Examination of Percentage Aluminium Saturattion As a Criterion for Liming Tropical Acid Soils of Nigeria
ME Ikiriko1, JAI Omueti2* and EY Thomas2
1Department of Crop and Soil Science, University of Port Harcourt, Nigeria
2Department of Agronomy, University of Ibadan, Nigeria
Submission: June 13, 2016; Published: June 23, 2016
*Corresponding author: JAI Omueti, Department of Agronomy, University of Ibadan, Oyo State, Nigeria, Email:email@example.com
How to cite this article: ME Ikiriko, JAI O, EY Thomas. Examination of Percentage Aluminium Saturattion As a Criterion for Liming Tropical Acid Soils of Nigeria. Agri Res & Tech: Open Access J. 2016; 1(5): 555574. DOI: 10.19080/ARTOAJ.2016.01.555574
Percentage aluminium saturation as a criterion for liming acid soils in Nigeria was examined. Surface soil (0-15 cm) samples with extreme acidity (3.8-4.9), formed on coastal plain sands (Obio-Akpor and Egor) and sandstone (Nsukka), as part of the soils occurring over the sedimentary rocks in the humid region of southern Nigeria were collected to grow a hybrid maize (DMR White) in pots in green house for six weeks. Four rates ranging from 0 to 3 tons/ha of calcium oxide (CaO) were used as the lime, ranging from 0 to 3 tons/ha for six weeks in greenhouse. The treatments were arranged in a completely randomized design (CRD) with three replications. Soil chemical properties tested were significantly (P<0.05) influenced by increased rates of lime application. Soil pH increased from 4.6 in the unlimed soils to 6.7 in soils treated with 3 t/ha CaO. The exchangeable calcium increased from an average of 0.44 cmolkg-1 at a pH 4.6 and 3.96 cmolkg-1 at a pH 6.7. Liming depressed the uptake of manganese and zinc in all the soils but increased the uptake of calcium and phosphorus. The exchangeable aluminium and percentage aluminium saturation decreased with increasing rates of lime application. Available Phosphorus was low even with a reduction of soluble aluminium in the soil solution, indicating that for proper management of these soils, liming should be supplemented with adequate phosphorus fertilization. Increase in calcium uptake at 3 t/ha was not reflected in the dry matter yield of maize compared to 1 t/ha of lime thus, the 3 t/ha of lime can be regarded as fertilizer rather than as soil amendment. The percentage aluminium saturation was reduced from the mean value of (68.7 to ≤ 33.3)% at 1 t/ha of lime established to be the most suitable criteria for liming acid soils of Nigeria; hence, it is recommended for maize cultivation.
Soil acidity poses a major problem to crop production in the tropics as a result of inherent soil infertility characterised by high hydrogen and aluminium ions in the soil . Most acid soils have been found to be low in fertility as a result of poor physical, chemical and biological properties. Crop production on such soils is seriously constrained, particularly in areas where adequate management practices have not been put in place .
Soil acidity is common in all regions where precipitation is high enough remove appreciable amounts of exchangeable bases from the surface layer of soils . The soil of humid tropics is highly weathered and subjected to frequent and intensive rainfall. In Nigeria, acid soils occur in the southern zone, particularly in parts of Lagos, Ogun, Anambra, Imo, Cross River, Edo, Enugu, Akwa, Ibom, Delta and Rivers State.
The use of exchangeable aluminium as a criterion was first championed by Kamprath  and has been found to be reliable in the management of soils with problems associated with over liming the soil . Lime is routinely used to raise soil pH and at present, so many criteria for applying it are used in Nigeria. Studies on Nigeria soils do not support either raising soil pH to neutral or the use of exchangeable Al as a criterion for liming Nigeria soils  and there is a dearth of information on the appropriate means of liming Nigerian acid soils especially in the study area. The study determined the percentage of aluminium saturation as a criterion for liming tropical acid soils of Nigeria and to contribute to our knowledge of liming acid soils.
