1 January 2009

4 minute read

 While we've harvested from 2 to 5 tonnes, and consistently realized average yields of 3+ tonnes of dry matter from oats planted in July and August after a harvested wheat crop, its been apparent that yield and quality can vary greatly as planting date, nitrogen fertilization, and perhaps even oat variety differ from each field planted. In an effort to more clearly define the differences in quality and productivity created by dates of planting, nitrogen application rates and seed source, plots were planted this year in cooperation with the Wolfinger family in Fairfield County.

The 12 acre field which served as the plot site was no-til planted on three different dates (July 22, August 6 and August 20) using two different seed sources (certified Armor oats and bin run "feed oats" which originated in Canada). Each planting date and each seed source received 4 different rates of nitrogen (0, 25, 50 and 75 pounds of actual N/acre applied as ammonium nitrate). Volunteer wheat and weeds were killed prior to the first planting with glyphosate.

The first planting on July 22 was done into adequate soil moisture. However, during the balance of the summer and fall each of the three plantings received below normal monthly precipitation. From July through November, Weather Station 1 in Lancaster received a total of 5.67 inches below normal precipitation.

At 60 days after planting, the highest yield experienced in any of the plots was the bin run seed planted on August 6 with 50 units of nitrogen applied per acre. Yield totaled 4.2 tonnes of dry matter analyzed to have 14.39 per cent protein and 54.22 per cent TDN.

At 60 days after planting, the lowest yields came from the plots which had no supplemental nitrogen applied. Dry matter yields in the zero nitrogen plots ranged from 0.6 tonnes to 1.9 tonnes of dry matter. The plots which received 50 units of nitrogen yielded 2+ more tonnes of forage per acre at a total cost of ~$35 per acre, or less than $17 per ton of additional forage.

Plots receiving both 25 and 75 units of nitrogen had similar yields suggesting that nitrogen rates exceeding 50 pounds/acre actually suppressed yield this year. This was true with all three planting dates and regardless the seed source used.

Our observations based on this year's plot work and 7 total years of experience include:

• Optimum planting date for oats from the perspective of yield is the first week of August. Early August plantings also result in the highest total amount of TDN produced per acre. Later plantings will be slightly higher in quality, but not enough to offset the yield advantage of early August planting. Planting in July reduces both yield and quality. The earlier oat plantings also exhibit more susceptibility to rust.
• Optimum nitrogen application rate is 40 to 50 pounds per acre. This application not only produces the highest yields, but at the present values of nitrogen, it's also the most cost effective rate. The 75 pound/acre rate of nitrogen actually appears to depress yields, and is certainly less cost effective.
• Bin run oats originating in Canada out perform, but possess similar quality at harvest as certified Armor oats.
• The optimum combination of productivity and quality of August planted oats arrives 60 to 75 days after planting. Oats planted in July mature more quickly and thus, rapidly decline in quality beginning 50 to 60 days after planting.
• Oats harvested 50-60 days after planting and while still in the boot stage of maturity will regrow and offer regrowth that may be mechanically harvested or grazed a second time.
• A weed control application of glyphosate is a necessary and cost effective practice prior to oat planting.

An additional advantage observed when using oats for an annual forage crop is the opportunity to capture the total tonnage produced with a single harvest cutting if grazing is not an option. It's also important to note that the 3+ ton yield of oats planted in early August after wheat and straw harvest which has been experienced consistently in Fairfield County the past 7 years, exceeds the 2.89 tonnes/acre produced in Fairfield County and the 2.78 tonnes of dry hay produced per acre in Ohio, on average, over the same time period..

December 2008