Fall Incorporation of Cover Crops Reduces Snap Bean Stand

We tested whether it was better to incorporate cold-tender cover crops in the fall or spring in organic vegetable production. Fall tillage is often preferred because the soil is less likely to be wet, the soil warms and dries quickly in the spring, and freshly incorporated residue does not attract seed corn maggots. Delaying tillage until spring reduces erosion and allows more decomposition in place; it can also suppress winter annual weeds. We tested a crop of green beans following a cover crop of buckwheat, mustard, oats or sudangrass with plantings in Illinois, Michigan and New York in each of two years. With all four cover crops, the bean stand was lower if the ground was tilled in the fall. Fall tillage reduced the stand by >10% in three of five environments tested. Yield was reduced significantly in one of four environments where it was evaluated. Fall incorporation of cover crops represents a high risk relative to spring incorporation for organic bean management.