April 28, 2015 -- To commemorate the International Year of Soil 2015 (IYS), the Soil Science Society of America (SSSA), an international scientific society advancing the field of soil science and fostering the transfer of knowledge and practices to sustain global soils, is coordinating a series of activities to educate the public about the importance of soil. With April's theme being "Soils Clean and Capture Water," the organization is researching the importance of adopting stormwater management strategies and considering alternative agriculture water sources.
Stormwater Management: Soil Plays Large Role in Capturing, Cleaning Water
In SSSA's April 1 Soils Matter blog post (here), experts explain why communities are adopting more stormwater management programs and technologies. According to Gary Pierzynski, soil scientist and professor of agronomy at Kansas State University, as towns grow into cities, more of the earth's surface is covered with impervious materials, creating a need for systems to manage the runoff.
"Consider a highly urbanized area that might have more than 95 percent of the area covered by buildings or pavement," said Pierzynski. "These surfaces essentially absorb nothing -- all the rainfall becomes surface runoff. The amounts can be significant." A standard city block (1/8 mile by 1/8 mile, about 10 acres in size) creates nearly 300,000 gallons of surface runoff from a one-inch rainfall if none of it enters into the soil. Even residential areas can have more than half the surface covered with prohibitive surfaces.
Under-designed stormwater systems contribute to urban flooding during heavy precipitation events. The design has to handle the total amount of normal runoff as well as the peak amount. Five inches of rain falling over 24 hours creates a much different stormwater need compared to five inches of rain falling in two hours. As such, newer developments are correcting previous mistakes. Concrete-lined channels, for example, are preventing erosion at high flows and pumping stations to keep water moving if the natural landscape does not provide gravity flow.
Alternative Water Sources: "Green Water" Important for Agricultural Use
In SSSA's April 15 Soils Matter blog post (here), experts explain how scientists are looking to tap a different water source for agriculture: "green water." According to Pierzynski, the traditional source of water for agriculture has been from freshwater sources (lakes, rivers and streams). Scientists refer to this freshwater as "blue water." Green water is the water in soil that is potentially available for plants to take up and be used. It must pass through the region of soil found close to and influenced by roots.
The key to helping plants receive this green water is healthy soils. "Healthy soils with plenty of nutrients and soil physical properties favorable for root growth will lead to healthy plant root systems," said Pierzynski. Those roots will take up more water for transpiration than smaller root systems. The plants will grow larger and create lush canopies that, in turn, provide shade and decrease evaporation from the soil. More green water is then available for transpiration that will stimulate more crop growth.
Researchers are currently finding ways to capitalize on plant-soil feedbacks and optimize the community of soil microorganisms in the rhizosphere, one of the great frontiers in soil science. That work is a key ingredient in the recipe for better using green water and expanding crop production. Likewise, as part of their celebration of IYS, SSSA is developing a series of 12 two-minute educational videos. April's Soils Clean and Capture Water video can be viewed at www.soils.org/iys/monthly-videos.
AboutSoil Science Society of America
SSSA is a progressive international scientific society that fosters the transfer of knowledge and practices to sustain global soils. Based in Madison, WI, and founded in 1936, SSSA is the professional home for 6,000+ members and 1,000+ certified professionals dedicated to advancing the field of soil science. The Society provides information about soils in relation to crop production, environmental quality, ecosystem sustainability, bioremediation, waste management, recycling, and wise land use. For more information, visit www.soils.org.
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