Phosphorus Concentrations in Grain Size Fractions of Low-land soils of Egbema, Southeastern, Nigeria

London Journal of Research in Science: Natural and Formal
Volume | Issue | Compilation
Authored by Bethel.U Uzoho , NA
Classification: FOR Code: 050303
Keywords: phosphorus, texture, lowland soils, landunits and southern nigeria.
Language: English

Phosphorus concentration in grain size fraction of soils is significant in estimating soil P retention capacity and sustainable environmental management. Phosphorus forms (total, organic, saloid, Al, Fe, Ca and residual) in grain size fractions of soils of three land units (upland, levee and backswamp) in Egbema were evaluated using sequential extraction procedures. Phosphorus forms differed distinctly (LSD 0.05) with grain size fractions, being a decreasing order of total P > organic P > occluded P > residual P > Fe-P > Al- P > Ca-P > saloid P > H20 soluble P in sand fractions of the levee and backswamp and total P > organic P > residual P > Fe-P > Al- P > occluded P > Ca-P > saloid P = H20 soluble P in that of upland units, total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P = saloid P > water soluble P in silt fractions of upland, total P > organic P > residual P > occluded P > Fe-P > Al-P = Ca-P > saloid P > water soluble P in the levee and total P > organic P > residual P > Fe-P > occluded P > Al-P > Ca-P > saloid P > water soluble P in that of backswamp and total P > organic P > Fe-P > Al-P > residual P > occluded P > Ca-P > saloid P > water soluble P in clay fraction of the upland, total P > organic P > occluded P > residual P > Fe-P > Al-P > saloid P > Ca-P > water soluble P in the levee and total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P > saloid P > water soluble P in that of backswamp. Averaged over P forms, concentrations were higher in clay than other grain size fractions and in the subsoil than surface soil of most land units. This suggests that clay soils will be most active in regulating P activities in the land units.

               

Phosphorus Concentrations in Grain Size Fractions of Low-Land Soils of Egbema, Southeastern Nigeria

B.U. Uzoho

____________________________________________

  1. ABSTRACT

Phosphorus concentration in grain size fraction of soils is significant in estimating soil P retention capacity and sustainable environmental management. Phosphorus forms (total, organic, saloid, Al, Fe, Ca and residual) in grain size fractions of soils of three land units (upland, levee and backswamp) in Egbema were evaluated using sequential extraction procedures. Phosphorus forms differed distinctly (LSD 0.05) with grain size fractions, being a decreasing order of total P > organic P > occluded P > residual P > Fe-P > Al- P > Ca-P > saloid P > H20 soluble P in sand fractions of the levee and backswamp and total P > organic P > residual P > Fe-P > Al- P > occluded P > Ca-P > saloid P = H20 soluble P in that of upland units, total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P = saloid P > water soluble P in silt fractions of upland, total P > organic P > residual P > occluded P > Fe-P > Al-P = Ca-P > saloid P > water soluble P in the levee and total P > organic P > residual P > Fe-P > occluded P > Al-P > Ca-P > saloid P > water soluble P in that of backswamp and total P > organic P > Fe-P > Al-P > residual P > occluded P > Ca-P > saloid P > water soluble P in clay fraction of the upland, total P > organic P > occluded P > residual P > Fe-P > Al-P > saloid P > Ca-P > water soluble P in the levee and total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P > saloid P > water soluble P in that of backswamp. Averaged over P forms, concentrations were higher in clay than other grain size fractions and in the subsoil than surface soil of most land units. This suggests that clay soils will be most active in regulating P activities in the land units.

Keywords: phosphorus, texture, lowland soils, land units and southern nigeria.

Author: Dept of Soil Science and Technology, Federal University of Technology, Owerri.

