Essential Oil Yield and Yield Related of Basil (Ocimum basilicum L) as Affected by NPS and Nitrogen Fertilizer Rates at Wondo Genet, Southern Ethiopia

Abstract

The experiment was conducted on experimental field of Wondo Genet Agricultural Research Center (WGARC), southern Ethiopia under supplementary irrigation in 2017- 2018 cropping season, to assess the effects of NPS and N fertilizer rates on essential oil yield and yield related traits of basil. The experiment consisted of four rates of nitrogen (0, 23, 46, and 69 kg ha-1) and four rates of NPS fertilizer (0, 50,100 and 150 kg ha-1). The treatments were arranged in factorial combination using randomized complete block design (RCBD) with three replications. The analysis of variance revealed that the main effects of NPS and N fertilizer rates significantly affected plant height, number of leaves plant-1 and dry stem weight plant-1. The tallest plant height (32.87 cm) and highest dry stem weight (41.86 g plant-1) were recorded from 100 kg ha-1 NPS rate. Similarly, the tallest plant (31.90 cm) and highest dry stem weight (42.78 g plant-1) were recorded from the highest (69 kg N ha-1) rate. On other hand, the interaction effects of NPS and N fertilizer rates also significantly affected number of primary branches plant-1, fresh leaf weight plant-1, fresh stem weight plant-1, fresh inflorescence weight plant-1, aboveground dry biomass and essential oil yield of basil. Significantly, the highest fresh leaf weight (319.36 g plant-1) and fresh stem weight (176.30 g plant-1) were obtained from combined application of 150 kg ha-1 NPS + 69 kg ha-1 N rates. The highest number of primary branches plant-1(12.63), dry leaf weight (43.93 g plant-1) and aboveground dry biomass (4.64-ton ha-1) were obtained from combined application of 100 kg ha-1 NPS + 69 kg ha-1 N, whereas the highest essential oil yield (30.22 kg ha-1) was due to combination of 100 kg ha-1 NPS + 46 kg ha-1 N rate and it is statistically at par with 50 kg ha-1 NPS + 46 kg ha-1 N. Therefore, combined application of 50 kg ha-1 NPS + 46 kg ha-1 N would be suggested in case of basil used for extracting essential oil.