different types of extractants used for estimation of potassium in soils other than Ammonium acetate

1. New extractants developed for
estimation of potassium in soil
studies
Presentation by,
Md Mifta Faizullah
RAM/17-82
SSAC
Chairperson:-
Dr. T. Ramprakash

2. Sequence of presentation
• Introduction
• What are extractants
• Why other extractants when NH4OAc is in use?
• Different extractants used in estimation of
potassium
• Research findings
• Conclusion

3. Introduction
• Potassium is one of the essential major plant
nutrients after nitrogen and phosphorus.
• Potassium is the most abundant macronutrient
in soils.

4. Importance..
• K is important for nitrogen fixation in legumes
• Imparting resistance against environmental
stresses such as drought, frost e.t.c.
• It increases plumpiness of grains and seeds.
• Straw of cereals become strong and stiff and
thus it reduces lodging.
• It is considered as quality element for many
crops.

5. Deficiency symptoms
 Plantswill easilylodgeand sensitive to disease
infestation.
 Fruit and seed production will be impaired and
quality is poor.
 Scorching of leaves and burning appearance of
leaves.

6. K deficient leaves

7. Banana Maize

8. Forms of potassium
• Soil potassium can be divided into four main
fractions
1. K in soil solution
2. Exchangeable K
3. Non exchangeable K
4. K in mineral matrix.
Hoagland and Martin, (1933)

9. Forms of potassium

10. Extractants

11. What is extractant?
 A liquid used to extract a substance from
another material.
 Chemical solutions are added to soil samples
that mimic root and soil processes.

12. Nutrient extraction from soil by using
extractants
Provides an
“Index of Availability”

13. Why other extractants when NH4OAc is in use?
• Water soluble
• Exchangeable K
• Non exchangeable
• Fixed pool Failed

14. Different extractants used for
the estimation of potassium

15. Different extractants used for
estimation of potassium
Extractant Composition of
Extractants
Soil-
solution
ratio(W/V)
Equilibrium
time
Reference
Ammonium
acetate
1 N NH4OAc
(pH 7)
1:5 5 min Schollenberger, 1945
Ammonium
lactate
0.1 M Lactic acid
+ 0.4 M Acetic
acid + 0.1 M
ammonium
hydroxide
(pH 3.75)
1:20 120 min Egner et al.,1960
Ammonium
acetate- EDTA
0.5M Ammonium
acetate + 0.02 M
EDTA + 0.05 M
acetic acid
(pH 4.65)
1:5 60 min Lakenen., 1971

16. Extractant Composition of
Extractants
Soil- solution
ratio(W/V)
Equilibrium
time
Reference
Bray & kurtz NH4 F + HCl (pH
2.6)
1:10 5 min Jones, 2001
BaCl2 0.1 M Bacl2 1:40 30 min Simard and
Zizka., 194
Ammonium
bicarbonate-
DTPA
1 M Ammonium
bicarbonate +
0.005M DTPA
1:2 15 min Soltanpour and
Schwab., 1977
Calcium
chloride
0.01 M CaCl2 1:10 30 min Salmon., 1998
Hydrochloric
acid
0.1 M HCl 1:10 30 min Simard et
al.,1991
Nitric acid 0.1 M HNO3 1:2.5 30 min Kanani Iet al.,
1984
Water Distilled water 1:10 30 min Mehlich., 1984
Mehlich 1 0.05N HCl +
0.025N H2SO4
1:4 5 min Mehlich., 1984

17. Extractant Composition of
Extractants
Soil- solution
ratio(W/V)
Equilibrium
time
Reference
Mehlich 3 0.02M Acetic acid +
0.25M Ammonium
nitrate + 0.015M
NH4 F + 0.013M
HNO3 + 0.001M
EDTA
1:10 5 min Mehlich., 1984
Sodium
chloride
1 M NaCl
pH 7.0
1:10 15 min Keague.,1978
Nitric acid 1M HNO3 1:10 10 min Debnath et
al.,1994
Sodium
bicarbonate
0.5M NaHCO3
pH 8.5
1:20 30 min Olsen et al.,
1954
Citric acid 0.01M Citric acid
Strontium
chloride
0.002M Srcl2 1:10 30 min Simard et
a.,1991

