I. Morphological characteristics
The plant height is about 60cm. Taproot hypertrophy, multi-branched, fleshy; The rhizome is short and erect, with one node growing every year, commonly known as "reed head". Its shape is horse tooth (horse tooth reed), bamboo node (bamboo node reed) or cylindrical (round reed), with terminal overwintering buds and lateral adventitious roots. The taproot is stout, fleshy, cylindrical, oblique, with branches at the lower part and yellowish skin; The fibrous roots are long and have many warts. The stems are erect, simple and unbranched. Palmately compound leaves, whorled stem tips, with long stalks; There is one trifoliate compound leaf in one year, one trifoliate compound leaf in two years, two trifoliate compound leaves in three years, and one compound leaf will be added every year, up to 6 compound leaves. Leaflets are smaller in a pair on both sides, larger in the middle, oval, oblong or slightly obovate, 4-15 cm long and 2-6.5 cm wide, with a tapered tip, a wedge-shaped downward extension at the base, serrate edges, green or yellowish green on the top, sparse bristles on the veins and smooth on the bottom. Umbellies are solitary and terminal, and the total pedicel length can reach 30cm；. Flowers are small and numerous; Calyx 5-lobed; Petals 5, yellowish green; Stamens 5; Pistil 1, ovary inferior, 2-loculed, upper part of style 2-lobed; The disk is annular. The fruit is berry-shaped, flat kidney-shaped, bright red when ripe, and a few are yellow or orange. Contains 2 seeds. Seeds kidney-shaped, yellowish white or grayish white. The chromosome number is n=24, and the karyotype formula is 2n=22M+22SM+4ST (figure 14— 1).
Fig.14 ——1ginseng morphology diagram
1. Plant 2. Root
Second, biological characteristics
(a) the growth period and the whole growth period
The growth period of ginseng can be divided into seedling stage, leaf unfolding stage, flowering stage, fruiting stage and withering stage. One-and two-year-old ginseng has no flowering period and fruiting period. The early or late growth period of ginseng is closely related to its length, geographical location, climate change and cultivation conditions. The main producing area of ginseng in northeast China is located in the middle temperate zone, and the seedling stage is usually in the first and middle of May. The leaf exhibition period is in late May and early June; The flowering period is in the first and middle of June; The fruiting period is in the middle and late July; The withering period is in late September and early October of 10. The whole growth period is generally130-150 days, ranging from100-10 days to more than 180 days. The higher the latitude in the middle temperate zone to the north, the shorter the whole growth period and the corresponding delay of seedling emergence; The lower the mid-temperate zone to the south latitude, the longer the whole growth period and the earlier the seedling stage. At the same latitude, with the increase of altitude, the whole growth period is shortened and the emergence stage is delayed accordingly.
(2) Growth and development
1. Underground organs
(1) root
After autumn sowing or spring sowing, the mature seeds send out radicles and extend into the soil in the middle and late April to form young taproots, and then young branch roots grow on the young taproots. The young taproot and young branch root are mainly water-bearing and translucent, and then gradually cork. May-June is the main root elongation period, and then the main root growth period is vigorous. The root length can reach 5cm, and 20-30 young branch roots grow. In early June, the upper part of young taproots gradually became cork, and in early July, white taproots were formed. In early August, young branch roots began to be corked, most of which lost water and fell off, and a few became white branch roots. When the main and branch roots are corked, some of the root hairs of the fibrous roots are renewed with the epidermis falling off.
From the second year, the main and branch roots become thicker and the fibrous roots are developed, forming the basic root system. Since then, with the growth of the year, the root system of ginseng has developed, elongated, thickened and gained weight year by year, forming a balanced and complete root system with main branches and fibrous roots. Six-year-old ginseng roots, the main root length can reach more than 6cm, and the diameter can reach more than 2cm. Generally, there are 2-3 branch roots and dozens of fibrous roots, and the total length of the root can reach about 35cm. Generally, the average fresh weight of a single root is about 50-80g, and some of them are over 300g. According to the measurement, the annual growth of four to six-year-old ginseng roots generally increases with the annual growth (table14-1).
