Soil Quality Assessment and the Plant Materials ProgramSusan S. Andrews, Arlene J. Tugel, Ann Lewandowski, and Mike Hubbs, NRCS Soil

Quality Institute

The Soil Quality Test Kit Soil Quality and Restoration

Soil Quality is defined as the soil’s capacity to function. Critical soil functions include the ability to support plant growth and productivity, nutrient cycling, and water partitioning. Soil quality can affect plant establishment and vigor, community composition, and colonization of invasive species. The use of soil quality assessments may facilitate the technology development and transfer by plant materials program across the U.S.

Soil Quality

Air Quality Water

Quality

Environmental Quality

Soil is the foundation for health ecosystems

Rain

RunoffSoil

Infiltration

Redistributing water

Am. J. Alt. Agric., vol. 7, 1992

PPGrowing plants

SSCC PPNN

State and Transition Models: part of ecological site descriptions

Aggregate Stability, Milan, TN

Vegatation/Soil Stability RelationshipMimbres Ecological Site, Big Bend

National Park, April 2003

0

10

20

30

40

0.0 2.0 4.0 6.0 8.0Surface Stability

(SQ Test Kit Slake Test)

Line

Poi

nt T

otal

(#

Can

opy

hits

/100

on

50 m

tran

sect

)

R2= 0.93

Conservation planting success may depend on changing soil conditions

Contents of the SQ Test Kit

SQ Test Kit demonstration

The relationship between soil quality indicators and selected soil functions

Degraded systems lose not only plant species but also critical soil functions. For successful plant establishment, proper soil conditions must be present. Assessing soil quality indicators, whether using the SQ Test Kit or lab analyses, could aid in the prescription of soil remediation steps. Improved soil function (i.e. water or nutrient storage) can be critical to plant restoration success.

State & Transition Models are used to record our knowledge about ecosystem change. According to the model, once a threshold between plant communities (or states) is crossed, it is very difficult to change back. These changes occur not only above-ground but also below-ground among root-soil interactions and other dynamic soil properties.

Soil quality indicators were measured at Big Bend National Park, in different states of the same ecological site, using the test kit and lab analyses. Assessment of soil function will: •benefit assessment and monitoring activities, •enhance site descriptions of soil-vegetation dynamics, •add value to soil surveys, and •increase our knowledge of soil change. This knowledge could facilitate remediation at Big Bend and elsewhere.

Many PMC publications recommend testing soil properties before planting. The Soil Quality Test Kit is an in-field assessment tool that could be used by PMC staff or land-managers (following PMC recommendations) to rapidly assess soil properties and function.

In addition, using the Kit (or lab analyses) to assess soil function prior to conservation plantings has the potential to improve seedling emergence & establishment, when indicator results are used to prescribe soil treatments.When using the Kit, not all tests need to be performed each time. The selection of Kit indicators to assess depends on the soil function of interest.

The Kit has been used all over the country to:Assess & compare management practice effects on soil functionMonitor trends over timeEvaluate problem spotsFor example, the test kit was used in Milan, TN, to compare soil function in different tillage and cropping systems. In this study, no-till and diversified cropping improved soil stability function and reduced erosion. This can also lead to improved yields.

Soil Quality Test Kit training sessions are available through the Soil Quality Institute and NEDC.