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Ontario field crop report: April 24

April 24, 2014, Ontario – Winter cereal kill is significant but spotty, writes Peter Johnson in the latest field crop report from OMAF. 

Winter cereals have been extremely slow to “kick” with a late start and cold spring so far. Winterkill is significant, but extremely spotty, with micro-environments in fields playing havoc with the crop. Agricorp reports a significant number of damage reports. Almost every field has a few small “holes” in it from winterkill. The real decisions come with fields that have more and bigger holes. Assessing injury has been more difficult than normal, as injured wheat has been extremely slow to green up. In many cases, it takes a full two weeks after the good wheat shows new growth before injured wheat shows growth and an accurate assessment of winter survival can be made. Winter hardiness can easily be seen across species, with winter barley the most damaged, rye the least injured, and wheat intermediate.

Wheat fields south of London are now advanced enough to make the call on winter survival. Wheat to the north and east of London is in varying stages of growth, needing up to another two weeks of decent weather before survival can be assessed accurately. Many growers are questioning why the wheat is going “backward” this spring, after they think it has begun new growth. In most cases this is the old overwintering leaves dying, and new growth in a few days will make the wheat look much better again. As frustrating as it is, patience is needed before making the final call.

With spotty stands, the value of under-seeded clover is even greater. Broadcast single cut red clover (even in May) to help compete with weeds in bare spots. If winterkill spots are large enough, barley is a good choice to be seeded into those areas. Areas left unseeded will be weed havens, so try to seed something.

Nitrogen applications began in earnest on Monday April 21, and are full steam ahead where ground conditions allow. It is important to manage poor wheat crops as if they were good wheat crops. Research and experience have shown that cutting N rates or skimping on what appears to be a poor wheat crop is not a good management decision. A poor crop gets poorer if it is not managed, but it can do surprisingly well if it is managed well. Very few spring cereals have been planted so far. Above: Winter wheat with spotty winter kill.

Weed control
Scout for the presence of Canada fleabane in all fields as there are 12 counties with glyphosate resistant populations. If you don’t normally manage weeds in winter wheat it is strongly urged that you manage this species so as to eliminate the production of its wind dispersed and highly mobile seed.

Canada fleabane found in fields that will be planted to soybeans need to be controlled prior to planting as there are no effective options to control glyphosate resistant populations once the soybean crop has emerged. If found in corn, the use of dicamba-based herbicides are most effective at controlling Canada fleabane.

The Guide to Weed Control can be downloaded for free here

Early reports of winter survival are encouraging, although crop development is about one week behind normal. In some areas there has been new growth with minimal amounts of heaving along with healthy roots and crowns.

Now is the time to check forage stands and determine whether to manage an existing stand, re-seed or rotate to a different crop. This article provides guidance on what to look for when assessing your alfalfa stand.

If winterkill is identified early, the best option is usually to replace the winterkilled stand by seeding a new forage stand in a new field in the crop rotation. Growing corn in the winterkilled alfalfa field allows you to utilize the 110 kg/ha nitrogen credit, in addition to the 10 to 15 per cent yield benefit that corn receives following alfalfa in the rotation.

Other forage options exist to address feed inventory shortfalls as a result of alfalfa winterkill and are discussed in more detail here.

April 24, 2014  By OMAF


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