04 Dec, 2013
2013 HRSW 10" vs. 15" Row Spacing Trial


There are numerous selections to choose from when deciding on a new air drill. One such selection is row spacing. There is a frequently held belief that wider row spacing can limit yield potential in Hard Red Spring Wheat grown on the Northern Great Plains.
The purpose of this study is to compare the effects of 10” vs. 15” row spacing with all other factors created as equal as possible.


SeedMaster operates a 2000 acre research and development farm located in SE Saskatchewan. The soil is classified as a Black Chernozem, clay loam. Topography is categorized as gently to moderately rolling. Organic matter ranges from 3.8 to 4.9% with a ph of 6.9 – 8.0 on average.




The SeedMaster Research farm has access to a Leader SPEC Nova Ready TXB 100-15 with optional 20bu Front-Mounted UltraPro Canola tank and a Custom SPEC Nova XP 820. It is a 100’ wide toolbar with 80 openers on 15” row spacing. The toolbar houses a front mount 20bu on-frame tank that features individual row metering (IRM). The Nova XP 820 is a tow behind air seeder comprising of 4 compartments. 3 – 260bu tanks and 1 – 40bu tank. A John Deere 9630 tractor is used to pull the implement. A Viper Pro monitor controls drill/tank functions plus tractor guidance at RTK correction level.

A neighbour to the SeedMaster Research Farm owns and operates 2007 SeedMaster 43.33-10-TXB with a tow between John Deer 787 cart.  It is a 43.33’ wide toolbar with 52 openers on 10” row spacing.  The John Deere 787 is a tow between air seeder comprising of 2 compartments. 1 – 90bu tank and 1 – 140 bu tank.  Nh3 is normally pulled behind the toolbar to supplement fertilizer requirements but was not used for this trial.  A New Holland 9682 tractor was used to pull the implement. A Trimble FM750 monitor with EZ Steer Kit controls tractor guidance at WASS correction level.



Glenn HRSW was loaded into both the JD 787 and NovaXP from the same truck. Raxil MD seed treatment was applied at the recommended rate to the seed as the truck was being loaded. Both air seeders targeted a seed rate of 120 lbs/acre. The seed was directed to the seed knife on both toolbars at the SeedMaster factory depth setting of 0.75” below the packed soil surface.

A single granular fertilizer blend was loaded into both the JD 787 and NovaXP from the same truck.  Both air seeders targeted a total fertilizer rate of 200 lbs/acre (68-22-12-0).  The fertilizer was directed to the fertilizer knife on both toolbars at the SeedMaster factory setting of 0.75” below and 1.5” to the side of the seed.



Both air seeders traveled at the SeedMaster factory recommended speed of 5 MPH. Opener hydraulic down pressure on both units was maintained between 1000–1200 PSI while seeding. Both air seeders completed the trial on the afternoon of June 7th, 2013. 

Below is an as-applied map showing where the 15” row spacing SeedMaster applied seed. Green indicates on target rate, red indicates below target rate, purple indicates above target rate. White is where the 10” row spacing SeedMaster applied product. It can be seen that 4 passes were made with the 10” row spacing SeedMaster.



Below is a picture taken on July 3, 2013, 26 days after seeding.  10” row spacing is on left and 15” row spacing is on right.



It was observed after the crop headed, the 15” row spacing was approximately 1 - 2” taller than the 10” row spacing. Below is a picture of the 15” row spacing taken on Aug 8, 2013.



Below is a picture of the 10” row spacing taken on Aug 8, 2013.



A single pre-seed application and a single in-season application of herbicide were applied to both row spacing’s. Of the many farmers that visited this field during the growing season, some people thought that the 15” row spacing had weeds that were further advanced than the weeds in the 10” row spacing; some people thought that there was no noticeable difference. It is my opinion that if there was more weed pressure in the 15” row spacing, a yield penalty would result. 

Below is a picture taken on Oct 4, 2013 that shows the wild oats at time of harvest. The 15” row spacing is on the left, 10” row spacing on right. The picture may be slightly misleading due to the position of the sun.



Harvest of the plots commenced on the afternoon of Oct 4, 2013.  The trial area was squared off with the combine to eliminate the head lands and approximately 30’ into the AB lines.  Full combine widths were harvested and weighed using a grain cart equipped with load cells.  Below are the results.



The grade offer of #2 was received due to 50% hard vitreous kernels (HVK) caused by frost/heat stress (FRHTS). This was not surprising. The SeedMaster Research Farm received its first frost on the night of Sept 14, 2013. At that point, the crop was approximately mid-dough stage.

In year number one of the study, the 10” row spacing yielded higher than the 15” row spacing by 0.5% based on weight. It is my opinion that the scales on the grain cart used are less than 99.5% accurate. I would classify the yield difference as “statistically insignificant” in year # 1 of the study. 

It is interesting to note the protein difference between the 2 row spacing’s. We will see if a trend develops in future years. 

I consider the bushel weight and moisture differences to be “statistically insignificant”.


Future Considerations

Widening the row spacing has the obvious advantage of lower capital costs, fuel savings, reduced labour costs, increased opener trash flow characteristics, and improved timeliness of seeding operation. 

However, there are several other magnitudes to this subject; competition with weeds, discussions of seed bed utilization, incidence/severity of diseases, and ability to swath.

Personally, I found this study very fascinating as on our own farm we have naturally progressed from 9” – 10” – 12” – 14” and now to 15” row spacing. We have been very happy with 15” row spacing for the last 2 years and had not observed any negative side effects within our farming system. I look forward to replicating this study next growing season.

These results will vary in subsequent trials, depending on environmental conditions present throughout the growing season.

This trial should be repeated in time and multiple locations across a broad geography.



Special thanks to the following:
Hammy Tait – owner and operator of 10” row spacing drill. 
Hammy took the time and incurred cost to complete the 10” seeding portion of this trial. Without his help this trial would not have been possible.



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