References
- Adepetu , J. A. and Corey , R. B. 1975 . Organic phosphorus as a predictor of plant available phosphorus in soils of southern Nigeria . Soil Science , 122 ( 3 ) : 159 – 164 .
- Adetunji , M. T. 1994 . Evaluation of phosphorus supplying capacities of southwestern Nigerian soils . Journal of Indian Society of Soil Science , 42 ( 2 ) : 208 – 213 .
- Adetunji , M. T. and Adepetu , J. A. 1990 . Status and distribution of sulphur fractions in soils of southwestern Nigeria . Nigeria Journal of Soil Science , 24 ( 1–2 ) : 137 – 140 .
- Agboola , A. A. 1974 . Problem of improving soil fertility by the use of green manuring in tropical farming systems. In Organic Materials as Fertilizers . Soil Bulletin (FAO) , 27 : 147 – 163 .
- Bouyoucos , G. H. 1951 . A calibration of the hydrometer method for testing mechanical analysis of soils . Agronomy Journal. , 43 : 434 – 438 .
- Bray , R. H. and Kurtz , L. T. 1945 . Determination of total organic and available forms of phosphorus in soils . Soil Science , 59 : 39 – 45 .
- Chang , S. C. and Jackson , M. L. 1957 . Fractionation of soil phosphorus . Soil Science , 84 : 133 – 144 .
- Gupta , M. K. , Jha , M. N. and Singh , P. P. 1991 . Organic carbon status in silver and spruce forest soil under different silvicultural systems . Journal of Indian Society of Soil. Science , 39 : 435 – 440 .
- Mamo , T. and Haque , I. 1991 . Phosphorus status of some Ethiopian soils, II: Forms and distribution of inorganic phosphates and their relation to available phosphorus . Tropical Agriculturist (Trinidad) , 68 : 2 – 8 .
- Ojo , L. O. and Ola‐Adams , B. A. 1996 . Measurement of tree diversity in the Nigerian rainforest . Biodiversity and Conservation , 5 : 1253 – 1270 .
- 1990 . “ SAS/STAT user's guide, release 6 ” . In , 4th ed. Cary, N.C. : SAS Institute . SAS Institute
- Udo , E. J. 1981 . Phosphorus forms, adsorption and desorption in selected Nigerian soils . Nigeria Journal of Soil Science , 2 : 51 – 66 .
- Udo , E. J. and Uzu , F. O. 1972 . Characteristics of phosphorus adsorption by some Nigerian soils . Proceedings of Soil Science Society of America , 36 : 877 – 883 .
- 1994 . “ Keys to soil taxonomy ” . Washington, D.C. : U.S. Government Printing Office . USDA
- Uzu , F. O. , Juo , A. S.R. and Fayemi , A. A. 1975 . Forms of P in some important agricultural soils of Nigeria . Soil Science , 120 : 212 – 218 .
- Walkley , A. and Black , C. A. 1934 . An examination of the Degtjareff method for determining soil organic matter and a proposed modification of the chromic acid titration method . Soil Science , 37 : 29 – 38 .