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Cover Crop Grazing on a Vegetable Farm


Wayne Brown and his family graze cattle and breeding ewes all over the San Luis Valley’s high desert. Over the past three decades in Mosca, Colorado, the family has increased their herd numbers and found economic stability through long-term grazing agreements with farmers.

“We don’t have a ranch with enough acreage to do the ranch thing,” Brown said. “We are buying feed wherever I can find it throughout the year. Knowing you have a place you can go back to is big. It is a relief.”

Three years ago, Brown heard that Brendon Rockey, 42, a specialty potato farmer in Center, Colorado, had cover crops that he was turning into the soil at the end of the growing season. At the time, Rockey was terminating the crop as green manure because a previous grazing arrangement fell apart. Cattle broke through an electric fence, resulting in calls to the sheriff, angry neighbors and a threat to the cash crops. The deal was off.

“Planting a cover crop does not automatically mean you improve your soil health,” Rockey said. “You can actually send it the other direction. Same thing with cattle. Managing the cattle correctly improves your soil health.”

Finding a responsible rancher to graze cover crops in the middle of potato country was seemingly impossible. Rockey needed someone willing to take full responsibility for the labor, someone who could respond to an emergency within the day and respect government livestock and vegetable production regulations. There was interest from a certified organic rancher in the area, but Rockey is not certified organic. Despite his intensive biological practices, the absence of this label prevented that potential partnership.

When Brown heard about Rockey’s cover crops, he presented him with a plan that posed minimal risk — a plan that, if executed, would meet all his conditions and Brown’s, too. The first season, they agreed on grazing calf-cow pairs on an annual cover crop mix from July through the late fall using an electric fence around the perimeter of a 120-acre circle and a 60-acre half circle under center-pivot irrigation. under center-pivot irrigation.

Colorado rancher Wayne Brown and his sheep in the Rio Grande National Forest.


The keys to successful cover crop grazing on a vegetable farm are tonnage, time, water and fencing.

“Is there enough?” Brown said he asks himself when considering entering into an agreement with a farmer. “If it takes me three days to get ready, I want more than a week — the longer, the better. You don’t want to drive all day for one cow.”

During the winter months, Brown’s goal is to maintain his 60 head of Angus crossbred cows and 800 head of Merino breeding ewes. He grazes his livestock all year except for during spring calving and lambing when the animals are bale-fed at his ranch.

“Those are the most expensive months when you are feeding hay,” he said.

When he is grazing cattle in a circle with center-pivot irrigation, Brown uses a two-strand electric fence around the outer perimeter and runs one strand of fencing from the center pivot to the perimeter to create a pie slice in the circle. Every forth post on the perimeter is a t-post. He runs a second strand from the center pivot to this post to create a second pie slice. This design, he said, makes it easier to control the cattle when they open up the subsequent paddock. It creates a “leap frog” situation.

“It is a portable fence you can move everyday,” he said. “You decide on how big of a piece you want grazed depending on what the farmer wants. You want to clean it up and figure how long it will last.”

Brown’s cows spend 8 to 10 months out of the year behind a hot wire, and understand that they must eat everything — including, most importantly to the farmer, weeds.

Nutritional value is a crucial factor. Based on the number of cattle Brown turns out in the field and the forecasted time it will take to graze each pie slice, Rockey choses to plant his cover crops in phases to accommodate the cattle’s diet. This timing also ensures the cover crop won’t go to seed too early and reestablish on the farm the following year.

“You assume the nutritional value will be there and for the most part it is,” Brown said. “You have to go off of the body condition of the cow. You have to visually be watching and that is tough because it can change quick.”

Brown’s bulls have foundered on Rockey Farms because the feed is too rich, resulting in sore feet. One remedy, he said, is bringing in roughage. However, convincing the cattle to eat it is not easy. He’s found giving the animals time to adapt is the best first reaction.

Brown turns out his cattle on to five to six farms throughout the year. Some of the fields, especially those that are only one or two cover crop species, are also very rich. It seems that the more diverse the mix, the healthier the animal.

