Record Details
Field | Value |
---|---|
Title | Response of 'Pinot noir' grapevines to a perennial ryegrass cover crop and irrigation in the Willamette Valley |
Names |
Wilson, William D. (William Donald), 1955-
(creator) Lombard, Porter B. (advisor) |
Date Issued | 1985-11-15 (iso8601) |
Note | Graduation date: 1986 |
Abstract | A perennial grass grown in strips between the rows of grapevines, with a bare soil herbicide strip under the rows of vines, is a common form of vineyard soil management. Irrigation, though not practiced for grape culture in western Oregon at this time, could be used to supplement the soil reservoir on shallow soils, or during years of drought, to improve productivity. These two management systems were used in an experiment implemented in 1984 to study their effects on vineyard soil water utilization, and on grapevine productivity. Perennial ryegrass strip soil management versus overall herbicide soil management, and irrigation (to replace the equivalent depth of water lost, every other day) versus no-irrigation were the factors in a split plot design experiment in a commercial 'Pinot noir' vineyard. Grass strip soil management did not have significant effects on vine growth, fruit quality or yield, compared to overall herbicide management - whether irrigation,was applied or not. Irrigation was responsible for a significant increase in shoot growth rate, resulting in a 29% increase in shoot growth and an 8% increase in pruning weight. There was a decrease in the amount of juice soluble solids associated with the irrigation/overall herbicide treatment (17.5 °Brix) compared to the mean of the other treatments (18.3 °Brix). Irrigation effects on other fruit quality parameters were negligible, although the general tendency was for reduced quality (higher acidity, reduced anthocyanins, and lower phenolics). Yield was increased by 24% due to irrigation, which was due to an increase in berry size. Two adjacent non-irrigated plots, of three vines each, were used to evaluate the effect of grass strip soil management and overall herbicide management on soil water. The maximum difference in water content between the two treatments occurred by July 31, which was 70 mm of water (equivalent depth) in the 105 cm deep profile. Most of this difference (48 mm equivalent depth) existed on July 9, ten days after the end of precipitation, indicating that maximal water use by the grass occurred when water was plentiful in the soil. The maximum measured difference between the in-row and inter-row areas of the grass strip plot was 15 mm of water (equivalent depth) on July 17. Significant differences in soil water depletion rate at all depths, and volume water content, between the grass strip and overall herbicide plots occurred when the grass was active. Significant greater depletion rates were measured in the inter-row area of the overall herbicide plot compared to the grass strip plot when the grass strip plot dried down to low soil water potentials, and the vines probably used a substantial amount of water from below 105 cm depth. Greater depletion rates of the inter-row versus in-row area of the overall herbicide plot could be due to differential soil heating of the inter-row area of the overall herbicide plot, or to renewed grape root development in the inter-row area. The former hypothesis can be explained by diffusive water flow upwards in the inter-row soil, to be driven off in the evaporative stream. |
Genre | Thesis/Dissertation |
Topic | Grapes -- Oregon -- Willamette River Valley -- Water requirements |
Identifier | http://hdl.handle.net/1957/25557 |