  1. INTRODUCTION

Phosphorus is a component of nucleic acids and nucleoside triphosphates, the basis of enzyme synthesis and energy transfer systems at the cellular level (Uzoho, 2010). It is associated with eutrophication of surface and ground water systems and thus important in the sustainability of environmental quality (Azadi and Baghernejad, 2016; Zhang and Li, 2016). Phosphorus involves in several complex soil reactions that affects its solubility and mobility. Its two forms are organic and inorganic, with the organic constituting 20-80% of total soil P and include inositol phosphate, nucleic acids, nucleotides, phospholipids and sugar phosphates (Mustapha et al., 2007; Uzoho, 2010).  Inorganic phosphorus fractions include Fe-P, Al-P, Ca-P, Saloid bound P, Occluded and residual P and important in regulating soil P availability as well as losses through uptake, leaching and erosion (Azadi and Baghernejad 2016).  Soloid bound P represent the easily soluble and loosely bound P fraction extractible with NH4Cl, Al, Fe and Ca-P are fractions extractible with 0.5N NH4F, 0.1N NaOH and 0.5N H2S04 respectively  

Distribution of soil phosphorus fractions varies and affected by land use types, landscape position, soil management, pH, redox potential and climatic condition (Solomon et al., 2002; Mustapha et al., 2007; Sheklabadi et al., 2014; Aminda Moreira de Carvalho et al., 2014; Ghulam, 2015). Impact of land use, soil management and climate has been reported to include increased NaHCO3 and NaOH inorganic P fractions at 5-10 cm soil depth under no-tillage in the rainy season and a high organic P concentration at 0-5 cm depth for no-tillage and 5-10 cm depth for conventional tillage systems in the dry season for Oxisols under Cajanus cajan land use type in Central Savanna region of Brazil (Arminda Moreira de Carvalho et al., 2014). Also, a decreased order of Total P > Fe-P > Al-P > Occlude Fe-Al-P > Reductant Soluble –P > Ca-P > Available P  in surface and subsurface depths of various landscape positions have been reported for some Haplic Plinthaquults in Bauchi, Nigeria      (Mustaphar et al., 2007). Others included high labile relative to occluded P in herbaceous perennial and reverse of occluded to labile fraction in annual agroecosystems (Crews and Brookes, 2014), available and Ca-P in plantation and Fe-P in arable in soils of three cropping systems in Lower Indo-Gangetic Alluvial plain, India (Ghulam, 2015) and high Ca-P in Andisols across Riparian buffer and adjacent cropped area in Dian Lake, China (Zhang and Li, 2016).  

Concentration of soil P forms differs with textural class fractions. It has been reported that soil texture can modify P equilibrium and availability due to its influence on P sorption- desorption-diffusion processes and through soil organic matter mineralization (Suner and Galantini, 2015). Several workers have noted increased concentration of P fractions in fine (clay and silt) than coarse soil fractions (Suner and Galatini, 2015; Zhang and Li, 2016). High concentration of P forms in the clay fraction has been ascribed to its being both a source for the labile and sinks for recalcitrant P fractions (Suner and Galatini, 2015) and enrichment of organic P in the fine fraction (Zhang and Li, 2016). Others noted that low inorganic P concentration in coarse particle size fractions could be as a result of assimilation by vegetation, transformation of inorganic P, leaching and erosion (Roberts et al., 2012).  

Egbema lies in the low area of southeastern Nigeria that is usually flooded during the raining season thus causing their submergence and alteration of chemistry of some nutrients especially P. It has been indicated that P in submerged soils is dominated by Fe-P and Al-P fractions (Gbulam, 2015) since its concentration is governed by reducing soil condition (Nartey et al., 1997). The main objective of the present study was to determine the P forms in grain size fractions of lowland soils of Egbema, southeastern, Nigeria

  1. MATERIALS AND METHODS

3.1  Study Location and Soil Sampling

The study location, soil sample collection and preparation have been described in another study (Uzoho et al., 2016).

3.2  Laboratory Analyses

Laboratory analyses were conducted on subsamples of fine earth soil fractions using standard methods. Particle size distribution (Gee and Or, 2002), pH in 1:2.5 soil/water ratio (Thomas, 1996), Available P (Olsen, 1982), Exchangeable cations (Thomas, 1996), OM (Nelson, 1996) and bulk density (Blake and Hartge, 1986).

