Peter Motavalli, Bunjirtluk Jintaridth, Johannes Peter Motavalli, Bunjirtluk Jintaridth, Johannes Lehmann, Keith Goyne, and Jere GillesLehmann, Keith Goyne, and Jere Gilles

ASSESSING AND MANAGING SOIL ASSESSING AND MANAGING SOIL QUALITY FOR SUSTAINABLE QUALITY FOR SUSTAINABLE

AGRICULTURAL SYSTEMSAGRICULTURAL SYSTEMS

SANREM-CRSP CROSS-CUTTING INITIATIVESANREM-CRSP CROSS-CUTTING INITIATIVE

• Soil degradation is a major global Soil degradation is a major global environmental problem, resulting in environmental problem, resulting in increased poverty and severe increased poverty and severe environmental problems (e.g., environmental problems (e.g., decreased biodiversity and water decreased biodiversity and water quality) (Eswaran et al., 1997).quality) (Eswaran et al., 1997).

• For example, the loss of potential For example, the loss of potential productivity due to soil erosion world productivity due to soil erosion world wide is estimated to be equivalent to wide is estimated to be equivalent to some 20 million tons of grain per year some 20 million tons of grain per year (UNEP, 1999). (UNEP, 1999).

INTRODUCTIONINTRODUCTION

• Almost 75% of Central America’s, Almost 75% of Central America’s, 45% of South America’s, and 11% 45% of South America’s, and 11% of Asia’s agricultural land have of Asia’s agricultural land have been seriously degraded. (Scherr, been seriously degraded. (Scherr, 1999; Heerink, 2001). 1999; Heerink, 2001).

• Three-quarters of Africa’s farmland Three-quarters of Africa’s farmland has severe soil degradation has severe soil degradation caused by wind and soil erosion caused by wind and soil erosion and loss of mineral nutrients and loss of mineral nutrients (Heano and Baanante, 2006). (Heano and Baanante, 2006).

INTRODUCTION (CONT.)INTRODUCTION (CONT.)

Definition :Definition :

“ “ the capacity of a soil …. to the capacity of a soil …. to sustain biological productivity, sustain biological productivity, maintain environmental maintain environmental quality, and promote plant and quality, and promote plant and animal health” (Doran and animal health” (Doran and Parkin,1994).Parkin,1994).

SOIL QUALITYSOIL QUALITY

• Soil quality depends on the capacity of a soil Soil quality depends on the capacity of a soil to perform a desired ecosystem functionto perform a desired ecosystem function

• Soil functions –Soil functions – sustaining biological activity, diversity, andsustaining biological activity, diversity, and

productivityproductivity regulating and partitioning water and solute flowregulating and partitioning water and solute flow filtering, degrading, immobilizing and detoxifyingfiltering, degrading, immobilizing and detoxifying

organic and inorganic speciesorganic and inorganic species storing and cycling of nutrientsstoring and cycling of nutrients providing structural supportproviding structural support

SOIL QUALITY (CONT.)SOIL QUALITY (CONT.)

• Biological indicatorsBiological indicators – (e.g., microbial – (e.g., microbial community structure and activity)community structure and activity)

• Chemical indicatorsChemical indicators – (e.g., pH , CEC) – (e.g., pH , CEC)

• Physical indicatorsPhysical indicators – (e.g., infiltration, bulk – (e.g., infiltration, bulk density, water-holding capacity)density, water-holding capacity)

• Soil organic matterSoil organic matter is an important is an importantsoil quality index because ofsoil quality index because ofits integral role in soil biological,its integral role in soil biological,physical and chemical processesphysical and chemical processes(Carter, 2002)(Carter, 2002)

SOIL QUALITY (CONT.)SOIL QUALITY (CONT.)

USDA Soil Quality Test KitUSDA Soil Quality Test Kit

• Assess community perceptions and indicators of Assess community perceptions and indicators of soil quality, including differences in perceptions of soil quality, including differences in perceptions of soil quality due to gender, environment and socio-soil quality due to gender, environment and socio-economic factors. economic factors.

• Determine the effectiveness of spectroscopic-based Determine the effectiveness of spectroscopic-based (i.e., near-infrared, mid-infrared, and visible range) (i.e., near-infrared, mid-infrared, and visible range) analytical methods to evaluate soil organic matter analytical methods to evaluate soil organic matter fractions and soil quality in degraded and non-fractions and soil quality in degraded and non-degraded soils in a wide range of environments.degraded soils in a wide range of environments.

• To collaborate in the evaluation of soil metagenomic To collaborate in the evaluation of soil metagenomic methods as an indicator of soil degradation.methods as an indicator of soil degradation.

