After a successful bean crop in the 2024-2025 season, the three systems were planted in cover crops for the winter. The Conventional was planted with ryegrass, the Hybrid with ryegrass, Balansa clover and crimson clover, and the Regenerative was the same as the Hybrid but with the addition of vetch.
The Canopeo phone app has been used weekly to monitor the canopy development of the cover crops. All three treatments achieved impressive canopy coverage, reaching over 90% canopy cover after just eight weeks. This rapid establishment is attributed to the ryegrass component, which typically establishes ground cover faster than other cover crop species used previously in the Carbon Positive trial.
Sheep were brought on to the Conventional plots in early July, after which they had a gradual reduction in canopy cover due to ongoing grazing, reaching its lowest point at 85% canopy cover.
The Hybrid system presented a unique challenge as it developed a significant nettle problem. This is probably an artefact of the site, rather than being caused by the Hybrid management strategy. To manage the nettles, the Hybrid was mowed in mid-July before the nettle set seed. Mowing reduced the Hybrid’s canopy cover to 65%, but the resilience of the cover crop mix was demonstrated as it quickly regrew to full canopy cover. Sheep were introduced in mid-August to reduce biomass before strip spraying.
The Regenerative treatment maintained steady canopy cover (90-100%) until sheep were introduced in mid-August to reduce biomass in preparation for strip spraying. The small fluctuations in the data are due strong shadows on bright days impacting the green percentage calculation in the app.
Cover crop biomass measurements were taken before grazing. The Conventional system produced an average of 3,987 kg/ha of dry matter from April to mid-July, compared to the Regenerative system, which produced an average of 5169 kg of dry matter per hectare from April to mid-August.
Fortnightly nitrate quick tests throughout the cover crop have provided insights into nitrogen dynamics within the different systems. Nitrate-N levels peaked approximately one month after cover crop establishment, with the Hybrid and Regenerative treatments showing higher levels than the Conventional treatment. [The Conventional Bean crop had received significantly more N fertiliser but yielded lower than the other treatments.] All treatments have shown steady decreases in nitrate-N. We haven’t seen a significant increase in nitrate-N from sheep grazing in any of the three treatments, although a slight lift in the Conventional plots may show some effect.
The Hybrid and Regenerative plots were strip sprayed on 15 September using our prototype twin-row sprayer. We wait in anticipation to see the results!
