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ARS Home » Northeast Area » Wyndmoor, Pennsylvania » Eastern Regional Research Center » Molecular Characterization of Foodborne Pathogens Research » Research » Publications at this Location » Publication #315200

Title: Inoculation of sweet potatoes with AM fungi produced on-farm increases yield in high P soil

item Douds, David
item Lee, Joseph - Joe
item SHENK, JOHN - Shenk'S Berry Farm
item GANSER, STEVE - Eagle Point Farm

Submitted to: Journal of Applied Horticulture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2015
Publication Date: 4/1/2016
Publication URL:
Citation: Douds, D.D., Lee, J., Shenk, J., Ganser, S. 2016. Inoculation of sweet potatoes with AM fungi produced on-farm increases yield in high P soil. Journal of Applied Horticulture. 17(3):171-175.

Interpretive Summary: Arbuscular mycorrhizal [AM] fungi are naturally-occurring soil fungi that form a beneficial symbiosis with the roots of most crop plants. Among the benefits the plant receives are increased nutrient uptake from the soil and enhanced disease and drought resistance. These benefits make utilization of these fungi an important component of sustainable agriculture systems. We tried two methods of inoculating sweet potato plants with AM fungi: 1) placing the fungi in the planting hole in the field and 2) growing the small plants first for two weeks in the greenhouse in horticultural potting media inoculated with the AM fungi. The experiments were conducted over 5 years. Results showed an average increase in yield of sweet potatoes due to inoculation of 10% over the uninoculated controls. Routine use of AM fungus inoculum in vegetable production could yield significant benefits.

Technical Abstract: Vegetable farmers who grow seedlings for later outplanting to the field have the opportunity to incorporate arbuscular mycorrhizal [AM] fungus inocula into potting media to produce plants ready to benefit from the symbiosis upon outplanting. Inocula of AM fungi are available commercially or may be grown on-farm. The impact of AM fungus inoculum produced on-farm upon yield of sweet potato (Ipomoea batatus L.) was studied in a field experiment over six site-years. Rooted cuttings were inoculated with AM fungi either directly in the planting hole or were grown first in a greenhouse in potting media amended with AM fungus inoculum. Controls received the same compost and vermiculite mixture in which the inoculum was grown. Available P levels in the soil ranged from 242 to 599 kg ha-1. Mean increase in yield of sweet potatoes of the inoculated plants for the experiment was statistically significant at 10.0 +/- 1.9% over uninoculated controls. Further, roots collected from the soil at the time of harvest indicated significantly greater colonization by AM fungi of previously inoculated plants than in controls which became colonized by the indigenous population of AM fungi. Utilization of AM fungi produced on-farm reliably increased the yield of sweet potato in high P soils.