Good Fruit Grower

November 2013

Issue link:

Contents of this Issue


Page 29 of 47

Grapes Managing nutrients in NW vineyards Pacific Northwest vineyards have different n utrient sampling needs than those in California. by Melissa Hansen F or years, vineyardists in the Pacific Northwest have followed California recommendations to sample leaf petioles at bloom to assess the nutrient status of vines. But at Washington State University's grape field day this summer, growers learned that a different timing and sampling technique are needed for their cooler Northwest climate. "The best time for us to sample is not at bloom, like in California, but at veraison," said Dr. Joan Davenport, WSU soil scientist. Recent WSU research involving several years of tissue-sample analysis shows that for the Pacific Inland Northwest region (Washington, Idaho, and Oregon), the whole leaf—blade and petiole—should be analyzed, not just the petiole, as in California. Additionally, research found that veraison was the best time to sample in Northwest vineyards. When Davenport compared Northwest nitrate levels with California nutrient standards, the Northwest s amples were almost always deficient in nitrogen. Her work led to new critical values for grape leaf concentrations in Washington and Oregon. She will soon have vineyard nutrient values developed for Northwest soils. She believes there are several reasons why the Northwest plant tissue samples appeared on paper to be d eficient in nitrogen. For one, soils in eastern Washington usually stay cool until bloom time, which would reduce plant nutrient uptake. "Also, Northwest growers may not have started irrigation before bloom and the nutrients may not yet be moving into the plant," she explains. Moreover, her research showed that whole leaves were better for sampling because petiole analysis was inconsistent in the irrigated Pacific Northwest. "And, whole leaves are much easier to work with than petioles because they are not time-of-day sensitive," Davenport said. Growers: Attract and maintain a steady labor force by offering on-farm housing that sleeps up to 20 workers in high quality, low maintenance structures. Sampling tips W ashington State University researchers recently updated nutrient sampling guidelines for wine and juice grapes grown in the Pacific Northwest. Dr. Joan Davenport, WSU soil scientist, provided the following soil and plant tissue sampling tips during a summer grape field day. Process—Use the same sampling techniques for both juice and wine grapes. Timing—Best time to sample plant tissue is when 40 to 60 percent of the berries have reached veraison (the onset of ripening when grapes begin changing color). Soil samples can be taken at same time. Frequency—Take plant tissue samples annually and run a full nutrient panel; soil samples can be taken every three to five years unless you're trying to make significant changes through soils amendments. What to sample—Collect whole leaves (blade and petiole) for tissue samples. Soil core samples should be taken 18 inches deep. Sample containers—Use paper bags for plant tissue samples and sealable plastic bags for soil. Leaves will be dried and ground at lab, so samples don't need to be kept moist. However, soil should be kept moist and chilled if necessary. How to sample—For a plant tissue sample, collect the fifth leaf inward from the end of a randomly selected shoot. Be sure to sample on both sides of the canopy. For a soil sample, it is easiest to use a soil probe that collects a core of soil, but a shovel will do. Always avoid sampling the edges of the vineyard. Soil sample locations depend on the type of irrigation. For overhead sprinkler irrigation, sample between rows in a zigzag pattern, but avoid sampling from the absolute row middle. Sample every third or more rows. For drip irrigation, sample 8 to 16 inches away from the drip line, never directly below it. For overhead sprinkler irrigated, sample between rows in a zigzag pattern, avoiding row middles. Number of samples to collect—For plant tissue, collect 50 leaves for the first acre and 25 more leaves for each additional acre, up to a total of 300 leaves per block. Sample red and white varieties separately until you've learned which varieties are similar. For soil, collect 25 to 50 cores per blocks of one acre or less. Increase in increments of five cores per acre for up to 100 cores per block. If the block has multiple varieties, keep samples separate. Mixing soil sample—Place soil cores in a large container or bucket and mix well before putting at least a cup of soil in sealable plastic bag. Label bag with vineyard name, grower name, date, location. Keep cool until delivered to lab. Use a qualified lab—Seek a lab that participates in the North American Proficiency Testing Program, a voluntary quality control program for laboratories. A listing of soil and plant tissue laboratories can be found on WSU's viticulture and enology Web site at http:// services.  —M. Hansen 1 2 3 4 5 6 7 OVER 215 units already SOLD! We use these quality components: • James Hardie Fiber Cement Siding • Jeld-Wen windows with double-strength glass • Copper water lines • Large capacity water heaters We have over 25 years' experience in building quality farm housing. We have several floor plans approved by the Washington State Department of Health– fully self-contained units, and dormitory only. They include: • showers • eating area • toilets/sinks • sleeping area • kitchen with appliances - GE • social area • plumbed for washer/dryer Experienced in building H-2A Housing. Our homes are built to perform under the conditions required. VALLEY MANUFACTURED HOUSING INC. 1717 South 4th Street • Sunnyside, WA 98944 Call Brad Busey: 509.839.9409 30 NOVEMBER 2013 Good Fruit Grower 8 9

Articles in this issue

Links on this page

Archives of this issue

view archives of Good Fruit Grower - November 2013