[1]
Akunda, E. M. W. (2001). Crop yields of sorghum and soybean in an intercrop. Journal Food Tech. in Africa, 6: 2-4.
Google Scholar
[2]
Anyaebunam, H. N; Aswugba, G. N; Nwosu, K. L (2008) Guide to improved sweet potato production in Nigeria. Extension Guide 2 ; 1-2
Google Scholar
[3]
Babatunde, F. E ; Dantata, I. J and Olawuyu, O. J (2011) Performance of sweet potato and soybeans as affected by cropping sequence in Northern Guinea Savannah of Nigeria. J. Agric. Sci. 1(3) 36-40.
DOI: 10.3923/ja.2012.22.26
Google Scholar
[4]
Baukamp J.C. (1985). Production requirements,pp.1-33, In: J.C. Bauwkamp (ed). Sweet potato Products: A natural resource for the tropics. CRC Press, Boca Raton,FL.
Google Scholar
[5]
Belehu, T. (2003) Agronomical and physiological factors affecting growth, development and yield of sweet potato in Ethiopia. PhD Thesis, Dept. of Plant Production and Soil Science, University of Pretoria, Pretoria.
Google Scholar
[6]
BNARDA (2003). Annual report of Benue State Agricultural and Rural Development Authority, 2003. Makurdi,Nigeria, 21.
Google Scholar
[7]
BNARDA (2008). Implementation completion report reports of National Special Program for Food Security (NSPFS), Benue State Agricultural and Rural Development Authority, Makurdi, Benue State, Nigeria. pp.3-5
DOI: 10.18697/ajfand.90.17980
Google Scholar
[7]
Bouyoucos G.H. (1962). Hydrometer method improved for making particle size analysis of soils. Agron. J., 1(54)>465-470
DOI: 10.2134/agronj1962.00021962005400050028x
Google Scholar
[8]
Bray, R.H. and Kurtz, L.T. (1945). Determination of total organic and available forms of phosphorus in soils. Soil Sci., 59: 39-45
DOI: 10.1097/00010694-194501000-00006
Google Scholar
[9]
Chaykin, S. (1969). Assay of nicotinamide deaminase. Determination of ammonium by thje indolphenol reaction. Annals of Biochemistry, 32:375-382
Google Scholar
[10]
Dantata, I. J., Babatunde, F. E., Mustapha, S., Fagam, A. S. (2010) Influence of variety and plant spacing on tuber size , tuber shape and fresh marketable yield of sweet potato in Bauchi, Nigeria. Biology and Environmental Science Journal of the Tropics 7(3): 140 – 144.
Google Scholar
[11]
Davis, J. H. C and Wooley, J. N (1993) genotype requirement for intercropping. Field crops Research, 34: 407-430.
Google Scholar
[12]
Egbe, O. M. and Idoko, J. A. (2009). Agronomic assessment of some sweet potato varieties for intercropping with pigeonpea in southern guinea savanna of Nigeria: ARPN Journal of Agriculture and Biological Sciences, 4(4): 23-32.
DOI: 10.4314/as.v8i2.51100
Google Scholar
[13]
Ennin, S. A; Ciegg, M. D and Francis, C. A (2002). Resource utilization in soybean/maize intercrop. Africa Crop Science Journal, 10(3) :251-261.
Google Scholar
[14]
Evans, A. C and Streedharan, A. (1982). Studies of intercropping 11: Castor bean with groundnut or soybeans. East Africa Agriculture and Forestry Journal, 28: 7-20.
Google Scholar
[15]
FAO (2001) FAO Production Year Book. Basic data unit, Statistics Division, FAO, Rome, Italy, 53-95.
Google Scholar
[16]
Fujita,K. and Ofosu-Budu K.G.(1996). Significance of legumes in intercropping systems, In: Ito,O., Katayama,K., Johansen, C., Kumar Rao, J.V.D.K.., Adu-Gyamfi, J.J. and Rego,TJ (eds.) Roots and nitrogen in cropping systems of the semi-arid troipcs. JIRCAS Int. Agric. Series No.3, Japan. pp.19-40
Google Scholar
[17]
Heanes, D.L. (1984). Determination of total organic C in soils by an improved chromic digestion and spectrophotometric procedure. Communications in Soil Science and Plant Analysis, 15: 1191-1213.
DOI: 10.1080/00103628409367551
Google Scholar
[18]
Henriet, J. G. A; Van, E. K; Blade, S. F and Singh, B. B (1997) Quantitative assessment of traditional cropping systems in Sudan Savannah of Nigeria 1: Rapid survey of prevalent cropping systems. Savanna Journal of Agricultural Research, 14: 27-45.
Google Scholar
[19]
Ijoyah, M. O and Jimba, J (2011). Effects of planting methods, planting dates and intercropping systems on sweet potato-okra yields in Makurdi, Nigeria.Agricultural Science Research Journal, 1 (8):184-190.
Google Scholar
[20]
Jou, A.S.R. ( 1983). Selected method for soil and plant analysis. Manual Series, No.1, Ibadan Nigeria,IITA.
Google Scholar
[21]
Njoku, S. E., Muoneke, C. O., Okpara, D. A. and Agbo, F. M. O. (2007). Effect of intercropping varieties of sweet potato and okra on ultisol of South Eastern Nigeria. Africa Journal of Biotechnology, 6(14) 1560-1654.
Google Scholar
[22]
Ofori, F. and Stern, W.R. (1987). Cereal – legume intercropping systems. Advances in Agronomy, 41: 41 - 90
DOI: 10.1016/s0065-2113(08)60802-0
Google Scholar
[23]
Onochei, B. E (1975). The potential value of soybean supplement in Nigeria diet. Proceedings of the 3rd Annual Conference of Agricultural Society of Nigeria, 41:43-45.
Google Scholar
[24]
Ossom, E. M. (2010). Influence of sweet potato/ maize association on ecological properties and crop yields in Swaziland. International Journal of Agriculture and Biology, 12: 481-488.
Google Scholar
[25]
Tel, D. and Rao, P. ( 1982). Automated and semi-automated methods for soil and plant analysis. IITA Manual Series, No. 7.
Google Scholar
[26]
Willey, R. W. (1985). An evaluation and presentation of intercropping advantage. Experimental Agriculture 21: 115-155.
Google Scholar
[27]
Willey, R. W.,Rao, M. R. (1980). A competitive ratio for qualifying competition between intercrops. Experimental Agriculture, 16: 117-125. ( Received 27 April 2015; accepted 10 May 2015 )
DOI: 10.1017/s0014479700010802
Google Scholar