Combining solar panels with a pastoral sheep farming system could have both positive and negative impacts on pasture growth, according to a Te Kunenga ki Pūrehuroa Massey University pilot study.
The researchers’ preliminary results from the first seven months of study indicate that these effects are dependent on where the panels are located.
Pasture growth was reduced by 84% directly under the panels, but increased by 38% in the larger areas between panels. Pasture growth in both cases was compared to pasture growth in areas away from the panels.
Professor Danny Donaghy from the School of Agriculture and Environment, who co-led the study, said direct shading under the panels likely has a negative influence on pasture growth, which was not the finding in some previous international research in generally hotter and drier climates.
In contrast, in the area between the solar panels, the panels might offer some “protective” effects, possibly by keeping soil temperatures cooler and also slowing down loss of soil moisture due to wind, compared to an open paddock.
“These results could be used to inform the design of future mixed solar and pastoral farms in New Zealand, including ideal height from the ground and spacing between the rows of installed panels. This would be a win-win for solar farming co-existing with pastoral systems, or even horticultural crops,” Donaghy said.
The research was funded by the Agricultural and Marketing Research and Development Trust (AGMARDT). Pasture performance was measured from July 2022 to January 2023.
Head of the School of Agriculture and Environment Professor Paul Kenyon, who is the other co-lead of the study, said he is pleased that there is New Zealand-based research to support the country’s farmers.
“We are really just starting to understand the potential impact of solar panels on pastures in our milder and wetter New Zealand climate. The next steps are to collect more data, from across New Zealand, in differing environments.
“It is important to get accurate data for New Zealand conditions. Data is needed over the entire year, or ideally over multiple years and sites, before firm conclusions can be drawn. “
The pilot project will continue until spring 2023, with additional details collected on pasture growth and quality and the prevalence of facial eczema spores on pasture.
