Seed production of smooth brome grass as influenced by applications of nitrogen

Three sets of plots of smooth brome grass were treated with ammonium sulfate at five different rates of application; one set in April, a second in May, and the third in June. The experiment was carried out during the first seed year and repeated on a new set of plots during the second seed year. Nitrogen applied in April or May of the first seed year resulted in seed yields greater than the controls, whereas the same applications in June did not consistently stimulate seed yields. In the second seed year, applications in April resulted in marked increases in seed yield when compared to the control. The May applications were generally not as effective as those in April, while applications in June resulted in seed yields only slightly greater than the control. Lodging was evident with the highest rates of application of nitrogen in June in the first seed year and in April and May in the second seed year. There were no apparent differences between the treated and the untreated plots in the time of maturity of the seed. Forage production was stimulated most by the applications of nitrogen in May in the first seed year and by the April applications in the second seed year. The number of fertile tillers and spikelets per panicle were only slightly influenced by the applications of nitrogen- whereas, the number of barren tillers and florets per spikelet were significantly increased. In both years of the experiment the protein analyses showed that the protein content of the forage at the time of seed harvest consistently increased as the rate of application of nitrogen increased. June was the most effective date of application in the first seed year; whereas, April was the most effective in the second seed year. Only the heavy applications of nitrogen in April, May, or June in the first seed year were associated with increased seed or forage yields in the second seed year when no further treatment was applied.