AVAILABLE AND ORGANIC PHOSPHORUS CONTENT OF SOME SELECTED SOILS AT DABAGI (CENTRE FOR AGRICULTURAL AND PASTORAL RESEARCH), USMANU DANFODIYO UNIVERSITY, SOKOTO, NIGERIA

Abstract

ABSTRACT This study was carried out to determine the status of the available and organic forms of phosphorus in some selected soils of Dabagi, Centre for Agricultural and Pastoral Research, Usmanu Danfodiyo University, Sokoto. Thirty Soil samples were collected from 3 different loca¬tions at 0-15 cm and 15-30 cm depth and subjected to soil physical and chemical analysis. Results revealed that the sand component of the soils which varied from 111 to 755 gkg-1 decreased with increased soil depth. The clay and silt fractions ranged from 106 to 753gkg-1and 53 to 563 gkg-1respectively. Soil reaction varied from very acid (3.4) to moderately acid (5.7) across the locations and significant difference was observed among the locations. The total nitrogen and organic carbon content of the soils were low and medium and the values were statistically different among the samples. Available P and organic P were low with values ranging from 0.99 to 2.24 mgkg-1 and 1.15 to 7.40 mgkg-1 respectively. The P forms decreased with increased soil depth except in the third location where there was higher available P in the subsoil. Correlation analysis revealed that available P correlated positively with clay, pH, cation exchange capacity, exchangeable Ca and organic P but negatively with sand, silt and organic matter while Organic P correlated positively with organic matter, clay, silt, exchangeable Ca and cation exchange capacity but negatively with sand and pH. All the soils were deficient in available P based on the established critical level of 10mgkg-1 P for Nigerian soils.

ABSTRACT This study was carried out to determine the status of the available and organic forms of phosphorus in some selected soils of Dabagi, Centre for Agricultural and Pastoral Research, Usmanu Danfodiyo University, Sokoto. Thirty Soil samples were collected from 3 different loca¬tions at 0-15 cm and 15-30 cm depth and subjected to soil physical and chemical analysis. Results revealed that the sand component of the soils which varied from 111 to 755 gkg-1 decreased with increased soil depth. The clay and silt fractions ranged from 106 to 753gkg-1and 53 to 563 gkg-1respectively. Soil reaction varied from very acid (3.4) to moderately acid (5.7) across the locations and significant difference was observed among the locations. The total nitrogen and organic carbon content of the soils were low and medium and the values were statistically different among the samples. Available P and organic P were low with values ranging from 0.99 to 2.24 mgkg-1 and 1.15 to 7.40 mgkg-1 respectively. The P forms decreased with increased soil depth except in the third location where there was higher available P in the subsoil. Correlation analysis revealed that available P correlated positively with clay, pH, cation exchange capacity, exchangeable Ca and organic P but negatively with sand, silt and organic matter while Organic P correlated positively with organic matter, clay, silt, exchangeable Ca and cation exchange capacity but negatively with sand and pH. All the soils were deficient in available P based on the established critical level of 10mgkg-1 P for Nigerian soils.