Table14 ——1Annual growth of two to six-year-old ginseng roots
According to the research, the growth process of perennial ginseng shows an S-shaped curve change in a year (Figure14-2). After the emergence of ginseng, the aboveground organs began to grow, mainly consuming the nutrients stored in the roots, and the weight of the roots gradually decreased, and the weight of the roots decreased to the lowest value from 20 to 25 days after the emergence of ginseng. At this stage, special attention should be paid to raising the temperature of the soil in the border, avoiding excessive soil moisture, promoting seedling emergence and preventing root rot. Ginseng entered the flowering stage, and both the aboveground and underground parts entered the vigorous growth stage at the same time, and the weight gain of ginseng roots increased linearly, reaching the highest value at126-130 days after emergence, that is, before ginseng withered. In this period, special attention should be paid to light adjustment, water supply and fertilization, and field management should be strengthened to meet the needs of ginseng growth for light, water and fertilizer. After the aerial part of ginseng withered, the root of ginseng no longer gained weight, but gradually lost weight due to respiratory consumption.
Fig.14-2 growth curve of four to six-year-old ginseng roots
(Ding Xiquan et al., 1985)
The growth rate of ginseng roots is different in each period during the growth of a year. According to the measurement, the growth rate of four to six-year-old ginseng roots showed a single-peak curve, and the peak appeared in the period of 2-2.5 months after emergence (Figure14-3), while the growth rate of ginseng roots was basically close to the maximum growth rate within 40 days before and after the peak. In this period, we should try our best to take effective cultivation and management measures to ensure the healthy growth of ginseng and improve photosynthetic efficiency.
Fig.14-3 growth rate curve of four to six-year-old ginseng roots
(Ding Xiquan et al., 1985)
The roots of ginseng belong to the downward contraction type, or contraction root. The main root contracts every year, and the rhizome is pulled down as long as the rhizome 1 is old, so that the overwintering buds at the end of the rhizome are often hidden in the soil.
Therefore, the life form of ginseng belongs to underground bud plants. Because the taproot has the characteristics of downward shrinkage, annular transverse stripes are produced on the taproot, which increase with the age. The shrinkage starts from the upper part of the taproot, increases with the age, and gradually extends to the middle and lower parts of the taproot. Therefore, the older the ginseng grows, the finer and deeper the lines are, and most of them are spiral lines.
(2) Rootstock
Or underground stem, inserted at the end of the taproot, is the hub connecting the taproot with the upper organs of the ground. There are overwintering buds on the rhizome, and the aboveground branches are drawn out every spring, and withered in autumn, leaving stem marks. The number of stem scars is an important basis for judging the growth age of ginseng. There is a latent bud protrusion on the outer edge of each stem scar. When the main root system is unfavorable or susceptible to diseases, the rhizome can generally grow1-5 adventitious roots, which plays the role of absorbing and storing nutrients by the main root system. The size and shape of rhizome are closely related to ginseng age, penetration and direction of taproot, growth environment and cultivation conditions. Rhizomes are often owned by perennial plants; The formation of rhizome is an adaptation to overwintering and other adverse environments. Rootstock is not only an organ for vegetative reproduction and renewal of ginseng, but also a place for storing nutrients.
(3) overwintering buds
Except for the annual seedlings sprouted from seeds, ginseng plants (aboveground branches) that are more than two years old are all formed by the growth and development of overwintering buds. The overwintering bud attached to the end of rhizome is covered with three white bud scales. There is a fully differentiated bud primordia in the axil of bud scales. When the temperature is suitable in spring, the overwintering buds begin to germinate, and complete overground branches can grow in about 8-10 days. In the axils of scales, there is a small conical protrusion at the base of both sides of the differentiated main bud. One is the original body of overwintering bud (larger, close to the stem scar). After the overground branches are extracted in spring, they begin to differentiate from June, and then increase to the middle and late July, forming overwintering buds before winter, and extracting overground branches in the following spring. The other is the primordial body of dormant buds, which is composed of a small group of meristems and rarely differentiates, and is located opposite to the former. When the overwintering bud is extracted from the aboveground branch in spring, it is located at the base of its stem; When the aboveground branch withers in autumn, it stays at the edge of the stem mark and is dormant. This dormant bud primitive remains one stem scar every year. If the overwintering buds are damaged for some reason in winter and spring, they will not germinate and grow overground branches in this year, and then new overwintering buds will be formed from the original overwintering buds, and overground branches will grow in the third year after overwintering. If not only the overwintering buds are harmed, but also the overwintering bud primordia, the dormant bud primordia are differentiated to form overwintering buds. If the whole overwintering bud is damaged (including the overwintering bud and the dormant bud primordia), it will develop into several new overwintering buds from the stem scar dormant bud primordia in the last year or more than two years, and correspondingly1-3 or more overground branches will be taken out in the next spring. This principle is used to promote the formation of multi-stem ginseng by artificial bud.
