THE EFFECT OF THREE YEARS OF TILLAGE AND\ud POULTRY MANURE APPLICATION ON SOIL AND PLANT\ud NUTRIENT COMPOSITION, GROWTH AND YIELD OF\ud COCOYAM

摘要

Tillage and use of organic manure are important agronomic practices that sustain high crop and soil\udproductivity. Hence, a three-year (2007 to 2009) study was conducted to evaluate the effect of site, tillage\udand poultry manure (PM) treatments on soil and plant nutrients composition, growth and yield of cocoyam\ud(Xanthosoma sagittifolium). The study was a 2 × 5 × 5 factorial experiment with two sites (Owo – site 1 and\udObasooto – site 2), five tillage methods; manual clearing (MC), manual ridging (MR), manual mounding\ud(MM), ploughing plus harrowing (P+H) and ploughing plus harrowing twice (P+2H) and five levels of\udPM (0, 2.5, 5.0, 7.5, 10.0 t ha−1). Treatments were replicated thrice. Soil OM, N, P, K, Ca, Mg and\udleaf nutrients reduced with increase in tillage intensity, thus MC conserved soil nutrients the most, and\udincreased nutrient uptake. Soil and plant nutrient concentration was lowest under the P+2H treatment.\udThe MC, MR and MM treatments led to faster growth and higher tuber yield. As PM increased from\ud0 to 10.0 t ha−1 soil pH, OM, soil and plant N, P, K, Ca and Mg increased. The 7.5 t ha−1 PM gave\udthe highest leaf K, Ca and Mg values. Owo site had significantly higher yield and growth parameters of\udcocoyam compared with Obasooto site. Yield and growth parameters of cocoyam increased with increase\udin PM level up to 7.5 t ha−1. Out of all tillage cum manure treatments, MC+7.5 t ha−1 PM gave the\udhighest values of yield and growth parameters.