józsef prokisch, dóra hovánszky, Éva széles, béla kovács, zoltán győri university of...
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József Prokisch, Dóra Hovánszky, Éva Széles, Béla Kovács, Zoltán Győri
University of Debrecen, Centre of Agricultural Sciences, Institute of Food Science, Quality Assurance and Microbiology 4032 Debrecen Böszörményi út 138. Hungary
Inhomogeneity of the agricultural soils in Hungary
Basic terms:
Homogenous, heterogenius, inhomogenousInhomogenity, Guide to the expression of uncertainty in measurement (GUM)Representative sampling
Question of this study:What is the real inhomogeneity of our soils in the practice?
Bottle with the certified reference material.Mass: 1.00 gParticle size distribution and concentration distribution are same than the real sample.
Sample intake for the measurement. Sample mass: (e.g.) ~10 mgConcentration of sample is calculated from analyte concentration in the individual particles
particle
analyte
Bottle with the certified reference material.Mass: 1.00 gParticle size distribution and concentration distribution are same than the real sample.
Sample intake for the measurement. Sample mass: (e.g.) ~10 mgConcentration of sample is calculated from analyte concentration in the individual particles
particle
analyte
0
0.5
1
1.5
2
2.5
1 10 100 1000
particle size [µm]
den
sity
dis
trib
uti
on q
3lg(
x)
"Sample A"
"Sample B"
"Sample C"
0
50
100
150
200
250
300
350
400
0 100 200 300 400 500
particle size [µm]
CD
NA [µ
g/m
L]
60
80
100
120
140
160
180
0.01 0.1 1 10 100
sample mass [mg]
CD
NA
[µ
g/m
l]
Sample CSample BSample A
The scale and theinhomogeneity
0
50
100
150
200
250
300
0 100 200 300 400 500 600
0
50
100
150
200
250
0 100 200 300 400 500 600
JPconv.exe
0
50
100
150
200
250
1 201 401 601
0
50
100
150
200
250
1 201 401 601
0
50
100
150
200
250
1 201 401 601
0
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100
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1 201 401 601
0
50
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1 201 401 601
0
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250
1 201 401 601
The scale and the measuredinhomogeneity
Questions of this study1. How many sample should I take from an arable field for getting results with a
certain confidence level?
2. Who is responsible for the uncertainity? Sampling or the laboratory? What is the acceptable uncertainity of a repeated measurement of soil from an arable field (5-30 ha)
35.6 ± 12.5 mg/kg25.3 ± 5.2 mg/kg45.6 ± 22.5 mg/kg
An example:
The sampling site and sampling strategy
Example:Nádudvar, Hungary, 47o26’36.8”N 21o13’37.9”E
1000 m * 300 m = 30 ha147 sample
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
Measured parameters:pH, CaCO3, N, P, K, „total” and „plant available” metals, pesticides
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
55-60
50-55
45-50
40-45
35-40
30-35
25-30
20-25
15-20
10-15
5-10
0-5
Cr („total”) [mg/kg](ICPOES)
1000 m * 300 m = 30 ha147 sample
Cost more than 6000€
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
36000-39000
33000-36000
30000-33000
27000-30000
24000-27000
21000-24000
18000-21000
15000-18000
12000-15000
9000-12000
6000-9000
3000-6000
0-3000
Al („total”) [mg/kg](ICPOES)
30
35
40
45
50
55
60
20000 25000 30000 35000 40000
Al [mg/kg]
Cr
[mg
/kg
]
Results:Spatial distribution of total aluminum and chromium in
the soil at the sampling site
0
10
20
30
40
50
60
10 100 1000 10000
Particle size [µm]
cc.H
NO
3 +H
2 O2
solu
ble
chro
miu
m [m
g/kg
]
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
3800-40003600-38003400-36003200-34003000-32002800-30002600-28002400-26002200-24002000-22001800-20001600-18001400-16001200-14001000-1200800-1000600-800400-600200-4000-200
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
2000-21001900-20001800-19001700-18001600-17001500-16001400-15001300-14001200-13001100-12001000-1100900-1000800-900700-800600-700500-600400-500300-400200-300100-2000-100
P („total”) [mg/kg](ICPOES)
P („Ammonium lactate soluble”) [mg/kg]
(Photometry)
1000 m * 300 m = 30 ha
Spatial distribution of total and AL soluble phosphorous in the soil at the sampling site
600
1100
1600
2100
2600
3100
3600
4100
20000 25000 30000 35000 40000
Al [mg/kg]
P [
mg
/kg
]
The developed and applied Monte-Carlo model for the sampling
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
55-60
50-55
45-50
40-45
35-40
30-35
25-30
20-25
15-20
10-15
5-10
0-5
Random selection of certain number of sample
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
55-60
50-55
45-50
40-45
35-40
30-35
25-30
20-25
15-20
10-15
5-10
0-5
Calculation of average
Repeating 100 times
Calculation of relative standard deviation of average values
number of sample RSD%1 10,942 6,953 5,884 5,385 4,996 4,698 4,1610 3,7320 1,9040 1,1250 0,7575 0,64100 0,56
0
5
10
15
20
25
30
35
40
45
0 10 20 30 40 50 60 70 80 90 100
number of samples
RS
D %
0
5
10
15
20
25
30
35
40
45
0 10 20 30 40 50 60 70 80 90 100
number of samples
RS
D %
P Cr
Results of the Monte-Carlo model
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
55-60
50-55
45-50
40-45
35-40
30-35
25-30
20-25
15-20
10-15
5-10
0-5
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21S1
S2
S3
S4
S5
S6
S7
3800-40003600-38003400-36003200-34003000-32002800-30002600-28002400-26002200-24002000-22001800-20001600-18001400-16001200-14001000-1200800-1000600-800400-600200-4000-200
Conclusions
0
5
10
15
20
25
30
35
40
45
0 50 100 150
number of samples
RS
D %
Comparison of standard procedures and practical results
5 ha = 1 sample (what was created by mixing 10-20 individual point)
30 ha = 6 sample (60 sample)
A repeated procedure should produce a results less than 3 % RSD% for the phosporous and less than 1 % for chromium.
1 or not enough sample can resulted high uncertainity
Correct sampling acceptable uncertainity reason of high uncertainity (>10%) in the land scale sampling is caused by the
wrong measurement in the laboratory or very high antropogenic contamination
Good sampling is not impossible!
Thanks for you attention!