Organic farming systems can significantly improve soil health over time. In a nine-year study on rich Iowa farmland, researchers found that an organic pasture system improved eight of 14 key soil health indicators, while a four-year organic rotation of corn, soybean, and alfalfa improved six. In comparison, the conventional corn–soybean system steadily lost soil organic carbon (SOC) at a rate of 0.35 g/kg per year. Organic systems maintained or improved SOC and boosted soil biological activity, nutrient cycling, and structure. 

The study compared three systems: a conventional corn–soybean rotation, an organic rotation with composted manure and alfalfa, and a perennial organic pasture of grasses, clover, and alfalfa managed without tillage. Each year, researchers measured biological, chemical, and physical soil indicators—such as microbial biomass carbon (MBC), mineralizable nitrogen (PMN), particulate organic matter, and water-stable aggregates (WAS). Improvements in soil biology and structure began showing at 3–7 years, with the pasture system responding fastest due to its continuous cover and no tillage. 

Changes in soil fertility (like phosphorus, potassium, and pH) were modest and inconsistent, depending on manure or compost inputs. While the organic rotation did include tillage and removed biomass during harvest, it still led to clear improvements, most notably during the perennial alfalfa phase and after compost application. 

The findings emphasize that building soil health through organic practices takes time, but comes with clear benefits. Farmers can quicken improvements by using perennials, reducing tillage, and applying compost strategically. Soil indicators like MBC and WAS can show early progress—even if fertility changes come more slowly. For organic advocates and policymakers, supporting diverse systems with long-term management in mind is key to restoring soil and ensuring resilient food systems. 

These organic systems offer an opportunity to build healthy soils, ensuring a sustainable agricultural future.