In the summer of 2021, the first diverse warm-season cover crop Kevin Pierce drilled into what had been a conventionally cropped monoculture of cereal rye on Noble Research Institute’s (Noble) Red River Ranch was a big success.

“That first year, it was great. It was huge,” he says of the 15-seed mix, half grasses and half broadleaves. “When all the seeds came up and they grew, we thought, ‘Well, this is easy.’ It looked great.”

They grew gourds, cowpeas, buckwheat, radishes and more, along with a mix of grasses.

He followed that in the fall with a cool-season cover crop mix that produced a decent stand of wheat, oats, rye, barley with vetch, clover, turnips and other crops mixed in.

Then came the drought. Whether it was from a lack of water or the possibility that whatever fertility was left from the last conventional year’s application was now depleted from the sandy soils – or both – very little of the next warm-season cover crop they seeded came up or grew.

“What little bit of stand we did get, the fields were really ugly,” Pierce says. “They were covered in marestail, and that wasn’t something you were really proud of, to be honest. You couldn’t even find a radish out there.”

It also was still dry the whole time they were trying to seed the cool-season mix in the fall, he says, and again, not much of what they seeded grew.

So what happened?

Context and observations

As the first of the six soil health principles for regenerative ranching says, context is important. Pierce describes some of the context that he and his team are dealing with on Red River Ranch:

1. Many of the fields in question were cropland acres that had been used to grow wheat or cereal rye for spring grazing for years. “And if we grew too much grass, we would bale it. We would take and take and take [from the land],” he says.
2. In the past, Noble staff applied synthetic fertilizers to feed the growing wheat or rye and used herbicides to terminate the crop before seeding the next one. With the change to regenerative agriculture on all Noble Ranches in 2021, those practices stopped cold.
3. Now they no-till drill cover crop mixes into still-growing forage, with no added inputs. He postulates that leftover synthetic fertilizer may have helped feed the new, diverse cover crops in 2021, but not enough nutrition was present in the sandy soil to support them in the next (quite dry) year.
4. Because their main goal with the new practices and cover crops is to build up the health of the sandy soils on the river bottom ranch, Pierce and his team based the diversity of their first cover crop mixes on what the soil needed according to Haney soil tests. That meant attempting to grow many species there for the first time.
5. Some of the ranch’s fields already have annual grasses such as crabgrass and johnsongrass growing in them, and they get a head start on the newly seeded warm-season cover crops. The competition is tough. In addition, he says, “By the time the warm-season cover crops you plant get ready to graze, all of that existing grass is already too rank and at low quality for grazing.”

Dorper sheep graze a cover-crop mix at Vos Farms near Hugoton, Kansas. Photo by Rob Mattson, courtesy of Noble Research Institute.

Observations and questions

While the jury is still out on what exactly happened (besides the drought) with many of the cover crops planted at Red River last year, Pierce is asking himself these questions about possible contributing factors:

1. Was the planting depth right?

He says it’s possible the depth he set wasn’t optimum for good germination and emergence in 2022. “I’ve been farming for 30 years, so I feel like I have a pretty good idea of what’s needed, but this is a new ballgame.”

2. Is it overreaching to try to grow two crops a year on this soil, in this context?

“Maybe we’re asking too much of [the land] after taking away all the inputs we were putting in before,” Pierce wonders. Not only that, but the timing was changing on him. No longer chemically terminating the cool-season crop ended up delaying the planting of the warm-season one, he says. “Instead of planting around May 1, we’re having to plant it in late May or early June because the cool-season crop’s not done yet. Now you’re late, and you’ve missed all the early rain.” Pierce tried mechanically terminating the crop in some areas by laying down the tall growth with a roller-crimper, and in other areas, he ran cattle across it to lay it down. However, he says neither method seemed to make a difference in helping get the warm-season crops planted on time. “From my experience so far, it’s hard to plant a crop into a crop that’s still growing.” That being said, he does want to use the cattle to incorporate the cover crop biomass for soil health. “We want to grow it up big and come back with the cattle, even if some of it is large and rank and the quality not that high. They’ll eat the good that they like and stomp the rest back down on the ground.”

