Cultivation of Panax notoginseng

Panax notoginseng, which originated in Tertiary, is a paleotropical relic plant, and its distribution is extremely narrow, which is mainly related to the physiological and ecological adaptability of Panax notoginseng to the environment.

Panax notoginseng is a perennial perennial herb with a growth cycle every year. In general, Panax notoginseng for more than two years has two growth peaks in one growth cycle, the vegetative growth peak from April to June and the reproductive peak from August to October. The germination temperature of Panax notoginseng seeds is 10 Mel 30 degrees, the optimum temperature is 20 degrees, and the dormancy period of seeds is 45d-60d. During dormancy, the seedlings need a period of low temperature treatment to germinate, and they are very sensitive to light. Traditionally, it is believed that 30% natural light is needed for normal growth and development, so the shade shed of Panax notoginseng has the saying that "30% transparent light, 70% shade" According to the latest research, the most suitable transmittance of Panax notoginseng shed is 8% color 12%, and the growth of more than 17% Panax notoginseng will be adversely affected!

It takes more than 3 years for Panax notoginseng to be sown and harvested; the roots of annual Panax notoginseng are usually used as seedlings, which can blossom and bear fruit from the second year, usually bud in July, blossom in August, bear fruit in September, and mature in batches from October to November.

The main producing area of Panax notoginseng in Yunnan Province is located in the low latitude plateau. The climate is characterized by long summer and warm winter, abundant heat and small annual temperature difference. The annual average temperature is 15.8-19.3 ℃ (reference Room of Yunnan Meteorological Bureau, 1982). Except for the daily temperature and low temperature from mid-December to mid-February of the following year, the average daily temperature is 0.0 ℃, and the average minimum temperature for many years is 0-2 ℃. Over the years, the daily mean temperature stable ≥ 10 ℃ days is 265-307 days, and the annual effective accumulated temperature is 4863.7-6436.8 ℃. Due to the concentrated rainfall in summer, the solar radiation decreased obviously, and the average temperature from June to August was 21. 5-22. 5 ℃. The suitable temperature and moisture conditions provided a favorable natural environment for the growth and development of Panax notoginseng. The monthly average temperature in winter is 11 ℃, and the growth of aboveground parts has stopped, but at this time the 5cm ground temperature still maintains 14 ℃ (regional average), which is the reason why the stems and leaves of Panax notoginseng can still keep alive in winter. The higher ground temperature is beneficial to the accumulation of root nutrients, especially to the morphological development of seed embryo after ripening of sown seeds, and the post-ripening period of seed embryo can be completed naturally through the winter stage, which is beneficial to the seedling raising of Panax notoginseng. It provides extremely favorable conditions to improve the emergence rate of seeds. Such a unique natural ecological environment is a favorable factor for the development of Panax notoginseng production in Wenshan Prefecture.

The topography of Panax notoginseng producing area is complex and undulating, resulting in a significant vertical difference in air temperature. Winter and spring (December to April) and late summer and early autumn (August to October) are affected by the invasion of cold air in the atmospheric circulation, resulting in short-term and local frost and low temperature disasters, especially low temperature chilling injury. Although there is no snow and frost, the temperature does not fall to 0 ℃. However, the sudden drop in temperature below the critical value of crop growth causes greater harm, which can happen almost every few years. In the producing area below 500m above sea level in Funing County, the temperature is higher in summer, coupled with the effect of incineration and local circulation, the temperature tends to increase, and the daily maximum temperature of ≥ 35 ℃ may occur, and evaporation is strengthened, which is likely to cause plant wilting. In the event of the above two situations, proper measures must be taken to minimize losses.

Through the cultivation practice, it is known that during the growth process of Panax notoginseng, it is appropriate to accept diffuse light and avoid the direct exposure of strong sunlight.