18. Extractant Composition of
Extractants
Soil-
solution
ratio(W/V)
Equilibrium
time
Reference
Strontium
chloride and
citric acid
0.02M Strontium
chloride + 0.05M
Citric acid
1:10 30 min Simard et a.,1991
Magnesium
nitrate
0.5M MgNO3 5:33 10 min Tofigi et al., 1999
Sodium
tetraphenyl
borate
NaBPh4 Scott et al., 1960
Sulphuric acid 6N H2SO4 Hunter and
Pratt.,1957

19. Research findings

20. Table 1(a):- Assessment of suitable extractants for predicting plant-available potassium
in indian coastal soils.
Sl no. Extractants
1 1 M NH4OAc
2 Distilled water
3 Bray & Kurtz No 1
4 0.5 M NaHCO3
5 0.02 M CaCl2
6 1 N HNO3
7 0.1 N HNO3
Panda and Patra., (2018)

21. Table 1(b):- Amount of extractable K (mg kg-1 ) determined by different chemical methods
in coastal soils
204.8175.5
Panda and Patra., (2018)

22. Table 1(c):- Coefficients of correlation between soil extractable K determined by different
chemical and biological methods
Extractant 1 N
NH4OAc
Distilled
water
Bray &
Kurtz No
1
0.5 M
NaHCO3
0.02 M
CaCl2
1 N HNO3 0.1 N
HNO3
Distilled
water
0.987**
Bray &
Kurtz No
1
0.590* 0.631*
0.5 M
NaHCO3
0.767* 0.769* 0.711*
0.02 M
CaCl2
0.824** 0.843** 0.704* 0.763**
1 N HNO3 0.700* 0.718* 0.734* 0.670* 0.720*
0.1 N
HNO3
0.699* 0.734* 0.844** 0.724* 0.706* 0.885**
Neubauer
test
values
0.813** 0.837** 0.831** 0.818** 0.805** 0.808** 0.848**
* Significance @1% probability
** Significance @0.1% probability Panda and Patra., (2018)

23. Table 1(d):- Coefficients of correlation between soil extractable K determined by different
chemical methods and forms of K
K form 1 N
NH4OAc
Distilled
water
Bray &
Kurtz
No 1
0.5 M
NaHCO3
0.02 M
CaCl2
1 N
HNO3
0.1 N
HNO3
Ex- K 0.998* 0.981* 0.579* 0.761* 0.809* 0.696* 0.696*
Nex-K 0.898* 0.883* 0.538* 0.692* 0.787* 0.567* 0.626*
Lattice- K 0.885* 0.877* 0.528* 0.639* 0.807* 0.578* 0.622*
* Significance @0.1% probability
Panda and Patra., (2018)

24. Table 2:- Range and mean of K (mg kg-1 ) as extracted by different extractants in K treated
air dry soil samples.
Treatment Methods for
estimation
Range Average
0 ppm K
NH4OAc 62-758 202
Mehlich-3 73-768 213
NaBPh4 573-1753 1134
100 ppm K
NH4OAc 109-817 272
Mehlich-3 127-829 277
NaBPh4 713-1797 1188
200 ppm K
NH4OAc 168-890 324
Mehlich-3 192-902 342
NaBPh4 678-1861 1248
400 ppm K
NH4OAc 254-1023 459
Mehlich-3 266-1028 479
NaBPh4 903-2055 1438
Grewal et al., (2017)

25. Table 3(a):- Minimum, maximum and average concentrations of soil potassium (mg kg-1 )
Determined by various extraction methods.
Parameter KAL KAA KAA-EDTA KBRAY KBaCl2
Min 57.10 52.68 51.60 36.95 55.60
Max 525.81 559.80 485.40 404.60 578.00
Average 179.57 170.0 161.0 130.25 202.73
Zebec et al., (2017)

26. Table 3(b):- Correlation coefficients and statistical significance of the comparative method
for the soil available potassium determination.
Method KAL KAA KAA-EDTA KBRAY KBaCl2
KAL 1
KAA 0.969** 1
KAA-EDTA 0.973** 0.986** 1
KBRAY 0.904** 0.918** 0.931** 1
KBaCl2
0.968** 0.960** 0.962** 0.906** 1
Zebec et al., (2017)
** significant at p=0.05

