# Effects of Liming on Dithionate and Oxalate Extractable Aluminium in Acid Soils

Esther Mwende Muindi

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Esther Mwende Muindi. Effects of Liming on Dithionate and Oxalate Extractable Aluminium in Acid Soils. Asian Journal of Soil Science and Plant Nutrition, 2020, pp.1-9.
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# Effects of Liming on Dithionate and Oxalate Extractable Aluminium in Acid Soils

Esther Mwende Muindi¹*

¹Pwani University, P.O. Box 195-80108, Kilifi, Kenya.

**Author's contribution**

*The author designed, analysed, interpreted and prepared the manuscript.*

**Article Information**

DOI: 10.9734/AJSSPN/2019/v5i330069

Editor(s):

(1) Dr. Sezer Sahin, Associate Professor, Department of Soil Science and Plant Nutrition, Gaziosmanpaşa University, Turkey.

Reviewers:

(1) Boško Gajić, University of Belgrade, Serbia.

(2) Fábio Henrique Portella Corrêa de Oliveira, Universidade Federal Rural de Pernambuco, Brazil.
Complete Peer review History: http://www.sdiarticle4.com/review-history/54010

**Original Research Article**

Received 16 November 2019

Accepted 21 January 2020

Published 25 January 2020

## ABSTRACT

Liming and phosphorus (P) applications are recommended practices for improving crop production in acid soils of the tropics. Although considerable work has been done to establish liming rates for acid soils in many parts of the world, information on the effects of lime on the forms of aluminium which actively sorb P in such soils is minimal. A greenhouse pot experiment was conducted at Waruhiu Farmers Training Centre, Githunguri to evaluate the effect of liming on oxalate and dithionate extractable aluminium in acid soils. Extremely (pH 4.48) and strongly (pH 4.59) acidic soils were evaluated. Four liming (CaO) rates namely 0, 2.2, 5.2 and 7.4 tonnes ha⁻¹ for extremely acidic and 0, 1.4, 3.2, and 4.5 tonnes ha⁻¹ for strongly acidic soils were evaluated. The experiment was laid out in a Randomized Complete Block Design (RCBD) and replicated three times. Data collected included: initial soil chemical properties, oxalate (Al₀) and dithionate (Al₉) aluminium levels. The tested soils had high exchangeable Al (> 2 cmol Al kg⁻¹), Al saturation of (> 20% Al) and low extractable P values (< 15 mg P kg⁻¹ soil). Liming significantly (p=.05) reduced Al₀ by 70% and 68% in extremely and strongly acidic soils respectively and Al₉ by 78% in both extremely and strongly acidic soils compared to control. Use of 7.4 tonnes ha⁻¹ of lime in extremely acidic soils and 4.5 tonnes ha⁻¹ of lime in strongly acidic soils significantly (p=.05) reduced both Al₀ and Al₉ by > 68% compared to no lime. It was, therefore, concluded that liming contributes to the reduction of soluble Al₀ and Al₉ in acid soils of the Kenya highlands leading to increased soluble P availability. Studies are required to provide short and long term optimal liming rates that reduce Al₀ and Al₉ without distabilizing availability of other nutrients in field conditions under wide range of acid soils.

<footnote>*Corresponding author: Email: e.muindi@pu.ac.ke, muidiede@gmail.com;</footnote>
Keywords: Lime; phosphorus; oxalate aluminium; dithionate aluminium; acid soils.

# 1. INTRODUCTION

Approximately 40-50% of the World's total potential arable land consists of acid soils. The acid soils (pH ≤ 5.5) comprise approximately 30% of the total earth area and they are associated with high levels of exchangeable aluminium (Al), hydrogen (H), iron (Fe) and manganese (Mn) in soil solution [1,2,3]. They are also associated with toxicities to plant roots in the soil solution and corresponding deficiencies of the available P, molybdenum (Mo), calcium (Ca), magnesium (Mg) and potassium (K) [4-8]. Although excess H⁺ ions are toxic and negatively affect root membrane permeability [9], the main constraint to crop production in highly acid soils is not high H⁺ ions but increased concentration of Fe³⁺ and Al³⁺ ions at pH < 5.5 [10,11]. Aluminium toxicity is, however, the most significant threat to plant survival in acid soils [12,13].

