Herbage productivity of a range of grass species under a silage cutting regime with high fertilizer nitrogen application

The productivity of fourteen grasses was measured under a silage cutting regime of four harvests per year for 3 years (1984‐86) with an annual fertilizer N rate of 360 kg ha⁻¹, applied at 120, 100, 80 and 60 kg ha⁻¹ for successive harvests. The grasses were: red fescue Festuca rubracvs Reptans, Dawson and Ruby, perennial ryegrass Lolium perennecvs Perma and Sprinter, Yorkshire Fog Holcus lanatuscommercial types I and II, smooth meadow‐grass Poa pratensiscvs Parade and Arena, creeping bentgrass {Agrostis stolonifera)cv. Penncross, crested dogstail {Cynosurus cristatus)cv. Southlands and rough meadow‐grass Poa trivialiscvs Dasas, Omega Øtofte and Sabre. Red fescue gave the highest dry‐matter (DM) production over the 3 years but because of low organic matter digestibility (OMD), its production of digestible organic matter (DOM) was lower than that of perennial ryegrass. Rough meadow‐grass was relatively low yielding in the first year and did not persist thereafter. Three‐year mean DM production ranged from 9‐22 kg ha”’(crested dogstail) to 14‐37 kg ha‐1 (red fescue cv. Reptans), while mean annual OMD values ranged from 0‐660 (smooth meadow grass cv. Arena) to 0766 (ryegrass cv. Sprinter). The mineral composition (P, K, Ca and Mg) differed among species; creeping bentgrass, crested dogstail, perennial ryegrass and Yorkshire fog had moderate to high mineral concentrations while smooth meadow‐grass had low concentrations. Mean two‐year (1985‐86) mineral composition (g kgDM⁻¹) ranged from 3‐1 to 40 (P), 234 to 31‐0 (K), 3‐8 to 6‐0 (Ca) and 1‐6 to 2‐6 (Mg), It was concluded that while red fescue and Yorkshire fog showed considerable potential for silage DM production, there is scope for breeding red fescue cultivars with improved digestibility and more winterhardy Yorkshire fog; characterization of their ensiling qualities would also be useful.