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52 WINES&VINES July 2018 Nutrients tightly held in soil organic matter do not show up in conventional soil tests. Neither do all the nutrients locked up in slow- to-dissolve minerals. At any one time, just a fraction of the ele- ments in a soil is in an exchange- able, soluble form plants can take up. Standard soil chemistry lab reports are missing something big: the potential for soil life to con- vert nutrients from mineral soil and organic matter into forms plants can use. Since the 1980s, advances in soil ecology and mi- crobiology have radically changed our understanding of how micro- bial life and organic matter inter- act to govern nutrient cycling and influence soil fertility. This wouldn't have surprised Sir Albert Howard, or the philoso- pher — farmers who founded this country. It should not surprise farmers today. Good farmers may not know all the details behind what makes for fertile soil, but they know it when they touch and see it. I have seen how they pick up soil and rub it between their fingers, asking themselves: Is it crumbly or dusty, slick or firm? Does it aggregate and hold to- gether, or disintegrate into dust at the touch? Above all, how much organic matter does it hold? In a way, it is easy to see whether soil is healthy or de- graded. The darker the soil the more organic matter — and car- bon — it contains. Several genera- tions ago, the amount of organic matter in the soil set the price of agricultural land. Every farmer knew that soil rich in organic mat- ter was more fertile, and so did their bankers. You might think of healthy soil as a particular mix of soil organ- isms, organic matter, and minerals that forms a thin skin on our planet, like a grand version of li- chen coating an alpine boulder. Part alive and part dead, the aver- age thickness of topsoil ranges from about one to three feet. Soil accounts for a thin sliver of Earth's 4,000-mile radius, but its propor- tions belie its importance. This delicate blanket of rotten rock is what makes our terrestrial world habitable. As the dynamic frontier between the living world of biol- ogy and Earth's rocky bones, soil is the realm in which microbial life recycles the remains of higher life into the raw materials for new life. The history of life on land is a collaborative tale of plants har- vesting solar energy, and micro- bial life mining and recycling nutrients. The first land plants evolved some 450 million years ago. They had partners right from the start — mycorrhizal fungi that hooked up with their roots. Like today's plants, the earliest ones periodically shed dead roots and leaves, and eventually died. All that organic matter became food for soil organisms that then mined more nutrients from the mineral soil and recycled the dead stuff back into nutrients for the plants to consume. More plants led to more organic matter, which led to richer, more fertile soil. Soon, and for ages ever since, vegetation covered all but the rockiest, driest, or ice-covered landscapes. Why was this partnership cru- cial? Consider where plants get their elemental building blocks. They use solar energy to combine carbon dioxide from air with hy- drogen from water to make car- bohydrates (sugars). Plants also get their nitrogen either indirectly from the air, with microbial as- sistance from nitrogen-fixing bac- teria living in specialized root nodules, or from nitrates they absorb through their roots. Other elements plants need to make their bodies come from rocks and decaying organic matter. Mycor- rhizal fungi and soil-dwelling mi- crobes extract mineral nutrients from soil particles and rock frag- ments and help break organic Vineyard Tools Battery Powered Pruning Shears • 1.25-inch and 1.5-inch cutting capacity models • 15,000 pruning cuts per battery charge • Includes lithium battery, harness, holster and carrying case www.zenportindustries.com | 503-524-7289 Gra ing Tools w zenportindustri Tying Tools & Supplies Harvest Shears ineyard T ols Pruning | Gra ing | Tying | Harvest The wine industry has trusted Kennedy/Jenks Consultants for professional environmental engineering services since the 1950s. We specialize in providing cost-saving, sustainable solutions to meet winery needs. Wastewater Water Supply Storm Water Solid Waste Facility Planning Design Construction Management Hazardous Materials Water/Energy Audits Air Emissions and Odors Regulatory Compliance Land-Use Permitting/CEQA e: BobChrobak@KennedyJenks.com t: 415.243.2150 www.KennedyJenks.com/wine OUR SERviCES inCLUDE: BOOK EXCERPT