Aluminium is a chemical element with the symbol Al and atomic number 13. It is silvery-while, soft, nonmagnetic and ductile metal in the boron group and third most abundant element in the earth's crust after oxygen and silicon making up about 7-8% of the earth's crust [13,14,15]. It is one of the group III elements consisting of aluminium, gallium, indium and thalium which have three electrons in their outer shell. Although the element is metallic in nature, it exhibits both ionic and cuvailent bonding which is dominated by trivalent state. The element has a diameter of 0.57Å and it is generally found in sixfold coordination with oxygen in the octahedral layer of many primary minerals such as micas, feldspar, cryolite and secondary phyllosilicates and ores such as bauxite [16,17]. It makes 8.1% of igneous, 8.2% of shale, 2.5% of sandstone and 0.4% of limestone rocks [12]. Despite being ubiquitous and available, Al has no specific biological function in plants [18].

The process of release of Al ions from octahedral co-ordination in minerals through weathering processes [12,19] usually depends on H⁺ ion concentration. In acid soils below pH 4.3, Al ions combine with water and solubilizes to form Al (H₂O) 6³⁺. At pH 4.5-6.5 aluminium-hydroxyls dominates, while in very acidic conditions of pH < 4.5, Al³⁺ dominates [20]. As H⁺ ions in the soil solution increases to pH 4 or below, the hydronium ions (OH³⁻) formed cause the dissolution of Al³⁺ from the edges of the mineral

structure. Upon release the Al ions become six fold coordinated with oxygen in OH₂ groups such as (Al(-OH₂)⁰.⁵⁺)⁶. This OH₂ groups are Al substituted hydronium ions, the Al having replaced one H from each of the six hydronium ions (OH³⁺). The Al substituted hydronium ions called aluminohexahydronium ions are often designated as Al⁶H₂O³⁺. Aluminium can also formulate other species such as Al(OH)²⁺, Al(OH)₂, Al(OH)₃⁻, and Al(OH)₄⁻ where Al³⁺ is considered as the most toxic form that have great impact on plants growth and development [14,21,22].

Increase in soil pH, cause subsequent dissociation into various species of Al [17,23]. The aluminohydronium ions sequentially dissociate H ions as base is added leaving OH ions in place of the OH₂ groups. The resulting Al forms range from simple monomeric species to polymeric species of varying molecular weight, either in combination with Fe or Si or both, depending on soil pH [24,25]. This is because, some of the resulting Al³⁺, (OH)Al²⁺, and (OH)₂Al⁺ ions remain in the soil solution and they may be adsorbed as monomers to the cation exchange sites of the soil or polymerized on clay mineral surfaces or adsorbed and then complexed by soil organic matter.

One of the major consequences of aluminium toxicity is growth inhibition in plants. Excess Al inhibits roots cell division, elongation, root hair formation and enhances development of swollen roots apices [26]. It also inhibits water and nutrients uptake of affected plants [13]. Several studies have indicated that excess Al alters nutrient levels such as N, K, Ca, Mg and P and reduces photosynthetic rates, stomatal conductance and leaf transpiration rate in plants [27,21,28,29]. The negative effects of Al in soil and plants can however, be managed by application of organic matter and lime. Soil organic matter has been reported to form stable complexes of Al with humic aliphatic organic acids to suppress detrimental effects of Al in soil solution [30]. Lime on the other hand is an important approach of correcting acidity by increasing soil pH, reducing Al toxicity [31,32,4] restoring Ca, P, availability as well as improving soil cation exchange capacity (CEC) [32,33].

The soil iron and aluminium released during weathering can be re precipitated as amorphous
<figure><img src="image_3.png" /><figcaption>Fig. 1. Effect of liming on oxalate aluminium (AlO) (cmol kg⁻¹) on acid soils</figcaption></figure>

