Agrotechniques development for Paeonia emodi Royle: Evaluation of soil composition, biomass, and secondary metabolites

Paeonia emodi Royle is an herbaceous plant used to cure several ailments like atopic eczema, cardiovascular disease and, diabetes, and also possesses anti-coagulant and anti-inflammatory properties. A steady depletion in the supply of raw material for this species has been observed in its natural habitats. Therefore, management and sustainable utilisation of P. emodi are of prime concern for long-term sustenance. In order to find the best cultivation and nursery practices for P. emodi, field trials were conducted using two different organic fertilisers, namely, farm yard manure (FYM) and vermicompost (VC), applied in 3 different bed types, i.e., slope, raised and, flat. Several parameters like growth performance, biomass, and secondary constituents in P. emodi were studied to find the optimal condition. Soil samples from beds (depth 0–15 cm) treated with vermicompost exhibited maximum moisture, organic carbon, nitrogen, potassium, and phosphorus contents. Likewise, the best sprouting, flowering and, average leaf length and width of the plants were recorded in the soil treated with vermicompost from the raised bed type (T5). Post-harvest agronomic characteristics showed maximum fresh weight in the roots harvested from the T1 bed (slope + farm yard manure). High performance liquid chromatography analysis of the samples (leaves and roots) collected from T5 beds and wild plants displayed the presence of various polyphenolic compounds, e.g., ascorbic acid, catechin, gallic acid, ferulic acid, quercetin, ellagic acid, phloridzin, and p- coumaric acid. However, higher phloridzin content was recorded in the leaves of cultivated plants in the T5 bed, as compared to wild plants. These findings showed a significant increase in the biomass yield and growth performance of P. emodi after the application of vermicompost in T5 bed. Additionally, the application of vermicompost prior to cultivation was found to enhance biomass and secondary metabolites, e.g., ascorbic acid, catechin, gallic acid, ferulic acid, quercetin, ellagic acid, phloridzin, and p-coumaric acid, in P. emodi plants, which could be used as a suitable agro-technique strategy for large-scale cultivation and conservation in the future.