Harvest date and fertilizer effects on native and interseeded wetland meadows

Abstract

Studies of harvest date by fertilizer interactions on hay meadows are rare and none have been published for prairie meadows. Our objective was to evaluate the effects of initial harvest date (15 June, 15 July, and 15 August) and spring-applied N (0, 45, 90, and 135 kg ha-1) on first cutting and regrowth dry matter yield and forage quality from native and interseeded wetland meadow sites. Regrowth was harvested on all plots in late September. 'Garrison' creeping foxtail (Alopecurus arundinaceus Poir.) was interseeded on plots 4 years prior to application of treatments. Native vegetation was dominated by sedges (Carex spp.). Interseeded plots were dominated by Garrison creeping foxtail. Yield and quality on different dates and response to N were similar for vegetation types despite differences in duration of spring flooding between years. Harvest date by fertilizer interactions occurred for first cutting yield and crude protein concentration. Yield response to applied N ranged from 8.5 to 31.2 kg ha-1 kg-1 N. Fertilizer had no effect on digestibility and increased crude protein concentration only in herbage harvested on 15 June. Within levels of N, first cutting yield was about 60% of peak standing crop on 15 June and 90% on 15 July compared with 15 August. Greater plant growth rates and response to N after prolonged spring flooding compensated for initial differences between years by 15 July. Regrowth dry matter yield was not affected by spring-applied N and increased by about 43 kg ha-1 day-1 after initial harvest in both years. Sedge-dominated, prairie meadows are productive and provide predictable forage and wildlife habitat management alternatives.