Subsamples of the fine earth soil fractions were fractionated into their various grain sizes using the method described by Sequaris and Lewandowski (2003) while P forms in each grain size from first (surface) and second (subsoil) soil depths of each land unit was fractionated using sequential extraction technique as outlined by Hedley et al., 1982).

3.3  Statistical Analysis

Data on soil P forms in grain size fractions of the various land units was subjected to Analysis of variance (ANOVA) and means separated using LSD at 5% probability levels.

  1. RESULTS AND DISCUSSION

4.1  Soil Characterization

Soils were dominantly sandy with variations of sand, loamy sand sandy clay loam and loamy sand amongst various horizons of the different land units (Table 1). Upper horizons were sandier with the trend decreasing down the depth while the reverse was the case for the clay. Sandiness of the soils could be due to alluvial deposition of sand particles. Silt/clay ratios were below unity and indicating the youthfulness of the soils. Bulk densities decreased while total porosity decreased with depth in the various land units ascribable to the high organic matter accumulation of the surface horizons.

Soils were slightly acidic with pH ranges between 5.27-5.62 and ascribable to high rainfall of the area and intense leaching of bases (Table 2). Exchangeable cations were low with values below critical limits for soils of southeastern Nigeria (Enwezor et al., 1990). In all land units, ECEC values were below 16 cmol kg-1 signifying that the soils are of low clay activity (Uzoho et al., 2007). Mean concentrations of soil OM, TN and P were better in the levee and back swamp than the upland with distribution down soil depth irregular in most land units due to variation in circles of sediment and material deposition

4.2  Phosphorus Fractions

Concentration of P forms in sand, silt and clay size fractions of soils of the various land units are presented in Tables 3, 4 and 5 respectively. Phosphorus forms in the sand size fractions of the various land units differed significantly LSD (0.05) being a decreasing order of total P > organic P > occluded P > residual P > Fe-P > Al- P > Ca-P > saloid P > H20 soluble P in the levee and backswamp and total P > organic P > residual P > Fe-P > Al- P > occluded P > Ca-P > saloid P = H20 soluble P in upland (Table 3). Concentrations of the different forms were higher in the subsurface than surface soil of most land units. Averaged over horizons, upland land unit had the least concentration of the P forms while the difference between levee and backswamp varied depending on forms.

Differences in P forms of the silt size fractions differed distinctly (LSD 0.05) and decreased in the order total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P = saloid P > water soluble P in the upland, total P > organic P > residual P > occluded P > Fe-P > Al-P = Ca-P > saloid P > water soluble P in the levee and total P > organic P > residual P > Fe-P > occluded P > Al-P > Ca-P > saloid P > water soluble P in the backswamp (Table 4). Concentrations of most forms were lower in surface than subsoil of some land units. Averaged over surface and subsoil horizons, mean concentrations of most P forms followed a decreasing sequence of levee > upland > backswamp.

Phosphorus forms in clay fraction of the soils differed seriously with soil horizons and land units (Table 5). Averaged over soil horizons, concentrations decreased in the order total P > organic P > Fe-P > Al-P > residual P > occluded P > Ca-P > saloid P > water soluble P in upland, total P > organic P > occluded P > residual P > Fe-P > Al-P > saloid P > Ca-P > water soluble P in levee and total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P > saloid P > water soluble P. Concentration of most P forms were better in the subsoil than surface soils and with mean value in the levee significantly (LSD 0.05) higher than the other land units. In general, P forms of the soils varied between land units, horizon depth and textural size fractions. Variation in P forms due to landscape position, soil depth, land use, management practices, soil and textural fractions have been reported (Mustapha et al., 2007; Malik and Khan, 2012; Sheklabadi et al., 2014; Aminda Moreira de Carvalho et al., 2014; Ghulam, 2015; Suner and Galatini, 2015; Zhang and Li, 2016). Concentrations in textural size fractions were higher in the levee than backswamp and upland land units probably due to depressed P sorption in the levee as a result of  poor drainage (Ghulam, 2015). Concentration of large number of the P forms were higher in the subsoil than surface horizons of most land units due probably to burial of sediments at lower depths with alluvial deposition and from leaching or erosion by runoff (Zhang and Li, 2016). Nartey et al. (1997) noted increased distribution with depth of two landscapes with those of well drained soils due to profile maturity and those of low lying soils due to drainage. Variation in most P forms in textural size fractions included high concentrations in clay and silt than sand fractions for most land units. Similar observations have been reported for clays and fine size fractions and ascribed to existence of surfaces for P retention (Suner and Galantini 2015; Zhang and Li, 2016) and accumulation of sesquioxides (Nartey et al., 1997). It could also be attributed to the enrichment of organic P in the finer particle size fractions (Christensen, 2001).