or crystalline oxides, hydroxides or oxhydroxides [34]. The amount, nature and distribution of this various forms of Fe and Al oxides with organic complexes can greatly influence soil physical and chemical properties [35] hence affecting ionic charge chemical characteristics and ionic adsorption especially phosphorus sorption, surface charge and specific surface area. Swelling and aggregate formation may also be significantly modified by the presence of amorphous Fe and Al oxides [36]. The amorphous (short range order) and crystalline (hematite and gibbsite) Fe and Al hydroxides are particularly important to P sorption in soils. Crystalline Fe and Al hydrous oxides sorb 5-10 times more P than crystalline alumina silicates clay minerals where else amorphous Fe oxide gel sorb 10-100 times more P than their crystalline counterparts. Amorphous Fe and Al hydroxides also often occur as coatings on other soil mineral surfaces [37]. Owing to the fact that increased P sorption on limed soils is attributed to formation of active x-ray amorphous Al hydroxyl polymers, which actively sorb more P than Al³⁺ [38]. The active Al hydroxyl polymers formed has also been associated with coating the surfaces of minerals, thereby affecting their surface charge characteristics [39]. Understanding of the amount of crystalline and amorphous forms of Fe and Al in acid soils and the effects of management practices on such forms is an important approach in the management of such soils. Amorphous forms can be evaluated by use of oxalate while dithionate evaluates crystalline forms. This study therefore aimed at evaluating the effects of lime

on oxalate and dithionate extractable Al in acid soils.

## 2. MATERIALS AND METHODS

### 2.1 Experimental Layout Design

A greenhouse pot experiment was carried out at Waruhiu Farmers' Training Centre, Githunguri, Kiambu County, Kenya. Two composite soil samples representing extremely acid (pH 4.0-4.5) and strongly acidic (pH 5.0-5.5) soils, as described by Kanyanjua, et al. [40] were used. The experiments were a 4² factorial laid down in a Randomized Complete Block Design (RCBD and replicated three times. The treatments were liming rates were chosen to obtain 0, 30, 70 or 100% reduction in amounts of M KCl-extractable Al originally present in the soil and the two levels of acidity (Table 1). Burnt lime (CaO) containing about 21% calcium oxide was used in this study.

Five kilogramme composite soil sample portions for both extremely and strongly acid soils were weighed into ten litre plastic pots. The six (6) lime levels as stipulated in Table 1 were weighed and incorporated into the soil samples by thoroughly mixing and incubating at moist conditions for a period of 21 days. Water was added every 2 days to compensate for evaporative losses. After incubation, soils from each liming level were air-dried, sieved and returned to the plastic pots. The soils were re-incubated at the same conditions for 14 days after which they were air dried. Subsamples of the soils were then used for chemical analyses.
<table><caption>Table 1. Actual amounts of lime added to the acid soils</caption><thead><tr><th rowspan="2">Soil</th><th colspan="4">Lime added (tonnes ha<sup>-1</sup>)</th></tr><tr><th>0%</th><th>30%</th><th>70%</th><th>100%</th></tr></thead><tbody><tr><td>Extremely Acidic</td><td>0</td><td>2.2</td><td>5.2</td><td>7.4</td></tr><tr><td>Strongly Acidic</td><td>0</td><td>1.4</td><td>3.2</td><td>4.5</td></tr></tbody></table>

<table><caption>Table 2. Physicochemical properties of the two soils prior to the pot experiment</caption><thead><tr><th></th><th>Extremely acidic</th><th>Strongly acidic</th></tr></thead><tbody><tr><td>pH (H<sub>2</sub>O)</td><td>4.48</td><td>4.59</td></tr><tr><td>Exch. Al (cmol kg<sup>-1</sup>)</td><td>3.85</td><td>3.90</td></tr><tr><td>P (mg kg<sup>-1</sup>)</td><td>9.25</td><td>10.50</td></tr><tr><td>Oxalate Al (cmol kg<sup>-1</sup>)</td><td>4.61</td><td>4.58</td></tr><tr><td>Dithionate Al (cmol kg<sup>-1</sup>)</td><td>3.85</td><td>3.48</td></tr><tr><td>Oxalate Fe (cmol kg<sup>-1</sup>)</td><td>6.75</td><td>6.85</td></tr><tr><td>Dithionate Fe (cmol kg<sup>-1</sup>)</td><td>3.85</td><td>3.82</td></tr><tr><td>Al Saturation (%)</td><td>55.82</td><td>49.66</td></tr><tr><td><strong>PSD*</strong></td><td></td><td></td></tr><tr><td>% Clay</td><td>56.32</td><td>50.00</td></tr><tr><td>% Silt</td><td>21.00</td><td>17.00</td></tr><tr><td>% Sand</td><td>22.68</td><td>33.00</td></tr><tr><td>Textural class</td><td>Clay</td><td>Clay</td></tr></tbody></table>