The development of overwintering bud primordia into normal overwintering buds, that is, overwintering buds that can germinate at suitable temperatures, must go through the following two stages.
The first stage is high temperature or morphological post-ripening stage, the temperature is18-20℃, and the time is about 4-5 months, which is slightly consistent with the natural conditions in summer. At this stage, the overwintering bud primordia developed into overwintering buds with stems, leaves and inflorescence rudiments.
The second stage is the low temperature stage or physiological post-ripening stage, which requires a temperature of 2-3℃ and a time of 4 months. After differentiation and molding, the overwintering buds must go through the low-temperature post-ripening stage before they can germinate and emerge.
The application of 100ppm gibberellin solution soaking 12 hours for overwintering buds without low temperature stage can replace low temperature, promote after-ripening and early emergence. Generally, it takes about 20-30 days to emerge after treatment.
2. The above-ground organs (
1) The stem is the main vegetative organ that plays the role of transporting and supporting the aerial parts of ginseng. The stems of ginseng are extracted every spring and die off in autumn. Annual stems (actually petioles) are issued by seeds; From the beginning of two years, it is all emitted by overwintering buds. Ginseng is generally single-stem, with few two, three or four stems. It is generally believed that the number of stems is related to heredity, climate, soil quality, year, cultivation area and conditions; In areas with a lot of precipitation, it is easy to produce many stems. The method of artificial sprouting can promote the formation of multiple stems. The stem of ginseng grows and thickens with the increase of age.
(2) Leaves
It is an important vegetative organ for photosynthesis, gas exchange and transpiration of ginseng. With the increase of age, the number of leaves increases and the leaf area increases. However, in the same year, different plants or different cultivation areas, the degree of leaf development is different. Generally, the annual leaf area is10-30cm 2; Generally, it can reach about 1500cm2 for five or six-year-old students. Growth is slower and smaller than that of ordinary crops.
Ginseng is a negative plant, which is not resistant to strong light. If the light is too strong, it will show obvious adaptation and growth inhibition in growth characteristics such as leaf state, leaf size and leaf color. When the light intensity reaches 60klx or 50klx and lasts for a long time, the leaves are erect (that is, the angle of leaf extension becomes smaller), the leaves are curled (the two halves of the leaves are rolled along the midvein), and the whole plant is inclined to the light (the direction and angle of inclination are slightly consistent with the sun's orientation under the maximum direct illumination), and the leaves are pale. In this way, it can avoid absorbing too much solar energy, so as to reduce leaf transpiration or prevent leaf temperature from rising sharply and avoid being harmed. If the strong light irradiation time is too long, when the leaf temperature reaches 30-33℃, the leaves will burn (commonly known as sun burning) and wither and fall off. Therefore, ginseng must be cultivated in shade shed. The growth inhibition is characterized by shorter stem height and smaller leaves (Table14-2).
Table14-2 Effects of Different Light Conditions on Growth Characteristics and Chlorophyll Content of Ginseng Plants
With the increase of light intensity, the leaves change from dark green or green to light green or yellow-green, and the chlorophyll content in the leaves is obviously reduced to reduce the absorption of light and avoid overheating and burning (Table14-2).
When ginseng emerges in spring, the leaves are small and shriveled, then gradually expand, and the leaf area expands rapidly within one month (from early June to early July) after the leaves are unfolded, and then rarely expand; The number of blades is fixed and will not increase.