Twenty-one surface soil samples (0 - 15 cm) were collected from coastal plain acid sands of Egor and Obio-Akpor and sandstone of Nsukka soils occurring over sedimentary rocks in the humid region of Nigeria . The vegetation largely consists of mangrove swamp in the coast through rainforest to derived savanna in the interior. The rainfall pattern is bimodal with the early rains (April - July) and late rains (August -October) with five months of dry season and a short dry period in August.
Soil samples were air dried, crushed with mortar and pestle to
break the clods and to enable the soil to pass through a 2 mm
sieve for particle size distribution and routine analysis. For the
determination of organic carbon and total nitrogen, the soil was
further passed through 0.5 mm sieve (Figure 1).
Three rates (1, 2 and 3 tons/ha) of lime with a control were
laid out in a completely randomized design in three replicates.
Four hundred grammes of 2 mm sieved soils were weighed into
700ml plastic water cups, which were perforated at the bottom
and covered with cotton wool to allow for easy drainage and
treated with the various rates of lime. The lime was thoroughly
mixed with the soil mass and moistened to approximately
field capacity and allowed to equilibrate for forty-eight hours.
Nutrient status of the soil was determined at the beginning of the
experiment and basal nutrients in the form of urea, muriate of
potash and single superphosphate were supplied to augment the
deficiency observed. Hybrid maize (D.M.R.white) was obtained
from Eagle seed service office at Ibadan. Each pot was sown with
four seeds and later thinned to two seedlings 2WAS. The plants
were allowed to grown for forty-two 42 days, the top-growth
was harvested and oven- dried at 60ºC for forty-eight hours and
Soil analysis was carried out before and after cropping.
Particle size analysis was done using the Bouyoucos hydrometer
method . The pH of the soils was determined in 1N KCL using
a 1:1 soil solution ratio with a glass electrode pH meter. Organic
carbon was estimated by Walkely and Black method as described
by Anderson . Total N, available P were determined by Bray’s
P-1 extraction and molybdenum blue method and the colour
intensity is read on a spectrophotometer, exchangeable cations
(Ca, Mg, K, and Na) and exchangeable acidity by 1 N KCL extraction
were determined by methods largely described by Thomas .
ECEC was determined by summation of exchangeable bases (Ca,
Mg, K, and Na) and exchangeable acidity. Free iron oxides was
determined using the method described by Blakemore  and Percentage aluminium saturation was calculated using the below
Data collected were subjected to analysis of variance
(ANOVA) and treatment means were separated using the least
significant difference at 5% probability level using Genstat
statistical package version 8.0.
The Egor soil had the lowest base saturation of 25 % while
Obio-Akpo and Nsukka have the highest with a close range
of 34 and 35 % respectively. The particle size analysis shows
dominance of sand fraction 64 to 70 % in the soils and the clay
content varies from 26.8 to 30.8 % and they all fall into the same
textural class which is sandy clay (Table 1). The clay content of
all the soils are all in the range 20 to 430 gkg-1 as reported for
tropical soils .
The exchangeable aluminium of the soils varied from (2.73
to 3.60) cmolkg-1 and percentage aluminium saturation ranged
from 65 to 75% which are considered high  and thus,
harmful to the growth of plants. The soils are generally low in
available phosphorus and organic carbon. The mean effective
cation exchange capacity was 4.18 cmolkg-1 for Nsukka, 4.55
cmolkg-1 for Obio-Akpor and 4.78 cmolkg-1 for Egor soils. The pH
of the soils was strongly acidic ranging from 3.8 for Egor, 4.5 for
Nsukka and 4.9 for Obio-Akpor soils (Table 2). The low nutrient
status of the soil could be attributed to losses due to leaching
resulting from high rainfall that characterised tropical soils .
The ammonium oxalate extractable Al ranged from 0.50 to
3.6 gkg-1 while the oxalate extractable iron varies from 0.66 to
1.35 gkg-1 for Obio-Akpor, Nsukka and Egor soils respectively.
