Abstract: The need for judicious management of resources and conservation of soil under intensive
cropping has become major areas of agronomic research. This study was therefore carried out to
compare the effects of complementary and sole applications of organic and inorganic fertilizers on the
growth and yield of cassava/maize/melon intercrop with a relayed cowpea. It was a randomized
complete block design experiment. Organic fertilizer (Poultry manure + decomposed urban refuse (1:1
by weight) was applied at 5 t / ha / year. Inorganic fertilizer (NPK 15-15-15) was applied at 400
kg/ha. The complementary application was 200 kg/ha NPK 15-15-15 + 2.5 t/ha/year poultry manure
+ decomposed urban refuse (1:1 by weight).There was also the no fertilizer control treatment. Results
showed that maize performed best in terms of growth and yield with complementary application of
inorganic and organic fertilizers. Melon yield under the various fertilizer treatments did not differ
statistically in both years. Cassava root yield with complementary application was comparable with
yield from sole inorganic fertilizer treatment in the first year of experimentation when sole organic
fertilizer had a significantly lower yield. By the second year however, yields under the various
fertilizer treatments were statistically similar. Cowpea yield was significantly higher with
complementary application of inorganic and organic fertilizers than from sole organic and inorganic
fertilizer treatments. Complementary application of 200 kg/ha NPK 15-15-15 with 2.5 t/ha/year poultry
manure + decomposed urban refuse (1:1 by weight) is therefore recommended for sustaining the
cultivation of cassava/maize/melon intercrop with a relayed cowpea.