Field experiments showed that the soil conservation advantages of no-till agriculture can be used in organic systems where soybeans are planted into standing residue of small grain cover crops planted the previous fall.
Three years of studies on various extracts from seeds of many crop plants show little potential for an easily-extracted plant-derived product that could provide residual weed suppression and substitute for synthetic herbicides in a no-till organic system.
Soybean yields were more affected by late planting in the no-till plots than by weeds or possible allelopathy from rye cover crops.
The specific objectives of the project were as follows:
1) Develop agronomic practices for managing allelopathic cover crops to control weeds while enhancing soil quality.
a. Evaluate planting time and methods for establishment.
b. Determine optimum proportions of mixed cover crop species for weed suppression.
c. Evaluate grower experience using cover crops for weed suppression.
2) Evaluate the effectiveness of various natural products for suppressing weeds;
a. Screen essential oils, vinegar products, organic soaps, etc. against typical grass and broadleaf weeds in greenhouse studies.
b. Evaluate effectiveness of promising natural materials for suppressing weeds that appear in a cover crop system.