Regional Silage Variety Trials: Pulse Mixtures (Pea-Cereal Mixtures)

Trial Site: Fairview Research Farm

Research Coordinator: Dr. Akim Omokanye

From: Peace Country Beef & Forage Association 2016 Annual Report

The growing of two crops simultaneously on the same field, particularly growing of legumes with cereals is known to offer scope for developing energy-efficient cropping systems and sustainable agriculture. Mixed cropping of certain annual legumes with cereals is extensively used for forage production in Alberta. Mixtures have different microenvironments compared to pure stands. Legumes such as peas are usually included in mixes to improve the quality of the feed. Pea silage could be 13-18% protein so theoretically a pea/cereal mix should have higher protein than a cereal silage alone which is usually about 10% protein. In reality however, the potential protein benefits of peas in silage mixtures often are not attained because of the competitive effects of the cereal crop. In addition to the findings presented here from our trial, the results from the RSVTs across the different trial sites in the province will also be reported in the Alberta Seed Guide (www.seed.ab.ca).

Methods

The study site was at the Fairview Research Farm (NW5-82-3W6) on RR #35, MD of Fairview. The site had soybeans in 2015. Soil test at 0-6” soil depth done at Exova laboratory (Edmonton) prior to seeding showed an organic matter content of 7.3%, a pH of 5.4 (acidic) and an electrical conductivity of 0.58 dS/m. The field was cultivated before seeding.

We used randomized complete block design in 4 replications.

Treatments: 3 Mono-crop cereals (1 barley, 1 oat & 1 spring triticale) & 2 pea varieties (CDC Meadow & CDC Horizon) were used in the following pea-cereal mixtures:

1. Taza triticale mono-crop

2. CDC Baler oat mono-crop

3. CDC Austenson barley mono-crop

4. Taza triticale/CDC Meadow pea mixture

5. Taza triticale/CDC Horizon pea mixture

6. CDC Austenson barley /CDC Horizon pea mixture

7. CDC Baler oat /CDC Meadow pea mixture

8. CDC Austenson barley/CDC Meadow pea mixture

9. CDC Baler oat/CDC Horizon pea mixture

Seeding Rates:

1. CDC Austenson barley- 300 plants/m2 (27.8 plants/ft2)

2. CDC Baler oat - 300 plants/m2 (27.8 plants/ft2)

3. Taza triticale - 370 plants/m2 (34.3 plants/ft2)

4. Pea-cereal mixtures - 75% of pea seeding rate + 50% of cereal seeding rate

- Pea seeding rate used was 90 plants/m2 (8.3 plants/ft2)

A 6-row Fabro plot drill at 9” row spacing was used to seed. Seeding was done on May 16.

Fertility according to soil tests (actual lbs/acre): 0 N + 33 P + 47 K + 0 S (broadcast). Soil test showed adequate amounts of N & S for the crop, so N & S were not applied.

Roundup WeatherMAX® was used as pre-emergent 7 days after seeding. In-crop spraying was done with 2, 4 - D 700 at 0.35 L/acre for triticale, oat and barley. Basagran Forte was used on pea-cereal mixtures.

At harvest, plants in the 4 centre rows 10 feet long were harvested, weighed fresh, sub-sampled (about 500 grams), air dried for some days and then weighed to determine dry matter (DM) content. Forage samples were analyzed for quality using standard procedures for wet chemistry at A & L Laboratory, Toronto.

Results & Interpretation

Forage Moisture

The forage moisture content at harvest was far lower for Taza triticale mono-crop and pea-triticale mixtures than other mono-crop cereals (barley & oat) or pea-cereal mixtures (Table 1). The CDC Baler oat and CDC Austenson barley and their mixtures with peas had the right moisture content for silage at harvest.

Forage DM yield

The Taza triticale/CDC Horizon pea mixture had significantly higher forage DM yield (8451 lbs/acre) than other mono-crop cereals (7030 - 7573 lbs/acre) and pea-cereal mixtures (6816 - 7726 lbs/acre). Compared to check (CDC Austenson barley) used in this test, only two mixtures (CDC Austenson barley/CDC Meadow pea and CDC Baler oat/CDC Meadow pea) appeared not have any yield advantage over check (Table 1). Looking at a particular cereal and its mixtures with any of the peas (CDC Horizon & CDC Meadow), only pea-triticale mixtures appeared to have some yield advantage over the mono-crop triticale (Taza) tested. Barley and oat when mixed with peas did not seem to have any influence on forage DM yield.

Forage Quality

Protein - The forage CP content was generally above 10% for all mono-crop cereals and pea-cereal mixtures. For some reason, CP was significantly higher for CDC Baler oat/CDC Meadow peas (15% CP) than others. With the exception of pea-oat mixtures (CDC Baler oat/CDC Horizon pea and CDC Baler oat/CDC Meadow pea) which appeared to improve forage CP over moncrop oat, other pea-cereal mixtures did not seem to improve forage CP over their respective mono-crop cereals. Overall, the 3 cereals and the pea-cereal mixtures had adequate CP for a mature beef cow. Only Taza triticale and Taza triticale/CDC Meadow pea fell slightly short of meeting the 12-13% protein needed by growing and finishing calves. CDC Baler oat/CDC Meadow pea far exceeded the protein requirements of all categories of beef cattle.

Minerals - The forage Ca, K, Mg, Na, Fe and Mn contents appeared to be higher for CDC Baler oat/CDC Meadow pea mixture (Table 2) than other mono-crop cereals or pea-cereal mixtures. There was no consistent improvement in forage minerals for pea-cereal mixtures over their respective mono-crop cereals. Generally, the requirements of a gestating cow in the mid-and late-pregnancy stages have all been met for the minerals (except for Cu) analyzed in this study.

Energy

The forage energy (TDN) was generally >60% for the mono-crops and the pea-cereal mixtures (Table 3). Mono-crop Taza triticale and CDC Austenson barley and their mixtures with peas had significantly higher TDN than mono-crop CDC Baler oat and pea-CDC Baler oat mixtures.

Generally, all mono-crop cereals and pea-cereal mixtures were able to meet the TDN requirements of a gestating beef cow. For a lactating beef cow, which requires 65% TDN, monocrop Taza triticale and CDC Austenson barley and their mixtures with peas exceeded the requirement. Monocrop CDC Baler oat and its mixtures with peas all fell short of meeting the 65% TDN needed by a lactating beef cow. This shows that using silage from monocrop oats or pea-oat mixtures for lactating beef cows may require additional energy sources.