Influence of Blended Npsb Fertilizer Rates on Growth of Sweet Potato (<i>Ipomoea batatas</i> (L.) Lam) Varieties in Bako District, West Shewa Zone

Abstract

Sweet potato (<i>Ipomoea batatas</i> (L) Lam) is one of the most important root crops. It is used as food and economically important crop in Ethiopia. However, its production and productivity is very low due to several factors: lack of information on the type and appropriate rate of fertilizers supplying major plant nutrients, which have been recognized to be deficient in Ethiopian soil and shortage of planting materials supplying system, Hence, a field experiment was conducted at Bako Agricultural Research Center in 2019/2020, to investigate the effect of blended NPSB fertilizer rates and sweet potato varieties on growth, components of sweet potato. Five different rates (0, 50, 100, 150 and 200 kg ha^-1) of blended NPSB fertilizer and two sweet potato varieties (Dimtu and Tola) were combined in a 5 X 2 factorial arrangement in a randomized complete block design with three replications. Data on growth components were collected and subjected to analyses of variance using SAS, version 9.3. The results of this experiment indicated that varieties and NPSB fertilizer rates highly significantly (p<0.01), and their interaction significantly (p<0.05) affected most of the growth parameters including: shoot fresh weight; shoot dry weight, vine length, days to bud sprout and days to physiological maturity. Tola at 100 kg ha^-1, 150 kg ha^-1 and 200kg ha^-1 NPSB fertilizer rates resulted in significantly (p<0.01) highest days to physiological maturity (136.69, 139.9 and 143.1) and the highest shoot fresh weight (653.3g, 668.3g and 690g), respectively. Dimtu at 0 kg ha^-1 fertilizer rates resulted in significantly (p<0.01) highest days to bud sprouting (14.0). In conclusion, the above findings indicated that the growth and productivity of sweet potato at the study area can be improved by the combined use of appropriate variety and application of optimum rate of blended NPSB fertilizer. However, as the results are limited to one season and location, further research needs to be conducted over more seasons and locations by considering also using the more than 200 kg ha^-1 of blended NPSB fertilizer rates and additional varieties to generate more reliable information.