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w i n e G R O WIN G comes from microbial decomposition of organic matter, but plant roots also produce a good deal of CO2 during respiration of the carbon-based sugars produced in leaves during photosynthesis and transported belowground. Soils are constantly accumulating carbon but also oxidizing and losing carbon as CO2. Sequestration requires the soil carbon pool to be refreshed at a higher rate than carbon is lost. The loss of soil carbon is accelerated after each tillage event, as formerly inaccessible organic matter in soil aggregates is mobilized and consumed by microorganisms. Other events like rainfall can accelerate soil carbon cycling and loss as CO2. It was therefore particularly important to Figure 3: Total soil carbon in samples taken from the plow horizon (depth of 15 cm) showing changes over seven years of management of a barley cover crop (CC) under minimum-tillage conditions (left bar), twice per year tilled cover crop (center bar), and once per year conventional-till/ weed management treatment (right bar). monitor soil respiration following rainfall and tillage events and during the spring root-flush. Our results show a close connection between total rainfall and soil respiration for this Mediterranean-climate vineyard: In 2010 there was 56% more rain than in 2009, and 67% higher soil respiration. The higher precipitation in spring 2010 Figure 4: Mid-day vine water potentials (MPa) from 101-14 Mgt vines. Significant differences were seen in summer 2009 but none in 2010. Samples were taken between 1 and 3 pm on 16 vines per treatment, and significance was declared using standard errors of the mean. Orchard Master Tools and Equipment Why Pay More? You know how good your Zinfandel is... Promote your wines to leading Zinfandel enthusiasts and extend your winery's relationship in the market. The Orchard Master electric pruner is qualitybuilt and perfectly suited to the orchard or vineyard. Our electronic pruners are durable and can be used all day on a single charge. These pruners are powerful and lightweight with a comfortable rubber grip. A light weight vest holds the 44 volt lithium battery and is comfortable while supplying a continuous power source. Join Us! We are champions of Zinfandel— America's Heritage Wine Become part of our proud legacy Invest in our Quality-built lithium battery powered electric pruners. Save time and money while reducing the risk of serious repetitive use injuries and associated labor and industry liabilities. Save on Labor Costs zinfandel.org • 530-274-4900 www.orchardmaster.com 855-5-PRUNER Use online promo "winesandvines" and get free shipping! 88 p racti c al w i ne ry & v i ne yard NOVEMBER 20 13 Zinfandel Advocates & Producers is a 501(c)(3) non-profit organization. ZAP is dedicated to advancing public knowledge of and appreciation for American Zinfandel and its unique place in our culture and history.