Seasonal Dry Matter Distribution and Annual Yields of a Cool‐season Sward as Altered by Frequency and Rate of Nitrogen Application1

Abstract

AbstractIn a 4‐year study we evaluated several frequencies, dates, and rates of nitrogen applications for stimulating growth of a Kentucky bluegrass‐orchardgrass‐white clover sward during midsummer.Stimulation of midseason production from the nitrogen variable was only obtained during favorable growing seasons. In such seasons the shift of nitrogen application from early March and early May to late March and late May delayed dry matter peak production by several weeks without reducing annual production.In general, seven applications of nitrogen, to obtain an annual total of 224 kg N/ha, were no better in stimulating midsummer growth than four or three. Likewise, four applications were of no advantage over three. However, when nitrogen levels reached 894 kg/ha, the more frequent application appeared superior to three or four. Little change in midseason dry matter production was associated with changing application date from late month to early month.Increasing nitrogen levels up to 448 kg/ha generally resulted in significant increases in dry matter production. However, when the relative yield distribution from the nitrogen treatments (1967) was compared to the check (plots receiving no nitrogen, but with adequate lime, P205 and K20) no difference was obtained.