Research Coordinator: Dr. Akim Omokanye
Location: Fairview Research Farm, RR#35 MD of Fairview
From: Peace Country Beef & Forage Association 2014 Annual Report
Mixing pulse (such as field peas) with a cereal for forage is being commonly done by some producers to improve forage quality, with a possible boost in yield. Peas and oats, barley or triticale are some of the common types of intercropping. Pea/cereal mixtures can produce better quality silage than cereals alone. 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. The success of these mixtures is highly dependent on the seeding rates for both crops and making sure that there are enough peas in the mixture to influence feed quality. Legumes don’t need nitrogen (N) fertilizer and have higher forage protein content than cereals. Seeding mixtures of peas and cereals may reduce land, inputs and labour costs per unit of forage production, which will improve beef production efficiency and contribution margin. The trial is part of the Regional Silage Variety Trials.
Objectives
To compare the mixtures of forage peas with barley, oat and triticale for forage yield and quality
To communicate findings to beef cattle producers in the Peace region and to other parts of Alberta through the RSVTs.
The results across the province will be reported in the Alberta Seed Guide (www.seed.ab.ca).
Methods
The trial was conducted at Fairview Research Farm (NW5-82-3W6) on RR #35, MD of Fairview. Soil samples (0-6” soil depth) sent to Exova laboratory (Edmonton) for soil test for the site showed a pH of 5.8 and 7.1% OM. The site was left to fallow in the summer of 2012 and 2013
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Prior to seeding, the site was harrowed and sprayed with Credit® for a pre-seed weed control. Three cereal varieties (Vivar barley, Pronghorn triticale & Murphy oat) and 3 forage type pea varieties (40-10, CDC Horizon, CDC Meadow) were used for the trial. The treatments (12) consisted of 3 monoculture cereal crops (Vivar barley, Pronghorn triticale & Murphy oat) and 9 mixtures of pea/cereal (each cereal mixed with each of 40-10, CDC Horizon and CDC Meadow pea).
The treatments were arranged in a randomized complete block design with four replications in small plots (8.5 m long 6 rows). A plot drill was used to seed on May 23, 2014. Row spacing was 23 cm (9”). All plots were fertilized with a blend of 48N-30P-10K-15S (lbs/acre). In crop spraying of the pure cereal plots was with Frontline XL. No spraying was done on the mixed plots. Hand weeding was done once to remove visible volunteer canola plants.
Harvesting for forage yield was done at the soft dough stage for monoculture, milk stage for oat and late milk stage for triticale. Each mixture was harvested 10 days later after the cereal in the mixture was harvested at the recommended stage of maturity for harvest. For each plot, two 4 m long inner rows were hand harvested and weighed for wet yield determination. About 0.5 kg of the freshly harvested materials was sub-sampled and air-dried for a few days to constant weight for forage dry matter (DM) yield estimation.
The forage quality (% DM basis) was determined using two dry composite forage samples per treatment, one for replications 1 & 2, and the other for replications 3 & 4. The samples were analyzed in a commercial laboratory (Central Testing Laboratory Ltd., Winnipeg, Manitoba) using standard laboratory procedures for wet chemistry analysis.
Results
Forage DM yield
The forage DM was highest for 40-10 peas/Pronghorn triticale mixture (6912 lbs/acre) and followed by CDC Horizon peas/Pronghorn triticale mixture (6639 lbs/acre) and then CDC Horizon/Murphy oat (6302 lbs/acre) (Figure 1). The mean DM from all crops was 6048 lbs/acre and only 2 of the 12 pea/cereal mixtures had higher DM (591-864 lbs/acre) than overall mean DM yield. Except for 40-10 pea/Pronghorn triticale, CDC Horizon pea/Pronghorn triticale, CDC Horizon/Murphy oats, which had 566-1253 lbs DM/acre than the respective monoculture cereals, generally pea/cereal mixtures did not show any significant yield advantage over monoculture cereals.
Forage Protein Content (Figure 2)
The forage crude protein (CP) content was less than 9.5% for Murphy oats and CDC Meadow/Vivar barley mixture. Except for CDC Meadow pea/Pronghorn triticale mixture which had 12.7% CP, monoculture Prong-horn triticale had significantly higher protein (14.9% CP) than all pea/cereal mixtures and other monoculture cereals (Vivar barley and Murphy oats). Generally, there was no pronounced improvement in the protein of pea/-cereal mixtures over those of monoculture cereals. The lack of any significant improvement in protein content in the pea/cereal mixtures could be attributed to the dry weather in 2014.
The CP of all monoculture cereals as well as pea/cereal mixtures tested had sufficient protein needed by a dry gestating cow (7-9% CP). Nine of 12 treatments had adequate protein (11% CP) that is required by a lactating cow. Monoculture Pronghorn triticale, CDC Meadow peas/Pronghorn triticale mixture and 40-10 pea/Vivar barley mixture were the only ones that sufficiently met the required 12-13% CP needed by growing and finishing calves.
Forage Energy (Figure 3)
The forage energy (%TDN) was generally above 60% TDN for all monoculture cereals as well as pea/cereal mixtures. Monoculture Murphy oats had the highest energy (77% TDN), followed by 40-10 pea/Pronghorn triticale (75% TDN) and then monoculture Pronghorn triticale (73% TDN). All monoculture cereals as well as pea/cereal mixtures tested had sufficient TDN for a dry gestating cow, which requires 55% TDN in mid pregnancy and 60% TDN in late pregnancy. For a lactating cow that requires 65% TDN, all treatments (except for monoculture Vivar barley and CDC Horizon pea/Murphy oats mixture) had enough TDN for this category of cow. Also, for growing and finishing calves that require 65-70% TDN, all treatments (except monoculture Vivar barley and CDC Horizon pea/Murphy oats) had the required TDN these calves.
Forage Macro Minerals (Table 1)
The forage Ca content varied from 0.11% Ca for monoculture Murphy oats to 0.87% Ca for CDC Meadow pea/Pronghorn triticale mixture. All treatments (except for monoculture Murphy oats) had adequate Ca (0.18% Ca) needed by a dry gestating cow. For a nursing cow, which requires 0.42% Ca, only 2 of the treatments (monoculture Murphy oats and CDC Horizon pea/Vivar barley mixture) did not have sufficient Ca for this category of beef cow.
Only 5 of the 12 treatments had sufficient P for a dry gestating cow (0.16% P). None of the treatments had adequate P for a nursing cow (0.26% P).
The requirements of Mg and K by growing and finishing calves, and a mature beef cow were all met by all monoculture and mixed crops.
Some Notes on Pea/Cereal Mixtures
An adequate pea seeding rate will be a significant input cost but the pea stand density should not be com-promised. Reducing the pea seeding rate usually results in the cereal crop out-competing the peas, producing minimal or non-existent feed quality gains even though the peas that were seeded increased production costs.
What are recommended seeding rates for spring cereal/winter cereal mixes?
Generally, spring and winter cereals should both be seeded at about 75% of what is normal for the area to balance silage/greenfeed yield with regrowth and pasture production. Increasing the relative proportion of the winter crop will give better regrowth and fall grazing potential but lower silage yield. Conversely, more spring cereal than winter cereal will increase the silage yield potential but at the expense of grazing production.
Intercropping can provide numerous benefits to cropping systems through increasing total yield and land use efficiency, improving yield stability, enhancing light, water, and nutrient use, and controlling weeds, in-sects, or diseases. In temperate climates, intercropping has been more successful when used for forage production than grain production.
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