Agronomic Evaluation of New Varieties of Cassava (Manihot esculenta Crantz) under Different Rates and Modes of NPK (12-12-17-2) Fertilizer Application in Two Seasons

A study was carried out at the Teaching and Research Farm of the Department of Crop Science, University of Nigeria, Nsukka to evaluate the growth and yield of four improved cassava varieties, determine their optimum NPK fertilizer rate and the best modes of fertilizer application for increased productivity. The experiment was factorial laid out in a randomized complete block design with three replications. Four varieties of cassava, four fertilizer rates and three modes of fertilizer application were used for the study. The early planting had higher survival count, number of leaves, tuber and garri yield when compared with late planting. The variety TMS 98 05 05 gave significantly (p< 0.05) higher number of leaves, tuber and garri yields of 39.8 and 9.68 t/ha, respectively, at 12 months. At 6 months of crop growth, 200 kg/ha fertilizer application rate gave significantly higher tuber and garri yield of 24.69 t/ha and 5.15 t/ha, respectively. Furthermore, 400 kg/ha of NPK fertilizer rate gave higher tuber and garri yields of 39.4 and 10.12 t/ha, respectively at 12 months of crop growth. Split application of fertilizer gave significantly higher tuber and garri yield from single application, though it is statistically similar to split-split application. Therefore, early planting, 400 kg/ha fertilizer rate and split application should be adopted for cassava production. The variety TMS 98 05 05 with higher growth and yield should also be adopted by farmers for cassava production in Nsukka derived savannah agro-ecology.