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PR-477

2002 Annual and Perennial Ryegrass Report

R.F. Spitaleri, J.C. Henning, G.D. Lacefield, and P.B. Burris

Introduction

Annual ryegrass (Lolium multiflorum) and perennial ryegrass (Lolium perenne) are high-quality, productive cool-season grasses used in Kentucky. Both have exceptionally high seedling vigor and are highly palatable to livestock.

Annual ryegrasses are increasing in use across Kentucky as more winter-hardy varieties are released and promoted. Annual ryegrass is used primarily for extra fall, winter, and early spring pasture. Winter growth occurs only during mild winters.

Perennial ryegrass can be used as a short-lived hay or pasture plant and has growth characteristics similar to tall fescue.

This report provides current yield data on annual and perennial ryegrass varieties in trials in Kentucky as well as guidelines for selecting varieties.

Important Considerations in
Selecting a Ryegrass Variety

Local Adaptation and Seasonal Yield. The variety should be adapted to Kentucky as indicated by good winter survival and good performance across years and locations in replicated yield trials such as those presented in this publication. Choose high-yielding varieties, but choose varieties that are productive during the desired season of use.

Annual ryegrass, also called Italian ryegrass, is planted in the fall and makes most of its growth from late February through June. In years when fall temperatures remain mild and ryegrass is planted in early September, there can also be substantial forage in October and November. Varieties differ in winter-hardiness, but this trait is undefined for many of the varieties in this trial. The winter of 2001-2002 was mild, and no varieties in this trial suffered winterkill. These results are no guarantee of future winter productivity or survival.

Perennial ryegrass is more winter-hardy and persistent than annual ryegrass (two- to three-year stand life) but less so than other cool-season grasses like tall fescue or orchardgrass. Hot, dry summers stress perennial ryegrass more than cold winters.

Seed Quality. Buy high-quality seed that is high in germination and purity and free from weed seed. Buy certified seed or proprietary seed of an improved variety. An improved variety is one that has performed well in independent trials. Other information on the label will include the test date, which must be within the previous nine months, the level of germination, and a listing of other crop and weed seed. Order seed well in advance of planting time to assure that it will be available when needed.

Important: When seeding perennial ryegrasses for horse pasture (of any kind), insist on an endophyte-free variety of perennial ryegrass. The endophyte level will be stated on a green tag on every bag of seed. Most forage types of perennial ryegrass are endophyte free, and most new turf types are infected. This endophyte is similar to the endophyte of tall fescue (which affects pregnant mares) but is different in its effect on horses. All horses grazing endophyte-infected perennial ryegrass may develop a neurological condition known as ryegrass staggers. In addition, infected perennial ryegrass may also produce ergot-type alkaloids like those in infected tall fescue.

Description of the Tests

Data from five studies are reported. In the fall of 2000 and 2001, an annual ryegrass test was established at Bowling Green and Lexington, respectively. A perennial ryegrass test was established in the fall of 2000 (Bowling Green and Princeton) and in the fall of 2001 (Lexington). The soils at Lexington, Bowling Green, and Princeton are well-drained silt loams (Maury, Pembroke, and Crider, respectively) and are well suited for ryegrass production.

Seedings were made at the rate of 20 lb/A into a prepared seedbed with a disk drill. Plots were 5 ft x 15 ft in a randomized complete block design with four replications. Nitrogen was topdressed at 60 lb/A of actual N in March and after each additional cutting. The tests were harvested using a sickle-type forage plot harvester. The first cutting was harvested at each location when all ryegrass varieties had reached at least the boot stage. Fresh weight samples were taken at each harvest to calculate dry matter production. Management practices for these tests regarding establishment, fertility, weed control, and harvest timing were in accordance with University of Kentucky recommendations.

Results and Discussion

Weather data for 2002 in Lexington, Bowling Green, and Princeton are presented in Table 1. After a wet spring, Kentucky experienced the fourth hottest and driest summer on record.

Ratings for maturity and dry matter yields (tons/acre) are reported in Tables 2 through 6. Yields are given by cutting date and as total annual production. Varieties are listed by total yield in descending order. Experimental varieties, listed separately at the bottom of the tables, are not available commercially.

Some annual ryegrass varieties planted in 2000 at Bowling Green continued to grow into 2002 (Table 2). They were rated for percent stand but not harvested for yield since weeds had invaded the weak stands. In most years, annual ryegrasses can be expected to die or become unproductive after mid-June in their first summer.

Several varieties in the new planting of annual ryegrass (Lexington) were extremely productive during the wet spring of 2002.

The perennial ryegrass tests contained several festuloliums that are hybrids of meadow fescue and perennial ryegrass, having some of the characteristics of both. Unlike annual ryegrasses, perennials should be productive under Kentucky conditions for two or more growing seasons.

Statistical analyses were performed on all data (including experimentals) to determine if the apparent differences are truly due to varietal differences or just due to chance. In the tables, varieties not significantly different from the top variety in the column for that characteristic are marked with one asterisk (*). To determine if two varieties are truly different, compare the difference between them to the LSD (Least Significant Difference) at the bottom of the column. If the difference is equal to or greater than the LSD, the varieties are truly different when grown under the conditions at the given locations. The Coefficient of Variation (CV) is a measure of the variability of the data and is included for each column of means. Low variability is desirable, and increased variability within a study results in higher CVs and larger LSDs.

Tables 7 and 8 summarize information about distributors and yield performance for all varieties currently included in tests discussed in this report. Varieties are listed in alphabetical order by species, with the experimental varieties at the bottom. Remember that experimental varieties are not available for farm use, while commercial varieties can be purchased from agricultural distributors. In Tables 7 and 8, a single asterisk (*) means that the variety was not significantly different from the top variety. It is best to choose a variety that has performed well over several years and locations. Remember to consider the relative spring maturity and the distribution of yield across the growing season when evaluating productivity of ryegrass varieties (Tables 2 through 6).

Summary

Selecting a good variety of annual or perennial ryegrass is an important first step in establishing a productive stand of grass. Proper management, beginning with seedbed preparation and continuing throughout the life of the stand, is necessary for even the highest-yielding variety to produce to its genetic potential.

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