Weed Management in Organic Conservation Tillage/No Tillage

2005 Annual Report for LNC04-240

Project Type: Research and Education
Funds awarded in 2004: $146,314.00
Projected End Date: 12/31/2008
Region: North Central
State: Ohio
Project Coordinator:
John Cardina
Ohio State University

Weed Management in Organic Conservation Tillage/No Tillage


Field and laboratory/greenhouse experiments were initiated in the fall of 2004 and repeated in 2005. Since funding availability was delayed until October 1, 2004, it was too late to plant brassica cover crops that year, but they were planted beginning in August of 2005. Laboratory studies were initiated immediately to evaluate plant extracts as potential natural herbicides. Extracts from several species, including wild carrot and wild chervil, have shown significant inhibition of weed seed germination without injury to crops. Three brassica varieties were planted at each of three dates in the fall of 2005; these will be used as cover crops for weed suppression in no-till soybeans. Wheat and rye cover crops have been planted for comparison.

Objectives/Performance Targets

The objectives for the upcoming growing season are as follows:

Field Studies:

1. Complete construction on an Ohio model cover crop roller to be used in field experiments.

2. Evaluate weed suppression by killed and rolled brassica, wheat, and rye cover crops for no-till soybeans.

3. Evaluate plant extracts and other natural products for weed suppression in the field.

Lab/greenhouse Studies:
1. Continue to evaluate plant essential oils and extracts in preliminary screenings.

2. Conduct advanced evaluation of extracts that have shown potential for weed suppression; this includes more varieties and additional weed species.

3. Evaluate concentrations and formulations to enhance the effectiveness of extracts.


Field Studies:

1. Excellent stands of wheat and rye are in the field, waiting for planting; stands of brassicas vary greatly with variety and planting date.

2. Construction has begun on our unique design for a cover crop roller, and should be completed within the month.

Lab/Greenhouse Studies:

1. A large scale screening was completed on about 30 plant essential oils to evaluate postemergence activity in comparison with ‘standard’ products like acetic acid.

2. In a pre-emergence screening trial, we identified two plant extracts that have significant germination suppression on annual grass and broadleaf weed species. Experiments continue to determine optimum concentrations, duration of activity, and safety to crops.

Impacts and Contributions/Outcomes

Since the project is new, the impacts are limited at this time. Additional growers in western Ohio have agreed to participate in the project by evaluating the cover crop roller for no-till pumpkin production. An undergraduate student will be completing his senior independent study project on the plant extracts.


Warren Dick

School of Natural Resources
1680 Madison Ave
Wooster, OH 44691
Office Phone: 3302633877
Debbie Stinner

Research Scientist
Organic Food and Farming Education and Research
1680 Madison Ave
Wooster, OH 44691
Office Phone: 3302633534