*Particle size distribution

## 2.2 Laboratory Analysis

Soil physicochemical analysis and P adsorption were determined before and after application of treatments. Soil pH, exchangeable aluminium, exchangeable Calcium, exchangeable magnesium and particle size distribution were analyzed as described by Okalebo, et al. [41]. Iron and aluminium contents were extracted using ammonium oxalate at pH 4.0 [42] and dithionate-citrate-bicarbonate (DCB) [43]. Extractable P was determined as described by [44]. The lime requirements of the soils were calculated using the equation of Cochrane, et al. [45]. The equation aims at reducing the % Al saturation to a level that is commensurate with crop Al tolerance, and is given as: Lime required (CaCO₃ equiv.) tones ha⁻¹ = 1.8 [Al - RAS (Al + Ca + Mg) /100] where Al = cmol kg⁻¹ soil in the original exchange complex, RAS = Required percentage Al saturation, Ca = cmol kg⁻¹ soil in the original exchange complex, Mg = cmol kg⁻¹ soil in the original exchange complex. A RAS value of 20% was used. Soil characterization data in Table 2 was used for lime requirement determinations.

## 2.3 Statistical Analysis

Data obtained were subjected to Analysis of Variance (ANOVA) using the GenStat statistical package [46] and treatment effects were tested for significance using the F-test at 5% level of

significance. Means were ranked using Duncan's New Multiple Range Test (DNMRT). Dependency tests were also conducted to find out if there was a relationship between the various variables assessed.

# 3. RESULTS

## 3.1 Initial Soil Physical and Chemical Characteristics

The tested soils were acidic with pH < 5.5 (Table 2). Dithionate and oxalate extractable Al and exchangeable Al levels were high >2 cmol kg⁻¹ in both soils. Percent aluminium saturation was also high; > 20% and extractable P (< 15 mg kg⁻¹) was low. The tested soils had clay texture.

## 3.2 Effects of Liming on Soils pH, Aluminium Levels

Liming significantly (p=.05) increased soil pH levels and reduced extractable Al and percent Al saturation (Table 3). The reduction of soil pH was in the order: 0 % reduction of Al³⁺ < 30% reduction of Al³⁺ < 70% reduction of Al³⁺, 100% reduction of Al³⁺. The significant (p=.05) decrease of exchangeable Al on liming followed the order: 0% reduction of Al³⁺ < 30% reduction of Al³⁺ < 70% reduction of Al³⁺ < 100% reduction of Al³⁺ in both extremely and strongly acidic soils. Liming aimed at 100% reduction of exchangeable Al led to 50% reduction of
exchangeable Al in extremely acidic soils and 55% reduction in moderately acidic soils compared to liming aimed at 0% reduction of exchangeable Al. The significant (p=.05) decrease of % Al saturation followed the order: 0% reduction of Al³⁺ < 30% reduction of Al³⁺ < 70% reduction of Al³⁺ < 100% reduction of Al³⁺ in both extremely acidic and strongly acidic soils. Liming to give 100% reduction of exchangeable Al led to 46% and 61% reduction of % Al saturation in extremely and moderately acidic soils respectively.

Liming significantly (p=.05) reduced oxalate extractable aluminium (Al₀) in the acid soils (Fig. 1). The Al₀ was reduced from ≥ 6.0 cmol kg⁻¹ to < 3 cmol kg⁻¹ in both extremely acidic and strongly acidic soils. Oxalate extractable Al was reduced

by 70% in extremely acidic soils and 68% in strongly acidic soils compared to the control (0% reduction in Al³⁺ treatment).

Liming significantly (p=.05) reduced dithionate extractable aluminium (Al₉) in the acid soils (Fig. 2). The Al₉ was reduced from > 5.0 cmol kg⁻¹ to < 2.5 cmol kg⁻¹ in both extremely acidic and strongly acidic soils. Dithionate extractable Al was reduced by 78% in both extremely acidic and strongly acidic soils compared to the control.

