Effects of nitrogen fertilizer on the growth, yield, nutritional and phytochemical qualities of basil cultivars

Abstract

Pot experiment was conducted at the Teaching and Research Farm, Ladoke Akintola University of Technology, Ogbomoso in 2015. Three Basil cultivars (purple, sweet and local small leaves) and five nitrogen fertilizer rates (0, 30, 60, 90 and 120 kg N/ha) were evaluated. The experiment was laid out as 3 x 5 factorial fitted into a randomized complete block design replicated three times. Data were subjected to analysis of variance and treatments means were compared using least significant difference at 0.05 probability level. Results revealed that fertilizer rates, significantly (p < 0.05) influenced the growth and yield parameters of basil cultivars. The plants that received 120 kg N/ha produced the tallest (42.50 cm) plants while the shortest (26.30 cm) plants were obtained from 0 kg N/ha. The widest leaf area (19.67cm2) was recorded for local basil at 90 kg N/ha while sweet basil gave the least (4.00 cm2) value when no fertilizer was applied at 12 weeks after planting (WAP). The highest seed weight (9.19 kg/ha) was recorded for the local basil plants that received 120 kg N/ha while the plants in the control plots gave the least (1.59 kg/ha, 3.30 kg/ha and 4.25 kg/ha) values for all cultivars. Purple basil produced the highest fresh shoot yield (94.87 g/plant), dry leaf (19.60 g) and dry shoots (38.78 g) yield while the sweet basil recorded the least values of 48.35 g, 10.02 g and 17.80 g, respectively at 120 kg N/ha. However, the highest dry seed yield (7.33 g) per plant was observed from local basil while sweet basil recorded the least value (14.1 g), irrespective of fertilizer rate. Purple basil gave highest (25.65 g/mg) leave crude protein, while sweet basil gave least (17.70 g/mg) value. Application of nitrogen fertilizer at 90 kg N/ha produced optimum performance of basil and this fertilizer rate is most efficient with the purple basil. Application of 90 kg N/ha with purple basil could be recommended in the study area.