Thomas G. Chastain

Figure 1. Annual ryegrass. (T.G. Chastain photo)

Seed yields of several important Willamette Valley grass seed crop species have increased over the last 36 years (Fig. 2).  Seed yield increases in the region over this period have ranged from 261 lbs/acre for annual ryegrass to 1024 lbs/acre for tall fescue.

Figure 2. Grass seed yield trends in the Willamette Valley (click to enlarge)

These increases in seed yield are the result of better crop management, technological advances, and genetic improvement.  The modest change in annual ryegrass seed yield is likely the result of fewer new cultivar introductions and the fact that much of the acreage of annual ryegrass is grown from saved seed or from volunteered stands.  The reduction in field burning acreages in the Willamette Valley during the 1990s and the elimination of the practice for most of the perennial ryegrass and tall fescue seed crop acreage in recent years have not had any appreciable effects on seed yield of these crops.  However, current rules for burning maintain the availability of burning for much of the Willamette Valley Chewings fescue crop.

Acreages of some Willamette Valley grass seed crops such as perennial ryegrass and tall fescue have increased dramatically over this period but have declined again with the recession and general economic downturn of recent years (Fig. 3).  On the other hand, acreages of other grass seed crops such as annual ryegrass and Chewings fescue have remained stable over time and have showed little in the way of major acreage shifts.

Figure 3. Grass seed crop acreage trends in the Willamette Valley (click to enlarge)

Losses in perennial ryegrass and tall fescue seed crop acreages during this downturn have been replaced by growers turning to wheat and other crops.  But annual ryegrass seed crop acreages have not varied appreciably because this crop is predominately grown on soils with drainage characteristics that do not permit economic cultivation of wheat or other crops.  Chewings fescue is grown largely in the hills near Silverton where wheat and other crop possibilities are likewise limited because of steep slopes, erodible soils, and poor yield potential for cropping alternatives.

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