Effects of Regulated Deficit Irrigation on Soil Nutrients, Growth and Morbidity of Panax notoginseng in Yunnan High Altitude Areas, China

This study investigated the responses of Panax notoginseng in a high-altitude area to regulated deficit irrigation at different growth stages (seedling stage, vegetative growth stage, flowering stage, and root weight gain stage) by observing indicators such as plant growth, soil nutrients, and morbidity. Conventional irrigation (70%-80% FC) was applied at the seedling stage and the root weight gain stage. Three regulated deficit irrigation levels (50%-60% FC, 40%-50% FC, and 30%-40% FC) were applied during the vegetative growth period, and three regulated deficit irrigation levels (70%-80% FC, 50%-60% FC, and 40%-50% FC) were used in the flowering period. Conventional irrigation was also applied throughout the growth stage as a control (CK). The results showed that the content of available phosphorus, available potassium, and nitrate-nitrogen in the soil was the lowest under the T4 treatment, and the cutting+main root length, rib length, root surface area, root volume, and main root diameter all reached their maximum values under this treatment. Under the T4 treatment, the total saponin content and total dry weight were the highest, the irrigation water use efficiency was the highest, and the P. notoginseng morbidity rate was the lowest. Morbidity was reduced by 53.42 percent in individuals who received the CK therapy, whereas total saponin content increased by 8.65 percent. The T4 therapy had the highest score of all the treatments in principal component analysis. As a result, planting P. notoginseng under the T4 treatment can effectively reduce irrigation water usage, enhance production and quality, and minimize the incidence of sickness in P. notoginseng.