OBJECTIVESOBJECTIVES

• Will use participatory workshops of community Will use participatory workshops of community members and professionalsmembers and professionals

• What are the specific soil quality indicators that What are the specific soil quality indicators that community members use to evaluate soil quality community members use to evaluate soil quality among the different soil types and crops?among the different soil types and crops?

• How has soil quality changed over time and How has soil quality changed over time and why?why?

• The communities will be surveyed to determine The communities will be surveyed to determine the characteristics of a field soil quality testing the characteristics of a field soil quality testing procedure that would be appropriate for their procedure that would be appropriate for their conditions and for evaluating sustainable conditions and for evaluating sustainable agricultural management practices.agricultural management practices.

METHODOLOGYMETHODOLOGY

COMMUNITY PERCEPTIONS OF SOIL RESOURCES COMMUNITY PERCEPTIONS OF SOIL RESOURCES

AND SOIL-RELATED PROBLEMS IN BOLIVIAAND SOIL-RELATED PROBLEMS IN BOLIVIA

• Soil-related problems are only one of several Soil-related problems are only one of several factors limiting crop production.factors limiting crop production.

• Soil management problems identified were:Soil management problems identified were:

Low soil quality and soil fertilityLow soil quality and soil fertility((low soil nutrient content, high clay content and stoniness)low soil nutrient content, high clay content and stoniness)

Excessive water and wind-induced soil erosionExcessive water and wind-induced soil erosion Insufficient soil moisture due to lower rainfallInsufficient soil moisture due to lower rainfall Inadequate soil management practicesInadequate soil management practices

((Inappropriate tractor tillage practices, lack of a suitable crop Inappropriate tractor tillage practices, lack of a suitable crop rotation strategy, insufficient soil fertility inputs, and rotation strategy, insufficient soil fertility inputs, and overgrazing by sheep)overgrazing by sheep)

• Soils will be collected from depths of 0-10 to 10-20 cm Soils will be collected from depths of 0-10 to 10-20 cm from degraded and non-degraded agricultural fields (i.e., from degraded and non-degraded agricultural fields (i.e., Sanborn Field, Bolivian, Ecuadorian, Zambian, and Asian Sanborn Field, Bolivian, Ecuadorian, Zambian, and Asian studies)studies)

• The soil will be freeze-dried, ground and sieved to a size The soil will be freeze-dried, ground and sieved to a size fraction <2 mm diameter. fraction <2 mm diameter.

• Climatic information will be obtained.Climatic information will be obtained.• All samples will be analyzed by using spectroscopic All samples will be analyzed by using spectroscopic

methods. methods. • Soil texture, pH, CEC, total organic C, total N, water-Soil texture, pH, CEC, total organic C, total N, water-

soluble total organic C and total N, particulate organic soluble total organic C and total N, particulate organic matter C and N, soil test P (Bray 1 P), exch. K, Ca, and matter C and N, soil test P (Bray 1 P), exch. K, Ca, and Mg will be determined.Mg will be determined.

METHODOLOGYMETHODOLOGY

Labile C Determination Using KMnOLabile C Determination Using KMnO4 4 (Weil, 2003)(Weil, 2003)

Evaluating two methods:Evaluating two methods:

FIELD METHODSFIELD METHODS

•Portable field spectrometer – 550 nmPortable field spectrometer – 550 nm•Field chartField chart

Solución KMnO4 después de agitarlo con el suelo

Tabla de campo sobre Calidad de Suelos

Escala del Indice de Calidad de Suelos

>0 – 0.25 >0.25 – 0.50 >0.50 – 0.75 >0.75 – 1.0

Pobre Regular Bueno Excelente

Portable Field Near Infrared (NIR) SpectrometerPortable Field Near Infrared (NIR) Spectrometer

• Determination of soil organic C using a portable field NIR spectrometer, Determination of soil organic C using a portable field NIR spectrometer, Fieldspec Pro FR (Stevens et al., 2006) Fieldspec Pro FR (Stevens et al., 2006)

• It may relate to use of remotely sensed infrared imagery to improve diagnostic It may relate to use of remotely sensed infrared imagery to improve diagnostic capabilities to assess plant and soil health.capabilities to assess plant and soil health.

• For this study, we will do theFor this study, we will do theNIR analysis of soil samples NIR analysis of soil samples in the laboratory and not inin the laboratory and not inthe field.the field.

FIELD METHODSFIELD METHODS

Diffuse Reflectance Fourier Transform Infrared Analysis (DRIFT) – Mid Diffuse Reflectance Fourier Transform Infrared Analysis (DRIFT) – Mid Infrared AnalysisInfrared Analysis

•Can determine changes in ratios of reactive (O-containing) and Can determine changes in ratios of reactive (O-containing) and recalcitrant (C, H and/or N) functional groups due to management recalcitrant (C, H and/or N) functional groups due to management practices. practices.

