Winter annual cereal crops for forage are greening up very nicely thanks to the warm weather over the last several weeks.
Over the next several weeks before stem elongation, you will be deciding how much nitrogen to apply, and by the end of April, checking fields to select a harvest date. Nitrogen rates and harvest timing greatly effects forage yield and quality.
Nitrogen is not only a driving factor of yield but an even bigger driver of crude protein; it has little effect on digestibility. A study from New York found on average cereal rye removes 121 pounds of nitrogen with an average dry matter yield of 2.37 tons.
Selection of the most economical nitrogen rate revolves around yield potential, species planted, manure application history and soil drainage.
When a fall application of manure was made containing over 120 pounds of nitrogen on well-drained soils, and the crop was planted before Oct. 1, multiple studies have found little yield benefit to spring-applied nitrogen at green up to yield.
A linear increase was found through in crude protein from about 12% CP at zero nitrogen to 20% CP when 120 pounds of spring nitrogen was applied. Even though crude protein greatly increased with nitrogen fertilization, the economic return was often negative.
On poorly drained soil with a history of manure applications, a spring nitrogen application of 50-60 pounds at green up improved both yield and crude protein.
When the field did not have a fall manure application, on average the most economical spring nitrogen rate was 70 pounds per acre, but some fields saw returns with nitrogen rates as high as 120 pounds per acre.
On average winter annual cereal crops need 15.5 pounds of spring nitrogen per ton of forage dry matter produced. Utilizing higher rates than required may leave nitrogen in the soil for the following crop, but also increase the potential for lodging, which will cause harvest challenges.
Lodging is also affected by harvest timing and species. Rye is the most likely to lodge followed by triticale then wheat. There are large differences in lodging between different varieties of the same species.
Harvest timing has drastic effect on forage yield and quality. In 2020, we had a trial looking at the change in wheat, rye, and triticale as they matured from Feekes 10.0, head in the boot, to Feekes 10.5, head fully emerged but not in pollination yet. All species were treated the same with 50 of nitrogen applied at green up.
We found that on average, a half ton of dry matter was added with a delayed harvest from Feekes 10.0 to Feekes 10.5. Cereal rye was the fastest to mature in just 6 days with triticale maturing slower and wheat taking 15 days between harvest.
Between the two harvest dates, crude protein decreased 2-2.3 percent with triticale experiencing the least decline. Triticale also had the smallest decrease in total digestible nutrients as a measure of energy only decreasing 3 points compared to cereal rye which decreased 10 points.
There was also a sharp increase in NDF across all species with a 9 point increases in wheat and a 14 point increase in cereal rye. Each of these winter annual cereals remove about 5 pounds of P2O5 and 23 pounds of K2O per ton.
When selecting the correct nitrogen rate and harvest timing knowing your livestock’s nutrient requirements is important. For lactating cows, higher crude protein and digestibility is the goal.
Applying 50-70 pounds of nitrogen at green up and planning to harvest all species between Feekes 9 and 10 will allow you to have the best forage possible.
For heifer and dry cow rations, a delayed harvest at Feekes 10-10.5 may provide more tonnage and high enough quality feed. If harvest is delayed further, forage value will peak again when the grain is in soft dough stage.
At this point, you are maximizing non fiber carbohydrates instead of crude protein and digestibility. Late harvest forages will store much better as silage since it is very hard to get the soft dough grain dry enough at this point for dry hay and fermentation as baleage is often poor.
