It appears that every time you open a farm newspaper this winter you are faced with an article by a researcher or farmer stating how good or bad wide row spacings are. When asked why the row spacing effect on grain yield varied among the various studies done in Western Canada , Dr. Guy Lafond recently wrote in a paper for the Manitoba North Dakota Zero Tillage workshop Proceedings: "All field experiments have some inherent biases built into them. In some cases these can have significant influence on the results. Examples of biases in the context of row spacing studies might involve: (1) confounding effect of seeding rate (2) error in the calculation of effective harvest area (3) border effect which becomes magnified when only a few rows are used per plot (4) problems with fertilizer placement favoring one spacing over another due to availability or damage."
Regardless of yield there are other factors that may determine
whether a wide row spacing will fit into your
operation.
Advantages of wide row spacing.
Residue Management: The wider the row spacing the more residue you can clear with a hoe type seeder. This definitely has an impact if you are farming in the moister areas of the province where there is traditionally a large amount of straw is grown.
Water Conservation: This is important to the drier farming areas. you can trap more snow with taller stubble and hence increase soil moisture levels in the spring. It is also reported that stubble cut 10 - 16" can reduce wind speed at the soil surface by 60%.
Time required to seed: If you are pushed to the limit of your time in the spring to get all of your crop into the ground, moving from an 8' to 12' row spacing seeder allows you to increase your implement width by 33% with the same number of openers. The draft will be similar. You also have to make a judgment call on whether you believe you can have a better crop on the entire farm if you are able to seed it in a shorter time period compared to having some crop seeded early and some seeded late.
Weed Control: Some farmers have indicated that spot
spraying of particular weeds is easier with a wide row spacing.
Weeds are very easy to identify between the rows.
Disadvantages of wide row spacing
Swathing: If you plan to swath some of your cereal crops each year the wide row spacing will not work, especially on a dry year with a short crop. Most farmers that move to wide row spacing are committed to straight combining.
Fertilizer Placement: When you move to a wider row spacing the maximum amount of fertilizer that can be seed placed is reduced. Once you move to a 12" row spacing you can not apply all the nitrogen required for the crop with the seed. With these wider row spacing you need to have a seeder with double shoot capabilities or apply your fertilizer in a separate operation.
All of the trial that have been reported have used row spacings of 4" - 6" - 8" - 12" or 16" row spacings to compare. In the commercially manufactured drills on the market there is many 9" and 10" row spacings. Maybe these are a good compromise?
Whatever you choose for a row spacing on your seeder you can have a larger impact on yield with many of your other management decisions. i.e. rotations , herbicide applications, fertilizer rate and placement etc.