Figure 1: Perennial ryegrass seed heads in a production field prior to swathing in Roseau County, MN.

Perennial ryegrass (Lolium perenne L.) is a common turfgrass used for home lawns, sports fields, and golf courses. To meet consumer demand, large quantities of certified seed must be produced, packaged, and shipped to retailers. The largest production state for grass seed is Oregon; however few people know that Minnesota is also a major producer of turfgrass seed. Perennial ryegrass seed production is an important component of the agricultural economy in northern Minnesota, encompassing over 30,000 acres. Currently, perennial ryegrass is grown as a winter annual crop, meaning it is planted in the fall and harvested the following summer. Severe winter conditions are typically the precursor to major yield reductions going from the first to second year of seed production making multi-year seed production unprofitable.

Figure 2: A swathed perennial ryegrass field in late July ready to be combined.

Multi-year production of perennial ryegrass could increase sustainability and profitability for Minnesota growers. For example, perennial agriculture typically requires fewer inputs such as fertilizers and tillage and can utilize more of the growing season when compared to annual systems. Because of benefits such as these, our research team at the University of Minnesota has been exploring the possibility of multi-year perennial ryegrass seed production by testing several alternative management strategies to improve winter survival and boost second year seed yield. Fall residue management treatments as well as several plant growth regulators were evaluated on second year swards of perennial ryegrass.

Figure 3: Much of the research on grass seed production is conducted at the Magnusson Research Farm north of Roseau.

Our results indicated that there was a large effect of both year and fall residue management on seed yield.  Plant growth regulators had a small effect on winter survival; however this did not influence final seed yield. Previous perennial ryegrass research has found that first year seed yields in Minnesota range from 697 to 1500 lbs ac-1 (Koeritz et al., 2013 and Koeritz et al., 2015). Managing residue using field burning achieved the most favorable second year seed yields in our experiment, ranging from 774 to 1142 lbs ac-1.  These results are encouraging and may persuade farmers that perennial production is a realistic option for them to consider.

Figure 4: Combines take up swathed perennial ryegrass and separate seed from the chaff and straw. Seed is then taken off field for further cleaning, packaging, and distribution.

In summary, economically viable second year perennial ryegrass seed production is possible in northern Minnesota using current winter hardy commercial varieties, proven agronomics, and appropriate residue management. This study was the first step in multiyear seed production; future work could focus on economical trade-offs and environmental benefits to perennializing perennial ryegrass seed production. 

This research was funded by the Minnesota Agricultural Experimental Station Variety Development Fund.

References:

Koeritz, E.J., E. Watkins, and N.J. Ehlke. 2013. A split application approach to nitrogen and growth regulator management for perennial ryegrass seed production. Crop Sci. 53(4): 1762–1777.

Koeritz, E.J., E. Watkins, and N.J. Ehlke. 2015. Seeding rate, row spacing, and nitrogen rate effects on perennial ryegrass seed production. Crop Sci. 55(5): 2319–2333.