contamination to soil and its implications to plant health ... · soil analytical quality control...
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© Malvern Panalytical 2017
Contamination to soil and its implications to plant health: using NIR to check for health of plants in our garden city –NIR LabSpec/FieldSpec
Alice Ng (Application Specialist)
© Malvern Panalytical 2017
NIR Spectrum in Vegetation
Red edge refers to the region of rapid
change in reflectance of vegetation in the
near infrared range of the
electromagnetic spectrum. Chlorophyll
contained in vegetation absorbs most of
the light in the visible part of the spectrum
but becomes almost transparent at
wavelengths greater than 700 nm.
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Agricultural Applications
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Plant Species Mapping
DiPietro, et al, 2002
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Measurement of soil attributes
• Brazil study published in Geoderma 337 (2019) 111-121
• Multiple laboratories
• Used 4 ASD systems
• Analysis using the average lab result and 4 individual ASD
spectroradiometers
• Data compiled here is the average of the 4 ASD systems
Soil Analytical quality control by traditional and spectroscopic techniques: Constructing the future of a hybrid
laboratory for low environmental impact
Jose Alexandre M. Dematte, Andre Carnieletto Dotto, Luis Gustavo Bedin, Veridiana Maria Sayao, Arnaldo Barros e Sousza
Geoderma 337 (2019) 111–121
R2 RMSECV R2 RMSEP
Al 0.92 3.35 0.85 5.39
Ca 0.84 8.33 0.70 11.14
K 0.81 0.97 0.66 1.59
Mg 0.80 4.77 0.73 7.91
P 0.48 24.41 0.31 30.23
AS 0.84 8.04 0.63 13.17
BS 0.82 8.26 0.69 11.65
CEC 0.95 9.93 0.87 17.66
H+Al 0.91 10.20 0.81 14.89
SB 0.82 11.63 0.68 21.31
OM 0.90 3.30 0.79 4.41
pH 0.76 0.27 0.61 0.39
Sand 0.90 6.48 0.87 7.67
Clay 0.91 5.08 0.88 6.08
Silt 0.86 3.29 0.80 4.65
Calibration Validation
Root Mean Squared Error Cross Validation (RMSECV) is an internal method to
'test' your model (or calibration model) to make sure it isn't badly skewed by a
data point or if the model is over fitted, or if there are any outliers. RMSECV is
determined by the validation method chosen.
RMSEP stands for Root Mean Square Error of Prediction. SEP stands for Standard
Error of Prediction. RMSEP or SEP is the simplest and most efficient measure of
the uncertainty in NIR predictions. This value is a measure of the average
uncertainty that can be expected when predicting new samples.
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Measurement of Soil Organic Carbon
• Analysis of intact soil
• NIR predicted Cationic Exchange Capacity (CEC) well
• Real time
• Easy and fast
• Low cost measurement
• RSQ = 0.93, SECV = 1.6
• RSQ validation = 0.86, SEP =2.35
• RPD = 2.66
Malvern Panalytical using soil library of samples from Illinois from NRCS RaCA program
© Malvern Panalytical 2017
Investigation of water stress and relationship with Vegetative Indices
• Nanjing University of Information Science and Technology study
• Included 5 years of data of several vegetative indices including NDVI,
RDVI, TCARI, OSAVI, LWC, REP, TVI, LWC, LWP, LAI, Chlorophyll
content and CWSI (crop water stress index)
• NDVI, RDVI best related to chlorophyll content and LAI
• REP (Red Edge) best related to chlorophyll
• Paper was successful in investigating the relationship between water
stress and Vegetative Indices
Evaluating Structural, Chlorophyll-Based and Photochemical Indices to Detect Summer Maize Responses to Continuous
Water Stress, Meng Li, Ronghao Chu, Qian Yu, Abu Reza Md. Towfiqul Islam, Shuren Chou and Shuanghe Shen
Water 2018, 10, 500; doi:10.3390/w10040500
Leaf Area Index (LAI) is the ratio of foliage area to ground area. LAI can be determined directly by taking a statistically significant sample of foliage from a plant canopy, measuring the leaf area per sample plot and dividing it by the plot land surface area.
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Summary
• Wide variety of applications using NIR in agriculture
• Use of traditional Remote Sensing (i.e. Identify health of different species
of plants)
• Strategies for environmental bioremediation
• Soil quality measurements
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© Malvern Panalytical 2017
Thank You!
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