References
- Adetunji M.T. (1994): Phosphorus requirement of a maizecowpea sequential cropping on a paleudult. Fertilizer Research 39: 161-166.10.1007/BF00750243
- Adigbo S. O., Adigbo V.B. (2011): Effects of site and insecticide application on growth and grain yield of local and improved cowpea varieties in south-western Nigeria. Archives of Agronomy and Soil Science 57(2): 179-191.10.1080/03650340903225032
- Adigbo S. O., Momoh S. (2007): Sustainable Agriculture in Nigeria: the Relevance of Traditional Soil Fertility Maintenance Practice. Journal of Sustainable Agriculture and Environment 9 (1): 95-103.
- Allison J. R. (1990): The Economics of Using Legumes in Cropping System. In: K.J Mulongy, M. Gueye, D.S.C. Spencer (eds). Biological Nitrogen Fixation and Sustainability of Tropical Agriculture. Proceeding of the Tenth International Conference of the African Association for Biological Nitrogen Fixation (AABNF), held at the International Institute of Agriculture (IITA), Ibadan, Nigeria 24-28th Sept.1990.
- Bationo A., Mokwunye A.U. (1991): Role of manures and crop residue in alleviating soil fertility constraints to crop production: With special reference to the Sahelian and Sudanian zones of West Africa. Fertilizer Research 29 117-127.10.1007/BF01048993
- Burt R. (2004): Soil Survey laboratory methods manual. Soil survey investigation Report No. 42. United States Department of Agriculture, Natural Resources Conservation Service, Lincoln, Nebraska, USA.
- Carsky R.J., Singh B.B., Oyewole B. (2001): Contribution of early-season cowpea to late season maize in the savanna zone of West Africa. Biological Agriculture and Horticulture 18:303-315.10.1080/01448765.2001.9754894
- Carsky R.J.; Vanlauwe B., Lyasse O. (2004). Cowpea rotation as a resource management technology for cerealbased systems in the savanna of West Africa. Tropical Soil Biology and Fertility 10: 252-263.
- Crutzen P.J. (1981): Atmospheric chemical process of the oxides of nitrogen. In: C.C. Delunche ( Ed.): Denitrification, nitrification and atmospheric nitrous oxide. John Wiley & Sons, New York, pp. 17-44.
- Enwezor W.O., Udo E. J., Usoroh N.J., Ayotade K.A., Adepetu J.A., Chude V. O., Udegbe C.I. (2002): Soils of South - western Nigeria. In: Fertilizer use and management practices for crops in Nigeria Series No. 2. Bobma publisher, Ibadan, pp. 8-18.
- Gulleridge, R.C., Shelton, H.M. (1994): The role of forage tree legume in cropping and grazing systems. In: Gulleridge, R.C. and Shelton, H.M.1994 (Eds): Forage tree legumes in Tropical Agriculture CAB International UK, pp. 150-155
- Peterson T.A., Russelle M.P. (1991): Alfalfa and the nitrogen cycle in the corn belt. Journal of Soil Water Conservation 46: 229-235.
- Roger P.A. (1995): Biological N2-fixation and its management in wetland rice cultivation. Fertilizer Research 42: 261-276.10.1007/BF00750520
- Sarrantonio M. (1991): Methodologies for screening soilimproving legumes. Rodale Institute Research Center. Rodale Institute, USAID, USA.
- Singh B.B., Chambliss O.L., Sharma B. (1997): Recent advances in cowpea breeding. In: Advances in cowpea research (Ed) Singh, B.B; D.R Mohan Raj; K. E. Dashiell and L.E.N. Jackai. Colorcarft, Hong Kong, pp. 30-49.
- Swink S. N., Ketterings Q. M., Cox W. J. (2007): Nitrogen fertilizer replacement value of soybean for corn. Online. Crop Management. doi: 10.1094/CM-2007-1005-01-RV 10.1094/CM-2007-1005-01-RV