Rao Mylavarapu, Nancy Wilkinson, William d’Angelo, Jennifer
Frey, Cassandra Admire, Alex Bournique, Murthy Kadiyala
Soil & Water Science Department, IFAS
University of Florida
Objective
 Screen methods for determination of lime
requirement for acid-mineral soils of Florida
 Methods
 University of Kentucky- Sikora method
 Auburn University
- Huluka method
 Clemson University
- Sikora-Moore method
 University of Georgia - Single Titration method
Justification
 The current Adams-Evans Buffer method involves p-Nitrophenol, an
environmentally hazardous chemical
 An environmentally friendly alternative method is needed
 Primary need, however, is to identify a method that will be effective
for acid-mineral soils of Florida
Materials and Methods
 Collected 12 soil samples from 10 different counties-
Bradford, Clay, Columbia, Highlands, Hendry, Lake,
Marion, Sumter, Putnam (3 samples) and Jackson counties
 Samples were dried, sieved through 2.0mm mesh
 The 4 methods were replicated 4 times
 Water pH (1:2) was determined on all samples
 Soil pH ranged from 4.0 to 5.4
 AE-Buffer pH was determined and the Target pHs were
identified as 6.5 and 6.8
Materials and Methods
 Four replicates of each sample, weighing 200 grams,
were sent to each state Lab
 Each Lab ran their preferred method and determined
the lime requirement and returned the data
 Calcitic lime was added to all cups as per the
recommendation from each of the state labs and the
cups were incubated in the dark for a total of 63 days
Preparation
 The experiment was replicated 4 times





200 g of sample was weighed into each cup
Labeled with county, Lab, lime rate and replicate
12 counties labeled from A to L
4 Labs were labeled I, II, III, IV
Lime rates for a Target pH of 6.5 were labeled as 1 and for
a Target pH of 6.8 were labeled as 2
Preparation
 Pure CaCO3 was added to the cups as prescribed by each Lab
for Target pHs of 6.5 and 6.8, after converting from
Lb Acre-1 to g cup-1
 Soils was stirred well for homogeneity
 All the sample cups were maintained at 30% moisture
content for the entire duration of incubation by estimating
the bulk density and pore space
 The samples were weighed regularly and water was added
using syringe inserted into a straw, which stayed inserted
thru the incubation period, to bring the moisture content
back to 30%
Incubating cups were checked for any
moisture loss through evaporation by weekly
weighing
Water was injected slowly into the incubating
cups by a syringe inserted into a straw
reaching the bottom of the cups to replace
the moisture
Incubation
 All samples were kept in the dark and in a climate-controlled
area at 72°F for 63 days for incubation
Post-incubation
 All the straws were removed and the soils were stirred and let them dry for
a couple of days
 Determined the water pH (1:2) by subsampling the cups for 20 grams of
soil and adding 40 ml of water.
Results
Lime requirement calculated for 6.5 target pH by different methods
Sikora
(Kentuky)
Huluka
(Auburn)
5.22
5.21
Adams-Evans
(UF)
Bradford
5.44
Clay
4.58
6099
4.30
8549
4.43
9000
3.74
12681
5.40
1570
Columbia
5.01
6007
4.98
1575
5.07
3660
4.18
2130
4.90
1845
Highlands
5.08
6007
5.00
3772
5.11
5660
4.32
4477
5.40
1698
Immokalee
4.49
6129
4.44
2312
4.56
3552
3.54
3886
5.40
2498
Lake
4.67
6007
4.49
1849
4.59
3600
3.74
2926
4.50
12652
Marion
4.83
6050
4.70
1903
4.79
3460
4.04
2014
5.25
2511
Sumter
5.04
1850
