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Underseeding Wheat, Canola, and Flax with Frosty Berseem and Subterranean Clovers

Updated: Jun 27

Research Coordinator: Dr. Akim Omokanye

Location: Fairview Research Farm

From: Peace Country Beef & Forage Association 2020 Annual Report

Frosty berseem and subterranean clovers are both short lived (annual), high nitrogen producing crop. They are both relatively new to the Peace Country. Frosty berseem clover is a cool-season legume that is native to the Mediterranean region. It is a non-bloating legume, and has very low hard seed counts, allowing for quick establishment and lessening its potential to become a weed. Subterranean clover is a low-growing, branching legume. It will grow where most other clovers will not survive. The prostrate growth pattern of subterranean clover gives excellent weed suppression. Drought resistance of subterranean clover is fair, and shade tolerance is high.

PCBFA conducted a study to examine the impact of underseeding cash crops with frosty berseem and subterranean clovers, on forage and seed production. This report examines forage production and quality of the cash crops with and without frosty berseem and subterranean clovers.


Experimental Site: Fairview Research Farm (NW-5-82-3-W6M) on RR #35, MD of Fairview.

Site soil information from 0-6” depth at seeding: pH = 6.2, organic matter = 4.7% and electrical conductivity = 0.21 (dS/m).

Cropping history: Before the fall of 2018, when the site was sprayed out with Roundup at 1.0 L/acre and tilled, the previous crop was alfalfa hay for over 15 years.

Experimental design: RCBD was used in 3 replications in small plots (1.8 x 8 m).

The treatments consisted of 3 monocultures (canola, flax, and wheat) and 12 underseeding treatments (wheat, flax, and canola with frosty berseem and subterranean clover). The underseeding treatments were compared to the monocultures.

The cash crops (wheat, canola, and flax) were seeded at 100% of their recommended seeding rates. The clovers were seeded at 50 and 75% of their recommended seeding rates. The mixtures were seeded in the same rows.

Each plot was subsequently divided into halves, one half for forage production and feed quality, and the other half was for seed production. The report on seed production is not included here. This will be available later.

Crop varieties and monoculture seeding rates:

1. Canola - CS2500CL 7 seeds per square foot

2. Flax- CDC Plava 32 seeds per square foot

3. Wheat - AAC Brandon 33 seeds per square foot

4. Frosty berseem clover 15 lbs/acre

5. Subterranean clover (Sub-clover) 20 lbs/acre

· Seeded on May 29 using a 6-row plot drill with 9” row spacing.

· Soil temperature at seeding was 12°C.

· The peas were inoculated at seeding with granular inoculant.

· Fertility (actual lbs/acre): 50 lbs 12-52-0 per acre only.

· Spraying: Pre-emergent was with StartUp glyphosate + LI surfactant. Hand weeding was done.

Results and Some Implications

Forage DM Yield

Monoculture wheat and wheat underseeded with frosty and sub-clover produced higher forage DM yield than canola or flax monocultures and their respective mixtures (Figure 1.). Canola monoculture on the hand produced higher forage DM yield than flax monoculture. Overall, sub-clover seemed to perform better as an underseeding cropping system than frosty clover. Surprisingly, in the present study, frosty clover and sub-clovers at 50 and 75% seeding rates seemed to have negatively impacted wheat growth and forage production.

Sub-clover is a low growing annual forage legume that is suited for grazing, while frosty is a taller annual forage legume. They are both later maturing than crimson clover and several other annual clovers.

However, the characteristics of clover species differ and this may have been responsible for the large differences obtained in forage DM yield for both frosty and sub-clovers in this study, which was in favour of sub-clover. Some are more tolerant of certain climatic conditions, soil conditions, and/or management regimes than others. It is important to note that both clovers do perform well as monocultures in the Peace Country.

Clovers are wonderful plants that can contribute greatly to forage/livestock programs, to soil stabilization, and in other situations in which plant vegetation is desired. Benefits clovers can provide include improved forage quality, increased forage yield, and biological nitrogen fixation.

Forage Quality

Wheat, canola, and flax monocultures respectively had 10.2, 13.3 and 12.6% forage CP, indicating that canola monoculture seemed to produced higher CP than wheat and flax monocultures (Table 1). In general, underseeded crops plus the main crop had more than 10% CP. This shows that both monocultures and underseeded systems would provide adequate protein for a dry gestating beef cow in both mid to late pregnancy.

Canola monoculture and canola underseeded with both types of clovers seemed to have higher ADF and NDF content, lower energy (TDN), NDFD at 24- and 48-hr as well as NDF disappearance rate (Table 1). The lower TDN for canola monoculture and canola underseeded with clovers indicates the need for energy supplementation when feeding forage emanating from such systems to a pregnant beef cow. However, wheat monoculture and wheat underseeded with clovers would provide enough TDN for a dry gestating beef cow.

The forage Ca content was generally high for all treatments, varying from 0.79-1.18% for wheat monoculture and underseeding systems; 1.16-1.64% for canola and canola underseeding systems; 1.05-1.36% for flax and flax underseeded with clovers. With Ca being generally higher than the 0.57% required for a mature beef cow, Ca would be sufficient when feeding any of the monocultures or underseeding systems to mature beef cattle. However, both P and K would not always be adequate, so a feed test is required for the different systems tested here and mineral supplementation should be provided appropriately when feeding to cows.


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