Sponsored by Covers & Co, Crystal City, MB
Objective
To evaluate and quantify the benefits of Covers & Co’s Full Season Cover Crop Blend on plant health, crop production, and soil health.
Methods
The project was implemented at the Fairview Research Farm (820059 Range Rd, 35 Fairview, AB). Site soil information from the surface soil (0-6" soil depth) before seeding: pH = 5.8, organic matter = 6.1 electrical conductivity = 0.42 dS/m, while the nutrient analysis of the soil gave N = 42 ppm, P = 17 ppm, K= 155 ppm and S = 5 ppm. The crop history of the site: Canola (2020), Wheat (2021) and Canola (2022).
Experimental design includes randomized complete block design using four replications in small plots measuring 8 m x 1.14 m. Seeding was carried out using a 6-row Fabro Plot Drill with disc-type openers on 23 cm row spacing complete with side banding. Four treatments were evaluated (Table 1). Seeding and crop management practices are provided in Table 1.
Observations
The site experienced exceedingly hot temperatures in May, June, and July with a precipitation event shortly after seeding the trial. In total, the growing season received approximately 230 mm (9.1“) of rain. With smoke from regional wildfires, UV Index was possibly reduced and this diminished stress on crops during times of little moisture. Pest pressure was evident throughout the region with grasshoppers having major impacts on hay, pastureland and some annual crops. As pest measurement wasn’t a part of this project, we observed some beneficial insects and grasshoppers in the demonstration site through the use of pitfall traps. Analysis is still to be completed on these traps as these results are part of a larger regional program.
Results
Soil Moisture, temperature, Bulk Density and Canopy Vegetation Cover
Results obtained for some in-field measurements are shown in Table 2 below. For comparison between T2 (Cover Mix without fertilizer), both the highest values for moisture content and aggregate stability were observed in this treatment. Bulk density readings were generally below 1.5 g/cm3 indicating some mobility of water and nutrients in the soil. The NDVI ranged from 0.66-0.78 with both Cover Crop Blend treatments showing higher indices compared to oat monoculture treatments while volumetric aggregate stability (VAST) widely ranged between 13% - 41%.
Forage Dry Matter Yield and Quality
Forage DM yield determined as silage (at the late milk stage for oats) varied significantly between treatments with Oats monoculture trumping all the other treatments (Table 3). Fertilizer application came with an advantage as both treatments with fertilizer showed an increase in forage DM yield compared to their respective controls. Cover Crop protein yields were significantly higher than mono-crop protein yields most likely due to the leguminous species contents. The CP contents of all species nonetheless were above 14%, the cut-off for highly demanding beef stock such as lactating or growing cattle. Energy (TDN) averaged 61% and did not differ significantly between treatments. The Cover Crop Blend significantly improved forage Ca, P, K , Mg and Cu contents over monoculture oats. Cu levels in all treatments were however lower than the requisite 10 ppm necessary to meet the nutritional requirements of most beef cattle stock.
Conclusion
Monocrop Oats produced higher forage DM yields compared to the full-season cover crop blend. There was a clear effect of fertilizer application on treatments. The cover crop blend outperformed mono-crops in protein content, but this was not particularly significant since all treatments had CP contents above 14%, which is the maximum required for high-demand beef cattle. The Cover Crops provided a good source of most macrominerals, but cattle grazing solely on them would still need copper (Cu) supplementation.
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