This episode of Nature Notes was previously broadcast on March 3, 2013, and was written by Megan Wilde of the Chihuahuan Desert Research Institute.
When the morning whistle blows on Mimms Ranch, the cattle get to work. This herd has a job that might surprise a lot of people: improving the health of a desert grassland and its ability to absorb water. How are they doing it?
Just outside Marfa, Mimms Ranch is not your typical West Texas livestock operation. It’s a demonstration site of the Dixon Water Foundation, whose mission is to promote healthy watersheds through sustainable land management. Robert Potts is the foundation’s president and CEO.
Potts: Our purpose is improving the land and improving the water absorption of the land and using what is the most readily available tool to do that. And cattle we believe are the most readily available tool. Plus you have the additional benefit of food. So we’re also providing protein for people.
Potts says some people think of cattle as being bad for the land, and like any tool, they can be damaging if used improperly.
Potts: But the fact is all of these rangelands across North America and the world evolved with grazing. Grazing stimulates grasses’ root growth and makes the plants more vigorous. The problem is if the favorite plants are eaten every three or four days when it’s just starting to re-sprout.
Potts says their grazing system restored a tall-grass prairie on the foundation’s other demonstration ranches in north Texas.
Potts: We’d had very good luck enhancing the grass quality, enhancing the soil quality, and, for our mission most importantly, infiltrating more water to restore aquifers and groundwater systems and springs, that then feed creeks and rivers.
The foundation purchased Mimms Ranch in 2008 to try out their system in an arid grassland.
Temporary electric fences divide most of the ranch into 25- to 30-acre pastures, between which a herd of a hundred or so cattle are rotated. Almost every day, Potts or a ranch hand takes down an electric fence enclosing the herd and blows a whistle.
The cows have learned this means “fresh grass!” and dutifully walk to the next pasture. An electric fence is put back up to contain them, and the cattle don’t re-visit the old pasture for about a year. Grouping and rotating them between pastures this way simulates a bison herd’s grazing habits.
Potts: So what we do by moving the livestock is we’re giving that plant a chance to recover, to become a very vigorous plant. And once you have a healthy root system, you’ve got all sorts of microlife that are putting carbon back in the soil and making healthier soil that is not as hard, and therefore doesn’t shed water, but holds water and absorbs water.
To monitor how the grassland responds, the foundation has partnered with Sul Ross State University’s Borderlands Research Institute in Alpine.
Potts: There are costs associated with it. We have more infrastructure so we’re not saying this is the right thing for everyone to do. There are ranchers around here who’ve been doing well for a long time. But what we are saying is cattle are a tool to improve the range and that cattle can be a real part of a healthy range ecology. So there needs to be a greater appreciation for cattle and for ranching as a way of sustainably managing this landscape.