Features

Panax pseudoginseng is a remnant ancient tropical species originated from the Tertiary Period. It is narrowly distributed mostly due to its physiological and ecological adaptability to the environment.

As a perennial herb, panax pseudoginseng has one growth circle per year. In general, 2 years or older panax pseudoginseng has two growth peaks in a single growth circle, namely the vegetative growth peak in April – June, and generative growth peak in August – October. Panax pseudoginseng seeds sprout at 10 – 30 ℃, preferably 20℃. The dormant period of seeds is 45 days ~ 60 days. The seeds need to go through low temperature processing in dormant process so that the sprouting is induced. The seeds are very sensitive to light. Traditionally, the seeds grow and develop normally at 30% of natural illumination. That's why panax pseudoginseng shelves are built according to the theory of “30% transmittance and 70% shading”. The latest research findings show that the best transmittance of panax pseudoginseng shelves is 8% - 12%. Once the transmittance exceeds 17%, growth of panax pseudoginseng will be affected.
It takes three years from sowing to harvesting of a single crop of panax pseudoginseng. The annual panax pseudoginseng roots are mostly used as seedlings, which start to bloom and bear fruits in Year 2 when planted. Generally, the buds come out in July, bloom in August, and bear fruits in September. The crop tends to become ripe in October to November successively.

The main production areas of panax pseudoginseng inYunnanare distributed on low-latitude plateau. The local climate is characteristic of long summer time and warm winter, with rich heat, and small variation of annual temperature. The local mean annual temperature is 15.8 - 19.3℃ (1982 data. Source: Data Room, theYunnanProvincial Meteorological Service). Except for the period from mid-December to mid-February next year when the minimal daily temperature might be ≥0.0℃, the mean annual minimal temperature is 0-2℃. The mean annual average number of days with daily temperature ≥10℃ is 265-307 days. The annual effective accumulated temperature is as high as 4863.7-6436.8℃. In summers, as the rainfall is concentrated and sun radiation drops dramatically, the average temperature from June to August is 21.5-22.5℃. The ideal temperature and water conditions provide an ideal natural environment for growth of panax pseudoginseng. In winters when the average monthly temperature is 11℃, the portion above the ground ceases to grow. But the temperature 5 cm below the ground still stays at 14℃ (regional average value). That explains the reason why the panax pseudoginseng stems and leaves still remain vital in winter. The warm ground temperature is good for accumulation of nourishment at the roots, especially good for morphological development of embryos of sown seeds. The embryos can go through the latter stage of ripening in winters. It provides favorable conditions for better panax pseudoginseng seedling. Such unique natural ecological environment is a favorable factor for panax pseudoginseng production in Wenshan.

The production areas of panax pseudoginseng are characteristic of complex land form and big relief, which is the reason behind sharp temperature difference vertically. In the periods from winter to spring (December to  April next year) and late summer to early autumn (August-October), due to invasion of cold air brought by atmospheric circulation, short-period frost and low temperature disaster might occur in local areas, especially low temperature disaster. There is no snowfall and widespread frost, and the temperature won't fall to the frost degree (0℃ or lower), but the fact that the temperature drops dramatically to below critical value for crop growth (Zhou Yiren et al, 1980) will cause major effect. Such occurrence is reported at the intervals of a couple of years. In theFuningCountywhere the elevation is lower than 500m, the temperature is high in summer. Plus the effect of foehn and cellular circulation in local areas, the temperature is inclined to rise. The maximum daily temperature might hit 35℃ or higher, and evaporation is high. That is very likely to cause wilting plants. Actions must be taken to minimize losses that might be caused by occurrence mentioned above.

