Growth, yield, and quality responses of turmeric (Curcuma longa L.) to nitrogen fertilizer rate and timing of its application

Soil fertility decline is one of the factors that result in low productivity of turmeric (Curcuma longa, Zingiberaceae Lindl.,) in Ethiopia. An experiment was conducted to determine the effects of N rate and time of application on growth, yield, and quality of turmeric crops in Ethiopia. The trial consisted of five N rates: 0, 46, 69, 92, 115 kg ha−1, and five split application times: full dose at emergence, two times (1/2), three times (1/3), four times (1/4), and five times (1/5) equally split applications, arranged in a split plot design with three replications. Plant heights, tiller number per plant, pseudo-stem girth, mother and finger rhizome numbers and weights, fresh rhizome yield, oleoresin and essential oil contents – all were significantly affected by the interaction effects of N rate and time of application. The three times split application of 115 kg N ha−1 produced higher values of these crop characteristics. This application rate also produced a better yield and quality than did two times of application, the most commonly used practice. Therefore, turmeric producers in southwestern Ethiopia should apply 115 kg N ha−1 in three equally split applications to improve turmeric yield and quality.