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2011 Soil Science Research Impacts
Monitoring Soil Moisture Dynamics to Improve Water & Environmental Management

Soils regulate environmental moisture and temperature dynamics at scales ranging from the habitat of microbial organisms to continental weather patterns.
However, soil properties influencing moisture and temperature dynamics and the mechanisms by which combined moisture and energy transfer occur in soil are poorly understood and difficult to predict.

What Has Been Done
Scientists at North Carolina State University are
characterizing water and temperature dynamics in
 the soil at scales ranging from sub-centimeter to regional. Monitoring and predictive techniques are currently being refined through laboratory, field, and modeling experiments to allow improved agricultural and environmental management.

Implications include opportunities for improved water management in cropland, rangeland, and forested and urban systems; improved prediction of weather and climate dynamics; and improved management surface fluxes of greenhouse gases from soil.  

National Science Foundation (NSF)
US-Israel Binational Agricultural Research and Development Fund (BARD)
U.S. Department of Agriculture (USDA)
Water Resources Research Institute (WRRI)

Dr. Joshua L. Heitman, Assistant Professor, Department of Soil Science, N.C. State University
phone: (919) 513-1593

On-site Wastewater System Management

On-site wastewater systems account for 50% of the wastewater treatment systems in the State.
The current Best Management Practaices (BMPs) for siting such systems may lead to premature failure.  A failed septic system poses an environmental and
public health risk, and also severely reduces property values.

What Has Been Done
NCSU Research has shown that the current method of assessing soil wetness overestimates the depth to seasonal wetness. Seasonal wetness is a major cause of system failure; so overestimation of its depth results in system installation too deep in the soil, and subject to premature failure.   

By locating and installing systems at a shallower depth in the soil, based on revised soil criteria, we may save the cost of repairing or replacing a failing system. Currently, approximately $70 million (or 30% of the total estimated $250 million for the industry as a whole) is spent annually on repairing failed systems.  Proper system siting based on more conservative soil criteria could thus save North Carolinians several million dollars, as well as alleviate an environmental and public health risk.

Dr. David L. Lindbo, Associate Professor, Department of Soil Science, N.C. State University, Raleigh, NC 27695

Synthesizing Soil Phosphorus Agronomic and Molecular Research Findings for Practical Use

Information is being generated in all fields of science, including in the agricultural and environmental sciences,
at a staggering rate. Consequently, it is becoming increasingly difficult for scientists to make connections between very powerful fundamental research applying state-of-the art methods, the large body of existing science, and the solution of practical problems of societal concern.

Based on insights gained from his internationally recognized research program in molecular soil chemistry, Dr. Dean Hesterberg published a book chapter
¹ that connects the state-of-the-art science in emerging molecular-level chemistry of soil phosphorus with the existing body of knowledge in applied management of this elemental nutrient, which is essential to life.
This book chapter describes relationships between various practical measurements used to make fertilizer recommendations for crops, measurements used to prevent detrimental environmental impacts due to over-application of phosphorus on agricultural soils, laboratory measurements made to determine how much phosphorus a soil can hold (bind), and measurements of fundamental chemical processes that control plant availability and environmental impacts of phosphorus.
Because phosphorus is essential for all of life, this nutrient element has been the subject of immense research efforts.  More than 14,500 journal articles have been published on phosphorus since 1916, of which more than 300 are reviews of the scientific literature.  With the emergence of increasingly advanced analytical techniques for characterizing soil phosphorus offering unprecedented precision, and increased public pressure to solve water-quality problems, the gap between basic and applied research groups continues to widen.  This book chapter helps to close this knowledge gap between these divergent research groups by unifying scientific concepts from the molecular-process level to field applications.  

Funding Source
US Department of Agriculture-National Research Initiative (USDA-NRI)
North Carolina Agricultural Research Service (NCARS)
National Synchrotron Light Source (NSLS), Broonkaven National Laboratory
Brookhaven National Laboratory
Advanced Photon Source (APS), Argonne National Laboratory

Dr. Dean Hesterberg, Professor, Department of Soil Science, N.C. State University
voice: (919) 513-3035  /  fax: (919) 515-2167

¹ Hesterberg, D. 2010. Macro-scale chemical properties and x-ray absorption spectroscopy of soil phosphorus. p. 313-356. In: B. Singh and M. Gräfe (Eds.). Synchrotron-based techniques in soils and sediments. Developments in Soil Science, Vol. 34. Elsevier, Burlington, MA.

Abating Water Pollution from Construction Activities


This issue is a complex one, and includes these factors:
•    Sediment and turbidity are by far the most widespread and pervasive pollutant of our surface waters. Construction activities can contribute very large amounts of sediment to these waters, even when required controls are in place.
•    Polyacrylamide (PAM) is widely used for erosion and turbidity control in irrigated agriculture and water treatment systems, but there is little research on its applications in the construction setting.
•    Indeed, many erosion and sediment control products do not have objective testing to support their use.
•    The U.S. EPA has established a rule, which will require construction sites to reduce turbidity to a specific level, far below typical discharges; this regulation will, in turn, require new approaches.
•    Construction site soils can be highly compacted, generating large amounts of runoff carrying many types of pollutants.

What Has Been Done
•    Dr. Richard McLaughlin's research and extension program is providing evaluations of current and newly developed systems to reduce off-site movement of sediment.  
•    His group continues studies on how effective PAM can be in various settings
such as erosion control on slopes, and turbidity reductions in runoff control structures.
•    They have also proven that certain design changes to sediment basins will greatly reduce sediment losses from construction sites.
•    They have clearly demonstrated the effectiveness of PAM and fiber check dams to reduce turbidity to acceptable ranges and are promoting their use.
•    They demonstrated that tillage can greatly reduce runoff rates, while increasing grass growth and rooting depth.


•    The systems developed by Dr. McLaughlin's group over the past five years are now considered a large part of new practices which can bring construction site runoff into compliance with the new national standard.
•    They determined that common materials used for ditch check dams on construction sites can disseminate flocculants and
reduce turbidity by up to 90%.
•    The North Carolina Department of Transportation (NCDOT) is now adopting the alternative check dams and PAM Dr. McLaughlin tested at three of their sites, and elsewhere.  
•    This group has have shown that deep tillage with fertilizer and lime can greatly increase infiltration, in turn reducing stormwater runoff volumes.
Funding Sources
North Carolina Department of Environment and Natural Resources (NCDNER)
North Carolina Department of Transportation
North Carolina Clean Water Management Trust Fund
HaloSource, Inc.
Dr. Richard A. McLaughlin, Department of Soil Science, N.C. State University
Phone 919 515 7306
Fax 919 515 7494

Visit Dr. McLaughlin's web page