Effect of Poultry Manure on Soil Chemical Properties and Root Yield of Sweet Potato (ipomoea Batatas (l) Lam) Grown in a Tropical Ultiso

A field trial was conducted at National Root Crops Research Institute Umudike in 2004/2005 cropping seasons. The aim was to evaluate the effect of poultry manure applied over time intervals on some soil chemical properties and root yield of Sweet potato. The time intervals were 2 weeks before planting, (WBP), at planting, 2, 4, and 6 weeks after planting (WAP). Sweet potato varieties used were TIS 87/0087, TIS 5320 P. 1.13 and Ex-Igbariam. Poultry manure was applied at 3.2 t ha-1 . Results showed that application at 2 WBP, 6 WAP and at planting reduced soil pH in 2004 while in 2005 there was increase in PH. Also N, P, K, Ca, and Mg increased in both years. Application of poultry manure at 4WAP favoured the yield of varieties TIS 87/0087 and TIS2532OP.1 .13 while application at 6WAP favoured the root yield of Ex-Igbariam.