ABSTRACT

The distribution of various forms of phosphorus was investigated along a typical toposequence located on a coastal plain sand parent material in Aniaoba 1me Ikwuano local Government Area of Abia State. Soil samples floin identified horizons were analyzed for Total phosphorus, Organic phosphorus, Availabic phosphorus and the Active forms of phosphorus (Fe-P Al-P Ca-P). Results obtained showed that Total phosphorus varied form I5O-787.5ppm with a mean value of 439 5ppin. Total P content was found to be highest at the upper slope for the topsoils the subsoil followed similar trend. Organic P varied from 33-186pprn with a mean value of 9lppm and was highest at the valley bottom and lowest at the middle slope for the top-soils , however sub-soils did not show similar trend. Available Pvaied from 0.69-11 .79pprn with the mean value of 3.63ppm, there was no regular pattern of distribution down the profiles and along the slope Fe-P varied form 21-1 96ppim with a mean value of 71.43ppm, Al-P varied from l.75-63.63pprn with a mean aluc of 15.57pprn, Ca-P 1.17 to 7.Oppm with a mean value of 3.26ppm, also they did not show a regular pattern of distribution. Total —P conelated positively with inactive P (r=0.93**) Organic P-correlated positively with clay (r= 0.43**) and negatively with sand (r=0.53**) Fe-P correlated positively and significantly with Magnesium (r=0.48**) Al-P correlated significantly with sand (r=0.40**) Topographic positions has significant influence on P levels, therefore in recommending —P fertilizers. the different in slope the toposequence of any cropped land should be put into consideration.