the effect of foliar application of humic acid and nano fertilizer (pharmks®) on yield and yield components of black cumin (nigella sativa l.)

in a sustainable agriculture system, application of the fertilizers which are nature friendly and suitable for plants is essential. this becomes more important when dealing with medicinal plants. therefore, a factorial experiment in a randomized complete block design with three replications was set up in the 2012-2013 on nigella sativa l. treatments were nano­fertilizer (pharmks®) (at 2 levels 0, 1 ml/l) and humic acid (at 4 levels zero, 1, 3, 6 ml/l) which were applied at three time of plant growth. results showed that different levels of humic acid imposed a significant effect on number of capsule per plant, number of seeds per capsule, seed weight, seed yield, biological yield and harvest index. but there were no significant effects on number of seeds per plant and weight of 1000 seed. the highest yield to levels 3, 6 ml/l humic acid treatments respectively. nano­fertilizer (pharmks®) application significantly increased the yield and yield components of n. sativa. combined treatment at various levels had significant effect on seed weight, seed yield, biological yield and harvest index respectively but had no significant effect on other traits. the lowest yield was detected at 1 ml/l humic acid and control treatments respectively. generally, it seems that application of nano­fertilizer (pharmks®) and humic acid due to having nutritional ingredients and different physiological effects improves n. sativa performance and reduces environmental pollution and it could be used as a natural material to increase and stabilize field crop production.