Thinking Outside the Box on Soil Health

Zack Smith and his business partners Sheldon Stevermer and Lance Peterson turned a winter brainstorm into a 2-acre pilot project that captured attention of farmers and consumers alike during the 2020 growing season.

Smith has spent nearly a decade adding practices including strip tillage and cover crops to improve soil health and long-term sustainability to his fifth-generation farm in north central Iowa. After years of low commodity prices, he knew he needed to also look for ways to add a new revenue stream to the farm.

“We were brainstorming ideas for intercropping alternative crops or relay cropping with traditional corn and soybean plantings to provide another revenue stream,” said Smith. “Lance suggested the idea of intercropping with grazing sheep instead of crops, and the concept took off from there.” 

What Smith refers to as “stock cropping” is a dynamic farming system that features row crops, grazing pasture and multiple animal species in a field at the same time. In the 2020 pilot project, Smith planted three 12 row strips of corn alternating with three 20-foot strips of a pasture mix including oats, annual rye, field peas, sorghum sudan grass, and forage rape. 

“The system allows us to harness the natural cycles of a plant-animal ecosystem to grow healthier animals, healthier soils, and lower the carbon footprint of the farm,” said Smith.

Smith and Stevermer built an autonomous mobile barn that moves through the pasture strips at a pace of about 10 feet each day. The 33 by 18-foot structure includes separate grazing pens for ruminants and pigs, with a covered shelter section in the middle. The shelter features water tanks fed by a rainwater collection system on the roof as well as supplementary feeders. A set of chicken “tractor” pens follow behind the main structure.

Regular Facebook posts, weekly video updates on YouTube and a live webcam feed provided insights into the health and growth of the animals and transparency to consumers.

Investing in the Future

Looking back on the first year of the project, Smith was pleased with both performance of the livestock and corn. Final harvested yield of the corn was about 260 bushels per acre, short of his original 300 bushel goal, but impressive for corn on corn given the very dry growing season in north central Iowa. All of the sheep, goats, pigs and chickens raised in the system were processed at local lockers and sold to consumers.

Plans for expansion in 2021 are already well underway with adjustments based on this season’s pilot run.

“We will manage the pasture differently and time seeding of the pasture mix according to when each section will be grazed, and are planning on adding laying hens to add another revenue stream,” he said.

Smith brings a well-rounded perspective in agronomy, business and production to the project. He graduated from Iowa State University with a degree in Agronomy and spent his career in agriculture retail and agronomy businesses. In addition to farming his family’s row crop acres, he owns and operates Smith Seed & Agronomy, which includes full service offering of crop protection, seed, and digital tools from Corteva Agriscience as well as soil sampling, cover crop seed and custom seeding, and other services.