Effects of nitrogen, potassium and soil moisture regime on growth, herbage, oil yield and nutrient uptake of South American marigold (Tagetes minuta L.) in a semi-arid tropical climate.

摘要

Two field experiments were conducted between 2001 and 2003 to study the effects of different nitrogen levels (0, 100 and 200 kg N ha-1) and potassium levels (0, 41.5 and 83.0 kg K ha-1) and, in a parallel experiment, soil moisture regimes [0.25, 0.50 and 0.75 irrigation water:cumulative pan evaporation (IW:CPE ratios)] and three nitrogen levels (0, 100 and 200 kg N ha-1) on growth, herbage, oil yield and nutrient uptake of South American marigold (Tagetes minuta L.). The application of nitrogen at 200 kg ha-1 significantly increased plant height, fresh weight, leaf/stem ratio, leaf+flower/stem ratio, herbage (biomass) yield, oil yield, oil content, and N, P and K uptake compared to controls without nitrogen fertiliser. Plant height, herbage yield, oil yield, and N, P and K uptake increased significantly at 83.0 kg K ha-1 compared to controls without K fertiliser. A soil moisture regime at an IW:CPE ratio of 0.5 significantly increased herbage, oil yield and nutrient uptake compared with an IW:CPE ratio of 0.25. Oil quality was not influenced by N, K or soil moisture regime..