the effect of organic fertilizers and different sowing dates on yield and yield components of flower and grain of pot marigold (calendula officinalis l.)

in order to find out suitable organic fertilizers for elimination of chemical fertilizers usage and the optimum sowing date in pot marigold cultivation, an experiment was conducted in the agricultural research station, ferdowsi university of mashhad, iran, in 2007 growing season. for this purpose a split plot experiment based on completely randomized block design with three replications was used. the main factor consist of four different fertilizers (50 kg.ha-1 n, 40 t.ha-1 cow manure, 20 t.ha-1 compost fertilizer and 10 t.ha-1 hen manure) beside control (without fertilizer) and three sowing dates (10th april, 1th may and 21th may) were allocated as sub factor. the results showed that the length time of emergence to budding, budding to flowering and flowering to ripening decreased by delay in sowing date, significantly. by delay in sowing date, plant height and dry matter also decreased because of reduction of vegetative growing duration. the various fertilizers had not significant effect on developmental stages and morphological characteristics of pot marigold. nitrogen fertilizer and hen manure in compare of other treatments had significantly (p≤0.05) higher level in number of inflorescences, yield of inflorescences, yield of petal and seed yield. thus, hen manure can be a suitable replacement of chemical fertilizers in pot marigold cultivation. the various sowing dates showed significant effect on the most measured characteristics of seed and inflorescences yield components of pot marigold. the highest of all studied characteristics were obtained in 10th april and 1th may than 21th may sowing dates.