An Investigation of Characteristics of Chinese Bellflower (Platycodon grandiflorum A.) Cultivated Soil

Abstract

In order to understand the characteristics of soil according to the cultivation environment of Chinese bellflower (Platycodon grandiflorum A.), soil chemical properties of 12 collected soil samples from 6 cultivated fields in Okcheon, Chungbuk province in August. 2017 were analyzed. The soil pH was distributed within the range of 4.61 to 5.25 at all cultivation years and E.C (Electric Conductivity) and T-N (Total Nitrogen) of the cultivation year were not significant. Available $P_2O_5$ was higher than the average for medicinal crops and P. grandiflorum in Korea and C.E.C (Cation Exchange Capacity) was inconsistent for each cultivation year. In particularly, it was validated that the content of exchangeable cations K, Ca, Ma, and Na in this experiment was similar to that of C.E.C according to the cultivation years, because C.E.C had a high correlation with the exchangeable cations. For the available $P_2O_5$, as affected by trans-planting, 5Y-NT-H (cultivated 5 years and non-transplanted) had 58 mg/kg, while 5Y-T-H (cultivated 5 years and transplanted) had 246 mg/kg. The soil pH was found to be lower (acidic) in diseased soils than healthy soils. E.C was confirmed to be was higher in diseased soils than healthy soils except for the one cultivated for 2 years. The contents of T-N and available $P_2O_5$ were higher in diseased soil except for the one cultivated for 5 years and 11 years. The exchangeable cation K and Na tended to be higher in diseased soils rather than that in healthy soils, and the exchangeable cation Ca and Mg contents were higher in healthy soils than in diseased soils. The C.E.C of the soil was lower than that of healthy soils in all of the years except for the one which was cultivated for 5 years (transplanted).

Fig. 1. Soil sampling cites for soil properties analysis at P. grandiflorum from 3 fields of Okcheon-gun, Chungbuk province. (A) Soil samples of cultivated for 5 years (non transplanted) collected from Samnam, Okcheon-gun. (B) Soil samples of cultivated for 2 years (non transplanted) and 5 years (transplanted) collected from Gwongchon, Okcheon-gun. (C) Soil samples of cultivated for 6 years (transplanted), 11 years (transplanted) and 15 years (transplanted) collected from Soseo, Okcheon-gun.

Fig. 2. (A) 12 soil samples were collected from the root surface except for the topsoil layer (20 ㎝). Soil analysis was carried out on the basis of the Rural Development Administration soil chemical analysis. (B) Determination of T-N (Total Nitrogen) was performed by nitrogen auto analyzer (K-350, Buchi distillation unit). (C) Soil pH and E.C (Electronic Conductivity) were performed by electrode method (Orion 3 star, Thermo).

Table 1. List of soil samples collected from Okcheon-gun, Chungbuk province

Table 2. Soil properties as cultivated year of P. grandiflorum

Table 3. Soil properties of trans planting for 5 years of cultivation of P. grandiflorum

Table 4. Soil properties affected by root rot disease of P. grandiflorum