Response of yield and physiological characteristics of Purple Coneflower (Echinacea purpurea (L.) Moench) to nitrogen sources at different levels of irrigation

Purple coneflower (Echinacea purpurea L.) is a perennial and herbaceous medicinal plant belonged to Asteraceae. All plant organs, have medicinal properties, but roots, leaves and flowers use to provide pill and syrup in large-scale. Echinacea is widely used in treating urinary tract diseases, respiratory disorders and viral infections. Nitrogen has an important function in physiological responses of medicinal plants to drought. Application of nitrogen biological fertilizers to achieve proper and sustainable quality and also reducing chemical fertilizers is critical. This field experiment was conducted to study the response of yield and physiological characteristics of Purple coneflower to chemical and biological sources of nitrogen under different irrigation regimes.
The experiment was conducted in a research field in Lordegan county, Caharmahal and Bakhtiari provienc as a split plot based on a randomized complete block design with three replications during 2013–2014 and 2014-2015 cropping seasons. Irrigation treatments were scheduled based on the depletion percentage of the soil available water (SAWD) (25% SAWD, 50% SAWD and 75% SAWD) and allocated as main-plot, and five levels of nitrogen source including 80 kg N/ha, 40 kg N/ha, 40 kg N/ha 5 L/ha Niroxin, 5 L/ha Niroxin and non-nitrogen (control) were allocated as sub-plot factor. The measured characteristics included of chlorophyll a, chlorophyll b, total chlorophyll, leaf proline, soluble sugars, flourescence parameters and biological yield.
Results showed that different levels of irrigation and nitrogen for all traits (except the effect of nitrogen for total chlorophyll) were significant. Interaction of year×irrigation× nitrogen source for yield and all physiological characteristics except for soluble sugers was significant. During the two years of experiment application of nitrogen sources increased chlorophyll content in irrigation after 25% and 50 % SAWD. The minimum and maximum fluorescence yield, achieved from interaction between 80 kg nitrogen at 25% and 75 % SAWD in the second year, respectively. Maximum yield obtained from 80 kg nitrogen and 5 L/ha nitroxin 40 kg nitrogen at 50% SAWD in both years. Maximum biological yield in first year (5105.2 kg/ha) and second year (12178/8 kg/ha) obtained from 80 kg nitrogen and 5 L/h nitroxin 40 kg nitrogen at 50% SAWD in both years.
Irrigation after 50% SAWD can be suggest to obtain maximum biological yield of Echinacea purpurea. Application of Nitroxin as a biofertilizer and 40 kg N/ha as chemical nitrogen can be a proper alternative to the consumption of 80 kg N/ha.