It was in the REAP 2021 Emerging Agri-Tech panel that Sarah Morgan of Rothamsted Research outlined a new techno-grazing approach to managing grassland that kept the cattle penned into smaller cells and regularly moved to make more efficient use of the land.
Now a study published in the Journal of Environmental Management has shown that grassland can recover just as well from a highly-stocked cell-based approach as the traditional (set stocked) grazing model. The findings could have major implications for livestock management, allowing farmers to use less land to deliver similar quantities of high-quality protein without adversely affecting soil conditions.
The study, undertaken at Rothamsted’s North Wyke farm in Devon, compared soil disturbance in traditionally grazed and cell-grazed fields.
The issue with the traditional method is that the pasture isn’t grazed evenly and grass can be trampled. Also animals tend to cluster around features like water troughs leading to compaction and bare patches. The cell grazing animals are restricted to a small area and regularly moved. In this way more grass is grown and harvested, but there were concerns that the concentration of animals would damage the soil structure.
Techno-grazing offers high quality protein on less land
By measuring soil compaction in both systems over a season, the researchers found that there was no significant difference in how grazing affects soil structure and how well the pasture recovered over the winter break.
“The results suggest that with careful management of cell grazing including appropriate stocking densities and resting periods, stocking rates on grassland could be increased with no detrimental consequences in soil structure beyond what would normally occur on grazed pasture,” said Dr Alejandro Romero-Ruiz who led the study. “This means we can deliver more high-quality protein using the same land – thus contributing to meet the growing demand for animal-origin foods.”
GPS collars used to create ‘Moovement Model’
The team tracked the steers’ daily grazing patterns using GPS collars. The patterns were similar in both systems suggesting that the animals’ foraging was not affected by the relatively small size of the enclosures.
The grazing pattern was consistent with Lévy walk process, a phenomena observed in groups of animals, (including humans navigating through crowded pavements), which is considered optimal when searching for unpredictably distributed resources.
Using information from the trackers the research team developed a so-called “Moovement Model” linking grazing patterns with soil structure and soil functions which may have applications to assess the impacts of grazing in other localities.
Future versions of this could include the prediction of areas of dung and urine deposition. These can be linked with variations in vegetation and increased numbers of microbial communities that may represent hot-spots of increased greenhouse gas emissions from the soil.
“A better understanding of how livestock move and interact with their environment may offer new insights on how grazing practices impact soil and ecosystem functions. This will potentially also offer solutions to reducing the impact of cattle on soil health and the environment,” said Romero-Ruiz.
To read the paper: Grazing livestock move by Lévy walks: Implications for soil health and environment
Alejandro Romero-Ruiz, Sarah Morgan et al.
REAP Emerging Agri-Tech
The REAP Emerging Agri-Tech session provides an opportunity to gain an update on exciting science developments.
Scientists at REAP 2023 include:
Dr Richard Green Harper Adams University: Grasslands
Dr Jolanda van Munster SRUC: Livestock
Dr Ewan Gage Cranfield University: Vegetable Nutrition
Dr Jacqueline Stroud University of Warwick: Soil
Jonathan Ashworth Earlham Institute: Biodiversity
Dr Myriam Charpentier John Innes Centre: Crop Traits
Dr David Withall Rothamsted Research: Insects