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Grass Management Guidelines

Alfalfa-Grass mixtures

Approximately 85% of the alfalfa grown in New York State is sown in companion with a perennial grass. Our suggestion for what forages to plant is to let the soil, the environment, and the animal tell you what forages to grow. In New York State this means that alfalfa-grass is our ideal dairy forage crop, if the soil resource can support alfalfa. The impact of RR-alfalfa on the acreage of pure alfalfa in NY is not yet clear. If alfalfa will persist on a site for a reasonable number of years (usually a minimum of seeding year plus two years), then a winter-hardy, disease-resistant, leafhopper-resistant alfalfa variety should be matched with a perennial grass. In general, orchardgrass will be the most competitive with alfalfa, and timothy the least competitive. Some pure grass stands are also recommended for more manure management flexibility. Alfalfa-grass management is replaced by grass management when a stand drops below 50% alfalfa.

Grass Species

The following is our current ranking (based on results to date) for perennial grasses for various attributes (These rankings assume a low-endophyte tall fescue and a low-alkaloid reed canarygrass)

Ease of Establishment:

  1. Timothy
  2. Orchardgrass
  3. Smooth bromegrass
  4. Tall fescue
  5. Reed canarygrass

Tolerance to Wet Soils:

  1. Reed canarygrass
  2. Tall fescue
  3. Smooth bromegrass
  4. Orchardgrass
  5. Timothy

Regrowth Potential:

  1. Tall fescue
  2. Orchardgrass or Reed canarygrass
  3. Smooth bromegrass
  4. Timothy

Protein Content:

  1. Reed canarygrass
  2. Smooth bromegrass
  3. Orchardgrass
  4. Tall fescue
  5. Timothy

Potassium Content:

  1. Orchardgrass
  2. Tall fescue
  3. Reed canarygrass
  4. Smooth bromegrass
  5. Timothy

Overall Recommendation for Stored Feed for Milking Cows:

  1. Reed canarygrass or Orchardgrass
  2. Tall fescue
  3. Timothy
  4. Smooth bromegrass

Overall Recommendation for Grazing:

  1. Tall fescue
  2. Orchardgrass
  3. Timothy
  4. Smooth bromegrass or Reed canarygrass

Overall Recommendation for Dry Cow Forage:

  1. Timothy
  2. Smooth bromegrass
  3. Reed canarygrass
  4. Tall fescue
  5. Orchardgrass

Grass Varieties

As a dairy cattle feed, low endophyte tall fescue and low alkaloid reed canarygrass (‘Palaton’, ‘Venture’, or ‘Rival’) are necessary if using these two species. Assuming grass varieties are winter hardy, the primary selection criterion is heading date. If a large acreage of pure grass is planned, several varieties and/or species with a range in maturity should be selected for seeding in separate fields, to spread out the harvest window for high quality forage.

Manure Management

Manure alone will not provide enough N to meet the needs of intensively-managed perennial grasses during the first couple of years of the stand. However, after 2-3 years of repeated manure application, grass yields with manure have been similar to grass yields under recommended commercial N fertilization. The amount of N available to the growing crop from manure will be greatly reduced if a prolonged dry period follows manure application.

Nitrogen Management in Grasses

Economic return from N fertilization for early cut management for both timothy and reed canarygrass at Mt. Pleasant (assuming an $80/ton value for hay, and a fertilizer N cost of $0.28/lb N) ranged from approximately 200 lbs N/acre to over 400 lbs N/acre for 1994 and 1995. Obviously, environmental concerns will preclude N recommendations as high as 400 lbs N/acre. From model results, N fertilization above 200 lb N/acre may create problems with N balance in dairy cattle. Grass, in general, has yielded about 0.5 tons/acre less than alfalfa on good alfalfa land. However, orchardgrass (5 cuts) fertilized with the currently recommended N rate produced the same yields as alfalfa (4 cuts) under our tests. Protein content is significantly lower in timothy than other perennial grasses. Protein content is, in general, lower in regrowth, and the affect of N fertilization on CP eventually disappears with delayed harvest.

Nitrates in Grasses

Forages with nitrate concentrations under 1000 ppm nitrate nitrogen are generally considered safe for consumption by ruminants. It appears that fertilization of up to 240 lbs N/acre, when split-applied, will not normally result in forage nitrate levels unsafe for dairy cattle. When 240 lbs N was applied in the spring in a single application, however, nitrate levels were unsafe in the forage.

Potassium in Grasses

Grass varieties do not appear to be greatly different in K content. Grass species, on the other hand, show consistent differences, when there is adequate soil K available. If the soil has sufficient K available, then fertilization with N will increase K content of the forage. This is not true in soils deficient in K, where fertilization with N will actually decrease forage K content. Potassium content in the forage remains relatively high in the spring until late May and then declines with maturity. Potassium content of regrowth forage will often be considerably lower in K than spring-harvested grass.

Grass forage for dry cows

  1. Regular soil testing.
  2. Set aside fields lowest in K for dry cow feed (10 to 15% of total acreage).
  3. Avoid orchardgrass; consider timothy or smooth bromegrass. (Although with low availability of soil K, all grasses can produce low K forage.)
  4. Avoid all forms of K fertilization, including manure.
  5. Fertilize these fields with 100 lbs N/acre in the Spring and 50-100 lbs after 1st cut.
  6. Use a two-harvest management system.
  7. Harvest spring grass after flowering, harvest regrowth in the fall.
  8. Use grass regrowth as the forage for cows just prior to calving, but test for K content.
  9. If production declines over years due to low soil K, add some K fertilizer or manure.