Sustainable Land Development Today - February 2009 - (Page 6)

literally undermine the historical integrity of our precious land and water resources. In order to better grasp the range and magnitude of adverse affects associated with contemporary land-use practices, including row-crop agriculture, on the stability of local terrestrial and aquatic ecosystems, it is critical to gain an increased understanding of how these systems evolved and functioned historically. As a society, it is imperative that we acquaint ourselves with an understanding of local geology, soils, flora, fauna, hydrology, climate, and the his- deeply entrenched conventions as a whole will not be without its challenges. The good news, however, is that realistic, cost-effective solutions for these problems exist in every environment across the spectrum from urban to rural. We also believe that once the magnitude of the problem is properly understood, coupled with the potential for conversion to sustainable alternatives that not only support the restoration of ecological stability, but economic and social vitality as well, that knowledge will serve as an effective catalyst for change. Historical Patterns Historically, the terrestrial ecosystems of North America, particularly in the tallgrass prairie ecosystems of the upper Midwest, were very effective at receiving and absorbing rainfall. Very little water ran off the surface of the land. The historical patterns of hydrology throughout the region, and throughout most of the continent, were prevailingly dominated by groundwater hydrology coupled with contributions from direct precipitation. Most natural wetland and aquatic systems including lakes, streams, and rivers were predominantly formed and sustained by constant sources of groundwater discharge, or from surface-water systems derived from steady, stable groundwater discharge. Discharge occurred anywhere along the spectrum from higher to lower gradients, depending on the relationship of geology, soils, surface and groundwater gradients, and other factors. Virtually all of our endemic terrestrial and aquatic species, both flora and fauna, are adapted to such stable patterns of infiltration, evaporation, transpiration, groundwater discharge, consistent hydrology, and stable water chemistry. The richness and fertility of Midwestern soils owe their properties to the morphology and hydrology of the grasslands, where subterranean reduc- torical cultural influences that helped shape the “nature” of each and every place where we live, work, and play. This knowledge must be coupled with an increased awareness of the many liabilities associated with conventional land-use practices including traditional stormwater-management procedures. In the following paragraphs, I will provide a basic rationale for how and why such disasters are occurring at a magnitude and frequency that defies logic, and explain why my colleagues and I believe that such events will continue to occur with more frequency and severity with each passing year unless sweeping measures are introduced throughout urban, suburban, and rural watersheds. Since rain falls everywhere, cost effective, ecologically sound solutions must be developed, adapted, and applied everywhere. It is ultimately everyone’s responsibility to learn and participate in this process, although effecting positive change with respect to tion exceeded oxidation. Prairie lands, with their deep, water-holding root systems, once stored net amounts of soil organic carbon (SOC) each year in the creation of deep black topsoil. On average, 70-90 percent of a prairie grass’s total mass existed below ground. The root systems could reach or exceed depths of 10 - 15 feet. A typical tallgrass prairie generally contained 15 to 20 thousand kilograms of root mass/hectare, which equates to 12 - 18 thousand pounds of root mass/acre. Each year, approximately one-third of the root system died-off and formed partially decomposed matter that was rich in organic carbon through the process of photosynthesis. Depending on the dryness or wetness of any specific habitat, the average net accumulation rate of SOC throughout much of the region typically ranged from 0.5-2 tons/acre/year. In contrast, annual corn and soybean systems contain, on average, 300 to 600 kilograms of root mass/hectare, and result in an annual net loss of soil organic carbon, rather than a net gain, but more about that later. Prior to conversion to row-crop agriculture and urban/suburban development, prairie soils on average contained as much as 15 percent or more organic matter. The combination of vegetation cover, fibrous roots systems, and soils with low-bulk density and high, organicmatter content created a regional ecosystem where very little water ran off the 6 February 2009 Sustainable Land Development Today

Table of Contents Feed for the Digital Edition of Sustainable Land Development Today - February 2009

Sustainable Land Development Today - February 2009 Contents Our Voice Modern Flood Disasters Origin of the Sustainability Movement SLDI in Focus Calendar Build Smart Product Innovation Takeoff and Cost Management Industry News Products & Services Advertiser Index Editorial Board SLDT Resources Last Word

Sustainable Land Development Today - February 2009

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