27. Sl no. Extractants
1 1 M NH4OAc
2 1 M NaOAc ( Morgans reagent)
3 Bray & Kurtz No 1
4 0.5 M NaHCO3
5 0.02 M CaCl2
6 1 N HNO3
7 0.1 N HNO3
8 Distilled water
Table 4(a):- Evaluation of chemical extractantion methods for determining plant available
potassium in some soils of West Bengal, India.
Sarkar and Patra., (2017)

28. Table 4(b):- Available potassium (mg kg−1) in soils extracted by different reagents
205.6 143.95107.26
Sarkar and Patra., (2017)

29. Sarkar and Patra., (2017)
Table 4(c):- Coefficients of correlation between soil extractable K determined by different
chemical and biological methods.
* significant at p= 5%
** significant at p= 1%
NS - non significant
0.866**

30. Table 5(a):- Comparison of ammonium acetate at different concentrations and some
extractants for determination of plant-available potassium in Iran.
Sl no. Extractants
1 0.002M Srcl2
2 0.02M Strontium chloride + 0.05M Citric acid
3 0.5 M MgNO3
4 1 M NaCl
5 1 M NH4OAc
6 0.5 M NH4OAc
7 0.25 M NH4OAc
8 0.1 M NH4OAc
Zarenia et al., (2013)

31. Table 5(b):- Amount of available potassium (mg kg−1) in soils extracted by different extractants
Zarenia et al., (2013)
263

32. Table 5(c):- Correlation coefficient between K extracted by 8 extractants.
Extractants 0.02M
Strontium
chloride +
0.05M Citric
acid
0.5 M
MgNO3
1 M NaCl 1 M
NH4OAc
0.5 M
NH4OAc
0.25 M
NH4OAc
0.1 M
NH4OAc
0.002M Srcl2 0.97a 0.46ns 0.97a 0.54b 0.50ns 0.50ns 0.50ns
0.02M
Strontium
chloride +
0.05M Citric
acid
0.55b 0.97a 0.65a 0.61b 0.60b 0.61b
0.5 M
MgNO3
0.52b 0.75a 0.74a 0.76a 0.75a
1 M NaCl 0.63b 0.60b 0.60b 0.60b
1 M NH4OAc 0.99a 0.99a 0.99a
0.5 M
NH4OAc
0.99a 0.99a
0.25 M
NH4OAc
0.99a
Zarenia et al., (2013)
a - significant at p= 0.05%
b - significant at p= 0.01%
ns - non significant

33. Table 5(d):- Correlation coefficient between K extracted by 9 extractants and K uptake by
plants
Sl
no.
Extractants K uptake
1 0.002M Srcl2 0.79a
2 0.02M Strontium chloride
+ 0.05M Citric acid
0.79a
3 0.5 M MgNO3 0.57b
4 1 M NaCl 0.79a
5 1 M NH4OAc 0.49ns
6 0.5 M NH4OAc 0.47ns
7 0.25 M NH4OAc 0.48ns
8 0.1 M NH4OAc 0.49ns
Zarenia et al., (2013)
a - significant at p= 0.05%
b - significant at p= 0.01%
ns - non significant

34. Table 6(a):- Evaluating chemical extractants to estimate available potassium for pinto beans
(Pheseolus vulgaris) in some calcareous soils.
Sl no. Extractants
1 0.1 M Bacl2
2 AB-DTPA
3 Mehlich 1
4 0.01M CaCl2
5 0.1M HCl
6 1 M NH4OAc
7 0.1 M HNO3
8 1 M HNO3
9 Distilled water
Hosseinpur and Zarenia., (2012)

35. Table 6(b):- Amount of available K (mg kg-1 ) in studied soils
1543
Hosseinpur and Zarenia., (2012)

36. Table 6(c):- Correlation coefficient between K extracted by 9 extractants and K uptake by
plants
Sl
no.
Extractants K uptake
1 0.1 M Bacl2 0.56b
2 AB-DTPA 0.64b
3 Mehlich 1 0.82a
4 0.01M CaCl2 0.85a
5 0.1M HCl 0.77a
6 1 M NH4OAc 0.49ns
7 0.1 M HNO3 0.80a
8 1 M HNO3 0.57b
9 Distilled water 0.75a
a– significant at p=0.05
b – significant at p=0.01
ns - not significant
Hosseinpur and Zarenia., (2012)