Through the planting practice, it is understood that panax pseudoginseng prefers diffused light and hates exposure to direct sunlight. That means panax pseudoginseng is a typical shade plant. Such ecological habit is consistent with panax pseudoginseng's own tissue structure. Experienced panax pseudoginseng farmers arrange the light condition for the development period with roughly 30% light transmittance and 70% shading. In practice, the need of light transmittance in different growth stages varies with the plant age. According to the climate status and traits of the growing periods, through adjusting the density of shading items over the sun shades (Ji Dagan et al, 1970), the transmittance can be adjusted. For example, in early May, when young panax pseudoginseng is in its early growing period, the precipitation is small, sun radiation is strong, and the sunshine duration is long. To maintain normal growth of the young panax pseudoginseng, the shading should be enhanced as appropriate. The transmittance under sun shade should be approx. 25-30%. When it's in the rainy season, due to excessive clouds, high relative humidity, and less sunshine duration compared to the spring season, the total radiation is also low. It is just the vigorous growth period of panax pseudoginseng. In this period, the shading should be reduced accordingly to increase sunlight under the sun shade by increasing the transmittance to 40%. In practice, the exact applicable transmittance depends on the exact condition.

The climate in the planting areas of panax pseudoginseng is the same with that in the rest of the province, with distinct difference between dry and wet seasons. The Wenshan prefecture has plenty of precipitation a year. In the past 10 years, the mean annual precipitation is 1163 mm (more than 1300 mm in the south part). Panax pseudoginseng in the growth & development periods demands moist environment. To ensure normal growth of the plant seedlings, soil moisture of 25-40% and ambient RH of 70-80% is essential. In the rainy seasons, 80% of annual precipitation is concentrated in May to October, the natural precipitation may be made full use of. In some areas with high soil percolate, whenever the non-precipitation streak lasts long, drought is inclined to be formed, and artificial shower has to be carried out to make sure that substantial relative humidity is maintained. Artificial moisture regulation is mainly needed in winters and springs, when fine days with plentiful sunshine, few precipitation and strong wind dominate. As the evaporation is high, the soil moisture decreases sharply. In this period, in addition to artificial shower, appropriate field management should be exercised. By providing covering grass and adjusting the sun shade, the relative humidity can be maintained. In the meantime, young panax pseudoginseng in different growth & development stages has different requirement of moisture, such as the period from sowing to seedling leaf expansion, seeding stage of branches, and the period when fruits turn from green to red. When drought occurs, water must be spread to prevent physiological drought, or else it may affect harvest of the red seeds. As the annual precipitation may vary with the areas, the local water source condition must be taken into consideration as an important factor when panax pseudoginseng gardens are designed and constructed. In years or areas with plentiful annual precipitation, flood should be warded off and drained immediately when downpour occurs, so that no water is accumulated in the gardens. High soil moisture will cause poor ventilation. Long drowning will impose direct risk to survival of the plant. In other words, it may cause death of panax pseudoginseng due to drowned and rotten roots. When the relative humidity is excessive, it is likely to cause outbreak of various plagues. This is a nonnegligible issue in day-to-day management. It is basis for survival of panax pseudoginseng. The plant obtains the essential moisture, nutrients, air and heat via soil, and the soil structure, fertility and permeability has direct link to growth and development of panax pseudoginseng. Panax pseudoginseng is planted in 8 counties across the Wenshan prefecture. The elevation varies dramatically with the production areas, ranging from 340 – 1800 m above sea level. The complex land forms distinct space difference in the heat, water and soil conditions, which has direct link to the water and heat condition in some local areas. Plus a good variety of soilforming rocks distributed, soil texture and fertility also vary greatly. As far as the writer understands, panax pseudoginseng can grow in soil with high cohesion, poor permeability, and pH value ranging from 4.5 to 5.6 acidic red soil and yellow soil, and in black sandy loam with nearly neutral pH value. This is completely a result of human production activities for many years. Through plough, fertilizer application, shower, and rotation production, soil structure and fertility has been improved to some degree. This is the reason blamed for difference of the way in which panax pseudoginseng grows and the production between new and old production areas. Clearly, soil utilization plays the equal part with nutriment in production of panax pseudoginseng. According to the traits of the local soil quality and fertility, fertilizer may be applied properly. Through proper expedient of tillage, and balancing the soil moisture, fertility, air and heat status, ideal living condition for microorganism may be created to accelerate mineralization of organic substances, promote nutrient increase, gradually improve the soil structure and fertility, and prevent soil deterioration. What's notable, in mountain areas where it is difficult to implement shower, field management should be strengthened to adjust the nutrient status and gradually improve the soil fertility, so that the soil develops in a direction instrumental to human activities.