The disk method of tillage should not be used because it brings up weed seeds near the soil surface to germinate. Cover crops that are planted too thick and grow too tall in the spring can bring additional problems. The spring rye growth of 12 inches is shredded just before planting. Research funded by the Leopold Center for Sustainable Agriculture demonstrated that 2 to 4 bushels per acre of broadcast oats over soybeans at leaf yellow produced the most cover and did not reduce corn yields the following year. The oats will winterkill in Iowa.
Weeds serve as a cover crop before planting.
Weeds between the rows between cultivations act as cover and then become green manure after cultivation. The livestock manure and the biosolids from the city of Boone provide the fertility needs of this 300-acre farm. These products are stored in a cement bunker to preserve nutrients. We spread twice a year, covering it with the moldboard plow in the fall and with the ridge-till planter in the spring. The remaining increase in labor and management return comes from reduced input costs.