UPDATE BY MIKE PLUMER BELOW

Ryegrass Management

Mike Plumer, U of Il. Extension

Establishing ryegrass:

Fields need to be weed free when the ryegrass is seeded. In the fall, winter annuals are becoming established and are very difficult to see. Henbit, chickweed, cheat, downy brome and winter annual barley can become very competitive with the germinating ryegrass. If the field has a history of winter annuals, a low rate herbicide application before planting will ensure a clean field and quick start for the ryegrass. Select a field that will not have winter wheat in the rotation. No-till drilling will give the quickest stand of ryegrass with a reduced seeding rate and seed depth should be ¼ to ½”. Broadcast seeding with an airflow spreader allows ryegrass to be mixed in fertilizer and gives a uniform spread of the seed and fertilizer. This reduces the time and expense that drilling requires. The main drawback is that emergence is weather dependant and requires 3-5# more seed per acre. Fertilizer buggy seeding requires that everything be double spread to ensure that the ryegrass seed is uniformly distributed due to the difference in weight between the fertilizer and the seed.

Date of seeding:

The rule of thumb is as soon as possible after crop harvest. From Interstate 70 south, the seeding dates that have worked are September 1 to October 15th. (North of I-70 plant in September and use 30+ pounds of nitrogen or manure to stimulate growth.) Plantings after the October 15th date are subject to problems with stand loss, slow growth, and less winter hardiness. Earlier seedings may get too large and reduce the winter hardiness, which isn’t all bad. Drilling the ryegrass ensures quicker germination and emergence (often 7-10 days compared to broadcast), better root development, quicker stands in poor field conditions, improved winter hardiness, and therefore allows for a later planting date and lower seeding rates. The addition of 30# Nitrogen/ A. or manure at planting greatly increases the vigor of the ryegrass seedlings, significantly increases the top growth and establishment, and is recommended when seedings are delayed. This nitrogen fertility can be part of the fall fertilization program if diammonium phosphate is used and the nitrogen component is very little additional cost. Seeding rates for drill establishment are 12-18#/A. Broadcast seedings need to be 15-20#/a and increased by October 15th or later.

Growth and Development:

If the interest is in having a ground cover for the winter, then the ryegrass must be established before October 1st and needs 30#nitrogen/ acre. After this date most ryegrass will not develop more than 2 or 3 leaves going into winter. The stand may look thin and poor, but will develop roots all winter and grow rapidly in the spring. It has been observed that October planted ryegrass may only have 2 leaves by December, but measured root development has been 10-14” deep in fragipan soils. So long as the roots are not frozen, some development occurs during the winter. By April 9th and sometimes earlier, it has been observed that most of the root growth in depth has occurred. Rooting in first year no-till fields has been in the 28 to 31” range for fragipan and claypan soils. After 3 years of no-till crops and ryegrass cover crops each year, rooting has been 45-52” deep. At this time top growth is normally 6-12”.

Ryegrass Control:

Control of the ryegrass cover crop is best done when the plant is small, 4-8” in height and before the first node has developed, that means late March to the first part of April. Once the first node has developed the plant can and will have dormant buds that will regrow causing escapes or what looks like poor control. While one herbicide application can work, the herbicide program should plan for two applications. Annual ryegrass has the ability to regrow since it has such a large root mass even though it is small it requires full rates of herbicides. Low rates will often stress the plant making it more difficult to control. The early killing of the cover crop makes control easier, reduces the amount of residue to plant into, doesn’t have too much residue that impairs soil dry down and allows for significant decomposition of the ryegrass residue and the release any nitrogen or nutrients to the system. More mature ryegrass may take several years to completely decompose. It is important to not let the ryegrass go to seed or it may create additional control problems in the future. In corn production, apply 2-3 pints/a of glyphosate with ammonium sulfate and surfactant in late March to early April. If going into corn production, add 1 # /a simazine(Princep) for better weed control. Gramoxone plus simazine and atrazine has not given good control in the spring especially if the plant has developed 1 or 2 nodes. Princep, Balance Pro and Basis have shown good activity on annual ryegrass and trials have shown no problems when applied with the glyphosate burndown. After the crop emerges, escapes can be controlled with labeled rates of Accent, Steadfast, or Option. In soybean production, it is still recommended that the first spray be done in late March to early April and to use a glyphosate product at the rate of 2-3 pts/a with ammonium sulfate and surfactant. The use of Roundup Ready seed makes controlling escapes much easier. At planting time, the use of a burn down product like glyphosate gives very good control. Gramoxone plus Sencor following an early glyphosate burndown has at times given good control but depends on the plant stage of growth when the first glyphosate was applied. After the crop emerges, escapes can be controlled with Fusion, Select or Post Plus. Glyphosate can be used in RR soybeans.

The use of annual ryegrass requires good management and timing. It must be seeded on time and it must be sprayed on time. Late planting reduces the effectiveness and amount of soil benefits. Late spraying can result in poor control, more residue that is slow to break down, potential for reduction in subsoil moisture and a negative effect on crop yields and increased costs. Potential benefits are significant changes in soil properties, improvement in soil conditions to allow greater crop rooting, increased soil tilth and water infiltration, better soil aggregation, and potential for increased crop yields.

From "Growing Annual Ryegrass: What We Know to Date", by S.A. Ebelhar and M.P. Plumer, courtesy of the Oregon Ryegrass Growers Seed Commission.

Why Annual Ryegrass?

• Alternative to Rye grain (less "stemy" growth, easier no-till planting).
• Suppression of weeds.
• Scavenger for left-over nitrogen.
• Cover for erosion control.
• Mulch for moisture conservation.
• Increase organic matter.

Where does it fit?

• After corn or soybean harvest.
• Best fit is after corn harvest as a cover crop for soybeans

Fall Management

• Tillage or choppping corn stalks is unnecessary with good no-till equipment.
• Drill (desired) at 20 lbs./acre or overseed at 25-30 lbs./acre.
• Plant between mid-September and mid-October (earlier is better).
• Plant at 1/4" to 1/2" depth.

Spring Management

• Spray between April 15 and May 1.
• May be advantageous to allow growth to May 1 during wet spring.
• Allowing ryegrass to grow past May 1 may cause stem growth and seed head. (Never allow seed heads to develop.)

Herbicides

• RoundUp Ultra and Touchdown work well as burndown (use full label rate).
• Gramoxone kills tops but regrowth can occur.

Potential Drawbacks

• Cannot allow ryegrass to set seed.
• Can be a problem in wheat.
• Hoelon and Achieve herbicides give good, but not excellent control of annual ryegrass in wheat.
• Severe yield losses can occur if ryegrass not controlled in wheat.
• Too much spring growth of ryegrass can cause poor planter performance and result in reduced stands. Critical to observe that planter's ability to no-till drill.