References
- Aduayi , E.A. 1980 . Effects of ammonium sulphate fertilization on soil chemical composition, fruit yield and nutrient content of Okra . Ife J. Agric. , 2 : 16 – 34 .
- Agboola , A.A. , Obigbesan , G.O. and Fayemi , A.O. 1974 . “ Inter‐relations between organic and mineral fertilizers in the tropical rainforest of Western Nigeria ” . In In Organic materiaisas fertilizers, Report of the FAO/S.DA Expert Consultation, Rome, Soil Bull 337 – 351 .
- Grunes , D.L. 1959 . Effect of nitrogen on the availability of soil and fertilizer phosphorus to plants . Adv. Agron. , 11 : 369 – 396 .
- Harpstead , M.I. 1974 . The classification of some Nigerian soils . Soil Sci. , 116 : 437 – 443 .
- Jankovic , M. and Popovic , Z. 1966 . Comparative investigation of the action of different nitrogenous fertilizers on yield and the effects of these on chemical changes in the soil . Abstracted from Soil and Fertilizers , 33 ( 4 )
- Jones , M.J. 1974 . Effects of three nitrogen fertilizers and lime on pH and exchangeable cation content at different depths in cropped soils of two sites in the Nigerian Savanna . Trop. Agric. , 53 : 243 – 254 .
- Jones , M.J. 1976 . “ Changes in soil properties resulting from fertilizer use and its effects on crop yield ” . In Report on FAO/ NORAD and Federal Department of Agriculture Seminar on Ferti lizer‐use Development in Nigeria. FAO/AGL/MISC/76/3 59 – 62 .
- Juo , A.S.R. and Ballaux , J.C. 1977 . Retention and leaching of nutrients in a limed ultisol under cropping . Soil Sci Soc. Amer. J. , 41 : 757 – 761 .
- Nelson , L.B. 1975 . “ Fertilizers for all‐out food production ” . In All‐out Food Production Strategy and Resource Implications , 15 – 28 . American Society of Agronomy . Special Publication No. 23
- Obi , A.O. 1976 . Relative effects of N fertilizers on soil pH and crop yield in a Western Nigerian soil . Niger. Agric. J. , 13 : 95 – 101 .
- Rafanan , E.C. and Vicaria , B.T. 1973 . The effect of nitrogen materials on the pH, the time requirement of and nitrate and ammonium ions concentration in Novaliches Clay loam soil . Philippines Inst. of Agric. Res. J. , 20 : 7 – 15 .
- Saiter , R.M. and Barnes , E.E. 1935 . The efficiency of soil and fertilizer phosphorus as affected by soil reaction . Ohio Agric. Exp. Stat. Bull , : 553
- Smyth , A.J. and Montgomery , R.F. 1962 . Soil and Land Use in Central Western Nigeria , 100 – 120 . Ibadan : The Government of Western Nigeria Printing Press .