This is where cover crops can help. These plants are grown during the off season to prepare the soil for the following summer.

"The use of cover crops in organic grain systems has many potential benefits," says Sarah Isbell. "These include improvements in soil quality, increased nutrient retention, prevention of erosion, and suppression of weeds." Isbell worked on cover crop and organic farm research as part of her doctoral degree at Pennsylvania State University. "In organic systems where synthetic inputs are not used, cover crops can be managed to reduce nitrate leaching through soils and supply nitrogen to cash crops."

The study was published in Agronomy Journal.

One major issue for cover crops is determining when to plant them. Cover crop seeds are usually sown after harvesting the primary crop. For corn, this is typically in the fall. This is because fields are uncultivated at this time, so cover crops can access all the resources needed to grow, and farmers can easily access the fields. The problem is crops like corn are harvested late in the season, leaving little time for cover crops to start growing and take effect.

Isbell and her team studied an alternative method: interseeding. This technique sows cover crop seeds in between rows of growing cash crops. That way, the cover crops can start growing, ready to take off when they get more sun after harvest. In an experiment at a Pennsylvania research site, the team compared the effects of interseeding versus post-harvest planting of cover crops with corn. Some of the corn was harvested for grain, while other plots were harvested for silage.