Features Agronomy Soybeans
Early planted soybean fields starting to emerge

May 28, 2013, Ontario – Soil conditions have generally been excellent and early planted soybean fields have started to emerge, according to the latest Ontario Field Crop Report from OMAFRA.

Canola/Edible beans
Most canola has been planted into warm, moist soil conditions resulting in good emergence in five to seven days. Monitor emerged canola for flea beetles up to four leaf stage. Good growing conditions will allow canola seedlings to outgrow light to moderate flea beetle damage. Highest populations of flea beetles are in outside margins of fields, as adults migrate in from overwintering shelterbelts and fence rows. In some cases, only the outside area of a field may require treatment. Foliar products have only a short residual providing only three to four days of protection. Swede midge adults are now being caught in insect traps. A monitoring project has been established in most canola growing areas.

Cereals
Early wheat fields in the deep southwest are heading. The majority of the crop is at flag leaf emergence, and all herbicides should have been applied a week ago. Late wheat or wheat in shorter season areas is at first node. Rye for forage harvest is complete, with good yields and quality. Significant N loss is apparent on heavy clay soils where early N applications and 6+ inches of April rain occurred. Dry May conditions have exacerbated this problem. Wheat will respond to late N applications where N is deficient. In severe situations immediately applying additional N would increase yield. Tremendous leaf burn has occurred from spray applications of any nature although yield impact will be minimal. This has been caused by predominantly cool, cloudy conditions which result in thin cuticles more susceptible to leaf injury. Shallow planting depths and aggressive tillage, coupled with dry weather have resulted in extremely variable spring cereal stands in Eastern Ontario. Seeding into moisture is critical in achieving vigorous uniform stands. Early fields are tillering. All spring cereals are now at the critical stage for weed control.

Corn
Corn planting is virtually complete across the province. Corn planted at the beginning of May is at the third leaf stage. Localized intense rainfall events have reminded us of the importance of leaving 30 per cent residue cover on all soil surfaces. Replant decisions on some of the thinner stands may benefit from the Replant Decision Aid posted to www.gocorn.net. Be sure to get accurate plant counts of the current stand and to consider all of the replanting economics (yield potential, crop insurance, seed, herbicide and equipment costs, etc). Weed control should be the priority for those crops that are moving into that critical three- to four-leaf stage. Delaying herbicide applications past the fourth leaf stage in order to have more weeds emerged to the first pass is almost always the wrong decision. Producers applying UAN via streamer nozzles in the next few weeks should use the full pre-plant rate not the side-dress rate which is typically 10 to 20 per cent lower.

Soybeans
The majority of soybeans have now been planted, although considerable acreage is yet to be seeded in some areas. Soil conditions have generally been excellent and early planted fields have started to emerge. Although many producers roll fields immediately after planting, some rolling does occur after emergence. Rolling soybeans after emergence does not reduce yields, but keep these points in mind:

- Roll during the heat of the day to ensure that soybeans are limp. Soybeans are most turgid (stiff) during the morning hours, so rolling during this time will result in more plant injury.

- Do not roll soybeans that are in the hook stage since they are most vulnerable to stem breakage when just emerging out of the ground. The best time to roll soybeans is during the unifoliate stage since all beans will have emerged by then. Rolling can be completed successfully up to the second-trifoliate leaf stage.

May 28, 2013  By OMAFRA/Ontario Soil and Crop Improvement Association