Panax notoginseng is a typical shade plant, which is consistent with the tissue structure of Panax notoginseng itself. For Panax notoginseng with rich production experience, the suitable light conditions for the growth and development period of Panax notoginseng are roughly 30% and 70% shade, which are different according to the age of Panax notoginseng and the demand of light transmission in different growth stages. According to the climatic conditions and growth period characteristics of the year, the light transmittance in the garden was adjusted by adjusting the density of the shade on the canopy. For example, in early May, when all kinds of Panax notoginseng seedlings are in the early growth stage, the annual precipitation is less, the solar radiation is strong, and the sunshine hours are long. In order to maintain the normal growth of Panax notoginseng seedlings at this stage, the shade degree should be increased appropriately, and the transmittance in the shed is about 25-30%. After entering the rainy season, due to the increase of cloud cover and atmospheric humidity, the number of sunshine hours is less than that in spring, and the total radiation is also lower, while Panax notoginseng is entering a period of vigorous growth, at this time, it is appropriate to reduce shade, increase the light in the garden, and the transmittance can be increased to 40%. The specific control of the shade degree in the park should be determined according to the local actual situation at that time, and do not copy mechanically.

The climate of Panax notoginseng producing area is the same as that of the whole province, and the dry and wet season is very obvious. The annual precipitation in Wenshan Prefecture is abundant, and the average precipitation is 1163mm in the past 10 years. The southern region is above 1300mm. The growth and development period of Panax notoginseng requires a relatively humid environment, the normal growth of the plant requires to maintain 25-40% soil moisture, and requires the relative humidity in the panax notoginseng garden to reach 70-80%. During the rainy season, more than 80% of the annual precipitation is concentrated in May-October, during which the park can rely on atmospheric precipitation. In some areas, soil infiltration is large, as long as there is no precipitation for a long time, drought may be formed, and artificial irrigation is needed in the garden to maintain a certain amount of humidity. The artificial regulation of moisture is mainly in winter and spring, when the weather is sunny, the sunshine is sufficient, the precipitation is scarce and the wind speed is large, the evaporation power is strong, and the soil moisture decreases rapidly. at this time, in addition to artificial irrigation, we must also pay attention to proper field management. use to cover the grass and adjust the ceiling in the garden to maintain the humidity in the garden. At the same time, we must also pay attention to the different growth and development stages of Panax notoginseng seedlings, special requirements for water, such as sowing to seedling leaf expansion stage, seed emergence stage and green fruit to red fruit stage and so on. Drought must be watered in case of drought to prevent physiological drought and directly affect the harvest of red seeds.

The annual precipitation varies in different places, which must be based on the specific local conditions. At the same time, when selecting and building Panax notoginseng gardens, water conditions should be taken into account as an important issue. In years or areas with more annual precipitation, flood control and drainage should be achieved after heavy rain or torrential rain, and the stagnant water in the garden should be eliminated in time, the soil water content is too much and the ventilation is poor. If the garden is in a state of water for a long time, it will directly endanger the survival of plants and may cause Panax notoginseng to be killed by roots. When the relative humidity in the park is too high, it is easy to cause the outbreak of various diseases, which can not be ignored in the daily management. Is the basis for the survival of Panax notoginseng, plants through the soil to obtain the necessary water, nutrients, air and heat, soil structure, fertility and permeability directly affect the growth and development of Panax notoginseng. The cultivation of Panax notoginseng in Wenshan Prefecture has spread to 8 counties in Wenshan Prefecture, and there is a significant difference in altitude in the producing areas. There are all Panax notoginseng planting areas from 340 m to 1800 m above sea level. The spatial differences in heat, water and soil formed by complex landforms are prominent, which directly affect the water and heat conditions in local areas. Coupled with the diversity of soil parent rock types, the natural differences in soil texture and soil fertility are relatively large.

Panax notoginseng can almost grow in acidic red soil and yellow soil with heavy viscosity, poor permeability and pH 4.5-5.6, and it can also grow in black sandy soil with near neutral pH value, which is completely the result of man-made production activities for a long time. Through ploughing, fertilization, irrigation, rotation and other production methods, the soil structure and soil fertility have been improved to a certain extent, which is also the reason for the difference in the growth and yield of Panax notoginseng between new and old producing areas. Therefore, in the development of Panax notoginseng production, the use of soil should be both important and important, and rational fertilization should be carried out according to the characteristics of soil quality and fertility in this area. Through correct farming methods, we can coordinate the conditions of water, fertilizer, gas and heat in soil, create suitable living conditions for microorganisms, accelerate the mineralization of organic matter, promote the increase of nutrients, gradually improve soil structure, improve soil fertility and prevent soil deterioration. Especially in the mountainous areas where irrigation is difficult, by strengthening field management, adjusting nutrient status, and gradually improving soil fertility, the soil will develop in the direction of favorable human activities.