•Will test sample preparation methodWill test sample preparation method Extraction of HA fraction of SOMExtraction of HA fraction of SOM Removal of mineral constituents using hydrofluoric acidRemoval of mineral constituents using hydrofluoric acid Analysis of intact soilAnalysis of intact soil

LABORATORY METHODLABORATORY METHOD

Peak assignmentPeak assignment Wave number (cmWave number (cm-1-1))

Mineral OH Mineral OH 36903690CHCH22 symmetric stretch symmetric stretch 2962-29502962-2950

CO-OH H bondedCO-OH H bonded 25002500C=O stretchC=O stretch 1850 1850C=O ketonic, COOH C=O ketonic, COOH 1735-17131735-1713C=O, C=O-H bonded,C=O, C=O-H bonded, 16501650C=C aromatic C=C aromatic 1630-16081630-1608Aromatic ring, amide Aromatic ring, amide 15091509CO, COOH, COC, phenol OH CO, COOH, COC, phenol OH 1260-12401260-1240Aliphatic, alcoholic OH Aliphatic, alcoholic OH 1190-11271190-1127CO aliphatic alcohol CO aliphatic alcohol 1080-10501080-1050Aliphatic COC, aromatic ether, Si-O Aliphatic COC, aromatic ether, Si-O 10301030CH aromatic bend CH aromatic bend 779779COO salt, Mg/Si-O aliphaticCOO salt, Mg/Si-O aliphatic 560560 ((Adapted from Stevenson, 1982 and Baes and Bloom, 1989)Adapted from Stevenson, 1982 and Baes and Bloom, 1989)

DRIFT INFRARED SPECTRA PEAK DRIFT INFRARED SPECTRA PEAK ASSIGNMENTSASSIGNMENTS

cooH

cooHaromatic

aromatic

(Ding et al., 2002)(Ding et al., 2002)

Conservation TillageConservation Tillage Conventional TillageConventional Tillage

EFFECT OF TILLAGE ON DRIFT SPECTRAEFFECT OF TILLAGE ON DRIFT SPECTRA

0 – 5 cm0 – 5 cm

5 – 10 cm5 – 10 cm

10 – 15 cm10 – 15 cm

0 – 5 cm0 – 5 cm

5 – 10 cm5 – 10 cm

10 – 15 cm10 – 15 cm

HAHA Depth (cm) Depth (cm) Total O/R ratioTotal O/R ratio (1727+1650+1160+1127+1050) (1727+1650+1160+1127+1050) (2950+2924+2850+1530+1509+1457+1420+779 (2950+2924+2850+1530+1509+1457+1420+779

Conservation tillageConservation tillage

CnT1 CnT1 0-5 0-5 0.87 a 0.87 a CnT2CnT2 5-10 5-10 0.69 b 0.69 b CnT3CnT3 10-15 10-15 0.70 b 0.70 b Conventional tillageConventional tillage

CTCT 1 0-51 0-5 0.74 ab 0.74 ab CTCT 22 5-105-10 0.69 b0.69 b CTCT 33 10-15 10-15 0.67 b0.67 b

* Means with different letters are significantly different P = 0.05

EFFECT OF TILLAGE ON DRIFT SPECTRAEFFECT OF TILLAGE ON DRIFT SPECTRA

(Ding et al., 2002)(Ding et al., 2002)

The ratio of O/R The ratio of O/R (reactive/recalcitrant) (reactive/recalcitrant) was highest in was highest in conservation tillage conservation tillage (CnT) at 0-5 cm, (CnT) at 0-5 cm, suggesting relative suggesting relative enrichment of O-enrichment of O-associated C over associated C over time in CnT plots as time in CnT plots as compared with compared with conventional conventional tillage(CT). tillage(CT).

• Coordinate soil quality survey with collaborators in Coordinate soil quality survey with collaborators in the SANREM Projectsthe SANREM Projects

• Distribute and organize field tests with soil quality Distribute and organize field tests with soil quality kits with collaboratorskits with collaborators

• Obtain soil samples and site histories from Obtain soil samples and site histories from degraded and non-degraded sites in coordination degraded and non-degraded sites in coordination with SANREM and soil metagenomic projectswith SANREM and soil metagenomic projects

• Develop laboratory methodologies and conduct Develop laboratory methodologies and conduct analyses.analyses.

• Two graduate students (one Thai Two graduate students (one Thai and one Bolivian)are being trained.and one Bolivian)are being trained.

TASKSTASKS

QUESTIONS?QUESTIONS?COMMENTS?COMMENTS?

SUGGESTIONS?SUGGESTIONS?