A significant (p=.05) positive relationship was observed between soil pH, lime and exchangeable P (Table 4). Lime was also positively correlated with exchangeable P. On the contrary, soil pH, lime, exchangeable P,

<table><caption>**Table 3. Effect of liming on the pH (water), exchangeable aluminium and percent aluminium saturation of the acid soils**</caption><thead><tr><th rowspan="2">Lime to give:</th><th colspan="3">Extremely acidic</th><th colspan="3">Moderately acidic</th></tr><tr><th>pH(water)</th><th>Exch. Al</th><th>Al Sat.</th><th>pH(water)</th><th>Exch. Al</th><th>Al Sat.</th></tr></thead><tbody><tr><td>0% reduction in Al³⁺</td><td>4.2a</td><td>3.6d</td><td>64.1d</td><td>4.1a</td><td>3.8c</td><td>71.5d</td></tr><tr><td>30% reduction in Al³⁺</td><td>5.2b</td><td>2.9c</td><td>49.2c</td><td>5.3b</td><td>2.8ab</td><td>45.5c</td></tr><tr><td>70% reduction in Al³⁺</td><td>6.3c</td><td>2.3b</td><td>42.9b</td><td>5.6bc</td><td>2.2a</td><td>38.1b</td></tr><tr><td>100% reduction in Al³⁺</td><td>6.4d</td><td>1.8a</td><td>34.8a</td><td>6.4bc</td><td>1.7a</td><td>27.6a</td></tr><tr><td>% CV</td><td>0.6</td><td>1.6</td><td>7.9</td><td>0.9</td><td>0.8</td><td>3.2</td></tr></tbody></table>

Values followed by the same letter(s) on the same column are not significantly different at p=.05. CV-coefficient of variation

<figure><img src="image_4.png" /><figcaption>**Fig. 2. Effect of liming on dithionate aluminium (Al₉) (cmol kg⁻¹) on acid soils**</figcaption></figure>

<table><caption>**Table 4. Relationship between soil pH, P, aluminium saturation, Al₀, Al₉ and lime in the two acid soils**</caption><thead><tr><th></th><th>pH</th><th>Lime</th><th>Al₀</th><th>Al₉</th><th>Al. Sat.</th></tr></thead><tbody><tr><td>pH</td><td>-</td><td>0.94</td><td>-0.95</td><td>-0.96</td><td>-0.84</td></tr><tr><td>Lime</td><td>0.94</td><td>-</td><td>-0.98</td><td>-0.97</td><td>-0.86</td></tr><tr><td>P</td><td>0.38</td><td>-</td><td>-0.29</td><td>-0.33</td><td>-0.28</td></tr></tbody></table>

All correlations had high significant relationship of p=.05
aluminium saturation, Al₀ and Al₉, were observed to have a significant (p=.05) negative correlation.

# 4. DISCUSSION

## 4.1 Soil Chemical and Physical Characteristic of the Soils

As per the rating suggested by Landon [47] the soils had low levels of P (< 10 bicarbonate extractable P) and high levels of exchangeable aluminium (> 2.0 cmol kg⁻¹) and Al saturation (> 20%) implying that they were of high acidity levels and low fertility status. The soils also had high levels of crystalline and amorphous aluminium (> 2.0 cmol kg⁻¹). The high levels of Al and Al saturation are considered to be toxic to maize plants [41,47]. According to Kanyanjua, et al. [40], the soils were strongly to extremely acidic with pH of 4.48-4.58. Such acid soils with high Al³⁺ ions, low bases and CEC are characteristic of highly weathered soils, which have lost most of the basic cations through the process of leaching [47]. As a result, their high levels of Fe and Al sesquioxides may lead to high P fixation, resulting in low available P [47,48,49,50]. Additionally, the acidity could be attributed to the mineralogy of the parent materials [50] because most of these soils are developed from non-calcareous parent materials such as syenites, phololites, trachytes and nepholites which are acidic in nature [51].

## 4.2 The Effects of Lime on Soil pH and Aluminium

The significant increase of soil pH with liming in the present study could be attributed to the presence of Ca²⁺ ions contained in the lime. The Ca²⁺ ions displaces H⁺ and Al³⁺ ions from the soil adsorption sites (Equation i and ii) which are subsequently neutralized resulting in increased soil pH [52].

$$3\text{Ca}(\text{OH})_2 + 2\text{Al}^{3+} \rightarrow 2\text{Al}(\text{OH})_3 + 3\text{Ca}^{2+} \quad (i)$$

$$2\text{H}^+ + \text{Ca}(\text{OH})_2 \rightarrow \text{Ca}^{2+} + 2\text{H}_2\text{O} \quad (ii)$$

The significant reduction of exchangeable Al and aluminium saturation, oxalate Al and dithionate Al upon liming could be attributed to reaction of the calcium oxide with carbon dioxide and water in the soil to yield Ca bicarbonate (CaHCO₃). The resulting Calcium bicarbonate reacts with exchangeable and residual soil acidity, hence replacing H⁺ and Al³⁺ on the colloidal complex [6, 53] that is subsequently neutralized.

