This discussion will focus on the variety of field tools available that can be used to assess how well the soil is functioning for its intended use. Tools are available to assess soil chemical properties such as soil pH, electrical conductivity, and nitrate nitrogen, physical properties such as root growth, soil bulk density and soil water movement, and soil biological activity.
A field assessment can be as simple as walking across a field and recording observations of plant growth or erosion or it can be a numerical measurement of pounds of CO2 carbon per acre leaving the field daily through organic matter decomposition. What we are trying to assess is how well the soil is functioning for our intended use. If the soil is being used for structural support, we’ll assess it differently than if it is being used for the production of food and forage or to store and partition water. An assessment of soil that is frequently irrigated will be assessed differently than rain fed agriculture just like soil from a frigid temperature regime will be assessed differently than soils from tropical climates.
In an agricultural setting, we will look at how well the soil functions related to the production of food and forage, how well it stores and cycles nutrients, its ability to store and partition water, and possibly it’s filtering and buffering capacity. In an urban setting, we may be more interested in the soils ability to support roads and structures, its ability to store and cycle water, and possibly how well it buffers and filters contaminants.
The Soil Quality Field Assessment should mirror steps one through six of the Nine Steps of Planning.
Steps one and two should be completed before we take any soil measurement or assessment. In other words, we need to know the intended use and function of the soil where the objective is to optimize the intended use and function.Our field assessment than begins with step three. The Soil Quality Toolkit developed by ARS for NRCS provides a variety of both qualitative and quantitative measurements of the soils physical, chemical, and biological properties. The properties we choose to measure should be reflective of the soils intended use and function. If standing water in the field is a problem, a measurement of water infiltration or bulk density will be much more valuable than soil pH.
The assessment only becomes complete after we’ve had a chance to analyze any data collected and to develop recommendations designed to optimize the intended use.
Mike Sucik - Mike Sucik has served as the State Soil Scientist in Iowa for the Natural Resources Conservation Service since 1999. He received a Bachelor’s degree in soil science from the University of Wisconsin – Stevens Point in 1982 and started his career with NRCS that same year. Mike has mapped soils in Colorado, Iowa, Kansas, Minnesota, Nevada, North Dakota, and Texas. He has also traveled to Nigeria on several occasions conducting soil investigations. In 1998, Mike was instrumental in the design and development for the NRCS training course, ‘Soil Quality – Assessment and Applications for Field Staff’ and has instructed hundreds of individuals across the country on various aspects of soil quality. Mike is also the State Resource Inventory Coordinator in Iowa providing leadership for the state in all Natural Resource Inventory activities.