Direct Seeding on Grey Wooded Soils

By Tim Nerbas,

SSCA Soil Conservationist

One of the first rebuttals farmers give when asked if they direct seed is "that may work for the soils in your area, but it won't work where I'm farming." This attitude prompted the SSCA to include a research site four miles northeast of Loon Lake, Saskatchewan.

The site is one of more than 20 "Do's and Don'ts of Direct Seeding" plots in Saskatchewan. Located at the Ag Canada research substation at Loon Lake, the site is situated in an area of little direct seeding activity.

Our goal was to demonstrate that direct seeding is a viable alternative for this area.

These grey wooded soils have little organic matter in the upper soil horizon. Typically in this area canola is not planted in the year following summerfallow. The risk of crusting on the soil surface results in reduced emergence. Producers in this region typically grow canola following wheat or barley to put residue in the surface soil. This rotation helps break up the crusting area creating accessible spaces for seedlings to break through the surface.

The Loon Lake plots included all of the following trials on both wheat and canola:

1) seed placed at the proper depth with 235 lbs of 34-17-0 fertilizer placed using a single side band opener

2) deep seeded with the same as (1)

3) deep seeded with 235 lbs of 34-17-0 fertilizer seed placed

4) the same as (3) but fertilizer coated with Agrotain

5) seed placed at the proper depth with 235 lbs of 34-17-0 fertilizer seed placed coated with Agrotain

We included a product called Agrotain in our comparisons. Agrotain is a urease inhibitor. When coated on the fertilizer, it slows the breakdown of urea to plant-available ammonium. This is desirable because during the conversion of urea to ammonium, ammonia gas is given off which can significantly damage germinating seedlings.

When everything was done correctly, with proper fertilizer separation and seed placement, we had our best plant counts.

Deep seeding wheat did not affect the results, but deep seeding canola significantly reduced plant numbers. Combined with seed placed fertilizer, deep seeding dramatically dropped the canola count.

The Agrotain coated fertilizer improved emergence numbers particularly when the seed placement depth was more ideal. Agrotain allowed seed placement of more fertilizer with a reduced risk of damage to the seedling.

Direct seeding's ability to maintain a level of residue in the soil surface is significant. It is this residue that will aid producers in their success with farming grey wooded soils.

The greatest benefit of these plots at Loon Lake is they demonstrate that direct seeding works and will work for those looking to change the way they seed.

Table 1

Loon Lake "Do's and Don'ts of Direct Seeding" demonstration plot

(Plant number counts per 1 metre length of row, 12 inch row spacing)