Table 1: Selected Physical Properties of Soils Studied

Land Unit

Depth

Horizon

Sand

Silt

Clay

Si/Cl ratio

Bd

TP

MC

TC

 

cm

 

g kg-1

 

g cm-3

%

 

 

Upland

0-12

A

935.20

4.72

60.08

0.27

1.26

50.80

37.50

S

12-45

AB

895.20

4.72

100.08

0.82

1.31

48.80

30.90

S

45-70

Bt1

815.20

4.72

180.08

0.40

1.38

46.10

11.80

LS

70-120

Bt2

815.20

4.72

180.08

0.34

1.34

47.70

13.50

LS

Mean

870.20

47.20

125.08

0.46

1.32

48.35

23.43

LS

Levee

0-7

A

855.20

27.20

117.60

0.23

1.52

40.63

14.90

LS

7-13

B

435.20

167.20

397.60

0.42

1.79

30.10

12.40

SCL

Mean

744.00

72.20

193.80

0.36

1.49

41.70

16.06

LS

Back swamp

0-10

A

855.20

47.20

97.60

0.23

1.45

43.30

20.00

S

10-45

AB

815.20

47.20

137.60

0.42

1.19

53.50

19.50

LS

45-65

Bt1

855.20

67.20

77.60

0.87

2.27

11.30

20.00

S

65-100

Bt2

795.20

47.20

157.60

0.30

1.36

46.90

20.60

LS

 

 

Mean

830.20

52.20

117.60

0.45

1.57

38.78

20.03

LS

Si = Silt, Cl = Clay, Bd = Bulk Density, TP = Total Porosity and TC = Textural Class.

Table 2: Selected Chemical Properties

Land Unit

Depth

Horizon

pH(H2O)

OM

TN

P

Ca

Mg

K

Na

Al

H

ECEC

 

cm

 

 

g kg-1

mg kg-1

cmol kg-1

Upland

0-12

A

5.60

8.26

0.50

18.2

0.1

0.08

0.1

0.34

0.6

0.92

2.14

12-45

AB

5.70

9.63

0.50

11.20

0.20

0.33

0.09

0.3

0.60

0.80

2.32

45-70

Bt1

5.62

7.91

0.40

15.20

0.10

0.17

0.07

0.16

1.72

0.28

2.50

70-120

Bt2

5.38

8.26

0.40

9.10

0.30

0.33

0.10

0.4

1.73

1.80

2.93

Mean

5.58

8.43

0.50

13.48

0.18

0.23

0.09

0.3

1.16

0.95

2.32

Levee

0-7

A

5.67

15.14

8.60

9.10

2.10

1.00

0.14

0.38

2.92

0.80

6.54

7-13

B

5.67

17.20

0.90

29.40

1.30

1.17

0.21

0.4

5.04

0.84

8.12

Mean

5.67

9.36

4.75

17.33

1.19

1.09

0.14

0.36

3.04

0.82

5.66

Back Swamp

0-10

A

5.62

17.54

0.90

11.20

1.30

0.83

0.17

0.19

0.44

1.12

4.05

10-40

AB

5.27

14.10

0.70

21.70

0.50

1.33

0.13

0.4

0.43

1.80

4.17

40-65

Bt1

5.75

16.17

0.80

12.60

0.20

1.00

0.07

0.32

0.56

0.76

2.91

65-100

Bt2

5.40

6.19

0.30

11.90

1.10

1.33

0.10

0.31

0.64

0.52

4.00

 

 

