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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #135157

Title: OREGON BLUEBERRY SURVEY: ERICOID MYCORRHIZAL FUNGI, ROOT DISTRIBUTION AND SOIL CHARACTERISTICS

Author
item Scagel, Carolyn
item YANG, WEI

Submitted to: Proceedings of the Oregon Horticultural Society
Publication Type: Proceedings
Publication Acceptance Date: 8/23/2002
Publication Date: 9/17/2002
Citation: Scagel, C.F., Yang, W. 2002. Oregon blueberry survey: ericoid mycorrhizal fungi, root distribution and soil characteristics. Proceedings of the Oregon Horticultural Society.

Interpretive Summary: Blueberry plants form symbiotic associations with specific soil fungi called ericoid mycorrhizal fungi (EMF). These fungi can help the plant with the uptake of nutrients from different sources. There is no available information about the mycorrhizal status of blueberry plants grown in Oregon. In August of 2001, we sampled 55 fields in Oregon to assess the mycorrhizal status of blueberry plants under production conditions and to determine whether any relationships exist between field characteristics, root distribution, soil factors and level of colonization by EMF. We found that root biomass was lower in the upper 15 cm of the soil compared to the 15-30 cm depth however roots in the upper 15 cm of the soil were longer and finer than roots lower in the soil profile. Variation in root biomass, root length, and root type occurred with cultivar, field age, bed type, irrigation and mulch. Root colonization by EMF ranged from 0.5 to 44% of total root length. Average colonization was 22% with higher colonization occurring in the upper 15 cm of the soil where the majority of finer roots were found. Variation in root colonization occurred with cultivar, field age, bed type, irrigation and mulch. Colonization generally increased with increasing plant age with highest levels of colonization in roots from the upper 15 cm of soil in younger plants and the highest levels of colonization in roots at the 15-30 cm depth in older plants.Almost one third of the fields sampled had a soil pH above what is considered optimal for blueberry production. Differences in soil characteristics, root type and distribution, and mycorrhizal colonization found in this study now need to be investigated in terms of production efficiency of blueberry in Oregon.

Technical Abstract: Blueberry plants form symbiotic associations with specific soil fungi called ericoid mycorrhizal fungi (EMF). In return for carbohydrates from the plants, these fungi can help with the uptake of nutrients. In August of 2001, we sampled 55 fields in Oregon to assess the mycorrhizal status of blueberry plants under production conditions and to determine whether any relationships exist between cultural practices, root distribution, soil factors and level of colonization by EMF. Root biomass was lower in the upper 15 cm of the soil compared to the 15-30 cm depth. Root length was greatest in the upper 15 cm of the soil. Lower root biomass and higher root length resulted in a lower specific root weight (smaller, finer roots) in the upper 15 cm of the soil. Variation in root biomass, length, and type occurred with cultivar, field age, bed type, irrigation and mulch. Average colonization across all fields was approximately 22% with higher colonization generally occurring in the upper 15 cm of the soil where the majority of smaller, finer roots were found. Variation in root colonization occurred with cultivar, field age, bed type, irrigation and mulch. Colonization generally increased with increasing plant age with highest levels of colonization in roots from the upper 15 cm of soil in younger plants and the highest levels of colonization in roots at the 15-30 cm depth in older plants. We found that increased soil pH was positively correlated with increased levels of available calcium and nitrate in the soil and negatively correlated with levels of available ammonium. Differences in soil characteristics, root type and distribution, and mycorrhizal colonization found in this study now need to be investigated in terms of production efficiency of blueberry in Oregon.