(3) flowers
It is an important reproductive organ of ginseng. The flower buds of ginseng are formed during the differentiation of overwintering buds. Generally, flowers bloom every three years, and there are few biennial flowers. The florets of umbels increase with the age, from more than ten to dozens.
When ginseng blooms, the outer edge of the inflorescence opens first and then opens to the center one after another. The flowering days of each inflorescence range from 5 days to 15 days, usually 8-10 days. The time for each flower to bloom is 23-48 hours in sunny days; It takes 30-60 hours in rainy days. In one day, the flowering frequency is the highest at 7-13. Weather conditions have a great influence on flowering. There are many flowers in sunny days at high temperature; There are few flowers at low temperature in rainy days. Generally, when the temperature is17-20℃ and the relative humidity is 40-45%, the flowers bloom the most.
Ginseng belongs to cross-pollinated plants. On the one hand, cross-pollination is beneficial to prevent variety degradation, but on the other hand, in the breeding and breeding of improved varieties, effective measures should be taken to prevent cross-pollination so as not to affect the purity of varieties.
(4) Fruit
When ginseng fruit matures, the inner layer of ovary wall lignifies to form a hard endocarp; The outer layer of the ovary wall becomes fleshy red flesh. Each fruit contains two seeds. Five-year-old ginseng can harvest 4-5g fruit per plant; The seed rate (dry weight) of fruit is about 20-25%.
(5) seeds
Ginseng seeds belong to the type of incomplete embryonic structure development. The embryo of newly harvested seeds is very small, consisting of only a few embryonic cells, with a length of about 0.3-0.4 mm, a width of about 0.25mm and an embryo area of about 0.075mm2；. The endosperm is about 5-6 mm long and 4mm wide, and its area is 266 times that of embryo. Embryo is lock-shaped or half-moon-shaped, located in endosperm cavity. Therefore, ginseng seeds must go through post-ripening process before they can germinate and emerge. The post-ripening process can be divided into two stages: morphological post-ripening and physiological post-ripening. In the morphological post-ripening stage of the embryo, the primordial cells gradually differentiate and increase under appropriate conditions of water, temperature and oxygen. When the embryo is1.0-1.3 mm long, the seeds begin to crack, and when the embryo is 3.0-4.5 mm long, it differentiates into an embryo with cotyledon, embryo, hypocotyl and radicle, and the morphological post-ripening stage is basically completed (.
Figure14-4 ginseng seed profile
1. Newly harvested ginseng seeds 2. Matured ginseng seeds after morphological completion.
After the morphological post-ripening of ginseng seeds, they do not germinate even under suitable germination conditions, and must pass through the physiological post-ripening period at low temperature. At this stage, there is no morphological change, only the embryo body increases.
The morphological post-ripening stage of ginseng seed embryo needs a temperature change of18-12℃ for 3-4 months; The physiological post-ripening period needs a low temperature of 2-4℃ for 2-3 months. The post-ripening process of seeds is strictly sequential, and if it is not completed in the early stage, it cannot be carried out in the later stage; Seeds that are not fully ripened cannot germinate. After ripening, when the embryo is generally 5.0-5.5 mm long or the embryo rate (embryo length/endosperm length × 100) reaches 100%, the seeds will germinate and emerge at a suitable temperature.
During the post-ripening process of ginseng seeds, a series of physiological and biochemical changes occurred in the seeds. At the early stage of embryo morphological post-ripening, the activities of glycolytic enzyme, protein hydrolase and peroxidase were low, and gradually increased with the growth of embryo. When the embryo enters the physiological post-ripening stage, the activities of various enzymes are significantly improved, and cytochrome oxidase appears in endosperm and embryo, which is concentrated in the root tip.
The application of growth regulators can promote the post-ripening of ginseng seed embryos and break dormancy. According to Zhu Guixiang, soaking ginseng seeds with 40ppm gibberellin for 36 hours before germination treatment can shorten the germination time by at least 30-40 days. According to the research, soaking seeds for 24 hours with gibberellin 50ppm or 100ppm or 12 hours, soaking seeds for 96 hours with kinetin 50ppm or 75ppm, soaking seeds for 24 hours with 100ppm and 200ppm can replace low temperature, promote the physiological post-ripening of embryos, and shorten the time by half.
