Sheep grazing appears to have positive impact on soil health
The concept of regenerative agriculture is popular these days. The Rodale Institute states that regenerative agriculture “prioritizes soil health while simultaneously encompassing high standards for animal welfare and worker fairness. The idea is to create farm systems that work in harmony with nature to improve quality of life for every creature involved.”
On the page, this sounds promising. However, as an aspiring first-generation farmer and former researcher, I am left with a lot of questions about what this type of agriculture actually looks like on the ground.
Potato production is a dominant sector of agriculture in northwestern Washington. In Skagit County, potatoes are grown on 12,000 acres and the average yield is 20-25 tons/acre (Washington State University Skagit County Extension, 2019). Since potatoes can detrimentally impact soil nutrition and organic matter, soil quality has become an important priority for potato farmers in this area.
Arable land is limited in northwestern Washington and land sharing is a common practice in Skagit County. However, it is often difficult for potato farmers to find viable rotation crops based on the extensive amount of acreage they occupy.
My last name is French for “leg of lamb,” so perhaps it is not surprising that after falling in love with a few pet sheep I dedicated our small Skagit Valley farm, Harmony Fields, to all aspects of sheep production — milk, wool and meat. Fifty percent of our land is rented from a neighboring commercial potato farm. As our flock has increased, we have increasingly needed more pasture access. Our farm became Animal Welfare Approved by A Greener World in 2020, and pasture is critical to representing our values as well as maintaining certification.
Livestock rotations in crop production systems is considered to be a regenerative practice and can have positive effects on soil health, which is defined as “the continued capacity of the soil to function as a vital living ecosystem that sustains plants, animals and humans” (NRCS, 2012). There is limited information about how this actually works, however.
Several years ago, I came across an article from The Herald written by the late Rog Wood, a Scottish farm reporter, where he mentioned that “sheep were regarded as ‘the golden hoof’ that improved the fertility of the land. Their diet was not supplemented with valuable cereals or scarce fodder during the winter months, and they were left to scavenge over common grazing and fallow fields to spread their muck.” As a farm bordered on three sides by commercial potato fields and in need of more pasture, I wanted to explore whether our sheep’s grazing on rented fields was perhaps improving overall soil health. Instead of being the needy small, startup farm neighbor, could we have something valuable to offer in exchange?
Using funds from the Western SARE Farmer/Rancher grant, we conducted a two-year study to explore the value of animals in crop production rotations as well as ways in which small and large farms can work collaboratively. Due to food safety concerns and competitive markets, it is hard to run a mixed operation of both animals and crops, however, it may be possible for dairies/ranches and crop farmers to work together synergistically. I wanted to know if a “golden hoof” effect in Pacific Northwest (PNW) agricultural soils could influence soil health in potato systems, which could have implications for production on both sides of the state. Furthermore, it was important to document that the presence of sheep on the land would not exacerbate any serious soilborne disease issues for potato growers.
Working with the Cornell Soil Health Lab’s Comprehensive Analysis of Soil Health (CASH) we analyzed pasture plots that were the same soil type, but varied in sheep grazing duration from eight, four and two years; what we discovered is interesting. Based on this preliminary data, it appears pasture rotations/sheep grazing can improve several aspects of soil health as determined by direct and indirect CASH measurement which includes percent organic matter, aggregate stability and soil proteins — a measure of organically bound nitrogen (N) in the soil organic matter. Soil health indicators subtly increased with increasing sheep grazing durations across sites.
It does not appear — from our on-farm field and greenhouse studies — that sheep grazing rotations increased the incidence or severity of soilborne potato pathogens. However, a more robust, long-term study is needed as well as experimentation with alternative pasture species combinations.
Through this work, it is curious to see how soil health improvements are possible across land-use histories. Our farm’s pasture, with a history of eight years of continuous sheep grazing, had the highest soil quality rating (91/100, as determined by CASH rating system). While the neighboring pasture fields with a more recent history of potato production still had a relatively high rating (81-85/100), there is room for improvement.
Ultimately, this is what regenerative agriculture is about — the continued striving towards a balanced, agroecological system. Farmers need to consistently assess their regenerative practices in order to make agriculture as sustainable as possible across scales of production. It is not a destination, but a practice.
And when we discuss regenerative agriculture, we have to talk about relationships. This project made this clear. While land sharing between large, multigenerational farms is a common practice in the Skagit Valley farming region, transitions across generations and between large and small, old and new farms, is less common and reporting is limited. According to Hills et. al (2019), there are many barriers right now to improving soil health in PNW potato systems, including the need for intensive tillage, important tuber quality, limited crop residue left on fields and compaction. Animal rotations might be a viable solution, but like many idealized regenerative practices the right relationships are needed to actually make these practices practical, both logistically and economically. Components like proper fencing, lease durations, and rotation timing all have to be taken into consideration to guarantee success.
This project documents a viable, short-term exchange of land and ideas between two very different farm systems. The human capital here is key and will continue to develop and deepen over time, ideally.
For our farm, access to land is necessary for reducing feed costs, raising healthy animals, and staying financially viable. For our neighbors, affordable and easeful amendments are essential for long-term soil quality and productivity. Regenerative relationships, that are mutually beneficial, will ensure that agricultural systems can continue to thrive and evolve to meet the social and environmental demands of the future.
— Jessica Gigot is a farmer, writer and teacher. She runs a small, sheep creamery called Harmony Fields in the Skagit Valley with her husband and two daughters.
