In-Crop Fall Weed Control

In the last ten years, there has been a significant increase in the amount acres sprayed with glyphosate before harvest.  There are many reasons for this practice.  Anyone of the reasons can increase profitability on a farm.  This practice should be considered on all acres on the farm.  To be able to use this harvest tool properly, it is important to understand what the potential results might be.

Using glyphosate in the fall started out as a way to control hard to kill weeds.  Quack grass has been virtually eliminated from the fields of the area with this practice.  Canada thistle, sow thistle and dandelions have been reduced significantly as weed problems in area fields.  Problem weeds like Canada bluegrass have been brought under control in many fields with fall spraying.  Cleaner fields are easier to manage and higher yields result when there is less weed competition.

Forcing a crop to mature earlier than nature allows it has also been a benefit in many years.  Early maturity improves crop quality.  This is result of better quality kernels that what would be seen if the crop was left susceptible to frost.  Also, immature kernels in a crop sample will have a tendency to reduce bushel weight.  This reduction makes the product less marketable.  Green kernels can result when frost damage hits a crop.  If used properly, fall spraying of glyphosate can eliminate the risk of green kernels in a crop.

Early maturing fields also have another benefit besides quality.  Getting started harvest sooner is always a bonus in the northern areas.  We only have so many days to harvest a crop in the district.  Last year the snow came early and there were some fields left out over the winter.   This always will have an impact on quality and yield.  Having a few extra days of combining should allow for combining to be done in a timely fashion.

The practice of using glyphosate has been used on all crops in the area successfully.  Canola, peas, wheat, barley and oats all can see benefits from this practice if it managed properly.  In a given year, all or one of the advantages described could work for the producer.  The key to making it work properly is to identify the proper timing for applying the product.

Proper timing for application is described on the label.    Read the product label.  There are publications that have been put together by the people that manufacture glyphosate.  Talking to your agronomist could be very beneficial in helping a producer attain the maximum benefit of fall pre-harvest spraying.

When I think back as to what change in practices that have eliminated weed problems in local area fields, this is the one that seems to have made the biggest change in the last 15 years.  If you are looking at using a tool that will grow you more bushels, this is one that should be on your list.


 By Dave Cubbon, P Ag