Features Cereals Seeding/Planting
Go early with ultra-early seeded durum

Some durum farmers seed by calendar date. Others when pussy willows come out. Or when aspen grooves are in full leaf. Or by the crop insurance cut-off date. Or when soil temperatures get above 10 C, as suggested by some agricultural departments. But there’s a paradigm shift happening with research from Agriculture and Agri-Food Canada (AAFC): seeding durum ultra-early – even before robins have migrated back to the Prairies in the spring.

“Seeding ultra-early is a strategy to help deal with changing climate and increased average growing season temperatures,” says Brian Beres, research scientist with AAFC Lethbridge, Alta. “We’ve got over 50 site years of research showing that seeding hard red spring wheat at a soil temperature of 0–3 C in the top two inches of soil is the sweet spot for yield and yield stability.”

In Beres’ research on Canada Western Red Spring (CWRS) wheat, seeding at a soil temperature trigger of 10 C produced the lowest yield at 68 bu./ac. (4.57 tonnes/ha) with the highest yield of 74 bu./ac. (4.95 tonnes/ha) occurring when spring wheat was sown at 0–2.5 C. He attributes the difference to shifting the critical growth period – the onset of stem joint through 10 days after flowering – one month earlier when high temperatures can partially be avoided.

CDC Defy seeded ultra-early had the highest net return increase at $59/ac.

Based on the success of CWRS wheat, Beres turned his research attention to durum wheat with a three-year research program funded by the Saskatchewan Wheat Development Commission running from 2022 through 2024. Two experiments were conducted at Lethbridge, Alta. and Saskatoon, Indian Head and Swift Current, Sask.

The first experiment compared trigger temperatures at a two-inch depth (5 cm) at intervals of 0, 2, 4, 6, 8 and 10 C. The earliest seeding date was at Lethbridge on February 9, 2022 for the 0 C trigger planting. That treatment had 69 days below 0 C after seeding with the lowest temperature recorded at –29 C. The five durum varieties compared were AAC Donlow, CDC Defy, CDC Desire, AAC Stronghold and AC Transcend.

The second experiment compared CDC Defy, AAC Stronghold and AC Transcend seeded at one or three inches deep. Triggers were dormant seeded in late fall/early winter when soil temperatures fell to less than 0–2 C. Spring temperature triggers were 0 to 3, 5, 7.5 and 10 C.

Preliminary results favour ultra-early seeding

Durum seed quality was high with ultra-early seeding.

While the full analysis is still underway, preliminary results for the first experiment show that ultra-early durum yield and stability mirrors the results for CWRS research. No yield difference was observed among AAC Donlow, CDC Defy and AAC Stronghold, but CDC Desire trended lower and AC Transcend had significantly lower yield.

Beres says the downward yield trend observed with later plantings is likely attributed to sensitivity to abiotic stress such as heat and drought stress, as crop growth and development are not completed before the onset of heat or drought in semi-arid Prairie locations.

There was a trend to higher grain protein with warmer trigger temperatures, but the preliminary results showed it was not linearly or quadratically significant. The first two years of data showed the 0 C trigger had the lowest protein content at 14.4 per cent and the 10 C planting had 14.7 per cent grain protein.

Fall dormant seeding was less successful
The second preliminary experiment results showed that fall dormant seeding had the lowest yield by a large margin. Similar to the first experiment, the earliest spring soil trigger of 0–3 C yielded the highest with a linear decrease in yield as soil trigger temperatures increased. There was a trend for CDC Defy to have higher yield than AAC Stronghold and AC Transcend.

The one-inch seeding depth favoured higher yields across all seeding temperatures in the spring. However, the three-inch seeding depth had higher yields when durum was dormant planted in the fall. This may have been the result of shallow, dormant-planted durum germinating when temperatures fluctuated over the fall/winter months. Yield stability for dormant-planted durum was also highly variable.

“Dormant planting in fall tended to produce binary results – either the crop establishment was acceptable and produced okay yield or it was a train wreck. For example, the dormant treatment produced acceptable grain yield at the Lethbridge dryland site in the 2022 season, while it was entirely unsuccessful in the 2023 season,” says Beres.

Soil ‘trigger’ effects on grain yield of Canada Western Amber Durum (2022-24). Chart courtesy of Beres et al., 2024.

Overall, Beres says that both experiments indicate that ultra-early planting of durum has no detrimental effect on Canada Western Amber Durum (CWAD) grain yield in western Canadian growing environments. Planting durum wheat as early as when the top two-inch soil temperatures are between 2 and 6 C consistently resulted in high and often stable grain yield, regardless of variety.

“This isn’t to say you will improve yield with ultra-early planting every year, but you will almost definitely protect it while enjoying a lot of intangible benefits. It’s obviously easier for us in Lethbridge to plant at 2 C every year compared to say Indian Head, and that’s reflected in the variability of the yield data, but I think we’ve all been surprised at how most areas in Alberta and Saskatchewan have been able to go much earlier than what was considered feasible and free of risk,” says Beres.

Cultivar effects on yield responses to ultra-early and dormant-planted durum (2022-24). Chart courtesy of Beres et al., 2024.

In conducting an economic analysis of these two experiments for the first two years, and based on 2023 prices, ultra-early planted durum produced higher net returns. Averaged across all locations, cultivars and sowing depths, an increase of $45/ac. ($112/ha) occurred when planting at 0–3 C soil trigger temperature compared to delayed plantings when the soil temperature was 10 C. The increased returns were even higher for CDC Defy with a net return increase of $59/ac. ($146/ha).

For farmers wanting to try ultra-early seeding, Beres recommends seeding shallow, consider a fungicide/insecticide seed treatment and laying down a fall-applied soil residual herbicide to replace a spring pre-seed burnoff.

“What ultra-early seeding programs capture is some of the benefits of a winter wheat system. By shifting the critical growth period into June, it helps to avoid flower abortions from higher summer temperatures, resulting in increased yield and yield stability. This was best exemplified in 2024 when we harvested the ultra-early rainfed durum in Lethbridge on August 1, which I’ve never experienced unless the crop was a train wreck, and that treatment was the top dog at 72 bushels per acre,” says Beres.