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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #121452
Title: SEASONAL DYNAMICS OF ROOTS, MYCORRHIZAL FUNGI, AND THE MINERAL NUTRITION OFPINOT NOIR

Author
item Schreiner, Roger - Paul

Submitted to: Agricultural Experiment Station Oregon State University Progress Reports
Publication Type: Proceedings
Publication Acceptance Date: 3/1/2001
Publication Date: 3/1/2001
Citation: page 49-60

Interpretive Summary: .

Technical Abstract: The spatial and temporal development of grapevine root systems and associated mycorrhizal fungi was studied over the 1999 & 2000 growing seasons in a 20-year-old block of Pinot noir vines at Woodhall Research Vineyard. We determined the root length density of woody roots and fine roots deemed to be physiologically active (based on color and cellular integrity) at monthly intervals throughout the year. The majority of fine roots occurred within the upper 50 cm of the soil profile. Fifty-nine percent of fine roots occurred within the vine row and 31% occurred in the alley-way at 0-50 cm depth. Only 10% of the fine roots were found below 50 cm. Fine root density did not change dramatically over the 1999 or 2000 seasons until after harvest. Apparently, new root growth kept pace with turnover (death) until after the fruit was removed, when new root growth was faster than turnover. Colonization of fine roots by vesicular arbuscular mycorrhizal (VAM) fungi was consistently high in the vine row all year long but was lower in roots growing in the alley-way. Arbuscular colonization (a measure of the "activity" of the mycorrhiza) increased throughout the growing season and did not decline until after leaf fall. Relationships between mycorrhizal fungi, roots, and tissue minerals showed that fine roots alone supplied the majority of N, P, & K needed by the canopy in June and July. Minerals were re-allocated from stored reserves in fine roots during this time. In August and September, when roots had high levels of VAM activity and soil minerals were at higher concentrations, the supply of minerals to the shoot came from root uptake. The extent of mineral uptake after harvest appears to be dependent on the length of time between harvest and leaf-fall and on the extent of autumn rains.