Spring irrigation of tall fescue for seed production

No information is available on irrigation management in tall fescue [Schedonorus phoenix (Scop.) Holub] seed crops. The objective of this study was to investigate spring irrigation effects on six cultivars of tall fescue managed for seed production. Field trials were conducted with three irrigation treatments: none (control), single irrigation to fill the soil profile to field capacity at anthesis, and multiple irrigations to maintain soil water deficit ≤50 mm below field capacity until the beginning of seed fill. Wet conditions in Year 1 prevented multiple irrigations, so only the single (78 mm) application was made. Dry conditions in Year 2 were conducive to both single (112 mm) and multiple (172 mm) treatments. Crop responses to single irrigation were the same as multiple irrigations. Fertile tiller number, spikelets panicle−1, and florets spikelet−1 were not affected by irrigation treatments. Irrigation × cultivar interactions for seed yield were evident in both years. Yield increases varied among cultivars and irrigation treatment, ranging from 15% to 47% in Year 1. In Year 2, seed yield in ‘Velocity’ was not affected by irrigation but was increased by 14% across other cultivars. Seed number and weight were independently influenced by irrigation and cultivar. Irrigation consistently increased seed weight, but increased seed number only in Year 1 which led to the greatest seed yield increases observed. There was no effect of irrigation on HI but WUE was influenced by irrigation × cultivar interactions. Tall fescue seed yield can be increased by strategically timed spring irrigation but the response is dependent on year and cultivar.

► First study to demonstrate that spring irrigation increases seed yield in tall fescue.
► Seed yield responses to spring irrigation varied among the cultivars tested.
► Increased number of seed was most responsible for the seed yield improvement observed with spring irrigation.
► Strategic timing of spring irrigation to support seed filling was more important for increasing seed yield than season-long irrigation.