Trial Site: Fairview Research Farm
Research Coordinator: Dr. Akim Omokanye
From: Peace Country Beef & Forage Association 2016 Annual Report
Annual and Italian ryegrasses are easier to establish. Producers ask many questions about annual and Italian ryegrass varieties. Producers want to know what annual ryegrass varieties to seed as monocrop or in cocktail mixtures for greenfeed or silage and which varieties have better re-growth potential after cutting for the purpose of extending fall grazing. It’s important to choose a variety that establishes quickly, a variety that is well-adapted to the area, yields plenty, very palatable and yields consistently throughout the season after harvesting. Annual ryegrass varieties fall into two types, which are called tetraploid or diploid. Tetraploid varieties are usually marketed as producing more forage biomass than diploids, but this could depend on location, management, fertility, and environmental conditions. Diploids have the advantage of a greater cold tolerance and quicker recovery. Annual ryegrass as a cover crop has the following benefits: tolerance to a wide range of soils, can tolerate compacted soils, minimizes soil compaction, N scavenger, suppresses weeds in 4-6 weeks, good erosion control and improves soil aggregate.
The study site was at the Fairview Research Farm (NW5-82-3W6) on RR #35, MD of Fairview. Soil test at 0-6” soil depth done at Exova laboratory (Edmonton) prior to seeding showed an organic matter content of 7.1%, a pH of 5.5 (acidic) and an electrical conductivity of 0.35 dS/m. The field was cultivated before seeding.
The varieties were arranged in a randomized complete block design in 3 replications. Small plots measuring 11.04 m2 (118.8 ft2) were used.
Treatments (Varieties): The following 7 annual and Italian ryegrasses were tested in 2016 (see Table 1).
We seeded on May 18 at 12 lbs/acre with a 6-row Fabro plot drill at 9” row spacing.
Following initial soil tests, we applied (actual lbs/acre): 82 N + 24 P + 54 K + 0 S (broadcast). Soil test showed adequate amounts of S for the crop, so S was not applied.
Spraying: 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. Rouging was done a few times.
Harvesting for forage yield and quality determination was done twice, first on July 25th and then the re-growth was harvested on August 30th
Results & Discussion
Forage Dry Matter Yield (Figure 1)
Multiple harvest is possible with most annual and Italian ryegrass varieties in the Peace.
For the first harvest which took place on July 25th, the top 3 varieties with >3500 lbs/acre were Gulf, Sabroso and Tetilla. Gulf variety produced the highest DM yield (4061 lbs/acre), followed by Sabroso (3852 lbs/acre) and then Tetilla (3561 lbs/acre). The other 4 varieties had less than 3000 lbs/acre.
For the second harvest, only two (Sabroso & Italian) of the seven varieties had higher DM yields (2795 & 2698 lbs/acre) than other varieties. The other 5 varieties yielded less than 2000 lbs/acre.
Total DM yield from the 2 harvests was highest for Sabroso (6647 lbs/acre), followed by Gulf (5635 lbs/acre), Italian (5471 lbs/acre) and then Tetilla (5343 lbs/acre). Overall, Sabroso, Gulf, Italian and Tetilla varieties appeared to have 113 - 140% more DM yield than Common variety (check).
Crude Protein (Figure 2) - The forage crude protein (CP) content for the first harvest on July 25th varied from about 12% CP for both Common & Gulf varieties to about 21% CP for Green Spirit variety. For the second cut, Danegro had the highest protein (24% CP). Protein content was generally higher at the second harvest for all varieties (except for Sabroso). Generally, three (Danegro, Green Spirit and Italian) of the varieties consistently had >20% protein at any particular harvest. Overall, all varieties at any particular harvest exceeded the protein requirements of a mature beef cow.
The forage mineral contents (average of 2 harvests) are shown in Table 2.
Except for forage K, Na and Fe, all varieties had similar mineral contents.
The forage Ca content was generally above 0.40%.
The forage P content was highest for Green Spirit (0.28%).
Overall, except for P, Mg and Cu, the mineral requirements of a mature beef cow have all been met by the varieties tested. The forage P and Mg contents of all varieties for the most part were able to meet the requirements of a gestating cow in the mid- and late-pregnancy stages. Overall, only Green Spirit was able to meet the requirements for all minerals listed in Table 2 by a mature beef cow.
Detergent Fibers, Non-fibrous Carbohydrates (NFC) and Energy (Table 3)
The forage fiber content (measured by ADF or NDF) in particular is a strong predictor of forage quality, since it is the poorly-digested portion of the cell wall. Forages with higher ADF are lower in digestible energy than forages with lower ADF, which means that as the ADF level increases, digestible energy levels decrease. As NDF in the forage increases, animals will consume less forage.
Generally, lower ADF and NDF values are preferred . NFC is more rapidly digested than fiber. It is a significant source of energy for the rumen microbes. The microbes also use NFC to make microbial protein. Therefore, looking at the values of ADF, NDF and NFC obtained for the varieties tested here, the top 3 varieties with lower ADF & NDF, and higher NFC were Italian, Green Spirit and Danegro in that order. The forage quality of the top 3 varieties have also been reflected in their RFVs, which were higher than the other 4 varieties.
The energy contents (TDN and other forms of energy) also appeared to be consistently higher for Italian, Green Spirit and Danegro than other varieties. Italian, Green Spirit and Danegro had >67% TDN, while others had <65% TDN.
All varieties tested here had sufficient TDN for a dry gestating beef cow, but only Italian, Green Spirit, Danegro and Tetilla had adequate TDN content for a lactating beef cow. This therefore indicates that only Italian, Green Spirit, Danegro and Tetilla have been able to meet the energy requirements of mature beef cattle.