Growth and Rhizome Yield of Ginger (Zingiber officinale L.) as Influenced by Propagule Size and Nitrogen Levels in Ogbomoso, Southwestern Nigeria

The experiments were conducted at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso, Nigeria in 2010 and 2011 to determine the effect of propagule size and nitrogen levels on the growth and rhizome yield of ginger. The nitrogen source was from Tithonia compost (TC). Three propagule sizes were tested (20, 30 and 40 g) and seven nitrogen levels (0, 40, 60, 80, 100, 120 and 140g kg N/ha). The experimental pots were laid out in a randomized complete block design with three replicates. Data were collected on growth parameters (plant height, number of leaves, leaf length and leaf width); rhizome yield components (number of tillers and rhizomes, and rhizome weight and length); and proximate composition (crude protein (CP), crude fibre (CF), total lipid (TL); Total Ash (TA), Starch and water soluble extract). Data collected were subjected to analysis of variance and significant means were compared using Duncan Multiple Range Test (DMRT) (P ≤ 0.05). Propagule size, N levels and their interactions significantly (P≤ 0.05) influenced most of the parameters assessed. In most cases, the use of 30 and 40 g planting material gave similar results. Plants nourished with 140 kg N/ha significantly and consistently outperformed others fertilized with other nitrogen levels. Crude protein obtained from 40 g propagule size was significantly ( P ≤ 0.05) higher than other tested propagule sizes. The rhizome yields of fertilized plants were significantly higher than the non fertilized plants. Rhizome yields ranged from 1.57 t/ha in none fertilized plants to 3.71 t/ha in 140 kg N/ha. In conclusion, establishment of ginger with 40 g planting materials and its nourishment with 140 kg N/ha enhanced its growth, rhizome yield and proximate compositions of the plant.