Collaborating Producer: Thomas & Laura Claydon (MD of Smoky River)
Research Coordinator: Dr. Akim Omokanye
From: Peace Country Beef & Forage Association 2015 Annual Report
Cover crops are an important tool that farmers can use to generate benefits and services on the farm and for society, including improved soil health, nutrient supply to cash crops, weed suppression, insect pest management, forage production, pollinator resources, and clean water and air. There are many different cover crop species to choose from, and each cover crop species has different abilities to provide the services described above. Cocktail cover cropping involves using complex mixtures of cover crop seeds, which can be up to 5, 7, 8 or even 15 or 20 varieties of seed in a single mix - to achieve multiple soil-health, production and profit goals, usually in no-till farming systems.
Methods
The demonstration site was at Thomas & Laura Claydon’s farm, MD of Smoky River. Demonstration strip design was used on a 5-acre piece of land. The soil analysis (0-6” soil depth) done by Exova Laboratory, Edmonton prior to seeding this year showed a pH of 6.2 and an OM of 7.65%. The analysis also showed that the soil was deficient in N and P. The land was hayland prior to 2014. The land was disced in spring of 2014 and 2015. The collaborating producer (Thomas) seeded crop mixes containing 2-8 crop species against a single species oat crop (please see Table 1 below).
Seeding was done with a Melroe double disc press drill (14-ft wide) at 6” row spacing on June 7 into dry soil at approximately 3/4 inch depth. No fertilizer was applied.
As with most parts of the Peace in 2015, the site was also very dry, so no forage yield was determined, but forage samples were taken from the plots using 5 randomly placed 0.25 m x 0.25 m quadrats/plot when barley was at the soft dough stage. Composite forage samples were taken per treatment, dried and later shipped to Central Testing Laboratory Ltd., Winnipeg, Manitoba for feed quality analysis using standard laboratory procedures for wet chemistry.
Results
Forage Quality
Protein Content (Figure 1) - The forage crude protein (CP) content appeared to be generally higher for all mixtures compared to the oats check strip. Protein was highest for Mixture 1 (20% CP), followed by Mixture 3 (16% CP), Mixture 2 (14% CP), Mixture 4 (Pea-oat mix, 13% CP) and then Oats check strip (12% CP). It is evident from this study that cocktail mixtures containing more than 2 crops in the mixtures improved forage CP content compared to oats check strip and a mixture of pea-oat mix. Looking at the mixtures, it appears that mixtures which had kale and proso millet included in the mix (Mixtures 1 and 3) improved the forage CP over those mixtures which did not include Kale and proso millet.
Generally, the CP obtained for all mixtures as well as oats check strip met the protein requirements of a mature beef cow, that requires 7% CP and 9 % CP at the mid gestation stage and 11% CP after calving. For growing and finishing calves that require 12-13% CP, Mixtures 1, 2 and 3 far exceeded the protein required by these categories of calves.
Forage Energy Content (Figure 2)
The forage energy (total digestible content, TDN) was generally above 60% for all mixtures. Mixture 1 had the highest TDN (74%). A mature beef cow requires 55% TDN at the mid-pregnancy stage, 60% TDN at late-pregnancy stage and 65% TDN after calving. Looking at Figure 2, all mixtures as well as oats check strip were able to meet the energy requirements a dry gestating cow. But for a nursing, that requires 65% TDN, only Mixture 1 exceeded this requirement. Others either just barely met or slightly fell short of meeting the energy requirement of a nursing cow. Also, Mixture 1 exceeded the energy requirements of growing and finishing calves, that require 65-70% TDN.
Minerals (Table 2)
Forage Ca content varied form 0.26 to 0.95%. Only Mixture 2 fell below the Ca requirements of a mature beef cow, which needs 0.18% Ca during pregnancy and 0.42% Ca after calving.
Both Mixture 4 and the oats check strip fell short of meeting the 0.16% P requirements of a dry gestating cow. None of the mixtures and check strip had sufficient P amount needed by a lactating cow.
All the Mg, K and Na requirements of a dry gestating cow as well as a lactating cow have been met by all mixtures and oat check strips, except for Mixture 2, which fell short of 0.20% Mg and 0.10% Na that are needed by a lactating cow. Looking at Table 2, Mixture 2 appeared to have lower Ca, Mg, K and Na values than Mixtures 1 and 3.
Acid Detergent Fiber (ADF) (Table 2)
The forage ADF content was in order of oat check strip > Mixture 4 (Pea-oat Mix) > Mixture 2 > Mixture 3 > Mixture 1. The lower ADF obtained for Mixture 1 compared to other mixtures is an indication of its feed value. Considering that as ADF increases, digestibility of forage usually decreases, it will be sufficed to say that when all the mixtures as well as oats check strip are presented side by side to cows in a preference study, Mixture 1 would likely be preferred and consumed more than others because of its lower ADF value.
Other Forms of Energy (Table 2)
Mixture 1 consistently had higher other forms of energy listed in Table 2 (ME, NEG, NEL, NEM & DE) than other mixtures and oats check. Looking at the ME values in the present study, all treatments were well within the suggested daily ME requirements of 2.23 to 2.54 Mcal/kg of mature beef cattle. A mature beef cow requires 0.97-1.10 Mcal/kg of NEM at the dry gestation stage and 1.19-1.28 Mcal/kg NEM during lactation. All mixtures as well as oat check strip met the NEM requirement of a mature beef cow. For growing and finishing calves, that require 0.53-1.37 Mcal/kg of NEG, all mixtures as well as oat check strip were well within this range.
Conclusion - Though no forage DM yield is available in the present study, from the available forage quality information, Mixture 1 appeared to provide high forage quality for beef cattle taking into consideration the forage CP, TDN, Mg, K, Na, ADF and all other forms measured energy. Next to Mixture 1 in terms of forage quality for beef cattle is Mixture 3. Mixtures 1, 2 & 3 were only frequently able to meet the nutrients requirements of a dry gestating cow.