The dithionite citrate bicarbonate extractable Al also ranged
from (0.58 to 0.65) gkg-1 and the dithionite citrate extractable
iron varied from 1.32 to 1.93 gkg-1 for Obio-Akpor, Nsukka and
Egor soils respectively (Table 2). The high amount of free iron
oxides may be attributed to the low soil pH.
The exchangeable Al3+ values varied from 2.00 to 2.8
cmolkg-1 for all the soils in the control without lime treatment
and reduces as the lime rate increases. The lowest values of
exchangeable aluminium were 0.6 cmolkg-1, 0.9 cmolkg-1 and
0.4 cmolkg-1 at 3 t ha1 for Obio-Akpor, Nsukka and Egor soils
respectively. The exchangeable acidity values ranged from 2.1
to 3.2 cmolkg-1 for the soils in control without lime treatment
and reduced drastically as lime rate increases. The lowest values
of exchangeable acidity were 1.1 cmolkg-1, 1.2 cmolkg-1 and
1.0 cmolkg-1 at 3 t ha1 for Obio-Akpor, Nsukka and Egor soils
respectively (Table 3). Both the exchangeable aluminium and
acidity responded significantly (P<0.05) as the rates of lime
application increases. This result is similar to the findings of Buni
, who posited that the decrease in exchangeable aluminium
may be due to the increased displacement of aluminium by
calcium in the exchange site and by the subsequent precipitation
of aluminium as aluminium hydroxide as the soil was limed. Also,an increase in soil pH resulted in precipitation of exchangeable
Al3+ and insoluble aluminium hydroxides thus reducing
concentration of aluminium in the soil solution .
The exchangeable Ca2+ increased from 0.38 cmolkg-1 for Obio-
Akporsoils, 0.50 cmolkg-1 for Nsukka soils, and 0.45 cmolkg-1 for
Egor soils, all from the control without lime treatment to 3.62
cmolkg-1, 4.50 cmolkg-1 to 4.02 cmolkg-1 all at 3 t ha1. Nsukka and
Egor soils had the highest of exchangeable calcium followed by
Obio-Akpor soils with the lowest value (Table 3). The different
rates of application of lime significantly increase (P<0.05)
exchangeable Ca2+ in all the soils. This increased in exchangeable
Ca2+ could be attributed to calcium oxide used for the experiment,
which added calcium to the soils. This increase in calcium uptake
at 3 t/ha did not reflect in the dry matter yield as compare to the
1 t/ha of lime applied. Thus, the 3 t/ha of lime could be regarded
as fertilizer rather than as soil amendment. This result is similar
to the findings of Omueti , who reported that an increase in
exchangeable calcium is probably due to liming.
Exchangeable Mg2+ values for all the soils ranges from 0.69
to 0.86 cmolkg-1 in the control without lime treatment for Obio-
Akpor, Nsukka and Egor soils respectively. The highest values
of exchangeable Mg2+ varied from (1.02 to 1.89) cmolkg-1 and
were obtained at 3 tons per ha of lime in all the soils (Table 3).
The increase in exchangeable Mg2+ (P<0.05) may be due to the
application of lime which increased the soil pH to 6.5 and above,
a range in which more magnesium is found in soil solution.
The aluminium saturation values varied from 491 to 545
gkg-1 for all soils in the control without lime treatment and
the lowest values were 89 gkg-1 at 2 t ha1 for Obio-Akpor soils,
110 gkg-1 for Nsukka and 55 gkg-1 for Egor soils both at 3 t ha1.
Aluminium saturation decreased significantly (P<0.05) as the
rate of liming application increases (Table 3). The decreased
of percentage aluminium saturation could be attributed to the
decrease of exchangeable aluminium by exchange with cations
and also, the increase exchange capacity induced by the higher
electrolyte concentrations as predicted by theory or constant
potential surface . The base saturation varies from 377 to
460 gkg-1 for all the soils in the control without lime treatment
and the highest values were 812 gkg-1 for Obio-Akpor soils, 853
gkg-1 for Nsukka soils and 862 gkg-1 for Egor soils all at 3 t ha1
of lime. Base saturation increase significantly (P< 0.05) with
increases rate of lime application (Table 3). This increase may be
attributed to the dosage of lime applied which in turn supplied
calcium to the soil which replaced the exchangeable aluminium
from the exchange site.
