What is a hybrid grazing and mowing model, and why is it often favored by solar asset owners and operators? For this ASGA workshop, we heard from JR Howard (Texas Solar Sheep) and Evan Gunthorp (Gunthorp Farms), who gave a basic introduction to the hybrid model and covered the basics of how it can be adopted by solar graziers based on their region and solar site conditions. 

JR and Evan kicked off the event by sharing the advantages of a hybrid approach for solar vegetation management by combining sheep grazing with mechanical mowing. This approach offers flexibility for variable weather conditions and vegetation growth patters, while allowing adaptation for seasonal growth flushes that exceed the capacity of grazing alone. This addresses vegetation that sheep won’t consume and ensures a consistent ability to meet the height requirements regardless of conditions. Solar developers often prefer this approach because it allows them to work with a single vendor for complete vegetation management.

Next, Evan and JR covered the multiple vegetation management strategies integrated into the hybrid approach. Sheep are used as the primary vegetation management tool where appropriate, and mechanical equipment is employed in areas that sheep cannot effectively manage. The balance between grazing and mowing varies with the season and is based on growth patterns. Within this approach, it is important to select the proper equipment, choosing appropriate mowers based on site-specific conditions and limiting the use of herbicides for specific invasive species.

The hybrid model serves multiple stakeholders in the solar grazing ecosystem. These stakeholders include solar site owners, grazing operators, and sheep producers. Along with benefiting stakeholders, vegetation and local ecosystems are also positively impacted, with proper forage recovery periods and improved soil health and biodiversity.

JR and Evan also discussed the contexts where the hybrid model is most valuable. For example, high-rainfall regions experience vegetation growth that can quickly exceed sheep grazing capacity. Similarly, areas with spring flush periods experience cool-season grasses that grow faster than what sheep can consume. Sites with diverse vegetation or unpredictable weather also benefit, as do newly constructed sites.

With the grazing-mowing approach, it is important to find the right balance, which requires careful calculation of several factors. The grazier must be able to calculate how quickly vegetation regrows after grazing or mowing, and the daily forage needs of their flocks. Additionally, they must plan for how this balance will shift throughout the growing season and be able to calculate man-hours to fit those needs. When determining mowing efficiency, the grazier must consider the equipment type, site conditions, and time needed for maintenance, refueling, and equipment failures.

Choosing the appropriate equipment is critical for successful implementation. When determining what equipment to use, one must consider the panel height, row width, and terrain. Additionally, the proper transportation for moving the equipment between sites and a plan for servicing equipment and accessing spare parts is needed. Common mowers include zero-turn mowers, articulated mowers, and bat wing mowers, each of which provide their own advantages.

JR and Evan also discussed how the hybrid approach transforms the business model for solar grazing operations. Mechanical management requires significant equipment purchases, such as mowers, tractors, and transportation, as well as ongoing costs for repair and replacement. This necessitates budgeting for both livestock and mechanical operations. Additionally, coordination is needed for scheduling between grazing and mowing operations.