ORGANIC AND MINERAL FERTILIZERS EFFECTS ON THE PERFORMANCE OF SWEET MAIZE (ZEA MAYS L. SACCHARATA STRUT.) IN SOUTH EASTERN RAINFOREST ZONE OF NIGERIA

Abstract

Growth and yield response of sweet maize ( Zea mays L. saccharata Strut.) to rates of poultry manure (PM) and NPK 20-10-10 fertilizer was studied under field condition in 2010 late growing season in Calabar, a humid forest agro ecology of south eastern Nigeria. Treatments comprised of three rates of PM (0, 5 and 10t/ha), factorially combined with four rates of NPK (0, 200, 400 and 600 kg/ha) and arranged into a randomized complete block design with three replications. Application of PM at the highest rate significantly increased plant height, number of leaves/plant, number of cobs/plant, unhusked and dehusked green cob yields and also hastened days to 50% tasselling. The highest rates of PM and NPK maximized leaf area index (LAI), number of grains/cob and harvest index (HI) whereas total dry matter (TDM), weight of grains/cob, cob yield/ha and total grain yield peaked at 10t/ha PM and 400kg/ha NPK fertilizer. The 10t/ha PM rate and 400kg/ha NPK increased TDM by 43 and 91% and total grain yield by 101 and 34% respectively, compared with the control. Poultry manure at 10t/ha in combination with 400kg/ha NPK fertilizer out-yielded other treatments in terms of biomass yield, cob yield/ha, harvest index and total grain yield.