of ammonium and nitrate fertilizers, with and without sodium and potassium, on spring barley

Abstract

1. Thirteen experiments were made with spring barley from 1963 to 1965 on soils overlying chalk. They compared yields at ear emergence and of ripe grain from ammonium sulphate and from calcium nitrate, from sodium nitrate or sodium chloride or both, and from potassium nitrate or potassium chloride. Two rates of seedbed N were tested, though they were different each year, and in 1964 and 1965 N top-dressings were also applied. The amounts of N, K, Na and Mg in the green barley, and of N in the grain, were measured.greatly increased grain yields in all but one experiment, where the barley followed sugar beet. Calcium nitrate gave larger grain yields than ammonium sulphate in three-quarters of the comparisons, but gave much smaller yields than ammonium sulphate on one light soil in 1964 when much rain fell after the fertilizers had been applied. Grain yields from calcium, potassium and sodium nitrates were nearly the same.3. Na slightly increased grain yields in three and K in two experiments, but combine-drilled P or PK fertilizers increased them in every experiment.