Tips for optimizing soybean yield

Although weather has a big impact on yields, planning sowing is essential for optimizing soybean yield.

With adequate soil conditions, optimum pH, and well-managed compaction, the two management points most likely to increase your soybean yield are:

1. Planting date

2. Variety choice

Sowing soybeans before May 15 will get the maximum yield from your soybeans. The yield decreases by 4% during the second half of May, while sowing in June generates only 84% of the maximum yield of the season, according to our cumulative data since 2010 at Sollio Agriculture’s crop production research farm in Saint-Hyacinthe, Québec.

The choice of variety is essential for achieving high yields. However, selecting the best cultivar from 2020 does not guarantee the achievement of this objective in 2021.

New star varieties in 2020 benefited from perfect conditions and outclassed varieties with a history of yield stability during the previous years. How is it that varieties of soybeans that once ensured the profitability of Québec farms found themselves in the shadows of newcomers with no track record?
 

Looking back on the 2020 season

By analyzing the precipitation data from our weather station at our St-Hyacinthe research farm, the 2020 season was average in terms of seasonal precipitation. However, looking more closely at the data on graph #1, the 2020 season in Montérégie, Québec (yellow line), is the one with the driest months of May and June in recent history and with the most precipitation during the month of August. This is a yield-enhancing cocktail in soybeans due to the resulting absence of white mold, which usually steals the yield potential of varieties susceptible to this disease.

The no. 1 enemy of soybeans in Québec is white mould (caused by Sclerotinia sclerotiorum). Québec is the region in North America where the pressure of Sclerotinia is greatest. This is explained by our climate conditions, which favour the growth of the Sclerotinia fungus. The fungus develops in June, when soil conditions are wet and the temperature is cool, below 26°C. When these conditions are present during the two weeks before the soybeans bloom, the fungus germinates, grows and prepares to release its spores. The spores infect the sensitive soybean plants that flower a few days after the summer solstice. The infection period occurs during the first 15 to 20 days of July.
 

Precipitation from 2017 to 2020, weather station at Sollio Agriculture’s crop production research farm
 

Historically in Québec, under our normal seasonal conditions, soybeans with the best tolerance to white mold obtain the best yields.

Consequently, if your choice of soybean varieties for 2021 is based on the top performers for the 2020 season, it would be wise to introduce a fungicide into your management to achieve high yields with soybeans that lack a proven history under Québec conditions.

Applying a fungicide at the R2.5 stage, just before pods appear in one of the top four nodes of the plant, may help reduce the impact of Sclerotinia. This option, at a cost of around $80/ha, represents 4.5% of your yield potential gain. A new high-yield cultivar must have at least a 4.5% higher yield than varieties with a proven history before being profitable and justifying its place in your field.

The price of soybeans has risen sharply since the start of 2021, so selecting a soybean variety that has proven to be tolerant to white mould is a wise choice in risk management in 2021.

Katonda R2 and Hydra R2 soybeans have been industry leaders in Québec for several years. The stability of their performance over the years makes them first-choice cultivars to ensure soybean profitability in Québec. Katonda R2 and Hydra R2 have an extremely well-balanced agronomic profile with the highest tolerance to white mould on the market today.

Introducing new cultivars is an excellent way to push yields to new heights but only if they are introduced to about 20% of the seeded area. Achieving high returns begins with balanced risk management. The sowing date combined with the choice of a soybean variety that has demonstrated performance in the past is a guarantee of success.
 

Source: This article was originally published in French in the March 2021 issue of Coopérateur magazine.