(3) Photosynthetic characteristics
Ginseng belongs to C3 plant. The results showed that the δ 13C of ginseng was-26.80; PEPCase activity was14.33μ/mgport mim; The CO2 compensation point is 80-102ppm; The maximum photosynthetic rate is10.81/mgco2/dm2 h; There is no typical morphological and anatomical feature of C4 plant leaves. The diurnal variation of photosynthesis shows that the photosynthetic rate of ginseng is the highest from 9: 00 am to 9: 00 pm 15 in a day. The annual variation of photosynthesis, the average daily photosynthetic rate of ginseng in flowering period and green fruit period is the highest in a year. The annual total photosynthetic rate (PT), annual economic photosynthetic rate (PE) and PE/PT(%) of four-year-old and five-year-old ginseng were the highest. There is no obvious correlation between the leaf area of ginseng and the annual growth of ginseng roots, so ginseng should be planted in reasonable density and make full use of light energy.
(4) Requirements for environmental conditions
1. light
Ginseng is a negative plant and has strict requirements on light. The intensity of light directly affects the development, yield and quality of ginseng. The light compensation point of ginseng is about 400lx, from 400lx to 10klx, and the photosynthetic rate of ginseng increases linearly from 10klx to 33klx, and the photosynthetic rate of ginseng increases slowly (Figure14-5).
Figure14-5 Photosynthetic Intensity of Ginseng under Different Light Intensity
(Wang Tiesheng, 1983)
The optimum light intensity of ginseng growth generally increases with the increase of latitude. 7—10 klx in low latitude; At high latitudes, it is10-22klx. Under the same latitude or geographical and ecological conditions, different annual and growing seasons require different optimum light intensity.
2. Temperature
Ginseng is a temperate plant. It likes temperate or cool climate, and can be cultivated under the climatic conditions of annual average temperature of 2.4-13.9℃, accumulated temperature of ≥ 10℃ of1800-3800℃ and annual rainfall of 500—2000mm. In the subtropical mountainous area with low latitude and high altitude, the medicinal materials field of Tongle Brigade in Ziyuan County, Guangxi Province (26 3 ′ north latitude, 0//kloc-0 east longitude/0 38 ′ altitude 1450m, The annual average temperature 13. 1℃, the Jiuxianshan participation field in Daiyun Mountain, Dehua County, Fujian Province (25 43 ′ N1/8 06 ′ altitude 1650m, the annual average temperature1.
The optimum temperature for ginseng seed germination is12-15℃; The lowest temperature is 4-6℃; The maximum temperature is 30℃. Different growth stages of ginseng require different temperatures (Table14-3). When ginseng comes out of seedling stage, the temperature is high and rises quickly, which is beneficial to seedling emergence. The temperature is low and the duration of leaf exhibition is long. When the temperature is lower than 15℃, it seldom blooms, but when it exceeds 25℃, the flowering rate decreases.
Table14-3 Requirements for Temperature in Different Growth Stages of Ginseng
When the temperature is too high or too low during the growth period, it will have adverse effects on the growth and photosynthetic function organs of ginseng. Summer is hot and dry, and stems and leaves are prone to sunburn or wilting and dying. Ginseng has certain resistance to light cream (temperature -3℃); Severe frost with a temperature below -5℃ will be damaged by freezing. During the hibernation period of ginseng, due to improper cold protection and sudden change of soil temperature, the overwintering buds will be frozen, commonly known as slow yang freezing. Before and after freezing injury, overwintering buds are affected by drought, wet injury, bacterial infection, mechanical injury and soil suffocation, which will promote freezing injury or aggravate freezing injury. Therefore, the occurrence of freezing injury can be avoided or alleviated by doing a good job in wintering and wintering management and taking other effective measures such as drought prevention, drainage, wind prevention, soil disinfection and planting high-quality ginseng seedlings.
Step 3: Moisture
Water is one of the basic conditions for ginseng to live, and it is also an important condition and medium for using other living conditions such as light, heat, nutrients and air. Grasping the physiological and ecological water demand law of ginseng and meeting the balance between supply and demand of water metabolism in its life cycle is a prerequisite for obtaining high yield and high quality of ginseng.