37. Table 7(a):- Evaluation of extractants for estimation of available potassium in some
calcareous soils of western Iran.
Sl no. Extractants
1 1 M Nacl
2 0.025 M H2SO4
3 1 M NH4OAc
4 0.1 M BaCl2
5 0.01 M CaCl2
6 Distilled water
Zarrabi and Jalali., (2008)

38. Table 7(b):- Soil-extractable K values (mg kg-1) extracted by different methods
Zarrabi and Jalali., (2008)
312.2

39. Sl
no.
Extractants K uptake
1 1 M Nacl 0.83**
2 0.025 M H2SO4 0.79**
3 1 M NH4OAc 0.69*
4 0.1 M BaCl2 0.81**
5 0.01 M CaCl2 0.84**
6 Distilled water 0.81**
Table 7(c):- Correlation coefficient between K extracted by extractants and K uptake by
plants.
* significant at p= 0.05%
** significant at p= 0.01%
Zarrabi and Jalali., (2008)

40. Table 8(a):- Evaluation of chemical extractants for the determination of available
potassium
Sl no. Extractants
1 0.002M Srcl2
2 0.02M Strontium chloride + 0.05M Citric acid
3 0.1M HCl
4 0.1 M Bacl2
5 1 M NH4OAc
6 0.01M CaCl2
7 Mehlich 1
8 1 M NaOAc
9 AB-DTPA
10 Distilled water
Hosseinpur and Samavati., (2008)

41. Table 8(b):- Amount of extractable K (mg kg-1 ) determined by different chemical methods
Extractants Range Mean
0.002M Srcl2 10.6 – 51.5 31.5
0.02M Strontium
chloride + 0.05M
Citric acid
31.4 – 159.2 87.6
0.1M HCl 33.3 – 177.7 87.9
0.1 M Bacl2 183.4 – 316.7 255.9
1 M NH4OAc 67.1 – 253.8 154.1
0.01M CaCl2 20.0 – 75.3 46.6
Mehlich 1 13.3 – 128.4 52.5
1 M NaOAc 64.1 – 190.4 133.1
AB-DTPA 61.3 – 226.9 147.1
Distilled water 7.0 – 36.3 22.4
Hosseinpur and Samavati., (2008)

42. Table 8(c):- correlation coefficient between K extracted by 10 extractants
Extractants 0.002M
Srcl2
0.02M
Strontium
chloride +
0.05M
Citric acid
0.1M
HCl
0.1 M
Bacl2
1 M
NH4OAc
0.01M
CaCl2
Mehlich 1 1 M
NaOAc
AB-DTPA
0.02M
Strontium
chloride +
0.05M
Citric acid
0.94a
0.1M HCl 0.89a 0.98a
0.1 M Bacl2 0.93a 0.85b 0.79a
1 M
NH4OAc
0.73b
0.59c
0.52c 0.88a
0.01M
CaCl2
0.86a 0.79b 0.76b 0.86a 0.76b
Mehlich 1 0.78b 0.91b 0.95a 0.67b 0.38b 0.69b
1 M NaOAc 0.96a 0.87a 0.80a 0.98a 0.88b 0.87a 0.68b
AB-DTPA 0.76b 0.63b
0.56c 0.89a 0.99b 0.78b
0.40c 0.89a
Distilled
water
0.93a 0.88a 0.82a 0.89a 0.79b 0.78b 0.71b 0.92a 0.81a
a,b – significant at p=0.05
c- not significant at p=0.05
Hosseinpur and Samavati., (2008)

43. Table 8(d):- Correlation coefficient between K extracted by 10 extractants and K uptake by
plants
Extractants K uptake
0.002M Srcl2 0.81b
0.02M Strontium chloride +
0.05M Citric acid
0.73b
0.1M HCl 0.68b
0.1 M Bacl2 0.75b
1 M NH4OAc 0.65b
0.01M CaCl2 0.73b
Mehlich 1 0.77b
1 M NaOAc 0.81b
AB-DTPA 0.67b
Distilled water 0.81b
b – significant at p=0.05
Hosseinpur and Samavati., (2008)

44. Conclusion

45. Conclusion
• In Indian conditions it is proved N N NH4Ac is the best
predictor of plant available K.
• Further research is needed in order to test these extractants
in a wide range of soils, plants and climatic conditions and
would require calibration under field conditions.