The negative correlation between extractable P and Al₉ and Al₀ could be attributed to the fact that Al oxyhydroxides act as sinks for soluble phosphates [54]. According to Gasparatos, et al. [55] Vaananen, et al. [56], aluminium iron enriched concretions are major sinks of P, which control P dynamics in agricultural soils by maintaining high sorption capacity. Oxalate extraction method has the ability to extract poorly crystalline oxyhydroxides of Al, which are directly associated with P sorption and while dithionate extraction extracts the amorphous Al forms [54].

# 5. CONCLUSIONS AND RECOMMENDATIONS

Liming significantly increased soil pH and decreases exchangeable Al, % Al saturation, Al₀ and Al₉ levels. High rates of lime which resulted into 100% reduction of Al³⁺ were more effective as compared to lower rates in both extremely and strongly acidic soils. Liming significantly reduced Al₀ by 70% and 68% in extremely acidic and strongly acidic soils respectively while Al₉ was reduced by 78% in both extremely and strongly acidic soil compared to control. This implies that liming aimed at reducing 100% exchangeable Al is effective in the reduction of both crystalline and amorphous forms of Al. Further research is however required to evaluate the short and long term effects of the rates hence their interactions on crop yields, other plant nutrients and the environment under field conditions. The research will also evaluate the rates that are effective in management of Al in acid soils with highest return per capital.

# ACKNOWLEDGEMENT

The author would like to acknowledge Waruhiu Agricultural Training Center (ATC) for provision of research site and greenhouse facilities and Alliance for Green revolution Africa (AGRA) for funding the research work.

# COMPETING INTERESTS

Author has declared that no competing interests exist.

# REFERENCES

1. Rengel Z. Handbook of soil acidity. CRC Press. 2003;512.

2. Sade H, Meriga B, Surapu V, Gadi J, Sunita MS, Suravajhala P, Kavi Kishor PB. Toxicity and tolerance of aluminum in
plants: Tailoring plants to suit to acid soils.
Biometals. 2016;29(2):187-210.

3. Muindi EM, Semu E, Mrema JP, Mtakwa PW, Gachene CK, Njogu MK. Soil acidity management by farmers in the kenya highlands. J Agric & Ecology Res Intern. 2016;5(3):1-11.

4. Goulding KW. Soil acidification and the importance of liming agricultural soils with particular reference to the United Kingdom. Soil Use Manag. 2016;32(3): 390-399.

5. Jorge RA, Arrunda P. Aluminium induced organic acids exudation by roots of aluminium tolerant maize. Phytochemistry. 1997;45(4):675-681.

6. Brady CN, Weil RR. The Nature and Properties of Soils, 14th Ed; Pearson Prentice Hall, New Jersey. 2008:975.

7. Mohammadi K. Phosphorus solubilizing bacteria: Occurrence, mechanisms and their role in crop production. Res & Environ 2012;2:80-85.

8. Nduwumuremyi A. Soil acidification and lime quality; sources of soil acidity, effects on plant nutrients, efficiency of lime and liming requirements. Research reviews. J. Agric and Allied Sci. 2013;2(4): 26-34.

9. Foy CD. Physiological effects of hydrogen, aluminium and manganese toxicities in acid soil. In: Soil acidity and liming. (Edited by Adams, F.). American Society of Agronomy, Madison. 1984;57-97.

10. Schwertmann U. Solubility and dissolution of iron oxides. Plant and Soil. 1991;130:1-25.

11. Sale PWG, Mokwunye AU. Use of phosphate rocks in the tropics. Fert Res. 1993;35:33-45.

12. McLean EO. Chemistry of soil aluminium. Communications in soil science and plant analysis. 1976;7(7):619-636

13. Bojórquez-Quintal E, Escalante-Magaña C, Echevarría-Machado I, Martínez-Estévez M Front. Aluminum, a friend or foe of higher plants in acid soils. A review. Plant Sci. 2017;8:1767.

