No-till and cover crops build soil and restore moisture

In 1995 Jimmy and Ginger Emmons tired of the high input and machinery costs wrapped up in tilling their wheat fields black, and then keeping those fields weed-free. After generations of tillage and earlier years of "blowing dirt and sand," the soil also had no structure and no aggregates. They wanted to try something different: no-till to reduce both costs and erosion.

Unfortunately, their then farm partners — Jimmy's father and grandfather—balked. They said no-till just wouldn't work on their farm near Leedey in the semiarid northwestern corner of Oklahoma.

Back then, there wasn't a no-tiller to be found in the area, where the simple combo of growing winter wheat and grazing cattle was king. Still, the young couple held their ground. They started no-tilling on land they owned, but they ran into some bumps that they smoothed by adding cover crops. Grazing cattle on the cover crops ramped up the benefits the Emmonses were beginning to see.

Benefits Galore

Today their fields hardly resemble the land with which they began. Every one of their 1,800 acres grows a cover crop, and their cash crops these days are so diverse they're hard to count. Soil organic matter has jumped, and water infiltrates the soil as if it were a sponge. On top of that, input costs have plummeted.

Named Soil Health Champions by the National Association of Conservation Districts, the Emmonses also received in 2017 the Oklahoma Leopold Conservation Award for the conservation work they've done on their operation. As the soil health mentoring coordinator for the Oklahoma Conservation Commission (OCC), Jimmy Emmons often speaks to farmers looking to try no-till and cover crops.

"The hardest part is having patience," he says. "It can take three to five years to get a no-till/cover crop system cycling. But the longer it goes, the better it becomes."

"The key is to start getting carbon into the soil, start storing water in the soil, and start cutting back on inputs," he adds. "Give the soil microbiology a chance to start freeing up the nutrients you don't have to buy."

Trial and Error

None of this was in the Emmonses' playbook when they first started no-tilling. They learned by trial and error.

"In the beginning, we still thought the soil surface had to be clean, no residue," says Emmons. "Then we started getting compaction problems. After no-tilling for a while, we went back to tilling. I just couldn't get the system figured out."

At a conference, Emmons heard Ohio farmer David Brandt talk about his experience with no-till and growing cover crops.

"Growing cover crops seemed like the missing link to our system," says Emmons. "I wanted to grow some, but I didn't know how to do it in our arid environment. This is not Ohio! And friends and neighbors thought I was crazy for wanting to try."

Realizing he needed guidance, Emmons reached out to his district Natural Resources Conservation Service staff as well as to the Oklahoma Association of Conservation Districts, the OCC, and the Noble Research Institute. "I agreed to make my farm a demonstration farm for no-till and growing cover crops," he says.

The first perceived roadblock he had to overcome before jumping headfirst into growing cover crops was determining how much soil moisture they would take. Would they rob the farm of the moisture needed to grow wheat?

Test plots on his farm answered the question with a resounding no. Moisture sensors and temperature probes in a cover crop plot showed that "the cover crop canopy saved more water than what was evaporating off the control plot where there was no cover crop," he says.

Diverse Cropping System

Inspired by that experience, his planting of both cover crops and diverse cash crops expanded. Today, the Emmonses raise as many as 14 cash crops.

"Our warm-season rotation includes crops like soybeans, grain sorghum, and cowpeas for seed," says Emmons. "Our winter rotation includes barley and cereal rye for seed."

Depending on the year, the Emmonses might also grow winter wheat, canola, sunflowers, milo, or sesame.

"We usually won't grow the same crop on the same field for three to four years," he says.

After harvesting cash crops, the Emmonses plant a 14-way cover crop mix. However, double cropping in some fields provides both cash crop and cover crop benefits. For instance, they plant sesame and yellow sweet clover at the same time. After harvesting the sesame, the clover grows rapidly and is ready to be harvested for seed the following summer.

Grazing their cattle on the cover crops provides additional income as well as benefiting soil. The Emmonses have grazed their 220 cow-calf pairs as well as yearlings on cover crops. They have found the rate of gain on the cattle generates $115 to $120 per acre, more than offsetting the $20-per-acre cost for planting the cover crop. They crossfence fields in paddock sizes requiring cattle to be moved every one to three days.

Their management system has caused soil organic matter to increase.

"When we started," says Emmons, "the organic matter in some fields was as low as 0.4%. It now ranges from 1.5% to 3%."

Water infiltration has also improved. Water now infiltrates the soil at a rate of 3.5 inches in 40 seconds, notes Emmons. "Ten years ago, it took an hour for a half inch of moisture to soak in," he says.

Hand in hand with the conversion to no-till and adoption of cover crops has come a marked reduction in input costs.

"Our fuel bill used to run $128,000 a year," says Emmons. "Now we're down to $20,000 a year. "Besides that, we have cut our fertilizer inputs by 85% of what we used to apply," he adds. "We've also cut our applications of herbicide and insecticide by the same amount."

Carbon Sequestration

His years of experience with growing cover crops in a semiarid environment have shown Emmons how valuable the cover crops are in building soil health and resilient crops.

"The cover crops and diverse cash crops on our farm have sequestered carbon in the soil; they've held the soil in place, and their roots have provided food for the soil microbiology," he says. "A lot of people believe we don't have enough rainfall here to grow cover crops. But if your rainfall is infiltrating the soil at a rate of only a half inch an hour — like ours was — then the rest of the moisture in a big rainfall runs off. It can't be used by the crops. We need to keep every raindrop where it falls. By building soil, we can build the soil water bank crops need to grow."