Over the past two summers the Ontario Crops Research Centres New Liskeard (formerly NLARS) and Winchester have been conducting an oat agronomy trial and testing three different varieties with four main variables: row spacings, seeding depths, split nitrogen applications, and plant growth regulators. The trial amounted to over 1000 experimental plots. The 2021 data is not yet available, but the 2020 data yields some interesting results.
The first test compared rows of oats planted 5 and 7 inches apart. The narrower rows resulted in an average yield increase of 11% across the trial. In addition to the yield effects, the narrower rows saw no increase in lodging or decrease in grain quality, and a recent Agriculture and Agri-Food Canada study found that narrower rows also reduced weed pressure.
The second test compared the effects of three different sowing depths: the OMAFRA recommended one inch, as well as two and three inches. A delay in emergence was noted, for each half inch deeper the seed was sowed it took an extra day for the plant to emerge. The trial showed that seeding deeper than recommended had no effect on yield or lodging, despite that increase in time to emergence for the deeper sown oats.
The goal of the split nitrogen applications and plant growth regulators trial was to minimize lodging. Lodging occurs when the plant stem breaks, usually because the plant has grown too tall or too heavy to be able to hold itself upright. This reduces yields, makes the oats hard to harvest, and can expose the plant to diseases.
Applying too much nitrogen at once can result in lodging, so this trial tested splitting high nitrogen applications of 80 pounds per acre and applying either two thirds of the nitrogen pre-plant and one third in season, or vice versa. Treatments of no nitrogen at all, all of the nitrogen pre-plant, or all of the nitrogen in-season.
The treatments showed no significant difference in yield or protein, possibly as a result of naturally high nitrogen levels in the soil. The nitrogen application of one third pre-plant and two thirds in-season dramatically reduced the lodging score, compared to the opposite treatment.
The testing of the plant growth regulator (PGR) also had the goal of reducing lodging. The Moddus PGR product, which was tested in this trial, is intended to strengthen the stems of the oat plants to support increased growth of the head without lodging. Oat plots with nitrogen rates of 0, 40, 80, 120, and 160 lbs/ac were treated with the PGR and were assessed for yield and lodging. The PGR had a modest effect on yield and a more significant effect on reducing lodging for each nitrogen rate. Using the Belgian Lodging Index, where a score of 0 means the plots are not lodged and 9 means they are completely lodged, the plots treated with the PGR ranged mostly between scores of 1 and 2, with one treatment extending up to 4. The plots that weren’t treated with the PGR had much more variable and higher rates of lodging, ranging up to a 6 and 7 on the scale.
In summary, to increase yield without increasing lodging, row spacings can be narrowed down to 5 inches. To reduce lodging without affecting yield, split nitrogen applications and PGRs can be used.
A full report on this project will be released once the 2021 data is available.