2007 Annual Report 1a.Objectives (from AD-416) We propose to develop, refine, and transfer to farmers a new technology for "on-farm" production of AM fungus inocula. 1b.Approach (from AD-416) We will supply six farmers with host plants pre-colonized with individual species/isolates of AM fungi and who will then transplant them into enclosures filled with compost diluted with vermiculite. The plants grow for one growing season during which the fungi proliferate as the roots grow throughout the media. The following spring, the farmer can then deliver it to the field as he/she would apply and incorporate compost, or mix it into potting media in which vegetable seedlings are grown for transplant to the field. Outplanting performance of inoculated and non-inoculated controls will be monitored, yields measured, and economic return of the technology calculated. 3.Progress Report This report serves to document research progress under Cooperative Agreement 408-1935-186 with the University of Vermont. This agreement services the Sustainable Agriculture Research and Education grant no. LNE 03-179, “On-farm production of mycorrhizal fungus inocula,” awarded in 2003. This agreement was granted a no cost extension for calendar year 2007. Additional details of this research can be found in the report for the parent project 1935-12000-010-00D: Development of efficient and practical methods for producing arbuscular mycorrhizal fungi. This agreement contributes to Milestones of Objective 2 of the project. A core group of 6 farmers participated in a pilot project for the transfer of technology for the on-farm production and utilization of arbuscular mycorrhizal [AM] fungus inoculum. Inoculum was successfully produced at each farm in 2003 through 2006. The inoculum production systems are being replicated in the current growing season at two of those farms. Inoculum produced in 2005 was used in vegetable production systems in 2006 with success for the production of carrots, potatoes, and tomatoes. Recent work under this agreement addressed the need for a fertilizer regime and inoculum dosage for the growth of pepper and tomato seedlings well colonized by AM fungi during the greenhouse production phase. We found an inoculum level of 5-10% of the potting media by volume and watering with a nutrient solution containing 0.31 to 3.1 ppm phosphorus allowed the roots to become well colonized by AM fungi. Activities are monitored by the ADODR via site visits and active participation. (NP 202 Action Plan component Understanding and Managing Soil Biology and Rhizosphere Ecology, Performance Measures in the ARS Strategic Plan, 5.2.2 and 5.4.2).