Inoculation with mycorrhizal fungi increases the yield of green peppers in a high P soil

Arbuscular mycorrhizal [AM] fungi are mutualistic symbionts that impart a number of benefits to host plants, any one of which can make them important contributors to productivity of alternative agricultural systems. Inoculation of vegetable seedlings prior to outplanting is economically feasible. One of three inoculation treatments was imposed upon Capsicum annuum L. cv. Camelot seedlings: (1) Glomus intraradices, (2) a mixed inoculum of Glomus mosseae, Glomus etunicatum and Gigaspora rosea, and (3) uninoculated controls. Plants were transplanted into high P soil field plots that received either composted dairy cow manure or conventional chemical fertilizer. There were no significant differences in yield between nutrient amendments, but inoculation with AM fungi significantly affected fruit yield. The mixed inocula increased yields relative to controls by 14 to 23% in plots amended with compost and 34% one year with chemical fertilizers. Glomus intraradices depressed seedling growth relative to controls and decreased yields in one of two years. Inoculation with AM fungi is a management option that should not be ignored in high P soils, but proper selection of inoculum is essential.