Improvement of Echinacea purpurea performance by integration of phosphorus with soil microorganisms under different irrigation regimes

Biological yield and physiological indices of Echinacea purpurea were investigated in a split plot field experiment and a randomized complete block design with three replicates and two harvests in 2016 and 2017. The main factor consisted of three irrigation regimes (irrigation after 25, 50 and 75% of available water depletion) and a sub-factor consisting of six different treatments of plant P (phosphorus) supply [control, 100% chemical P, 50% chemical P + AMF (mycorrhizal arbuscular fungus), AMF, 50% chemical P + PFB (Pseudomonas fluorescens bacterium) and PFB]. Results indicated that with increase in irrigation intervals, the rates of minimum and maximum fluorescence showed an increasing trend while the minimum fluorescence to maximum fluorescence ratio pursued a decreasing trend. In irrigation regime of 50% available water depletion, and combination of chemical P with AMF or PFB increased the amount of soluble sugar (26% and 17%) and proline (increase 39% and 22%) compared with control. The catalase activity in sole application of AMF was increased by 24% than the control test. Overall, the results of this study showed a successful coexistence of bio-fertilizers with Echinacea purpurea in improvement of photosynthetic indices, biological yields and water use efficiency.