On-Farm Investigations of Stale Seedbeds with Biofumigation for Improved Management of Weeds and Soil-Borne Diseases in Chile Pepper

View the project final report

Commodities

Practices

• Education and Training: demonstration, display, extension, on-farm/ranch research
• Pest Management: biofumigation, cultural control, integrated pest management, prevention, weed ecology
• Production Systems: Vegetable production, non-organic

This project determined real-world benefits and limitations of false seedbeds and mustard-based techniques for weed control and disease management in chile pepper in New Mexico.  We hypothesized that false seedbeds implemented the summer prior to chile pepper seeding (herein “fallow season false seedbeds) can be combined with an overwinter mustard cover crop to produce a single, integrated tactic for improved pest management on commercial chile pepper fields in New Mexico.  We also hypothesized that mustard seed meal (MSM) added to soil before or after chile pepper seeding can suppress weeds and soil-borne diseases without harming chile pepper plants.  To test the first hypothesis, we measured the performance of mustard cover crops at sites with, and sites without, fallow season stale seedbeds.  To test our second hypothesis, we conducted field and greenhouse studies to determine the efficacy and crop safety of MSM amendments made before or after chile seeding.  Our results indicated that fallow season false seedbeds may not be compatible with a mustard cover crop because late-summer false seedbeds did not provide sufficient time for growth of the mustard cover crop before frost.  This was disappointing because fallow season false seedbeds reduce hoeing requirements in chile, and mustard cover crops are components of pest management strategies for solanaceous crops outside of New Mexico.  At sites where mustard cover crops grew successfully, buried-seed tests indicated that mustard cover crops potentially suppressed weeds in chile; however, this weed suppressive potential is not fully realized because of a lack of knowledge on best management practices for terminating a mustard cover crop preceding chile pepper in New Mexico. 

Results from the mustard seed meal studies indicated that MSM applications three weeks prior to chile pepper seeding reduced weed densities and hoeing times early in the chile pepper growing season.  MSM spread on the soil surface after crop emergence caused irrecoverable injury to chile pepper plants; however, chile pepper plants were not permanently injured, and fruit yield was not reduced, when MSM was incorporated in soil after crop emergence.  MSM applications after crop emergence suppressed emergence of Palmer amaranth (Amaranthus palmeri) and growth of Phytophthora capsici, which are common pest problems during the middle and later phases of chile pepper production in New Mexico. 

Our educational outreach program included presentations at field days and stakeholder meetings.  Total attendance across all outreach events exceeded 1100 people. Farmers and agricultural professionals who completed pre-then-post tests indicated that our presentations promoted understanding of the benefits and limitations of mustard cover crops and MSM amendments for weed and disease management in chile pepper.  Personal interactions with farmers indicated enthusiasm for fallow season stale seedbeds, and suggested adoption of this cultural strategy for suppressing weeds in chile pepper.    

1. Through on-farm research, determine if fallow-season false seedbeds can precede an overwinter mustard cover crop that reduces incidence of soil-borne disease, weed infestation severity, and weed management requirements in chile pepper.
2. Develop safe and effective strategies for using mustard seed meal to control weeds and soil-borne diseases in chile pepper.
3. Communicate the benefits and limitations of fallow season stale seedbeds, mustard cover crops, and mustard seed meal for weed and disease management in chile pepper.