Mean

5.51

13.42

0.70

14.35

0.78

1.12

0.12

0.3

0.55

1.05

3.78

Table 3: Phosphorus Forms (mg kg-1) in Sand Fraction of the Soils

Land Units

Depth  Horizon

  (cm)

Total    

P

Org. P

Saloid P

Al-P

Fe-P

Ca-P

Occl P

H2O

Sol P

Residual

P

Upland

0-12

Surface

3.00

1.68

0.10

0.25

0.80

0.11

0.21

0.13

0.66

12-45

Subsoil

3.85

1.99

0.20

0.80

0.75

0.23

0.45

0.17

1.11

Mean

3.43

1.84

0.15

0.53

0.78

0.17

0.33

0.15

0.89

Levee

0-7

Surface

5.52

0.96

0.48

0.81

0.88

0.43

0.91

0.10

0.93

7-13

Subsoil

6.82

3.24

0.83

0.89

1.40

0.96

1.84

0.37

1.38

Mean

6.17

2.10

0.66

0.85

1.14

0.70

1.38

0.24

1.16

Back Swamp

0-10

Surface

5.84

2.23

0.43

0.60

1.00

0.36

1.00

0.37

0.44

10-40

Subsoil

5.95

2.26

0.73

0.80

1.02

0.81

1.85

0.40

1.85

Mean

5.90

2.25

0.58

0.70

1.01

0.69

1.43

0.39

1.14

LSD 0.05

Fact A

0.65

-

0.10

-

0.13

0.07

0.08

0.06

0.38

Fact B

0.47

-

0.04

-

0.08

0.05

0.04

0.04

0.27

 

Fact A x B

0.74

-

0.10

-

0.14

0.08

0.08

0.07

0.43

Fact A = Land units, Fact B = Horizon, Org P = Organic P and Occl P = Occluded P

Table 4: Phosphorus Forms (mg kg-1) in Silt Fraction of the Soils

Land Units

Depth   Horizon

 (cm)

Total    P

Org. P

Saloid P

Al-P

Fe-P

Ca-P

Occl. P

H2O Sol P

Residual P

Upland

0-12

Surface

4.00

1.05

0.56

0.81

0.96

0.11

0.23

0.12

0.34

12-45

Subsoil

5.20

2.78

0.10

0.81

0.85

0.55

1.05

0.49

1.31

Mean

4.60

1.39

0.33

0.81

0.91

0.33

0.64

0.31

0.83

Levee

0-7

Surface

5.25

2.62

0.81

0.49

0.90

0.60

1.10

0.42

0.92

7-13

Subsoil

6.50

2.86

0.12

0.80

0.85

0.69

1.48

0.35

2.11

Mean

5.88

2.74

0.47

0.65

0.88

0.65

1.29

0.39

1.52

BackSwamp

0-10

Surface

4.25

1.68

0.20

0.68

0.77

0.30

0.51

0.16

1.27

10-40

Subsoil

4.26

4.72

0.40

0.15

0.76

0.45

0.86

0.16

1.56

Mean

4.26

3.20

0.30

0.42

0.77

0.38

0.69

0.16

1.42

LSD 0.05

Fact A

0.50

0.01

0.01

0.01

0.01

0.10

0.05

0.01

0.01

Fact B

0.40

0.01

0.004

0.01

0.01

0.08

0.04

0.01

0.01

 

Fact A x B

0.70

0.01

0.01

0.02

0.02

0.14

0.07

0.01

0.02

Fact A = Landunits, Fact B = Horizon, Org P = Organic P and Occl P = Occluded P

Table 5: Phosphorus Forms (mg kg-1) in Clay Fraction of the Soils

Land Units

Depth          Horizon

 (cm)    

