Alfalfa winterkill and winter injury occurred across much of the province this spring. Many areas in lower risk western and central Ontario were hit hard with extensive damage. Winterkill is about 10% in the normally higher risk Ottawa Valley, well below what is a more typical 30% for that area. There were also scattered reports of alfalfa heaving.
Cool spring weather delayed forage crop growth and development, but this is changing quickly with some warmer weather. Many fields that were fall cut are seeing delayed growth that will likely result in reduced 1st-cut yields. Spring carry-over forage inventories are generally adequate, with the exception of high quality hay. In some parts of the province, there is concern developing about producing adequate forage inventories for the coming year.
Keep On Eye On Marginal Stands
Winterkill and other forage agronomic issues always results in some anxiety as farmers put together alternate plans to produce enough forage to feed livetock for the coming year. Some marginal stands were left to reassess for plant health and yield potential after an early 1st-cut. Dig some plants and cut open the root and crown with a knife. Watch for crown and root rots, brownish disclouration, spongy texture, a lack of secondary roots and nodulation, and assymetrical crowns. As a general rule, at least 55 stems per square foot provide a maximum yield. The critical level of 40 stems per square foot or less will result in a 25% yield reduction and should be rotated. Stem count numbers assume no significant additional yield contribution from grasses. Refer to “Check Alfalfa Stands This Spring and Make A Plan” https://fieldcropnews.com/?p=5845 and “Frost Heaving of Alfalfa” https://fieldcropnews.com/?p=6344 .
Alternate Forage Options
Wet soil conditions and delayed diagnisis of winterkill have also delayed the progress of new seedings past the optimum dates. New seedings done after early-May followed by hot dry summer weather are generally less successful, so we are past the optimum date for spring seedings. When winterkill is identified early enough, the best option is usually to replace the stand by an alfalfa seeding in a new field in the crop rotation, and planting corn in the winterkilled alfalfa field. However, it is getting late for successful seedings of alfalfa mixtures and cool-season forage species such as cereals and peas. Late seeding of these species do not do well in hot, dry summer weather. Summer seedings of alfalfa are typically more successful than late spring seedings. (“Summer Seeding Alfalfa” https://fieldcropnews.com/?p=3316 ) After late-May, a better option to produce a decent yield of summer forage is to plant some warm-season forage such as sorghum-sudangrass. Sorghum-sudangrass can yield well well with good agronomics and harvest management. (“Forage Sorghum-Sudangrass” http://www.omafra.gov.on.ca/english/crops/facts/98-043.htm)
N Application To Grass Stands
If an injured stand has good grass content, an application of nitrogen can significantly increase yields and increase protein levels, easily paying for itself. In healthy grass stands, 1 lb of N can produce an additional 25 – 40 lbs of hay. (“Apply Nitrogen To Grass Stands To Increase Yields” https://fieldcropnews.com/?p=6830 )
Considerable acres of winter injured alfalfa was repaired by no-tilling in some Italian ryegrass. Seed supply of Italian ryegrass has become limited. Westerwold ryegrass is a true annual that will head during the year of seeding, so timely harvest management is important. (“Annual Ryegrass For Stored Feed and Pasture” http://www.omafra.gov.on.ca/english/crops/facts/98-039.htm) A nitrogen application of 50 lbs/acre will improve yields of ryegrass as well.
Pasture Report by Jack Kyle
Pasture growth has finally started. Many producers now have livestock on pasture. Watch carefully that paddocks are not over grazed as the limited amount of grass can be quickly consumed. The first rotation is when you get your pastures set for the remainder of the season. Do not overgraze. Leaving 3 – 4 inches of grass behind will allow for rapid re-growth and the development of a strong stand. It may be necessary to move livestock twice a day for the first week or ten days to avoid overgrazing.
Assess your pasture now to determine if you will need an annual crop for mid- or late-summer grazing. Sorghum-sudan, brassicas, cereals, annual rye grass or corn are crops to consider. Grass-based pastures will respond to nitrogen application but this is usually most effective if applied in early- to mid-June. The suggested rate is 45 kg per hectare of actual nitrogen.