effects of fertilizer types and irrigation intervals of on quantity criteria of lavender (lavandula angustifolia), rosemary (rosemarinus officinalis) and hyssop (hyssopus officinalis)

in order to investigate the effects of fertilizer types and irrigation regimes on quantitative criteria of three medicinal plants: lavander, rosemary and hyssop, an experiment was conducted at research field of faculty of agriculture, ferdowsi university of mashhad, during two growing years of 2007-2010. a split-split plot design with three replications was used. treatments were three irrigation intervals (10, 20, 30 days) as main plots and three types of fertilizers in six levels: control, nitroxin containing azotobacter sp. and azospirilum sp. (5lit/ha), nitrogen fertilizer (50 and 100 kg/ha), cow manure (10 and 20 ton/ha) as subplots. animal manure and chemical fertilizer were applied at the time of transferring seedlings to the field and nitroxin was used with the first irrigation. shoot harvesting was performed twice during the plant growth at the time of full flowering. increasing irrigation intervals reduced dry matter yield of three species and the highest yield of lavender (3990 kg/ha), rosemary (2380 kg/ha) and hyssop (7380 kg/ha) were obtained with 10 days interval. also the effect of fertilizer was not significant but the highest yield for lavender (3930kg/ha), rosemary (2535kg/ha) was obtained with 50 kg/ha chemical fertilizer and the highest yield of hyssop (6117kg/ha) resulted in application of 20 ton/ha animal manure. the ratio of leaf dry weight to stem dry weight for both years was gained with 30 days irrigation interval at 20 ton/ha animal manure. in general, the best treatment was 30 days interval irrigation and 20 ton/ha animal manure for the best yield and respective in local conditions