ASSESSING AND MANAGING SOIL QUALITY FOR SUSTAINABLE

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ASSESSING AND MANAGING SOIL QUALITY FOR
SUSTAINABLE AGRICULTURAL SYSTEM P.P. Motavalli1,
B. Jintaridth1, J. Lehmann1, K.W. Goyne1, and J.
Gilles1 1College of Agriculture, Food and
Natural Resources, University of Missouri,
Columbia, MO 65211 USA SANREM-CRSP
CROSS-CUTTING INITIATIVE

• Objective 2
• Soils will be collected from depths of 0-10
  to 10-20 cm from degraded and on-degraded
  agricultural fields (i.e. Sanborn Field,
  Bolivian, Ecuadorian, Zambian, and Asian studies)
• The soil will be freeze-dried, ground and
  sieved to a size fraction lt 2 mm diameter.
• Climatic information will be obtained.
• All samples will be analyzed by using
  spectroscopic methods.
• Soil texture, pH, CEC, total organic C, total
  N, water-soluble, total organic C and total N,
  particulate organic matter C and N, soil test P
  (Bray 1 P), exch. K, Ca, and Mg will be
  determined.

Introduction Soil quality
assessment is a process by which soil resources
are evaluated on the basis of soil function. Soil
organic matter (SOM) is one of the most widely
knowledge indicators of soil quality (Gregorich
et al., 1994). In general, SOC varies across
landscapes, soil types and climatic zones. It is
characterized by high levels of C in recalcitrant
or humified forms and small changes in SOC
resulting from changes in soil management are
difficult to measure. An approach to
evaluate the impact of agricultural management of
SOM dynamics is to separate SOM into pools which
will depend on differences in decomposition rates
(Wander et al., 1994). In two-pool exponential
decomposition models, the pool with the smallest
size and most rapid turnover is termed labile and
the larger pool with slow turnover is termed
recalcitrant. The lability of SOM is defined as
the ease and speed with which it is decomposed by
microbes and depends on both chemical
recalcitrance and physical protection from
microbes. Changes in labile fractions of SOC
provide an early indication of soil degradation
or improvement in response to management
practices (Islam and Weil,2000).
In this research, soil samples will be collected
from representative degraded and non- degraded
soils at ongoing SANREM field sites, establish
in-field and laboratory capacity to test soil
quality, and develop analytical methodologies for
the spectroscopic-based procedures. Collaboration
with CGIAR system (i.e., ICRAF), USDA-ARS and
USDA-NRCS are also important goals of this
project due to the ongoing efforts and resources
being invested at these institutions in
developing low-cost methods for soil quality
evaluation.
Objectives 1. To assess community perceptions
and indicators of soil quality, including
differences in perceptions of soil quality due to
gender, environment ad socio-economic factors.
2. To determine the effectiveness of
spectroscopic-based (i.e. near-infrared,
mid-infrared, and visible range) analytical
methods to evaluate soil organic matter fractions
and soil quality in degraded and non-degraded
soils in a wide range of environments. 3. To
collaborate in the evaluation of soil metagenomic
methods as an indicator of soil degradation.

• LABORATORY METHODS
• ? Mid Infrared (MIR) RANGE
• Diffuse Reflectance Fourier Transform Infrared
  Analysis (DRIFT)
• Can determine changes in ratios of reactive
  (O-containing) and recalcitrant (C, H and/or N)
  functional groups due to management practices.
• Will test sample preparation method
• - Extraction of HA fraction of soil
  organic matter
• - Removal of mineral constituents
• using hydrofluoric acid
• - Analysis of intact core

• FIELD METHODS
• The effectiveness of spectroscopic-based (i.e.,
  near Infrared, mid-infrared, and visible range)
  analytical methods
• ? VISIBLE RANGE
• Labile C Determination Using KMnO4 (Weil,
  2003)
• Evaluating two methods
• Portable field spectrometer (550 nm)
• Field chart
• ? Near Infrared (NIR) RANGE
• Portable Field Near Infrared (NIR)
  Spectrometer
• Determination of soil organic C using a
  portable field NIR spectrometer. Fieldspec Pro FR
  (Stevens et al., 2006).
• It may relate to use of remotely sensed
  infrared imagery to improve diagnostic
  capabilities to assess plant and soil health.
• For this study, we will do the NIR analysis of
  soil samples in the laboratory and not in the
  field.

• Tasks
• Coordinate soil quality survey with
  collaborators in the SANREM projects.
• Distribute and organize field tests with soil
  quality kits with collaborators.
• Obtain soil samples and site histories from
  degraded and non-degraded sites in coordination
  with SANREM and soil metagenomic projects.
• Develop laboratory methodologies and conduct
  analyses.
• Two graduate students (one Thai and one
  Bolivian) are being trained.

• Materials and Methods
• Objective 1
• Will use participatory workshops of community
  members and professionals
• What are the specific soil quality indicators
  that community members use to evaluate soil
  quality among the different soils types and
  crops?
• How has soil quality changed over time and why?
• The communities will be surveyed to determine
  the characteristics of a field soil quality
  testing procedure that would be appropriate for
  their conditions and for evaluating sustainable
  agricultural management practices.