14. Singh S, Tripathi DK, Singh S, Sharma S, Dubey NK, Chauhan DK, Vaculík M. Toxicity of aluminium on various levels of plant cells and organism: A review. Environ. Exp. Bot. 2017;137:177-193.

15. Marschner H. Mineral Nutrition of Higher Plants. Academic Press, London. 1986; 674.

16. Udin F. Montmorillonite: An introduction to properties and utilization. Intech Open. 2018:24.

17. Sposito G. Eds. The Environmental chemistry of Aluminum. Lewish Publishers. 1995;271-318.

18. Poschenrieder C, Gunsé B, Corrales I, Barceló J. A glance into aluminum toxicity and resistance in plants. Sci Total Environ. 2008;400(1-3):356-68.

19. Bernini T, Pereira A, Gervasio M, Lúcia A, Cunha dos H, Daniel Vidal P, Ademir F, Sebastião Barreiros C, Paulo Guilherme Salvador P. Quantification of aluminium in soil of the solimões formation, Acre State, Brazil. Revista Brasileira de Ciência do Solo. 2013;37(6):1587-1598

20. Carson CD, Dixon JB, Acidity. The Encyclopedia of Soil Science. Hutchinson. Ross Inc. Penn. 1979:1-3.

21. Pietraszewska MT. Effect of aluminium on plant growth and metabolism. A review. Acta Biochim Pol. 2001;48(3):673-86

22. Grevenstuk T, Romano A. Aluminium speciation and internal detoxification mechanisms in plants: Where do we stand? Metallomics. 2013;5(12):1584-94.

23. Kobayashi Y, Kobayashi Y, Watanabe T, Shaff JE, Ohta H, Kochian LV, Wagatsuma T, Kinraide TB, Koyama H. Molecular and physiological analysis of Al³⁺ and H⁺ rhizotoxicities at moderately acidic conditions. Plant Physiol. 2013;163(1):180-192.

24. Amarasiri SL, Olsen SR. Liming as related to solubility of P and plant growth in an acid tropical soil. Soil Sci Soc Amer J. 1973;37:716-720.

25. Fageria NK, Baligar VC. Ameliorating soil acidity of tropical oxisols by liming for sustainable crop production. Adv in Agron. 2008;99:345-389.

26. Clarkson DT. The Effect of aluminium and some other trivalent metal cations on cell division in the root apices of Allium cepa. Ann. Bot. 1965;29:309-315.

27. Bose J, et al. Specificity of ion uptake and homeostasis maintenance during acid and aluminium stresses. Aluminum Stress Adaptation in Plants. Springer, Cham. 2015;229-251.

28. Mariano ED, Keltjens WG. Long-term effects of aluminum exposure on nutrient uptake by maize genotypes differing in aluminum resistance. J. Plant Nutr. 2005; 28:323-333.
29. Chen ZC, Liao H. Organic acid anions: An effective defensive weapon for plants against aluminum toxicity and phosphorus deficiency in acidic soils. J Genet Genomics. 2016;43(11):631-638.

30. Muhrizal S, Shamshuddin J, Husni MHA, Fauziah I. Alleviation of aluminum toxicity in an acid sulfate soil in Malaysia using organic materials. Comm in Soil Sci and Plant Analy. 2003;34(19-20):2993-3012.

31. Mora ML, Cartes P, Demanet R, Cornforth IS. Effects of lime and gypsum on pasture growth and composition on an acid Andisol in Chile, South America. Commun. Soil Sci. Plant Anal. 2002;33:2069-2081.

32. Manson A, Findlay N. Agricultural Uses of Lime and Gypsum. KZN Department of Agriculture & Rural Development, Soil Fertility Research, Analytical Services; Cedara, South Africa. 2015;1-3.

33. Muindi EM, Mrema JP, Semu E, Mtakwa PW, Gachene CK, Njogu MK. Lime-Aluminium-Phosphorus interactions in the Kenya Highlands. Amer J of Exper Agric. 2015;9(4):1-10.

34. Guertal WR. The Pedologic Nature of Weathered Rock. In: Cremeens DL, et al. Eds., Whole Regolith Pe-dology, SSSA, Madison. 1994;21-40.

35. Torrent J, Barron V, Schwertmann U. Phosphate adsorption and desorption by goethites differing in crystal morphology. Soil Sc Soc of Amer J. 1990;54(17):1007-1012.

