- Agronomic: barley, corn, peanuts, sorghum (milo), soybeans
- Vegetables: sweet potatoes
- Crop Production: conservation tillage
- Education and Training: demonstration, extension, on-farm/ranch research
- Farm Business Management: budgets/cost and returns
- Pest Management: competition, integrated pest management, mulches - killed, mulches - living, physical control, prevention, weed ecology
- Soil Management: green manures, soil analysis
- Sustainable Communities: sustainability measures
Weed control is one of the biggest problems with low input sustainable systems and organic systems. In this project, we explore the possibility of controlling weeds through limiting N transfer from N2-fixing soybean plants. Soybean varieties have different capabilities for N transfer, but this does not appear related to differences in mycorrhizal colonization – mycorrhizae act as the ‘bridge’ for N transfer into weeds plants. Low transfer seems to be an inherent trait of individual soybean genotypes. The results show that weed competitiveness and reproduction decrease greatly when N availability is limited.
1. Critically evaluate the role of N transfer in the development of weed populations.
a. Determine N transfer distances and penetration into weed patches, and the impact of transfer on weed population dynamics.
b. Determine the influence of N on weed competitiveness and reproduction.
c. Determine the impact of N on the N nutritional status of weed seeds and the competitiveness of offspring.
2. Compare weed growth, patch development, and seed production in a traditional organic production system with the new, modified system that uses a “low N transfer” soybean variety in rotation with crops that have low N requirements and high N use efficiencies.