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Ontario field crop report: July 24

July 24, 2014, Ontario – Soybean aphids have been found in eastern and south central Ontario, so keep watch of plants until they have reached full seed growth stage, cautions Horst Bohner in the latest field crop report from OMAF. 

Soybean growth has been slow with many fields only now reaching full flower (R2), reports Horst Bohner. Flowering was delayed this year due to later planting and cool temperatures. Flowering is driven not only by day length but also by temperature. The crop is one to two weeks behind in development compared to other years. Early planted fields are at the R3 growth stage (beginning pod). R3 is achieved when small pods are visible at one of the top four nodes of the plant. Weather conditions over the next six weeks are crucial to seed development and will play a larger role in final yield than the first half of the growing season.

Soybean aphids have been found in Eastern Ontario as well as south central Ontario. Numbers remain low but fields will need to be monitored until plants have reached the R6 (full seed) growth stage. This stage usually does not occur until the end of August, and will not occur until September in many fields this year. Slow plant growth this year is revealing more problem areas within fields than in years with rapid plant growth. Yellow patches of stunted plants can be caused by a number of factors including root rots, soybean cyst nematode, or nutrient deficiencies. Take the time to diagnose the issue so that the correct management strategy can be employed. Soybean cyst nematode damage is more evident than usual this year.

Summer seeding alfalfa-grass mixtures can be a good way to establish new fields so that full season yields can be harvested the following year, report Joel Bagg and Jack Kyle. The challenge with following wheat is getting the volunteer wheat controlled and the new seeding done in a timely manner. Competition from volunteer wheat can be a significant problem. One approach is to do some light tillage to encourage the grain to germinate, followed by a burndown with glyphosate seven to 10 days later. To survive the winter, alfalfa needs at least six weeks of growth after germination to develop a crown before a killing frost. Recommended summer seeding dates in areas > 2,900 CHU areas is Aug. 10 to 20 and 2,500 – 2,900 CHU areas is Aug. 1 to 10. Summer seeding works best on light to medium textured, welldrained soils. Lack of moisture for timely germination and growth can be a significant risk. If soil conditions are extremely dry and no rain is in the forecast, plans for summer seeding should be abandoned. Conserving soil moisture is critical, so use as little tillage as possible to create a fine, firm seedbed, drill the seed rather than broadcasting it, and follow with a press wheel or packer to ensure good seed-soil contact. Do not use companion crops with summer seedings, as they compete for available soil moisture and reduce stand establishment. Seeding alfalfa after alfalfa is not recommended because of autotoxicity and disease. 

Seeding oats in early August following wheat for an early October harvest can be a useful double-crop, low-cost option for producing additional forage supplies. Oats can make excellent feed when harvested at the correct stage of maturity and made into “oatlage” or baleage. Peas can be added where higher forage quality is required. The challenges can sometimes be lack of adequate moisture in August for germination and growth, and having dry enough weather in October for adequate wilting.  

Adequate moisture and cool temperatures have supported good summer grass growth across the province. Rest and recovery is the key to good pasture forage production, a multiple paddock system allows the pasture manager to rest paddocks and allow the pasture grasses and legumes to recover from grazing and to re-grow. A multiple paddock system also facilitates having the livestock eat all of the forage present rather than being selective in what is grazed. If they are selective the less palatable plants are left to mature while the palatable plants are over grazed and will over time diminish in the pasture. Fly numbers are starting to increase; flies can have a very negative effect on animal performance, take steps to reduce the fly population – dust bags, back rubbers or pour on insecticides are options.

Cover crop planted after winter cereal harvest is an ideal way to gain some extra pasture (or stored feed), as well as having significant benefits for the soil and subsequent crops. For fall grazing, summer planted oats or Italian ryegrass are two options. Stubble turnips might also be considered. If you are looking for spring 2015 grazing, consider cereal rye.

July 24, 2014  By OMAF


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