Research Coordinator: Dr. Akim Omokanye
Location: Fairview Research Farm
From: Peace Country Beef & Forage Association 2019 Annual Report
Nitrogen is usually the most limiting nutrient for annual crop production. It is supplied to crops by mineralization of soil organic matter, commercial fertilizers, and atmospheric nitrogen fixed by legumes and rhizobia. Because biologically fixed nitrogen may cost less than commercial fertilizers, maximizing the proportion of fixed nitrogen in cropping systems reduces costs. Including forage legumes in annual crop mixtures (cocktails), cereal/legume intercropping or rotation with annual crops can be a useful management strategy to increase the availability of fixed nitrogen (N). For PCBFA to be able to recommend the right types of annual forage legumes for use in cocktails or intercropping systems, PCBFA continues to evaluate several annual forage legumes as they become available.
Objective
To test introduced forage-type annual legumes for forage potential and inclusion in cover crop cocktail mixtures or intercropping systems.
Methods
Experimental Site: Fairview Research Farm (NW-5-82-3 W6M) on RR #35, MD of Fairview.
Previous Crop: The previous crop at the site was an alfalfa hay crop for several years until the Fall of 2018.
Land Preparation: In the Fall of 2018, the site was sprayed with Roundup at 1.0 L/acre (to kill the existing alfalfa dominated vegetation) and plowed. The site was disced & harrowed in the spring of 2019.
Soil analysis completed in the Fall of 2018 from 0-6” soil interval showed an organic matter content of 8.2%, pH of 6.2 and an electrical conductivity of 0.21 ds/m. The soil test reports showed 10 lbs N/acre, 14 lbs P/acre and 485 lbs K/acre as well as 9 lb S/acre.
Spring soil moisture at seeding was 12.4% (0-5 cm soil depth) and 14.1% (0-20 cm soil depth). Spring soil temperature at seeding was 9.19°C (0-5 cm soil depth) and 7.79°C (0-20 cm soil depth).
Experimental Design: Randomized Complete Block Design with 4 replications.
Treatments: 12 legume crop species & varieties were tested
1. Hairy vetch - seeded at 20 lbs/acre
2. Chickling Vetch (AC Greenfix) - seeded at 60 lbs/acre
3. Ebena coomon vetch - seeded at 20 lbs/acre
4. HO Crimson clover - seeded at 15 lbs/acre
5. Subterranean clover - seeded at 20 lbs/acre
6. Winner brand berseem clover - seeded at 15 lbs/acre
7. Frosty berseem clover - seeded at 15 lbs/acre
8. Frontier balansa clover - seeded at 6 lbs/acre
9. Fixation balansa lover - seeded at 6 lbs/acre
10. Laser brand Persian clover - seeded at 15 lbs/acre
11. Serradella - seeded at 4 lbs/acre
12. Crimson clover - seeded at 15 lbs/acre
Seeding date was on May 23.
The seeds were sown using a Fabro plot drill equipped with disc-type openers on 9” row spacing. Six rows that were 8 m long were sown per plot. Seeding depth was 0.75”.
Fertility (actual lbs/acre): 60 lbs/acre of 11-52-0 was applied to all legumes.
Spraying: Pre-emergent herbicide with StartUp (Glyphosate, 540 grams acid equivalent per litre, present as potassium salt) was applied at 0.67 L/acre. StartUp is a water soluble herbicide for non-selective weed control. In-crop herbicide application was Basagran Forte at 800 mL/acre.
Harvesting for forage dry matter (DM) yield determination and quality analysis was completed on September 9. Two composite forage samples were sent to A & L laboratory in Ontario for quality determination.
Rainfall received from seeding to forage harvest was 188.2 mm (or 7.41”) compared to 207.9 mm (8.19”) for long-term average for the same period.
Results and Implications
Forage Dry Matter Yield
Both crimson clovers and frosty berseem clover had higher forage DM yield (8,134-8,738 lbs/acre) than other forage legumes (1,645-7,433 lbs/acre) tested within this trial (Table 1).
Of the 8 clover species/varieties tested, frosty berseem clover, H.O. crimson clover and common crimson clover produced higher forage DM yield than other clovers. The least forage DM yield from the clovers came from subterranean clover, a very low-growing annual forage legume.
The 3 types of vetches (hairy, Ebena and chickling) produced similar forage DM yield (5,066-5,744 lbs/acre).
On a general note, the two crimson clovers and chickling vetch germinated faster than other legumes. The lower DM yield from the two balansa clovers (fixation and frontier) was due to scanty plant stands as both varieties did not generally have good establishment counts. Of the 12 legumes tested, only 4 (the 2 vetches, subterranean clover and frosty berseem clover) did not flower at all. Others had flowers and some even had pods. The plant standability of frosty berseem clover was greater than those of the 2 crimson clovers tested within this trial (see picture on the Right).
Forage Quality (Table 1)
The forage CP varied from 10.9% for common crimson clover to 23.6% for ebena common vetch. In most cases, the clovers seemed to have lower forage CP than the vetches. Overall, the forage legumes had adequate CP for different categories of mature beef cattle, which require 7, 9 and 11% CP at mid pregnancy, late pregnancy and during lactation, respectively. Because of the generally higher forage CP values in the vetches, the vetches can be used to supplement lower protein feeds such as those from cereal greenfeed or silage or grass hay. In addition, the vetches could also help increase the protein content of annual crop mixtures (cocktails).
Except for H.O. crimson clover, which had 59.0% TDN, the forage energy content (%TDN) was generally above 60% TDN. Winner brand berseem clover, fixation balansa clover and laser brand Persian clover all had >70% TDN. Other legumes had <70% TDN. Except for both H.O. crimson clover and hairy vetch, all legumes had enough %TDN for mature beef cattle. Both H.O. crimson clover and hairy vetch seemed to have sufficient %TDN for a dry gestating beef cow.
The forage Ca content was generally high for all forage legumes, varying from 0.97 to 2.47% Ca. With the high forage Ca content, all forage legumes therefore have been able to meet the Ca requirements of mature beef cattle, which needs 0.18% Ca both in mid and late pregnancy, and 0.58% Ca during lactation. Similarly, the requirements of both K, Mg, Fe, have been met by all forage legumes tested within this study.
The forage P, Mg and Na were respectively highest for Ebena common vetch, Serra della and laser brand Persian clover.
Generally, none of the forage legumes tested were able to completely meet the mineral (both macro and trace) requirements of mature beef cattle. So, when feeding any of these forage legumes, some mineral supplementation would be needed. It is important to note that the requirements of Cu (10 ppm) by both young and mature beef cattle can hardly be met by most forage feed types that are available in the Peace River region. Of the legumes tested, only 4 legumes (subterranean clover, hairy vetch, chickling vetch and ebena common vetch) have been able to produce up to 10 ppm Cu or more. This shows that all the vetches are able to provide higher forage Cu content than most forage legumes.