Effect of Fertilizer Mixture and Time of Application on Crop Establishment and Root Yield of Sweet Potato in an Ultisol of South Eastern Nigeria

Abstract

A field study was carried out at National Root Crops research Institute Umudike in 2004 /2005 cropping seasons to determine the effect of the rate of nutrient mixture and time of application on crop establishment and root yield of sweet potato. The study involved the application of six rates of a mixture of poultry manure and inorganic fertilizer and four application periods on Sweet potato variety, Tis 87/0087. The results showed that application of 50% each of poultry manure and inorganic fertilizer (nutrient mixture) gave the best establishment of the crop (86.5 and 88.55% in both years) while time of application varied. In 2004, application at six weeks after planting gave higher root yield than two weeks after planting obtained in 2005 cropping season. Since there was no significant difference in root yield obtained between two and six weeks after planting for the two years and other parameters such as top yield root number were consistently higher at two weeks after planting , it is recommended that 50% each of such mixture be applied at two weeks for optimum establishment and root yield. Sweet potato.

Key words: Fertilizer mixture, Time of application, Establishment and Sweetpotato root yield.