Last fall, Brown found fresh feed for 1,400 breeding ewes on a 60-acre mature cover crop half circle that rotates with Rockey Farm’s specialty seed potato lots. The 17-day graze was completed without a hitch, and the expected carbon cycle and weed control benefits are highly anticipated.ing down into the pit on a regular basis.

Cows graze a Rockey Farm’s cover crop in mid-July. Water tanks are placed at the center pivot for easy access.


For Rockey Farms, the economics of grazing Brown’s livestock is the foundation of the relationship. The pasture rent, calculated per head, balances out the seed costs, reduces the farmer’s labor and complements the carbon cycle.

“I don’t have to go out and mow anymore,” Rockey said, emphasizing that the livestock are controlling unwanted pigweed without compacting the soil. “This is another huge advantage. Then there is the nutrient cycling — the stimulation of microbial activity.”

The stimulation improves the health of the cash crop, specialty potatoes, which is planted the following year.

“When we had barley stubble instead of the cover crop, we had a huge nutrient tie up,” Rockey said. “Now, when the nutrients goes through the cow, produces that manure, the nutrients are ready to go and we have a better cash crop.”

Before bringing livestock into his fields, Rockey would mechanically incorporate the green manure, never terminating with chemicals. He’s found that the livestock’s grabbing and pulling of the plants releases root exudates and feed the soil’s biology in ways mowing does not.

“When you are just using green manure, it is a closed loop,” Rockey said. “There is nothing in that biomass that didn’t come from the soil. Having the cattle out there is still a closed loop, but you are adding one more component to it.”

When you incorporate the green manure, it is broken down biologically. “The fungi and bacteria are doing the job for you,” Rockey explained. “But now you are more dependent on soil temperature. If that residue is out there the next spring, you have to give it enough time to warm up so that biology can break it down so that the nutrient becomes available. The cows have a huge jump start on that process.”

That rumen stimulation, along with compost and biological fertilizer applications, he added, are crucial to efficient nutrient cycling. The compost is taking an outside source and bringing it in, similar to a situation where you would supplement feed with hay bales.

“I struggle with a lot of people because they see the cattle out there and they see the manure out there and they think I just added nutrient to my soil,” Rockey said. “No, I didn’t. I just cycled what is already out there.”

Timing is a crucial factor for successful cover crop grazing for Rockey, too, particularly because the San Luis Valley’s growing season is no more than 100 days.

“We are planting potatoes as soon as we can and we are still pushing going into cold soils,” Rockey said. “There is a lot of opportunity for disaster. In some other areas, where me. You have to be very careful. You have to pay attention.”

The sprinkler stays ahead of the cattle, keeping the cover crop growing throughout the season. Rockey and Brown communicate regularly about the water and field management.

There is also no guarantee the cattle won’t escape, which Rockey has experienced first hand.

“There is potential for a wreck,” Brown confirmed. “We deal with that year round. Getting to know each other and what you are comfortable with is part of all this. We work with people all year. You have to learn to read people.”


Brown and Rockey are committed to their grazing relationship as long as they can meet everyone’s, and every animal’s, needs.

“The most beneficial is running your own cows,” Brown said, having worked with farmers that ended up buying their own cattle or sheep. “That is one of the problems I run into now. There is not enough money for both of us. You have to decide what is best for you.”

Rockey has no interest in getting into the livestock business. He will graze both Brown’s cattle and sheep on his cover crops this season, and hopefully for many seasons to come.

“The way I look at economics is a lot different,” Rockey said. “Most farmers are really set on short-term economics. Having Wayne on our place benefits our economics long term. There is a longer pay back on it, but it is definitely there.”

He added, “Most farmers are only going to be interested in bringing you out if you are going to increase tonnage on the potato crop next year. To me, I am content with my tonnage, but I am looking to reduce my inputs to maintain that tonnage. That is a different mindset.”

Lauren Krizansky and her husband Brendan Rockey run Rockey Farms in Colorado’s San Luis Valley.