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Seeding Into Sod

In northern Alberta, producers grow forages for hay and pasture and grow grass seed crops, such as fescue and timothy. When producers decide to terminate these crops or pastures, they can either direct seed into sod or use the traditional approach of plowing down the field, which requires several passes. Using extensive tillage requires an excessive amount of fuel and time and puts fields at risk to soil erosion.

In 2010, the Peace Agriculture Research and Demonstration Association (PARDA) at Fairview, Alberta initiated a demonstration project with two farmer co-operators to look at the benefits of sod seeding. As part of the Agriculture Research and Extension Council of Alberta’s (ARECA) Energy Conservation and Energy Efficiency (ECEE) project, the objectives were to examine the fuel usage and agronomic factors of seeding an annual crop directly into sod without tillage. The ECEE project has various demonstrations across the province and is working with farmers to collect fuel-use data.

“We worked with two farmers from the Fairview area to demonstrate direct seeding canola and peas into fescue sod,” explains Michelle Holden, PARDA research and program manager. “Although the Peace region suffered from severe drought conditions this year as well as the past two years, we were still fairly pleased with the results. Overall the direct seeding was successful and the farmers saw huge fuel savings, lower machinery costs and significant time savings.”

Co-operator Ken Rewerts, Kenro Enterprises Ltd. farms 3,500 acres near Fairview. The field selected for the demonstration was a quarter section separated by a strip of bush, with 40 acres of fescue sod and 60 acres of annual crops. Rewerts uses a 66-foot Seed Hawk air drill with a Quad Track tractor and has been using zero tillage for the past 10 years. He direct seeded canola into the fescue sod and into the adjacent 60 acres on wheat stubble for comparison.

“We sprayed the fescue out in the fall of 2009 with 2.3 l/acre of glyphosate, the old 360 equivalent rate, instead of discing or plowing like we normally would,” explains Rewerts. “In the spring we did a second application of two l/acre of glyphosate before seeding to control the regrowth of fescue. Fescue can be quite difficult to kill. We seeded Roundup Ready canola and with the extremely dry growing conditions, we only applied a one-half-litre-per-acre rate in-crop.” Rewerts seeded much slower, at about 3.4 m.p.h. as compared to a typical speed of 4.1 or 4.2 m.p.h., to minimize sod disturbance.

The crop did suffer some early frost damage but recovered during the growing season. The canola seeded to sod yielded 16 bu./acre and the canola on wheat stubble yielded 7.25 bu./acre. The results were surprising, however Rewerts thinks that the sod may have held more moisture early in the spring, improving the yields.

Rewerts would like to continue the demonstration to be able to do a longer-term economic comparison of sod seeding and yields. “Although the direct seeding was done in one pass compared to probably having to disc five times and certainly saves fuel, there are still the total costs of the glyphosate and the potential yield reductions in the first couple of years,” says Rewerts. “I did direct seed into timothy sod three years ago, which has actually turned out really good and would use direct seeding into sod again.”

Nolan Robertson farms 6,700 acres with his father near Fairview and provided a half section of fescue sod for the demonstration project. Robertson rented the land for the first time in 2010. He has a 72-foot Seed Hawk air drill and has been using zero tillage for several years. The previous landowner had sprayed the fescue sod with two l/acre of glyphosate in 2009 and then burned the field in the fall.

“We direct seeded peas into the fescue sod quite early on April 24 and then rolled the field,” says Robertson. “We used a seeding rate of between 3.5 and four bu./acre to ensure we got a good stand established. Although the crop did germinate very well, we noticed some damage to the plants at the end of May and expect it was some sort of residual chemical damage. We considered spraying out the crop, but decided to leave it. It recovered fairly well, with a yield of 20 bu./acre, about five to 10 bushels less than our other pea crops.”

Although Robertson hates to admit it, in the fall of 2010 he did disc down the demonstration plot. “The field was so rough and because it is quite large and I plan to rent it over the long term, I didn’t want to have to continue to deal with the rough conditions. However, because I direct seeded into the sod this spring, we only had to work it twice instead of four times without sod seeding plus a couple of heavy harrow passes. It saved us one or two passes of working the field, which is very viable.” Robertson does plan to direct seed canola into brome sod next year. “The direct seeding into sod did work well enough for us that we are planning to do it again.”

Holden and both co-operators were happy with the outcomes of the demonstration project. “The yields were pretty good, despite the serious drought conditions,” says Holden. “In terms of fuel usage, Roberston averaged 2.0 l/acre of fuel for the seeding operation. Rewerts averaged 2.03 l/acre at seeding, which is less than the other research results of 2.51 l/acre. The project showed that direct seeding canola and peas into sod can be done successfully, even under very dry conditions. The fuel savings were substantial and the yields were good for the year and growing conditions.”

Sod seeding rules of thumb

PARDA recommends a few rules of thumb for sod seeding.

1. The best time for forage termination is the year before seeding an annual crop. Glyphosate translocates best when forage is actively growing, in the early summer just before haying. The best kill of the forage occurs when the crop is almost mature.

2. Don’t skimp on the glyphosate. On forages, the full 720-g active ingredient per acre provides the best termination of grasses, legumes and perennial weeds.

3. Observe the preharvest interval. Give the glyphosate three to seven days to work before harvesting or pasturing.

4. Watch nitrogen fertility. It’s hard to get a good soil test on a forage or pasture field that has been terminated, because N mineralization is hard to predict, so bump up N rates by 25 per cent to make up for the lack of N mineralization.

5. Seeding equipment dictated by fertility requirements. A double-shoot opener or the parallel linkage-type openers that separate seed and fertilizer can work well as long as they are low disturbance.

6. Peas better than oats better than barley better than wheat. Peas can be seeded early in the spring and they can tolerate being seeded fairly deep. Another advantage is that because N fertilizer isn’t usually required, a simple, single shoot, narrow knife or disc opener can be used for seeding.

7. Seed slower; maybe seed deeper. No matter the opener or implement, slower seeding is necessary to help ensure that the sod isn’t disturbed very much.

This article was prepared in co-operation with ARECA. For more information visit the website at

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