Water is the primary condition for accelerating germination and post-ripening of ginseng seeds. The water absorption of ginseng seeds is 30-50% of the seed weight, so it should be fully absorbed before germination. The humidity of sand reservoir in the post-ripening stage of seeds is10-24%. Insufficient water absorption of seeds affects the process of accelerating germination; Excessive moisture affects seed respiration, resulting in rotten seeds.
The water demand of ginseng varies in different growth stages and years. At the stage of seedling emergence and leaf development, the temperature is low, the transpiration intensity of leaf surface is weak, and the water demand is not much; After leaf spreading, the temperature rises, the leaf area increases rapidly, the root system continues to elongate (June-July) and thicken (July-September), and the physiological and ecological water demand increases. Different soil moisture during the growth period has certain influence on the growth status of ginseng plants. When the suitable water ratio is under the condition of insufficient water (below 60%) or excessive humidity (100%), it is beneficial to leaf growth, leaf area increase and leaf width widen.
The soil moisture during the growth period has an important influence on the accumulation of dry matter of ginseng. The relative water content of soil is above 80%, which is beneficial to the growth and weight gain of ginseng roots, so that the dry matter accumulation is fast, the biological yield is high and the economic coefficient is large; When the relative soil water content reaches 100% or 60-80%, it also has adverse effects on the dry matter accumulation of ginseng. The relative water content of soil is 40-60%, which will seriously affect the weight gain and even reduce the yield of ginseng roots. It shows that ginseng is a kind of plant that is afraid of drying. The relative water content of soil in the whole growth period is 80%, and the highest photosynthetic rate of ginseng is 4.3 Co2mg/dm2 h, so it is beneficial to dry matter accumulation.
In a word, ginseng is a mesogenic negative plant, which is neither drought-tolerant nor waterlogging-tolerant. Under the condition of soil relative water content of 80% in the whole growth period, ginseng grows healthily, with high photosynthetic rate and fast weight gain of ginseng roots, thus achieving high yield and good quality; When the soil moisture is insufficient (60%), ginseng roots often show burning whiskers; When the soil moisture is too high (100%), ginseng roots are prone to rot. Therefore, soil moisture disorder is an important reason for ginseng yield reduction. When the soil moisture is too high during dormancy, freezing injury often occurs. With the annual growth of ginseng, the water demand increases and the drought resistance increases. The soil is dry, and the roots of ginseng are stunted, ranging from "burning whiskers" to wilting and death.
According to the measurement, the transpiration intensity of ginseng is 6.25 g/h m2, the transpiration coefficient is 168, and the transpiration efficiency is 6. The total water demand in the whole growth period is 135kg/m2. The water evapotranspiration and water demand modulus coefficient of ginseng at different growth stages are shown in figure14-6 and table14-4. The daily water demand and water demand modulus coefficient of ginseng are important basis for formulating the irrigation system and rational water use of ginseng. The daily water evapotranspiration of ginseng is the largest at seedling stage and flowering stage, so it is very important to meet the physiological and ecological water demand of ginseng at this stage.
Figure14-6 Daily Water Evapotranspiration of Ginseng at Different Growth Stages
(Wang Tiesheng et al., 1987)
Table 14—4 Water demand modulus coefficient of ginseng
4. Mineral nutrition
The leaf area of ginseng is limited, and the average leaf area of a plant growing for 2 years is 0.59dm2；; 4 years growth is 5.48dm2；; Growth for 6 years is13.64 dm2; The photosynthetic rate is low, generally 6-9 CO2 mg/dm2 h.. The growth is slow, and the average annual weight gain of cultivated ginseng is 6-9 g; Wild ginseng is only1-1.5g, and the highest one can reach 3g. Therefore, the demand of ginseng for mineral nutrition is lower than that of ordinary cultivated crops. Compared with carbon, mineral elements account for only a small proportion in ginseng, but they are an important basis for building ginseng body and active physiological functions. According to Yu Derong's report, ginseng plants contain 27 kinds of inorganic elements, among which Ca, K, S, N and Mg have an average content above 1000ppm. The average content >100-1000 ppm are p, Na, Fe and a1; The average content >10—100 ppm are Zn, Ba, Sr and Mn; The average content >1—10ppm are B, Ti, Cu, Cr, As and Sn; The rest <1ppm are Pb, Ni, V, Li, Mo, CO, La and Gd (table14-5). It can be seen that the absorption ratio of ginseng to the three elements is about n ∶ p ∶ k = 2 ∶1∶ 4.4; The absorption of Ca by ginseng is about 1.4 times that of K; The contents of Ca, S, Mg, Fe, Al, Zn, Ba, Mn and B are higher in the aerial parts of ginseng. However, the content of N and P is higher in roots. These can be used as theoretical and technical basis for scientific fertilization of ginseng.