The soil pH increased with increasing rate of lime irrespective
of the rate of application. The soil pH values were significantly
increased (P<0.05) with increasing rate of lime application in
all location. Soil pH significantly increased from 4.1 to 4.9 in
the control pots without lime application to 6.5, 6.9 and 6.3 at
the rate of lime 3 tons ha-1 for Obio-Akpor, Nsukka and Egor
respectively (Table 3). This responses of pH to lime has also been
observed in tropical soils in several regions of the world .
The increased in soil pH is probably due to the increase in basic
cations (Ca) and neutralization at the exchange complex .
Liming significantly (P<0.05) increases the available
phosphorus for Obio-Akpor and Egor soils, although the increase
were not consistent in all the soils. The highest values of available
phosphorus ranged from 18.87 mgkg-1 at 1 tons per ha for Obio-
Akpor, 25.8 mgkg-1 at 2 t ha1 for Nsukka and 21.52 mgkg-1 at 3 t/ha
for Egor soils (Table 3). The available phosphorus in all the soils
still falls within the sufficiency range. The increase of available
phosphorus can be explained in terms of the activities of iron,
aluminium and manganese at low pH. When the soil pH is low,
the activities of iron, aluminium and manganese are significantly
form complexes with the soluble forms of phosphorus thus
fixing the element. With lime application, the pH is increased
and the iron and aluminium which dominate the soils become
less active, thus releasing the soluble phosphate ions in form of
the diphosphates and monophosphate. This result is similar to
Unagwu et al. , reduction in soil acidity leads to phosphorus
The uptake of available phosphorus from all the soils were
statistically significant, the increase of phosphorus uptake was
not consistent with the rates of lime of application (Table 4). The
lowest uptake were observed at 3 t/ha corresponding to 1.22 to
1.89 mgkg-1 and the highest values were observed at 1 tons per
ha corresponding to 2.89, 2.33 and 2.76 mgkg-1 for Obio-Akpor
soils, Nsukka soils and Egor soils respectively. This result is
similar to the findings of Amarasiri . Maximum P uptake by
plant occurred when soils were limed to pH between 5 and 6.
Liming of ultisols and oxisols to pH values above 6 will increased
fixation of phosphorus either through precipitation as calcium
phosphates or through sorption by freshly precipitated iron and
aluminium hydroxides in the limed soil .
Calcium uptake increased significantly (P<0.05) with
increasing rate of liming application over the control, the lowest
values were observed at 1 t ha1 corresponding to 1.88 to 3.63
cmolkg-1 and the maximum uptake were observed at 3 t ha1 with
the responding values of 6.00, 6.25 and 4.72 cmolkg-1 for Obio-
Akpor, Nsukka and Egor soils respectively (Table 4).
The total magnesium uptake for all soils were not significantly
influenced with increasing rates of liming application over the
control, the maximum values ranged from (0.43 to 0.58) cmolkg-1
and the minimum values were 0.38, 0.45 and 0.39 cmolkg-1 for
Obio-Akpor, Nsukka and Egor soils respectively (Table 4). Total
potassium uptake from all soils were significantly (P<0.05)
influenced with increasing rates of lime application (Table
4). The maximum potassium uptake were 3.54 , 3.33 and 3.03
cmolkg-1, all at 3 tons per ha and the minimum uptake were
1.69, 1.63 and 1.05 cmolkg-1 all at 1 t ha1 for Obio-Akpor, Nsukka
and Egor soils respectively.
The manganese uptake by maize plant from all soils
decreased with increasing rates of lime application over the
control but significant (P<0.05) for Nsukka and Egor soils
respectively (Table 4). The highest uptake of manganese values
(117,141 and114 mgkg-1) all at 1 t ha1 and the lowest values
uptake of manganese were 99, 98 and 84 mgkg-1 all at 3 tons per
ha Obio-Akpor, Nsukka and Egor soils respectively. The uptake of
manganese by plant reduced drastically with increasing soil pH
and rate of liming application. This result is in agreement with
the findings of Juo .