4.88
3611
5.00
5660
4.11
4736
4.95
1853
Putnam 1
3.77
1756
3.76
5373
3.83
8204
2.87
10971
4.06
4913
Putnam 2
3.89
1698
3.77
3055
3.76
5660
2.90
7126
4.09
2581
Putnam 3
4.78
1743
4.70
1950
4.78
3360
4.05
2411
4.86
1514
Jackson
4.79
1760
4.44
2204
4.51
3860
4.05
2891
4.63
1794
pH
LR
(lb/acre)
3360
Single
titration
(Georgia)
LR
(lb/acre)
1940
pH
LR
(lb/acre)
2258
Sikora-Moore
(Clemson)
pH
4.63
LR
(lb/acre)
2625
5.00
LR
(lb/acre)
2049
pH
pH
Lime requirement calculated for 6.8 target pH by various methods
Sikora
(Kentuky)
Huluka
(Auburn)
5.22
5.21
Adams-Evans
(UF)
Bradford
5.44
Clay
4.58
6589
4.30
9286
4.43
9000
3.74
14445
5.40
1919
Columbia
5.01
6479
4.98
1782
5.07
4400
4.18
2501
4.90
2094
Highlands
5.08
6479
5.00
4275
5.11
6400
4.32
5327
5.40
2076
Immokalee
4.49
6612
4.44
2519
4.56
4000
3.54
4380
5.40
3055
Lake
4.67
5809
4.49
2017
4.59
4100
3.74
3332
4.50
13772
Marion
4.83
6393
4.70
2097
4.79
4200
4.04
2338
5.25
2988
Sumter
5.04
2135
4.88
4054
5.00
6400
4.11
5529
4.95
2115
Putnam 1
3.77
2024
3.76
5829
3.83
8700
2.87
12056
4.06
5251
Putnam 2
3.89
1981
3.77
3317
3.76
6300
2.90
7839
4.09
2727
Putnam 3
4.78
2015
4.70
2151
4.78
4100
4.05
2800
4.86
1709
Jackson
4.79
2048
4.44
2399
4.51
4600
4.05
3350
4.63
1979
pH
LR
(lb/acre)
4100
Single
titration
(Georgia)
LR
(lb/acre)
2292
pH
LR
(lb/acre)
2613
Sikora-Moore
(Clemson)
pH
4.63
LR
(lb/acre)
3247
5.00
LR
(lb/acre)
2353
pH
pH
Measured pH after application of lime for target pH of 6.5
8.0
7.8
7.6
7.4
pH
7.2
7.0
6.8
6.6
6.4
6.2
6.0
Bradford
Clay
Columbia
Kentuky
Highlands
Immokalee
Auburn
Lake
Marion
Clemson
Sumter
Gerogia
Putnam 1
Putnam 2
Target
Putnam 3
Jackson
Measured pH after application of lime for target pH of 6.8
8.0
7.8
7.6
7.4
pH
7.2
7.0
6.8
6.6
6.4
6.2
6.0
Bradford
Clay
Columbia
Highlands
Kentuky
Immokalee
Auburn
Lake
Marion
Clemson
Sumter
Gerogia
Putnam 1
Putnam 2
Target
Putnam 3
Jackson
Average pH values measured after lime application
S.No
Lime requirement
method
pH measured
Target 6.5
Target 6.8
1
Sikora
7.38
7.49
2
Huluka
7.49
7.55
3
Sikora-Moore
7.64
7.68
4
Single Titration
7.56
7.60
LSD (P=0.05)
NS
NS
Average target pH values measured in various county samples
County
pH measured
Soil texture
Target 6.5
Target 6.8
OC (%)
Sand (%)
Silt (%)
Clay(%)
Bradford
7.03
7.12
3.04
96.86
1
2.14
Clay
6.78
6.87
10.35
98.36
0
1.64
Columbia
7.82
7.83
1.43
97.36
0.5
2.14
Highlands
7.71
7.73
4.73
98.36
0
1.64
Immokalee
7.87
7.87
1.73
98.36
0
1.64
Lake
7.65
7.65
1.66
98.36
0
1.64
Marion
7.82
7.88
1.76
98.36
0
1.64
Sumter
7.37
7.5
3.78
98.36
0
1.64
Putnam 1
7.37
7.49
5.20
98.36
0
1.64
Putnam 2
7.67
7.71
1.86
98.36
0
1.64
Putnam 3
7.38
7.52
1.35
98.36
0
1.64
Jackson
7.71
7.75
1.94
89.36
7
3.64
LSD (0.05%)
0.95
0.78
Take home messages
 All the methods have over-estimated the lime requirements




as indicated by the increase in pH beyond the Target pH at
the end of the incubation period
Differentials in Target pHs were not realized even with
different lime recommendation amounts, for any of the
methods
Soil pH determinations showed a high amount of variation,
with possible statistical significance in certain cases
Other soil physical and chemical parameters may be
influencing the lime efficacy
Field calibrations may further increase the variability
Conclusion
 There is a method that Florida can use……
OR
 There is no method that can be clearly identified as suitable
AND
Repeat the study with a few modifications !