Crop residue management immediately after harvest is extremely important for achieving good tall fescue seed yields the following season. Reproductive tillers are formed in the autumn and early winter, and accumulated straw, debris, or stubble can impair tiller development seriously, thereby lowering seed yields.
Straw should be removed immediately by either baling or burning. However, burning is legally allowed only on a very small area in the U.S. Pacific Northwest, and it probably will be prohibited in the near future (see Chapter 18). Advance tall fescue straw often is leafy and makes reasonable winter forage, and many New Zealand growers have found a ready market for straw sales to dairy farmers. Beef cattle winter feeders in the United States use tall fescue or ryegrass seed straw if the cultivar grown was endophyte free or contained a nontoxic novel endophyte. Burning has the advantage of helping to control volunteer seedlings by killing seed on the soil surface, reducing blind seed disease infections, and removing residue that will affect the activity of soil-applied herbicides. Hare (1992) compared the effects of baling straw, hard grazing, and burning immediately after harvest, when followed by three autumn managements: no defoliation, cutting, or grazing. There were no differences in seed yield among the treatments.
Grass seed growers in the Willamette Valley of Oregon have adopted nonthermal replacements for open field burning. Since 1988, the area burned has been reduced by more than 70% without a loss in seed yield or quality. In most situations straw is baled and removed, and the remaining stubble is flail chopped and left to decompose on the soil surface. More growers are using flail chopping of all standing straw to avoid the loss of nutrients in the straw, particularly K, when removed from the field. In New Zealand, autumn regrowth after harvest can produce large quantities of high quality forage that can be valuable for finishing lambs or cattle, or for contract grazing of dairy animals.
Where volunteer seedlings or ryegrass are a problem in autumn and winter, a herbicide program must be implemented. Volunteer seedlings can be controlled readily with a range of herbicides such as simazine (6-chloro-N2,N4-diethyl-1,3,5-triazine-2,4-diamine), atrazine, terbulthylazine (N2-tert-butyl-6-chloro-N4-ethyl-1,3,5-triazine-2,4-diamine), or diuron.
Seed yields for forage tall fescue commonly range from 400 to 2000 kg/ha depending on the cultivar, whereas turf tall fescue seed yields between 2000 and 3000 kg/ha are achieved by experienced growers.