Project Site: Mack Erno's Farm - Teepee Creek
Research Program Manager: Dr. Akim Omokanye From: Peace Country Beef & Forage Association 2018 Annual Report
Cover crops are increasingly recognized as a critical piece of sustainable agronomic production, based on their ability to enhance farm productivity, while reducing environmental risks (Snapp et al., 2005; Schipanski et al., 2014). Multi-species cover crop mixtures have been proposed as a strategy to augment services from cover crops, in part due to expected increases in biomass production from mixtures (Creamer et al., 1997; Smith et al., 2014). A multispecies annual crop mixture can be selected from a diversity of crop groups (e.g. grasses, legumes and brassicas). Previous PCBFA studies, as well as cover crop cocktail feed test reports, have shown improved forage quality from cover crop cocktails over other forage-based feed types (PCBFA Annual Report 2016, 2017). In the 2018 growing season, we tested 12 annual crop mixtures with 3-8 crops versus monoculture CDC Haymaker oats for forage yield and quality.
Methods
The study site was at Mack Erno’s farm in Teepee Creek. The site had canola the year before and it was sprayed with a pre-seed burnoff with Express + Roundup before seeding in 2018. Soil tests from 0-6” showed an organic matter of 5.2%, a pH of 5.5, and an electrical conductivity of 0.37 dS/m. The soil had 73 lbs N/acre, 29 lbs P/ac, 398 lbs K/ac and 25 lbs S/ac. Table 1 shows the cocktails tested.
· Seeding date: May 31
· All crops in a particular mixture were weighed separately and pre-mixed before seeding
· Legumes were inoculated at seeding
· No fertilizer was applied to any of the treatments including the Haymaker oats
· No in-crop spraying was done on any of the treatments including the Haymaker oats
· Harvest date: August 23
Results
Forage Dry Matter (DM) Yield
The highest forage DM yield came from CCC #1 (8445 lbs/acre), which had 7 crops in the mixture. Next to CCC #1 was CCC #8 with 7515 lbs/acre, followed by both CDC Haymaker oats (7309 lbs/acre) and CCC #3 (7308 lbs/acre), and then CCC #6 (7008 lbs/acre) (Table 2). Though not significantly different from CDC Haymaker oats (control), CCC #1 was the only CCC of the 12 CCCs tested that showed some forage DM yield advantage over CDC Haymaker oats, with 1136 lbs/acre more forage DM yield than CDC Haymaker oats. Four of the CCCs (#2, #3, #6, #8) compared favourably well with CDC Haymaker oats (control).
Forage Crude Protein (CP)
All CCCs showed significantly higher forage CP than CDC Haymaker oats. The highest forage CP content was from CCC #12 (15% CP), followed by CCC #10 (14.5% CP), CCC #9 (14.2% CP) and then CCC #11 (13.7% CP) (Table 2). Most CCCs had <12% CP.
Protein is a building block. The Beef Cow Rule of Thumb with protein is 7-9-11, which means an average mature beef cow requires a ration with crude protein of 7 per cent in mid pregnancy, 9 per cent in late pregnancy and 11 per cent after calving. In this study, only 7 of the 12 CCCs had adequate CP for a mature beef cow. Others, including CDC Haymaker oats, were only able to meet the CP requirements of a dry gestating beef cow.
Forage TDN
The TDN (total digestible nutrients) is a useful measure for energy content of beef cow rations that are primarily forage. For a mature beef cow, using percent TDN, the Beef Cow Rule of Thumb suggests 55% in mid pregnancy, 60% in late pregnancy and 65% after calving. The forage TDN values from all CCCs and CDC Haymaker oats were generally above thr 60% TDN needed by a dry gestating beef cow. Only CCC #11 appeared to fall short of meeting the 65% TDN required by a lactating beef cow. Four of the CCCs had >70% TDN, as well as higher TDN than CDC Haymaker oats (Table 2).
Forage Minerals (Table 3)
All CCCs had higher forage Ca than CDC Haymaker oats. CCCs #10, 11 and 12 showed higher forage K, S, Cu, Zn, and Mn than thr other CCCs and CDC Haymaker oats (control). All CCCs and CDC Haymaker oats were able to meet the requirements of K, Na, S, Fe and Mn for mature beef cattle. None of the CCCs or CDC Haymaker oats had sufficient Cu for a dry gestating beef cow. Five of the CCCs and CDC Haymaker oats did not have the 30 ppm Zn needed by a mature beef cow. All CCCs and CDC Haymaker oats were able to meet the Ca (except for CCC #9) and P requirements of a dry gestating beef cow. In most cases, CCCs #9, 10, 11, and 12 showed far higher forage Ca, K, S, Cu Fe, Zn, and Mn than CDC Haymaker oats.
Conclusion
CCC #1 produced more forage DM yield than CDC Haymaker oats (control), while 4 of the other CCCs (#2, #3, #6, #8) compared favourably well with CDC Haymaker oats (control) in terms of forage DM yield. All CCCs had higher forage CP than CDC Haymaker oats.