Planned Grazing benefits Soil Health at the Los Ranchos Agri-Nature Center

By Wes Brittenham, New Mexico Soil Health Champion and
Director of Horticulture at Los Poblanos, Historic Inn & Organic Farm in the Village of Los Ranchos

^{Churro sheep at the Los Ranchos Agri-Nature Center in December 2022. Photo by I. Jenniches CC BY 2.0}

The 25 acre Agri-Nature Center was created on the site of a former winery to preserve open space and maintain the Village of Los Rancho’s agricultural heritage through education, research, economic development, and community events. The Agri-Nature Center provides agricultural education for farmers and gardeners of all skill levels and ages and demonstrates best practices in regenerative agriculture. The overarching frame of reference is the practice of Regenerative Agriculture including Healthy Soil Principles.

One of the Healthy Soil Principles is keeping animals on the land, and as the Agri-Nature Center has been the summer home to a flock of Churro Sheep, there was an opportunity to have a soil test done on the pastures that had experienced planned grazing, and adjacent pasture which had no animals on it.

In Regenerative Agriculture it is understood that by utilizing planned grazing you can increase soil health and improve the amount and quality of forage as the animals move over the soil, deposit nutrients, slightly disturb the soil allowing for better water infiltration and aeration and are moved from area to area to reduce or eliminate overgrazing.

Agricultural Program Manager Joshua o’Halloran was curious to see what benefits were measurable, and whether the quality of the soil was improving or not. He took soil samples on December 21, 2022, on a two-acre field divided into 6 paddocks that had 13 sheep that were moved twice a week from paddock to paddock, and on an adjacent pasture with the same forage and irrigation schedule, but with no animals on it. These fields were irrigated by acequia every three weeks from April through October. 

We know that having animals on a piece of land without rotating them causes overgrazing, soil compaction and eventually degrades the land, reducing productivity, water infiltration and retention, and increases the opportunity for undesirable weeds to proliferate.

The soil samples were sent to Ward Laboratories for testing and analysis. These tests are referred to as PLFA tests, or a Phospholipid Fatty Acid Test, which measures the biomass of soil microbes. This form of test classifies groups of microorganisms but not species. For reference, one gram of healthy soil can contain 100 million bacteria, several yards to several miles of fungi, several thousand protozoa, and from ten to several hundred nematodes.

The results of the soil tests showed some interesting differences, with the pasture that was rotationally grazed having more microbial activity than the pasture with no animals on it. The pasture with the sheep had significantly more bacteria, actinomycetes, rhizobia, and total fungi including arbuscular mycorrhizal fungi and saprophytes. There were more protozoa present, and significantly more undifferentiated beneficial microorganisms.

This initial test shows the benefits of planned grazing, and the positive impacts well managed livestock can have to help improve and increase the volume and activity of these microorganisms in the soil. This increase in healthy soil improves water infiltration, promotes strong root growth, helps to aerate the soil, and increases the availability of nutrients to the root systems of the plant community. This results in higher quality, more nutritious forage, quicker regeneration from grazing, and improves overall habitat for wildlife as well, including beneficial insects and pollinators.