Biofumigants in Commercial Onion Production to Enhance Soil Nutrient Availability, Soil Quality, and Control of Weed, Nematode, and Disease Pests

View the project final report

• 2002 annual report
• 2003 annual report
• 2004 annual report

Commodities

• Agronomic: barley, wheat
• Vegetables: onions

Practices

• Crop Production: cover crops, nutrient cycling, application rate management
• Education and Training: extension, on-farm/ranch research, participatory research
• Farm Business Management: whole farm planning
• Pest Management: biological control, competition, mulching - vegetative
• Production Systems: general crop production
• Soil Management: green manures, organic matter, nutrient mineralization

Biofumigant treatments (Idagold, mustard; Sunrise, canola; Colonel, oilradish) did not increase P and N concentrations in onions, but mineralization of N increased on an infrequent basis. Fumigation, metam sodium, stunted early and late season onion growth at low soil P, biofumigant treatments had little effect on early or late season development. Stands and yields were reduced by biofumigants in some years. Biofumigant treatments had little affect on pink root and are not recommended for control. Metam sodium treatments had the greatest affect on pink root and is recommended, but it sunted early growth and tended to reduce stands and lowered Mycorrhizae colonization. Metam sodium controlled the most weeds but was not acceptable, Colonel and Sunrise volunteered. The high-input herbicide program was the best, followed by the low input program; both were better than an untreated check.

The objectives of this work are:
1. Evaluate a mustard and oilradish cultivar for the ability to reduce onion production problems, and compare them to soil fumigated with Metam Sodium and not fumigated.

2. Evaluate summer-fall bio-fumigant crop effects on both P and N availability to subsequent onions.

3. Evaluate and compare soil properties such as cation exchange capacity, infiltration and permeability rates, water-holding capacity and bulk density.

4. Determine if a bio-fumigant crop positively or negatively impacts root populations of mycorrhizae and Phoma terrestris.

5. Determine if the use of bio-fumigant crops in onion production has potential to reduce the use of synthetic fumigants and herbicides applied for weed control by reducing weed germination and growth.

6. Evaluate the effects of fallow, Metam Sodium, a mustard and oilradish cultivar on nematode population and subsequent nematode damage to onions.

7. Disseminate information by conducting research on grower farms, presenting data at field days, workshops and annual growers meetings.