Assessment effects of drought stress, superabsorbent and manure on agronomic and chemical traits in German chamomile (Matricaria chamomilla L.)

To evaluate the effects of superabsorbent polymer and manure on dryflower yield, absorption of sodium and potassium, as well as chlorophyll a, b and total under drought stress conditions in German chamomile, split-factorial experiment in a randomized complete block design with four replications was conducted in 2016. Drought stress treatment in three levels of 95, 65 and 45% of field capacity as the main factor and manure in two levels of use and non-use and superabsorbent at three levels of 0, 0.1 and 0.2 percent of soil weight were considered as sub plots. Results showed that in treatment of 45% compared to the 95%, the number of flowers per plant and dry flower yield decreased by 27.65 and 36.9 percentages. Also, with increasing drought stress the amount of leaf and flowers potassium decreased, but leaf and flowers sodium were increased. Maximum and minimum amounts of chlorophyll a, b and total, were observed in 95 and 45% field capacity, respectively. The use of manure compared with the non-application increased increases the number of flowers per plant and dry flower yield by 13 and 10 percentage. The level of 0.2% weight superabsorbent compared with non-use increased number of flowers per plant and dry flower yield by 6% and 4%, respectively. In total, results showed that application of manure and superabsorbent reduced effects of drought stress and improved growth traits.