Features Agronomy Soybeans
Challenging growing season for Ontario soybeans

December 11, 2014 - Horst Bohner of OMAFRA says that the weather in 2014 made for a challenging soybean growing season in Ontario. 

Despite several issues, the overall provincial yield will be one of the highest on record. Rains in July and especially August made up for a lot of other production issues resulting in surprisingly high yields. Yields reported to AgriCorp at this point show the provincial average will be around 46 bu/ac this year. 1984 was the first time Ontario grew 1 million acres of soybeans. The five year average at that time was 34 bu/ac. In 1997 acreage reached 2 million with the 5 year average at that time being 39 bu/ac. 2014 was the first time Ontario grew 3 million acres with an expected 5 year average of over 46 bu/ac after this season. This has been an impressive increase in both acreage and yields. Much of this increased yield over the last 30 years is due to the better genetic yield potential from plant breeding but growers should also be given full credit for their efforts to get the most out of seed yield potential. Soybean management has steadily improved over the last 30 years. The key factor in soybean yields is still the weather and the last few years have been favourable for soybeans despite concerns caused by the weather during the season.

Planting
Soybean planting did not get fully underway until the last week of May and continued well into June for much of the southwest. It was estimated that less than 10 per cent of the crop was seeded by May 24th in the southwest. Eastern Ontario made better progress with well over 50 per cent of the crop being seeded by May 24th. By June 5th less than 30 per cent of Essex and Kent were planted and as little as 20 per cent of clay soils in Niagara were planted. The majority of the provincial crop was seeded by June 10th. Seedbed conditions were a challenge as soils dried out quickly and turned extremely hard. In some counties fields dried to the point it was difficult to seed into moisture and plant stand issues resulted from a lack of moisture. Inadequate down pressure on drills and some planters resulted in shallow planting into dry conditions. However, replanting was necessary on only limited acres.

Growing Season
Soil applied herbicide damage was an issue this year. Generally, impacted plants produced new growth from axillary buds, but in sprayer overlap areas the plants were actually killed. A yield reduction to soil applied herbicide burn is uncommon and this year was no exception. In fact because of the lush growing conditions in July and August, those fields with lower plant stands or fields stunted from other stresses did better than fields with very thick canopies. Lush growth and thick canopies resulted in considerable plant lodging, white mould, and lower yield by season end. The 2014 growing season was the worst year in recent memory for poor root nodulation and nitrogen (N) fixation. This was a particular problem in first time fields but was also observed in fields with limited soybean history.

Soybeans are a subtropical species and for optimal symbiotic activity between the soybean roots and the rhizobia the soil temperature should be between 25-30 C. In a cool spring nodules can be extremely slow to establish on the roots and may not occur at all in first time fields. The inoculant that was put on the seed may actually die in the soil before the plant allows the bacteria to invade the roots. When conditions turn dry and cool immediately after
seeding on a first time field as they did in 2014, the bacteria never have the opportunity to establish themselves on the roots before they die out in the soil. This problem has occurred previously in cool years so the general recommendation is to apply two inoculant products to increase the likelihood of good nodulation on first time fields. This greatly reduces the risk of a nodulation failure. Problems with poor nodulation happened across a wide geography and it occurred with several different inoculant products so it was not a product failure.

Northern counties and Eastern Ontario were hit with a killing frost on September 18th and 19th. Considerable acreage had not reached full maturity by that date and suffered yield and quality losses. Seed size was severely reduced and some green colour was also retained in the seed. Yields in the extreme northern soybean growing regions did not yield well do to the poor growing season.

Soybean Pests/Diseases
White mould was a tremendous issue this season and could be found right across the province. Severely impacted fields suffered yield losses over 50 per cent. Eastern Ontario was more impacted than the southwest. No-till fields were less impacted than tilled fields. Fortunately, the majority of fields in Ontario suffered from only small infestations which did not cause major losses. The application of foliar fungicides that were sprayed early significantly increased yields. In some research trials a yield gain of over 8 bu/ac was found if two applications of fungicide were applied. Take note of fields with white mould to make future management decisions. Fields with white mould should not be seeded to soybeans next year. Do not keep seed from severely infected fields as the sclerotia (overwintering bodies) of the mould are about the same size as soybean seed and can infect next year’s crop.

Most of te province did not report aphids in high concentrations this year, except for Eastern Ontario where some acreage was sprayed. Glyphosate resistant weeds are becoming a significant production challenge in affected counties. This problem will put further downward pressure on the number of no-till acres in the province.

Harvest
Harvest was a challenge. Fields generally matured later due to the cool growing season and late planting. Frequent showers meant that the number of days when seed had time to dry below 14% seed moisture were very limited. For the first time in many years a large percentage of the soybean crop needed to be dried at the elevator. Growers in northern counties were not able to finish soybean harvest until December. Fortunately yields were generally higher than anticipated and the overall average will be one of the best on record.Challenges/Opportunities for 2015
Soybean acres continue to increase every year in Ontario. Soybeans are by far the largest row crop in the province and it’s expected that acreage will be well over 3 million in 2015. Many of these fields will be second year soybeans. Soybeans are hard on soil structure, remove a tremendous amount of potassium and are more disease prone if there is a history of many soybean crops in that field. Shorter crop rotations will mean soybean growers need to be even more vigilant in selecting disease resistant varieties, scouting their crop, and applying inputs when required. Significant harvest rutting occurred in wet fields which will need to be addressed this fall or early next spring regardless of the crop to be grown.

December 12, 2014  By Top Crop Manager