Abstract
The distribution of various forms of phosphorus was evaluated along a toposequence located in an Alfisol in Teaching and Research Farm of the Federal University of Technology, Minna. The toposequence was delineated into different topographic units (Crest, Upper slope, Middle slope and Lower slope). Soil samples were collected from identified horizons in profile pits in each topographic unit. The soil samples were analyzed for organic, total, available and various active P forms. The results obtained showed that distribution of phosphorus varied widely with each topographic unit. Total P ranged from 102 ug g-1 at the lower shope to 422 ug g-1 at the upper shope, with a mean of 236.95μg g-1. Organic P also ranged from 21 - 132μg g-1 with a mean of 55.8μg g-1. Organic P was highest at the lower slope and lowest at the upper slope. Available P ranged from 0.4 – 5.54μg g-1 with a mean of 2.47μg g-1. The active P forms was in the order of Fe-P > Al-P > Ca-P, with Fe-P varying from 19 - 95μg g-1, Al – P ranged from 1.75 – 22μg g-1 and Ca – P ranged from 1.12- 4.3μg g-1. There was a positive correlation between organic P and clay (r = 0.56*) and between organic P and organic carbon (r = 0.52*). However, organic P correlated negatively with sand (r= -0.49*).Fe – P and Al – P correlated with magnesium (r = 0.51*) and sand (r = 0.45*) respectively. Available P also correlated positively with clay (r = 0.43*) and organic carbon (r = 0.52*).Keywords: Toposequence, Alfisol, Crest, Active P and Organic P.
Highlights
Phosphorus (P) is an important nutrient element classified as a macro-nutrient because of its relatively large amount required by plants
Phosphorus has been identified as one of the most limiting nutrient elements in tropical soils (Ahn, 1993). This low availability of phosphorus in tropical soils is attributed to the nature and forms of the soil phosphorus and the high contents of the oxides of iron and aluminium, which are associated with phosphate fixation (Osodeke and Osondu, 2006)
Exchangeable acidity was determined titrimetrically using 1.0N KCl extract (McLean, 1982).Available P was determined by the Bray P 1 method (Bray and Kurtz, 1945).Total P was determined by HCLO4 digestion (Jackson, 1958) and organic P was estimated according to Bray and Kurtz (1945) procedure
Summary
Phosphorus (P) is an important nutrient element classified as a macro-nutrient because of its relatively large amount required by plants. Phosphorus has been identified as one of the most limiting nutrient elements in tropical soils (Ahn, 1993). This low availability of phosphorus in tropical soils is attributed to the nature and forms of the soil phosphorus and the high contents of the oxides of iron and aluminium, which are associated with phosphate fixation (Osodeke and Osondu, 2006). No dealed study on the distribution of P along a toposequence has been conducted.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
