Transcript Sensor Based Technology for Predicting Soil Organic Carbon

Sensor Based Technology for
Predicting Soil Organic Carbon
(Organic Matter)
Kent Martin
Organic matter is the most complex,
dynamic, and reactive soil component.
Because of the importance of organic
matter in soils, its estimation is important
in disciplines ranging from soil fertility,
chemistry, and physics to land planning
and soil productivity.
Soil Organic Matter: Analysis and Interpretation
GLOBAL WARMING
ATMOSPHERE
N2O
NO
N2
PLANT
LOSS
INDUSTRIAL
FIXATION
N2 FIXATION
SYMBIOTIC
NON-SYMBIOTIC
MESQUITE
RHIZOBIUM
ALFALFA
SOYBEAN
BLUE-GREEN ALGAE
AZOTOBACTER
CLOSTRIDIUM
LIGHTNING,
RAINFALL
PLANT AND ANIMAL
RESIDUES
HABER BOSCH
(1200°C, 500 atm)
3H2 + N2
2NH3
MATERIALS WITH N
CONTENT > 1.5%
(COW MANURE)
FERTILIZATION
MATERIALS WITH N
CONTENT < 1.5%
(WHEAT STRAW)
AMINO
ACIDS
NH3
AMMONIA
VOLATILIZATION
AMINIZATION
ORGANIC
MATTER
HETEROTROPHIC
R-NH2 + ENERGY + CO2
BACTERIA (pH>6.0)
FUNGI (pH<6.0)
IMMOBILIZATION
Pseudomonas, Bacillus,
Thiobacillus Denitrificans,
and T. thioparus
N2O2MINERALIZATION
+ NITRIFICATION
R-OH + ENERGY + 2NH3
MICROBIAL/PLANT
SINK
2NH4+ + 2OHFIXED ON
EXCHANGE
SITES
NO2-
OXIDATION STATES
NH3 AMMONIA
-3
NH4+ AMMONIUM
-3
N2 DIATOMIC N
0
N2O NITROUS OXIDE 1
NO NITRIC OXIDE
2
NO2- NITRITE
3
NO3 NITRATE
5
pH>7.0
R-NH2 + H2O
AMMONIFICATION
NH2OH
NO3POOL
DENITRIFICATION
LEACHING
NITRIFICATION
2NO2- + H2O + 4H+
Nitrobacter
LEACHING
VOLATILIZATION
NITRIFICATION
+O2
+ O2
ADDITIONS
TEMP 50°F
LEACHING
LEACHING
LOSSES
LEACHING
pH 7.0
OXIDATION REACTIONS
REDUCTION REACTIONS
(SSCM) Site-specific Crop Management
Hummel and Sudduth
Aims to improve production efficiency
by adjusting crop treatments to varying
local conditions within the field.
Sudduth
Optical Sensor
Uses NIR reflectance data at many
different narrow-banded wavelengths
More complex, but more expensive and
less durable than single-band sensor
Intended use: soil organic matter
Steps of sensor operation
1. Emit light using fiber optics
2. Light is reflected from soil surface
3. Light is captured by photodetector
4. Data is sent to PC
Effective Sensing Range 1630- 2650nm
Prediction of organic carbon in the
laboratory
Prediction was based on many variable
soil types and variable moisture contents.
Accuracy for SOM r^2= 0.89
Accuracy for moisture r^2= 0.94
Benefits
• Gives a way to measure soil organic matter
• Measures soil moisture
• Can be added to data layers for specific
fields to generate maps
Negative Points
• Expensive
• Low durability
• Not yet acceptable for use in field
Possible uses of sensor
Estimation of soil organic matter
•
•
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Soil structure
Water holding capacity
Infiltration of water and air
Reduction of soil erosion
References
• Hummel, John W. Within-field Location
and Sensing Technology. 04/18/01 www.
odyssey.maine.edu/gisweb/spatdb/acsm/ac9
4071
• OSU. Oklahoma Soil Fertility Handbook.
2000
• Magdoff, F. R. Soil Organic Matter:
Analysis and Interpretation. 1996