Forage Crops – Eric McLenaghan
Including a forage crop in rotation has many benefits, one of which is weed control due to most forages highly competitive nature. In many cases, when a weed problem has become too severe and other options just do not seem to work, a forage crop may be the answer. An established forage stand is very good at outcompeting annual weeds, and can be used to deplete a weed species seed-bank. The fact that forages are often cut for hay also contributes to weed control, because if cutting is timed correctly it can make sure weeds are not allowed to set seed and reproduce.
When planning to use a forage it is important to know what weeds are problems in the field. Forages are can be very competitive against some weeds, but may increase the population of others. In the year of establishment it is a good idea to use direct seeding, as this tillage will stimulate weed seed germination so that they can be outcompeted.
The benefits of forage crops may not be fully realized until after a few growing seasons, so planning which fields are planted to them is important. It should also be noted that due to their deep rooting system forages may reduce subsoil moisture for later annual crops. It can also be complicated to establish and terminate forage stands.
Costs associated with this weed management technique would be that of mainly just seeding the crop and making sure the stand is established. This practice is economically feasible as it means even though the field is not producing crops, it can still bring in income from a hay market or as being used as cattle feed.
I believe this option is useful because forage crops also have the added benefit of rejuvenating nitrogen in soils. Using them in rotation can also be useful for reducing pest and disease occurrence, while still having an economic benefit.
Entz, M.H., W.J. Bullied, and F. Katepa-Mupondwa. 1995. Rotational benefits of forage crops in Canadian prairie cropping systems. J. Prod. Agric. 8:521-529.
Saskatchewan Soil Conservation Association. 2000. Soil Facts: Forages in Rotation. [Online] Available: http://www.ssca.ca/agronomics/pdfs/foragesinrotation.pdf [ 4 February 2014]