The dry matter yield obtained from all soils increased
significantly (P<0.05) with increasing rates of lime application
over the unlimed soils, although the increase were not consistent
among the soils. The dry matter yield values for the unlimed soils
varied from 1.42, 1.64 and 1.14 g pot-1 and the highest values
ranged from 4.14 to 4.58 g pot-1, and all were obtained for Obio-
Akpor, Nsukka and Egor soils respectively (Table 5). The dry
matter yield values obtained for unlimed soils were relatively low when compared to the limed soils. This could be attributed to
the inherent acidic nature of the soils associated with aluminium
and manganese toxicity of the soils, and low exchangeable
calcium of the soils under study (Table 2). The maximum yield
was obtained at an average soil pH of 5.4 for all the three soils
and dropped when the soils were limed to an average soil pH of
6.5. This result indicates that over liming depresses the maize
dry matter yield. According to Sanchez , the lower yield
obtained at higher rates of lime is attributed to the nearly flat
plateau. The yield values to deficiencies of micronutrients such as manganese and zinc which are induced by high rates of lime
application. The deficiencies of Mn and Zn were not observed but
suspected as their uptake were drastically depressed as the rates
of lime increases. The increase in calcium uptake at 3 t ha1 of lime
did not reflect in the dry matter yield of maize compared to the 1
t ha1 of lime applied (Table 5). Thus, the 3 t ha1 can be regarded
as fertilizer rather than as soil amendment.
From the above discussion, the appropriate lime requirement
for these soils is about 1 t ha1 having the mean yield of 4.34 g pot-1.
This lime rate reduced the percentage aluminium saturation from
the mean of 68.7% (Table 2) to 33.3% for all the soils (Table 5).
This finding is in agreement with the conclusion of IITA [20-22],
which stated that the critical level of exchangeable aluminium
saturation for maize (Cv.TZPB) required for 90 percent maximum
yield was about 35 percent. The lime rate of 1ton per ha was
sufficient enough to maintained the exchangeable aluminium at a
tolerant level for the variety of maize used. Hence, the removal of
exchangeable aluminium or the reduction of soluble aluminium
to about 33.3% of the effective cation exchange capacity is a
more reliable basis for predicting lime requirement of tropical
acid soils of Nigeria.
Soil acidity is often associated with aluminium toxicities
and soil nutrient depletion, which results in poor agricultural
production, experiment was carried out involving laboratory
and greenhouse study, to examine the percentage aluminium
saturation as a criterion for liming acid soils of the tropics,
especially Nigerian soils, using quick lime as the liming material.
In the laboratory experiment, lime reduced all acid parameters indicators (Exchangeable aluminium, exchangeable acidity, soil
pH and percentage aluminium saturation) associated with the
soils; and also, the availability of phosphorus was increased.
Liming reduced the amount of free iron oxides in all the soils
In the greenhouse studies, the 3 t ha1 of lime applied did
not reflect in the dry matter yield of maize. The percentage
aluminium saturation was reduced from a mean value of 68.7%
to 33.3%, which corresponds to 1 t/ha of lime application,
improved the dry matter yield of maize. The different rates of
lime application increased the uptake of P, K, Ca and Mg, but the
uptake of Zn, Mn and the K/Ca ratio in plant decreased as the
rates of lime application increases.
In conclusion, the use of percentage aluminium saturation as
the basis for calculating lime requirement is justified in terms of
the improved yield response obtained, although the lime applied
supplied calcium to the soil which was reflected in the effective
cation exchange capacity of the soil. The following are therefore
For efficient and prudent management of the soils
study, lime should always be applied with sufficient or
adequate phosphorus fertilizer application.
The most suitable criterion for liming was found to be
the reduction of percentage aluminium saturation in
soil solution to ≤ 33.3% at 1 t ha-1 of lime. At this level,
the soil pH will not be drastically increased.