Issue link: http://read.dmtmag.com/i/89494
VINEYARD SOIL & CELLAR have a low ratio of Ca:Mg, a high percentage of exchangeable sodi- um or a high sodium absorption ratio. Entire blocks can have gyp- sum injected into the irrigation system or broadcast throughout the vineyard. In blocks with small areas affected, gypsum or nutrients can be broadcast only in the affect- ed area, or if there is double poly installed, that can be used to deliv- er the gypsum or fertilizer directly to the affected area. CHECK FOR PESTS, ROOT ROT If soil structure and/or compo- sition are not causing the issues, there are root pests and diseases that can cause this type of vari- ability. When pulling soil samples, it makes sense to send nematode samples to a lab. If high quantities of harmful nematodes are discov- ered, this can be managed through the use of nematicides, and there are some organic choices. Certain cover crops can be planted to sup- press nematode populations. How- ever, cover crop interactions are complex, and the cover may affect other populations of nematodes or be too vigorous and competitive to the vines. Phylloxera can be another root pest that damages vines, and it is particularly damaging in heavy clay soils. Although resistant rootstocks have limited the damage of phyl- loxera, new research has shown that phylloxera can feed and form nodosities on the young roots of 101-14 rootstock, and can cause reduced vine health, especially in heavier clay sections of the vine- yard or block. Certain pesticides can be applied against phylloxera, and treatments that we have already dis- cussed, such as applying compost, high organic-matter cover crops, and reducing vine competition through the use of permanent cover crops can mitigate some of the damage from phylloxera feeding. Oak trees removed prior to plant- ing or at the edge of the vineyard may cause weak sections in the vineyard due to Armillaria root rot, also known as the oak root fungus. Removal of as many oak roots as 42 VINEYARD & WINERY MANAGEMENT NOV - DEC 2012 Oak tree roots that venture into vineyards can cause soil weakness. Photo: Thinkstock Quality Stainless Tanks 30 years of fabrication experience Custom tank designs & features Tank modifications & repairs Dependable quality & completion Quick & competitive price quotes Tanks from 250 to 50,000 gallons Quality Stainless Tanks "QST's previous clients are our best source of advertising" 510 Caletti Ave. Windsor, Ca. 95492 707-837-2721 or 877-598-0672 Fax 707-837-2733 www.qualitystainless.com winetanks@aol.com WWW.VWM-ONLINE.COM