3. When should starter fertilizer or other soil amendments be considered? What type is best and how much?

“I have more questions about whether or not to use fertilizer or other types of soil amendments than answers,” Pierce says. “If soil nutrient levels or pH is really low, would it not be better if we applied some ‘starter’ fertilizer, chicken litter or lime to help the plants get started growing good and then begin our adaptive grazing to cycle the nutrients? What are the trade-offs?” Like many area ranches, Red River has a lot of bermudagrass pastures, and crop fields planted in annual cover crops. Historically, these types of pastures were routinely fertilized according to soil test results to keep them productive. Red River stopped applying fertilizer to these pastures three years ago. Recent Haney soil tests indicate the soil nutrient levels of nitrogen, phosphorous and potassium are very low on most pastures, and the annual cover crops have been very slow to start growing each season, made worse by the drought conditions. This limits cover crop production and subsequent grazing until late in the growing season. 

Pierce’s experiences confirm it. “The cover crop plants grow very slow where the fertility is really low,” he says. “It takes several months for them to develop. It just doesn’t seem like the plants get enough nutrients from the soil to grow and become productive until most of the growing season is over. We can sure tell which pastures have the better soil tests.” It stands to reason that the more forage that is grown early in the growing season, the more regenerative grazing can be done to start rebuilding the soil. “We think some type of starter or low application rates of soil amendments at planting could speed up the process of regeneration,” but Pierce, being mindful of the economics adds, “What is the cost-benefit? Is it worth it? That’s the answer I want to know ... We wondered if a little starter fertilizer might help with early root growth,” said Pierce, “So we tried something on a couple of cover crops fields last year.” This last fall, Pierce applied pelleted chicken litter as a starter soil amendment on a portion of the cropland at the ranch to see what effect it has on the cool-season cover crops. “We didn’t have much rain since it was applied until this last month,” Pierce explains. “So the jury is still out on the results.”

Steers enter a fresh paddock of mixed cover crops at Noble Research Institute's Pasture Demonstration Facility in Ardmore, Oklahoma. Photo by Rob Mattson, courtesy of Noble Research Institute.

Lessons learned and things to try

1. Start small, and build off of what you learn

“If you go out there and experiment on a thousand acres instead of a hundred acres, you could be highly disappointed the first year and may not ever want to try again,” Pierce says. “There’s definitely a learning curve with cover crops.”

2. Experiment, adapt and change

After the past two years of experience, Pierce is considering trimming down his warm-season mix to three or four grasses he knows will grow, such as millets and sorghum, and a legume or two, such as cowpeas. This way, he hopes to grow the biomass he needs for soil health and save on seed costs. “Until we get to the point of having better soil health, I don’t know that we need to spend the money trying to plant some of those things [that aren’t growing well],” he says.

3. Consider a “target crop”

Targeting either a warm-season or cool-season cover crop as the priority in a given year may increase the odds of success. For Pierce, in some areas that may mean getting good grazing out of the warm-season grasses already growing in the summer and focusing on seeding and growing a more diverse cool-season crop. In others, it might be focusing on a warm-season crop and taking a break in the fall, keeping the ground covered with volunteer forage until it’s time to seed a summer cover crop mix again.

4. Keep good records of what you try

At Noble, Pierce and the other ranch managers use AgriWeb to track cattle inventories, records on individual animals, feed inventories and crop plantings. Now, as they start using PastureMap to plan and record daily grazing moves and the locations of temporary fences, they can look back and see how their grazing management and timing affected each area of the ranch.

Of all the changes in mindset and practices that come with starting the regenerative ranching journey, Pierce says, “This cover crop stuff has been the toughest part of this whole deal for me. I’m learning as I’m going.”

Marilyn Cummins is a freelance writer based in Missouri. This article was originally published by Noble Research Institute.