Table14-5 Inorganic Elements in Ginseng Plants (unit: ppm)
[Note] Take the average of 10 strains and repeat twice. Automatic nitrogen determinator for nitrogen.
5.pH
Ginseng likes slightly acidic soil, and pH 4.5-5.8 is the best for ginseng growth, while pH above 6.5 is unfavorable for ginseng growth.
Third, cultivation techniques
(1) Variety
Ginseng cultivation in China has a long history, but so far there are no varieties artificially created by breeding departments through various breeding methods according to scientific methods. Northeast China is the main producing area of ginseng in China. Under the natural and production conditions in the producing area, some so-called farm varieties or local varieties have been formed through long-term manual selection and natural selection, such as "Damaya", "Ermaya", "Long neck" and "Round reed", which are distinguished and named mainly according to the morphological characteristics of roots. In addition, phenotypes of different genotypes can be found in production, such as "pprrhh" and "PPRRHH". According to Lan Jin's report, there are obvious differences in morphological characteristics and total saponin content among four local varieties such as "Damaya" (Table14-6). "Trojan tooth" has fast growth, high yield and high content of total saponins. Second is "Ermaya"; "Long neck" and "round bladder and round reed" have slow growth, low yield and low total saponin content. Some researchers also reported that there was no significant difference in the content of total saponins among the above four varieties. At present, ginseng cultivated in production is a complex mixed line. The investigation by the Institute of Specialty of China Academy of Agricultural Sciences on the state-owned participating fields in six counties in the main producing areas shows that the mixed phenomenon of different varieties of ginseng is quite serious, among which "Damaya" accounts for 44.5% of the total output, "Ermaya" accounts for 40.0%, "Longbo" accounts for 8.8%, "Yuanbang Yuanlu" accounts for 2.7%, and the rest accounts for 4.0%. According to the local ecological conditions and cultivation characteristics, the mixed population can be selected and purified in ginseng producing areas, and local varieties with certain economic value, consistent heredity and suitable for local natural and production conditions can be selected for cultivation. According to Sun Xian's report, huinan county, Jilin Province, selected and purified "Damaya" varieties from seedling fields and cultivated them in a large area, which achieved obvious results in increasing production and income. The yield per unit area of 8500m2 improved seed field 1.55kg/m2 is 0.3kg/m2 higher than that of general field 1.25kg/m2, and the income is more than RMB 0.0000 yuan 10.
Table14-6 Morphological Characteristics of Different Ginseng Varieties
(2) Cultivation system
Ginseng cultivation system or cultivation method can be roughly divided into two types: one is direct seeding method, which does not transplant after sowing, and grows continuously for 4-6 years to harvest, during which the seedlings are thinned1-2 times. This cultivation system saves land for planting ginseng, shading materials and production labor, and the yield, quality and economic benefits of ginseng are not low. In Wangqingmen Township, Xinbin County, Liaoning Province, in 1978, the yield of ginseng in a five-year-old 700m2 direct-seeding field was 2kg, and the isoginseng accounted for 76%, which increased the yield by 70% compared with the transplanted field, increased the income by 20% and reduced the cost by 73%. It is the future development direction. Both Japan and South Korea have applications. American and Canadian American ginseng are cultivated by direct seeding. The second is transplanting method, which is equipped with seedling field and Honda. After sowing, the cultivation period is transplanted 1 time, such as "1, 5 system" (