EFFECT OF INTEGRATED NUTRIENT MANAGEMENT ON PERFORMANCE OF SWEET POTATO (Ipomoea batatas (L.) LAM) VARIETIES IN NYANYA ABUJA, NIGERIA.

Abstract

ABSTRACT Field trials were carried out in the 2019 and 2020 cropping seasons at the experimental station of the National Root Crops Research Institute Nyanya Out-Station to assess the effects of integrated nutrient management on the performance of sweet potato varieties in Nyanya, Nigeria as well as their residual effects on soil properties. Treatments consisted of factorial combinations inorganic (NPK) and Organic (poultry manure) fertilizer (Control, 400 kg ha-¹ NPK, 3t ha-¹Poultry Manure (PM), 200 kg ha-¹ NPK + 1.5 t ha-¹ PM, 300 kgha-¹ NPK + 0.75 tha-¹ PM,100 kgha-¹ NPK + 2.25 t ha-¹ PM) with two varieties of sweet potato (Butter milk and Umuspo1) laid in a Randomized Complete Block Design (RCBD) with three replications. Results indicated that the application of 200 kg ha-1 NPK + 1.5 t ha-1 PM and 300 kg ha-1 NPK + 0.75 t ha-1 PM in 2019 and all the fertilizer applications in 2020 recorded highest establishment count than the control which had the lowest establishment count in both years. The application of 200 kg ha-1 NPK + 1.5 t ha-1 PM consistently gave higher number of leaves and longer vines than the control which had the lowest in 2019 and 2020 respectively. Number of branches was highest with the application of 100 kg ha-1 NPK + 2.25 t ha-1 PM in 2019 and application of 3.0 t ha-1 PM in 2020 than the control which consistently recorded lower number of branches in both years. The application of sole and integrated fertilizer applications recorded significantly similar highest number of tubers and tuber yield (6.52 t ha-1) and (11.0 t ha-1) than the control which had the lowest (2.05 t ha-1) and (2.25 t ha-1) in 2019 and 2020 respectively. The application of 400 kg ha-1 NPK supported higher residual phosphorus and organic carbon content than the control which had the lowest. The application of 3.0 t ha-1 PM recorded higher residual total nitrogen content in the soil than the control which had the lowest nitrogen content in the soil. The variety Butter milk recorded increased growth, tuber yield and supported higher residual soil chemical properties than Umuspo 1 sweet potato variety. It is therefore recommended that farmers in this agro-ecological zone of Nigeria should apply 200 kg ha-1 NPK + 1.5 t ha-1 PM and Butter milk variety for optimum growth and tuber yield of potato, applications of 400 kg ha-1 NPK and 3.0 t ha-1 PM for highest residual chemical properties in the soil of the study area.