Manufacturing Soil


Scandia farmers hope to replace commercial fertilizers with compost

By Cynthia Scheer Telescope News

The Robisons are in the composting business. Brothers Delton and Doyle Robison began the composting project this spring and said they plan to have the compost available for purchase by Spring 2017. The brothers, who farm with their children and hired labor, use a highly refined recipe of alfalfa hay, corn stalks, soybean stubble, milo stalks, cattle manure and water to create a nutrient dense product that they said will reduce – and eventually eliminate – grain producers’ need for commercial fertilizers.

Doyle Robison said it all began with an article about composting.

“We wanted to improve our soil productivity,” he said of looking into composting.

The Robisons, who own Robison Farms, located north of Scandia, have been farming together their whole lives and have been in the alfalfa hay business for about 20 years.

The brothers said research on hummus compost shows that after a few years of use, soil fertilized with the compost becomes soft, and plants grown on the land require less water. They said studies show fields fertilized with compost and only half the normal amount of fertilizer yielded 10-percent more crop than fields fertilized with normal methods, and all conventional fertilizers may be eliminated after a few years of using the compost.

Business venture

The Robisons converted “high priced irrigated ground” into their compost yard. The yard will hold 88 compost rows, which are each 328 feet long. Each row has 351 cubic yards of material, they said.

They did extensive dirt work to the yard so that water would drain away from the compost windrows, and they created a runoff system that feeds into a lagoon. The Robisons said they hope to soon re-use water from the runoff lagoon.

The Robisons also purchased several pieces of “expensive” equipment, which they said allows for precision when making compost.

They purchase much of their compost ingredients. One compost row requires 18,000 pounds of corn stalks, 22,000 pounds of wheat straw, 26,000 pounds of soybean stubble, 26,000 pounds of “poorer grade” alfalfa, 20,000 pounds of milo stalks, 32,000 pounds of manure from a dairy farm, and lots of water. The moisture level of the mix is 40 percent, Doyle Robison said, which is why the mix begins to get hot within 30 minutes of being laid into windrows.

“The microbes are already working that fast,” he said.

Clay and manure from a local feedlot are applied to the tops of the windrows the day after they are formed.

The Robisons said people can use a variety of things to make compost; this is the recipe they’ve selected. The secret to success, they said, is to have the right carbon and nitrogen ratios.

The Robisons can make about two-and-ahalf compost windrows a day. It takes the Robisons eight loads of product mixed in a supreme mixer to make one windrow.

The compost crew checks the carbon dioxide levels and temperatures – temps of 130-160 degrees for five weeks kills weed seeds – of every windrow each day before the rows are turned with a special machine and water is added. Turning the compost rows pulls in oxygen to feed the microbes, which turn the ingredients into compost.

Doyle Robinson said it takes five weeks to make compost. Robison said the daily process of uncovering the rows, turning them, and covering them again, is labor intensive. They have been using 50-foot hay tarps that are held down by tires. He hopes to cut down on some of the required man power next year with the addition of 320-foot compost tarps and a tarp roller.

“Then we can do it with one guy,” he said. “Right now it takes four guys.”

Using compost

The hummus compost is mature at 11 weeks, and the Robisons send samples of the product to a lab to be tested for quality.

In the first eight rows that they made this past spring, Robison said a few rows tested 105; the desired number is 120. The brothers attributed the lower score to grinding the hay before mixing it – they don’t grind it anymore – and to the heavy rains and muddy conditions that kept them from turning their rows every day. A faulty water seal on the compost turner limited the amount of moisture that was added to the rows during the daily turning, they said, which also likely decreased the score.

The Robisons have been spreading their compost on “thousands of acres,” including their land as well as testing the product on the fields of neighbors.

They’ve also been deep ripping the compost into new hay ground and replanted hay fields.

They said they plan to begin selling the hummus compost in the spring. Compost with a score of 120-140 will sell for $205 a ton, the Robisons said, and platinum hummus compost, which scores 160 and above, will sell for $500 a ton.

The Robisons said the microbes from the platinum hummus compost can be extracted and put into a liquid solution that can be sprayed onto fields. They plan to start extracting microbes this spring, they said.