RESPONSE OF LEAF NUTRIENT CONTENT, GROWTH AND CORM YIELDudOF COCOYAM (Xanthosoma sagittifolium Schott) TO TILLAGE AND POULTRYudMANURE

摘要

In order to provide information on soil management requirement of cocoyam, three fieldudexperiments were carried out at two locations in 2007, 2008 and 2009 on an Alfisol atudOwo southwest Nigeria to evaluate the effects of different tillage methods and poultryudmanure levels on leaf nutrient content, growth and corm yield of cocoyam. The treatmentsudwere five tillage methods: manual clearing (MC), manual ridging (MR), manual moundingud(MM), ploughing plus harrowing (P+H) and ploughing plus harrowing twice (P+2H) andudfive poultry manure (PM) levels: 0.0, 2.5, 5.0, 7.5 and 10.0 t/ha). These were factoriallyudcombined and arranged in a randomized complete block design and replicated three times.udIn 2008, P+H had highest leaf N, P, K Ca and Mg, but in 2009, MC had the highest whileudP+2H had the least. In the first 2 years (2007 & 2008), MR, MM and P+H increasedudcocoyam growth and corm yield compared with MC, but in 2009, MC had highest growthudand yield of cocoyam and P+2H had the least. Irrespective of tillage method, leaf K, Ca,udMg, plant height, leaf area and corm yield of cocoyam only increased up to 7.5 t/ha PM,udalthough leaf N and P increased up to 10.0 t/ha PM. The mean data for the 3 years showedudthat P+H+7.5PM had highest corm yield (10.2 t/ha) while unmanured P+2H had the leastud(6.1 t/ha). Relative to P+2H, the P+H+7.5PM increased corm yield by 69%. In order toudmaximise performance of cocoyam, a combination of P+H+7.5 t/ha PM is recommended