Total

P

Org. P

Saloid P

Al-P

Fe-P

Ca-P

Occl P

H2O Sol P

Residual P

Upland

0-12

Surface

8.01

6.90

1.30

4.76

5.50

4.30

4.24

1.32

4.95

12-45

Subsoil

8.21

6.26

1.67

4.75

4.59

4.42

4.90

1.62

4.54

Mean

8.11

6.58

1.49

4.76

5.05

4.36

4.57

1.47

4.75

Levee

0-7

Surface

8.86

6.59

2.15

4.13

4.86

4.17

4.31

1.30

4.23

7-13

Subsoil

14.9

9.29

2.13

4.82

5.34

5.06

7.60

1.70

4.56

Mean

11.88

7.94

2.14

4.48

5.10

4.62

5.96

1.50

4.40

Backswamp

0-10

Surface

9.32

6.36

0.90

4.60

4.91

4.34

4.95

1.54

4.99

10-40

Subsoil

9.40

5.66

1.02

4.14

4.87

4.35

4.53

1.32

5.12

Mean

9.36

6.01

0.81

4.37

4.89

4.35

4.74

1.43

5.06

LSD 0.05

Fact A

0.07

0.06

0.06

0.06

0.01

0.05

0.07

0.05

0.01

Fact B

0.06

0.04

0.05

0.05

0.01

0.04

0.05

0.04

0.01

 

Fact A x B

 

0.10

0.08

0.08

0.08

0.02

0.07

0.09

0.07

0.01

Fact A = Land units, Fact B = Horizon, Org P = Organic P and Occl P = Occluded P

V.   CONCLUSION

Phosphorus forms in textural size fractions differed significantly with landunits and soil horizons with mean distribution being a decreasing order of total P > organic P > occluded P > residual P > Fe-P > Al- P > Ca-P > saloid P > H20 soluble P in the levee and backswamp and total P > organic P > residual P > Fe-P > Al- P > occluded P > Ca-P > saloid P = H20 soluble P in upland units for sand fraction, total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P = saloid P > water soluble P in the upland, total P > organic P > residual P > occluded P > Fe-P > Al-P = Ca-P > saloid P > water soluble P in the levee and total P > organic P > residual P > Fe-P > occluded P > Al-P > Ca-P > saloid P > water soluble P in the backswamp for silt fraction and total P > organic P > Fe-P > Al-P > residual P > occluded P > Ca-P > saloid P > water soluble P in upland, total P > organic P > occluded P > residual P > Fe-P > Al-P > saloid P > Ca-P > water soluble P in levee and total P > organic P > residual P > Fe-P > Al-P > occluded P > Ca-P > saloid P > water soluble P for clay fraction.

Concentration of most P forms were higher in the clay than other soil grain size fractions and in the subsoil than surface soils of most land units.

