Understanding the Rain-shelter and Water and Fertilizer Management in Reducing Root rot of Panax notoginseng

Abstract Purpose Panax notoginseng (Burk) F. H. Chen, a valuable Chinese medicinal herb,is widely used in chinese medicine products. The frequent root-rot, however, caused a large reduction of Panax notoginseng yields, which greatly affected the development of Panax notoginseng planting. Panax notoginseng root-rot is related to its warm and humid growing environment.Methods Thus, five-year-old Panax ginseng was selected to investigate the effects of water and fertilizer conditions in rain-sheltered and non-rain-sheltered environments on the incidence of Panax ginseng root-rot disease in field trials. Two irrigation (W1: 50% of field water holding capacity, W2: 70% field water holding capacity), and four fertilizer amounts (F0:0 kg ha-1, F1:75 kg ha-1, F2:105 kg ha-1, and F3:135 kg ha-1) were chosed in rain-sheltered and non-rain-sheltered, respectively.Results The results showed that water and fertilizer coupling under rain-sheltered or non-rain-sheltered conditions had significant effects on Panax notoginseng root-rot disease as well as agronomic traits. Compared with non-rain shelter cultivation, the rain-shelter treatments led to higher net photosynthetic rate, and root volume of Panax notoginseng, and promoted the soil respiration and soil enzyme activity, as well as decreased the soil moisture. Additionally, The incidence of root-rot in 50% irrigation level non-rain shelter treatment (RWF) were 52.97% -88.46% higher than that in corresponding 50% rain shelter treatment (P<0.05), and 97.80% -137.30% in 70% irrigation level. F2 fertilizer led to the lowest root-rot in rain-shelter treated Panax notoginseng, and F1 in non-rain-shelter treated Panax notoginseng. Structural equation modeling showed soil moisture was the main factor affecting root-rot with contribution of 0.545.Conclusions Comprehensive analysis of detected parameter of plant and soil, the DW2F2 was recommended with higher root valume and lower root-rot than the other treatments.