36. Angers DA, Chenu C. Dynamics of soil aggregation and carbon sequestration. In: Lal R, Kimble JM, Follett RF, Stewart BA, Eds., Soil processes and the carbon cycle, advances in soil science. CRC Press.1998; 199-206.

37. Bear J, Corapcioglu MY. Advances in transport processes in porous media. Springer science and Business Media. 1987;1030.

38. Roborage WP, Corey RB. Adsorption of phosphate by hydroxyl aluminium species on a cation exchange resin. Soil Sci Soc of Amer Journ.1979;43:481-487.

39. Sims JT, Ellis BG. Changes in phosphorus adsorption associated with aging of aluminum hydroxide suspensions. Soil Sci Soc of Amer Journ. 1983;47:912-916.

40. Kanyanjua SM, Ireri L, Wambua S, Nandwa SM. Acid soils in Kenya:

Constraints and remedial options. KARI Technical Note. 2002;11:24.

41. Okalebo JR, Gathua KW, Woomer PL. Laboratory methods of soil analysis: A working manual (2nd ed.). TSBR-CIAT and SACRED Africa, Nairobi, Kenya. 2002; 88.

42. McKeague JA, Day JH. Dithionite and oxalate extractable Fe and Al as aids in differentiating various classes of soils. Canad J of Soil Sci. 1966;46:13-22.

43. Mehra OP, Jackson ML. Iron oxide removal from soils and clay by a dithionite-citrate system buffered with sodium bicarbonate. Clays and Clay Minerals. 1960;7(3):17-327

44. Mechlich AA, Pinkerton RW, Kempton R. Mass analysis methods for soil fertility evaluation. Ministry of Agriculture, Nairobi. 1962;1-29.

45. Cochrane TT, Salinas JG, Sanchez PA. An equation for liming acid mineral soils to compensate crop aluminium tolerance. Tropical Agriculture (Trinidad). 1980;57: 33-40.

46. GenStat. The GenStat Teaching Edition. GenStat Release 7.22 TE, Copyright 2008, VSN International Ltd; 2010.

47. Landon JR. Booker tropical soils manual: A handbook for soil survey and agricultural land evaluation in the tropics and subtropics. John Wiley and Sons, New York. 1991;465.

48. Buresh RJ, Smithson PC, Hellums DT. Building soil phosphorus capital in Africa. In: Replenishing soil fertility in Africa. (Edited by Buresh PJ, et al.). Soil Science Society of America Special Publication, Madison. 1997;111-149

49. Sanchez PA, Shephard KD, Soule MJ, Place FM, Buresh RJ, Izac AN, Mokwunye AU, Kwesiga FR, Ndiritu CG, Woomer PL. Soil fertility replenishment in Africa: An investment in natural resource capital. In: Replenishing soil fertility in Africa, SSSA Special Publication (Edited by Buresh RJ, Sanchez PA, Calhoun F.) SSSA, Madison.1997;1-46.

50. Van Straaten P. Rocks for crops: Agro minerals for sub-Saharan Africa. ICRAF, Nairobi. 2002;25-28.

51. Sombroek WG, Braun HMH, van de Pouw. Exploratory soil map and agro-climatic zone map of Kenya. Scale 1:1000, 000.
Exploratory soil survey report No. E1.
Kenya Soil Survey, Nairobi. 1982;1-
78.

52. Kamprath E J. Crop response to lime in the tropics, In: Soil acidity and liming, 2nd Ed; Agronomy and Soil Science Society of America, Madison. 1984;349-68.

53. Lauchli A, Bieleski RL. Inorganic plant nutrition. Springer science and business media, New York. 2012:450.

54. Rayment GE, Lyons DJ. Soil chemical methods- Australasia. CSIRO publishers, Collingwood. 2011;482.

55. Gasparatos D, Haidouti C, Haroulis A, Tsaousidou P. Estimation of phosphorus status of soil Fe-enriched concentrations with the acid ammonium oxalate method. Comm in Soil Sc and Plant Analy. 2006; 37:2375-2387.

56. Vaananen R, Hristov J, Tanskanen N, Hartikainen H, Nieminen M, Ilvesniemi H. Phosphorus sorption properties in podzolic forest soils and soil solution phosphorus concentrations in undisturbed and disturbed soil profiles. Boreal Environ Res. 2008;13:553-567.

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