REFERENCES 

  1. Aminda Moreira de Carvalho, Mercedes Maria da Cunha Bustamante, Zayra Azeredo Prado Almondes and Cícero Célio de Figueiredo 2014. Forms of Phosphorus in an Oxisol under different soil tillage systems and cover plants in rotation with Maize. R. Bras. Ci. Solo, 38: 972-979.            
  2. Azadi, A and M. Baghernejad 2016. Evaluation of the Status of P Fractions and their Relationships with Selected Soil Properties in Some Calcareous Soils. Jordan Journal of Agricultural Sciences, 12(1): 275-287.                            
  3. Blake, G. R and K.H. Hartge 1986. Particle density, In: Methods of Soil Analysis, Part 1, 2nd Edn., edited         by: Klute, A., ASA and SSSA, Madison, WI, 377–382 pp.
  4. Christensen, B. T 2001. Physical fractionation of soil and structural and functional complexity in organic matter turnover, European Journal of Soil Science 52: 345–353.
  5. Crews, T. E. and P.C. Brookes 2014. Changes in soil phosphorus forms through time in perennial versus annual agroecosystems. Agriculture Ecosystem and Environment. 184: 168–181.        
  6. Enwezor, W.O, A.C.Ohiri, E.E. Opowaribo and E.D. Udo 1990. A review of soil fertility use in crops of Southeastern zone of Nigeria (in five volumes). Produced by the Federal Ministry of Agriculture and Natural Resources, Lagos.        
  7. Gee, G., W. and D.Or 2002. Particle size analysis. In: Dane, J. H. and G. C. Topps (eds.). Methods of soil analysis, Part 4. Physical methods. Soil Sci. Soc. Am. Book Series No. 5, ASA and SSSA, Madison, WI. pp, 255 –293.                         
  8. Ghulam, S 2015. The different types of Soil properties and phosphorus fractions in the three cropping systems of Lower indo- Gangetic alluvial plain. International Journal of Soil Science and Agronomy 2 (3): 051-059.
  9. Hedley, M. J, J. W. B.Stewart and B. S. Chauhan 1982. Changes in Inorganic and Organic Soil Phosphorus Fractions Induced by Cultivation Practices and by Laboratory Incubations. Soil Science Society America Journal 46: 970- 976.                
  10. Malik, M.A and K.S.Khan 2012. Phosphorus fractions, microbial biomass and enzyme activities in some alkaline calcareous subtropical soils. African Journal of Biotechnology 11(21): 4773-4781.
  11. Mustapha, S, S.I.Yerima, NVoncir and B.I. Ahmed 2007. Contents and Distribution of Phosphorus Forms in a Haplic Plinthaquults in Bauchi Local Government Area, Bauchi, State. International Journal of Soil Science 2 (3): 197-203.        
  12. Nartey, E, G.N. Dowuona, Y. Ahenkorah, A.R.Mermut and H.Tiessen 1997. Amounts and distribution of some forms of phosphorus in ferruginous soils of the interior savanna zone of Ghana. Ghana Journal Agricultural. Science. 30: 135-143.                
  13. Nelson, D. W and L.E. Sommers, L. E. 1996. Total carbon, organic carbon and organic matter. In; Sparks DL, ed. Methods of soil analysis. ASA. SSSA. Madison, Wisconsin, USA. 961-1010.         
  14. Olsen, S.R., Sommers, L.E. 1982. Phosphorus. In ‘Methods of soil analysis. Part 2. Chemical and microbiological properties’. (Eds AL Page, RH Miller, DR Keeney) pp. 403–430. (American Society of Agronomy: Madison, WI).                
  15. Roberts, W.M, M.I. Stutter and P.M. Haygarth 2012. Phosphorus retention and remobilization in vegetated buffer strips: a review. Journal of Environmental Quality. 41: 389–399.
  16. Séquaris, J. M. and H. Lewandowski 2003. Physicochemical characterization of potential colloids from agricultural topsoils, Colloids Surface Analysis 217: 93–99.
  17. Sheklabadi, M, H. Mahmoudzadeh, A.A. Mahboubi, B. Gharabaghi and B. Ahrens 2014. Land use effects on phosphorus sequestration in soil aggregates in western Iran, Environmental Monitoring and Assessment. 186: 6493–6503.
  18. Solomon, D, J. Lehmann, T. Mamo, F. Fritzsche and W. Zech 2002. Phosphorus forms and dynamics as         influenced by land use changes in the sub-humid Ethiopian highlands. Geoderma 105: 21–48.
  19. Suñer, L. and J.A. Galantini 2015. Texture influence on soil phosphorus content and distribution in semiarid pampean grasslands. International Journal of Plant Science. 7: 109–120.
  20. Thomas, G.W. 1996. Soil pH and soil acidity. In ‘Methods of soil analysis. Part 3.Chemical methods’.         (Ed. DL Sparks) pp. 475–490. (Soil Science Society of America: Madison, WI)            
  21. Uzoho, B.U, N.N. Oti and A. Ngwuta 2007. Fertility status under land use types on soils of similar lithology. Journal of American Science 3(4): 20-29.         
  22. Uzoho, B.U. 2010. Nitrogen and phosphorus dynamics of municipal solid waste compost- amended Ultisol in Southeastern, Nigeria. Ph. D Thesis. 210 pp.                         
  23. Uzoho, B.U, Emenyonu-Chris. C, M.I.Nwufor, E.O.Nze, J. A.L Effiong and G.U.Njoku 2016. Nitrogen concentration in grain size fraction of soils of contrasting land units in the humid rainforest, Southeastern Nigeria. International Journal of Environment and Pollution Research. 4 (3): 12-27.
  24. Zhang, G.S and J. C. Li 2016. Distribution of inorganic phosphorus in profiles and particle fractions of Anthrosols across an established riparian buffer and adjacent cropped area at the Dian Lake (China). Solid Earth, 7, 301–310.



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