Green Roofs - Living Architecture Monitor - Spring 2011 - (Page 28)

INNOVATION GROWIN Soil works. It holds water, moves minerals, and captures pollutants. Composed of sand, silt, and clay – plus organics – soil is amongst the most complex of materials in the biosphere. Soil is built around two elements from group IV on the top of the Periodic Table – carbon and silica – amongst the most common in the biosphere. The different scale of these materials, however, makes for an immense functional difference in how soils work and what makes them different. Sand can develop significant water-bearing capacity – thousands of pounds-per-square-foot, with sharp edges and points that hold the particles apart. This gritty fact means that a fifth of the volume is airspace and capillary films, essential stuff for plants and microbe growth, a property worth emulating. Soil may be the most powerful colloidal1 sponge on earth, a cubicfoot holding enough water, two gallons or more, to run a plant community for a week or more. Some 10,000 stomates2 per square centimeter of leafs allow plants to evaporate water in order to capture carbon dioxide (CO2), building a tenth of a pound of biomass per gallon lost. Not only is soil fantastic at holding water, it is near infinitely multidimensional. Each cubic centimeter is home to 10 million to 10 billion microbes. Under each square meter of northeastern temperate forest landscape are extremely fine roots that measure between 10 and 20 miles in length. What on the surface looks to be a mere cubic centimeter of humus unfolds into a fractal micro-landscape of between 1,000 and 2,000-square-meters of surface area. As if not to be outdone, each handful of clay has a total surface area equivalent of some 50 football fields. Humble in reputation, the complex multiphase macro-molecule at the heart of soil, humus, has attracted and confounded researchers for more than a century. Home to microbes, and housing an exquisite micro-net for sequestering metals plus a colloidal sponge for THE WONDE 28 LIVING ARCHITECTURE MONITOR SPRING 2011

Table of Contents for the Digital Edition of Green Roofs - Living Architecture Monitor - Spring 2011

Green Roofs - Living Architecture Monitor - Spring 2011
Adaptation Through Innovation
Award-Winning Leader
Living Building Challenge Update
On the Roof With...
The Black Arts
Green Walls
Stormwater Policy
Root Repellent Standards
Growing Media
Green Building Codes
New Corporate Members
The GRP Turns Two
Professional Calendar
My First Year as a GRP

Green Roofs - Living Architecture Monitor - Spring 2011