Vegetative Growth, Flowering and Essential Oil Content of Marigold Plants in Relation to Different Levels of Mineral N and Poultry Manure Applications

The main effects and interactions of four different mineral N levels (0, 50, 100 and 150kg fed -1 ) and four various poultry manure rates (0, 10, 15 and 20m 3 fed -1 ) on the vegetative growth, flowering, volatile oil content and chemical composition of marigold plants (Tagetes minuta) were investigated through two field experiments in 2000/2001 and 2001/2002. The obtained results, obviously, showed that; plant height, herb fresh and dry weights, number of branches plant -1 , number and fresh weight of inflorescences, concentrations of N, P and K in the herb and essential oil percentage of the herb and inflorescences successively increased as N application rate increased up to 100kg N fed -1 . Application of 15m 3 poultry manure fed -1 resulted in longest plant stature, heaviest herb fresh and dry weights and number of branches plant -1 . In addition, it was clear that, the higher the rate of poultry manure, the higher was the concentrations of photosynthetic pigments, carbohydrates and N, P and K in the herb. Similar trend on the essential oil content of both the herb and inflorescences was, also, noted. The interaction of 100kg N by 15m 3 poultry manure fed -1 was pronounced and gave the best results on the studied morphological characters, flowering traits and essential oil contents in the herb and inflorescences. However, the interaction of the two studied factors did not reflect any constant trend on the concentrations of N, P and