Effects of Poultry Manure on Soil Fertility, Growth and Yield of White Yam and Yellow Yam

Abstract

Field experiments were conducted at Owo in the forest-
savanna transition zone of southwestern Nigeria during 2007 and 2008
cropping seasons to study the effect of different levels of poultry manure
(0, 10, 20, 30 and 40 t/ha) on soil fertility, leaf nutrient content, growth
and tuber yield of two species of yam; namely, white yam (Dioscorea
rotundata Poir) and yellow yam (Dioscorea cayenensis Lam). The
treatments were factorially arranged in a randomized block design with
three replications. The soil was deficient in organic matter (OM), total N,
available P, exchangeable K, Ca and Mg. The results showed that poultry
manure increased soil and leaf N, P, K, Ca and Mg, and soil OM, growth
and tuber yield of the yams compared with the control treatments. White
yam produced significantly higher yield than yellow yam. Compared with
yellow yam, white yam increased tuber yield by 19%, 26%, 36%, 3% and
12%, respectively, for 0, 10, 20, 30 and 40 t/ha poultry manure.
Application of poultry manure at 20 t/ha and 30 t/ha significantly
improved growth and tuber yield of white yam and yellow yam,
respectively, compared with the other treatments. These levels of poultry
manure are, therefore, recommended for the two yam species in forest-
savanna transition zone of southwest Nigeria. Recommendations of
manure for yam production should be variety specific.