Abstract: The effects of soil tillage and fertilizer application on yield and chemical composition of sweet potato (Ipomoea batatas (L) Lam) grown for livestock feeding during the dry season was investigated. The experiment was conducted at the Teaching and Research Farm, University of Ibadan. A split plot design was used with tillage as the main plot factor and fertilizer application as sub plot factor. The four treatments namely; tilled, fertilized (TF); tilled, not fertilized (TNF); not tilled, fertilized (NTF); not tilled, not fertilized (NTNF, control) was replicated three times. Yield and chemical composition of the root was determined. Residual forage and biomass production were also measured. There were significant differences (P < 0.05) in dry matter yield of the root, residual forage, and biomass production of sweet potato (SP) among treatments. Root yield was 7.8, 4.4, 4.4 and 3.4 t ha-1; residual forage, 7.5, 5.1, 5.9, and 4.3 t ha-1; and biomass production, 15.3, 9.5, 10.3 and 7.6t ha-1 for TF, TNF, NTF and NTNF respectively. The treatments had no significant (P > 0.05) effect on chemical composition of SP root although there was a slight improvement in crude protein (CP) content and a reduction in fibre components of the root with fertilizer application. Tillage and fertilizer application had equal influence on root yield of SP but when forage yield is considered, fertilizer application seemed to be more beneficial to the crop than tillage. The best economic returns from SP grown for livestock feeding were realized when both cultural practices were combined.
O.A. Olorunnisomo , A.E. Salami and I.O.A. Adeleye , 2006. Improvement in yield and chemical composition of sweet potato for livestock feeding through tillage and fertilizer application . Agricultural Journal, 1: 206-210.