Planting Methods and Management Techniques for Schisandra chinensis Seedlings

The planting methods for Schisandra chinensis seedlings and the management techniques after planting directly affect the survival rate of the seedlings and the growth condition of the plants, and are also an important foundation for whether early cultivation of Schisandra chinensis can achieve high and stable yields. In recent years, with the continuous expansion of Schisandra chinensis cultivation area, people have summarized some relatively mature experience in the planting of Schisandra chinensis seedlings and post-planting management techniques, which are briefly introduced as follows:

1 Planting and management of finished seedlings

1.1 Planting period

Schisandra chinensis finished seedlings can be planted in autumn or spring. Autumn planting is carried out before the soil freezes; spring planting can be carried out after the soil layer 50cm below the surface has thawed.

1.2 Planting of finished seedlings

1.2.1 Soaking seedlings in water

Seedlings that have been stored over winter or transported from elsewhere often have insufficient water content. To facilitate budding and root development, the whole plant should be soaked in clean water for 12 to 24 hours.

1.2.2 Planting

Before planting, the seedlings should be headed back, leaving 4 to 5 plump buds on the main stem, and the underground horizontal rhizomes should be cut off; diseased and rotten roots should be removed and overly long roots should be shortened.

1.2.2.1 Digging planting holes (trenches) On land that has already been deeply plowed and matured, level each planting row, and dig planting holes according to the marked plant spacing. The planting hole is round, with a diameter of 40cm and a depth of 30cm. If the plant spacing is relatively close, planting trenches can also be dug. When using a trellis cultivation, the planting point should be on the projection line of the trellis. To ensure accurate planting of the plants, a steel tape measure or a pull line with clear markings (the length of the plant spacing) should be used for measurement.

1.2.2.2 Planting method Each planting hole requires 2.5kg of high-quality decomposed organic fertilizer. The fertilizer should first be mixed thoroughly with the surface soil, then half of it should be backfilled into the hole, with the center raised in a steamed bun shape, and treaded firm so that it is about 10cm from the ground level. Place the selected seedling in the center of the hole, spread the root system out in all directions, crush the remaining soil and bury it over the roots, shake gently so that the roots come into close contact with the soil. After filling and firming the soil, make a round water basin with a diameter of 50cm around the seedling using soil, or make an irrigation ditch 50cm wide, and water thoroughly. After the water seeps down, rake flat the soil ridge used to make the water basin. From the start of taking out the seedlings to the completion of burying the soil, pay attention to careful operation throughout the entire planting process; the seedling roots should not be exposed for a long time, to prevent wind and sun from drying the roots and affecting the survival rate. For autumn-planted seedlings, before winter, mound soil 20 to 30cm thick on the stems, covering the entire seedling in soil, and then remove the soil mound after spring begins. For spring planting, after the water seeps down, soil should also be covered to prevent the soil in the tree basin from drying and cracking and losing moisture.

1.3 Management in the year of planting

In the central and northern regions of Northeast China, the winter climate is cold, and the suitable growth period for the annual development cycle of Schisandra chinensis is very short, only about 150 days, and the frost-free period is only about 120 days. In addition, the root system of Schisandra chinensis seedlings is very underdeveloped, and the branches are relatively thin and weak. In the first year of planting, the growth amount is generally small. Only by strengthening management can the growth amount of Schisandra chinensis seedlings in the year of planting be increased and a relatively high survival rate be ensured.

1.3.1 Soil management

Although soil management in the year of planting Schisandra chinensis is relatively simple, it is very important. To ensure vigorous growth of the seedlings, clean cultivation should be carried out throughout the orchard. Carry out intertillage and weeding more than 5 times throughout the year, keeping the soil in the Schisandra chinensis planting row loose and free of weeds.

Generally, after the Schisandra chinensis planted in the current year sprouts, there is a relatively slow growth period. During this period, individual plants may show terminal bud formation. The main reason is that the root system has not yet grown enough absorbing roots, and the plant mainly relies on consuming nutrients accumulated in itself, so new shoots grow slowly. When the leaves grow to a certain extent, they can produce enough nutrients and transport them to the plant and root system, thereby promoting root growth. During this period, urea or foliar fertilizer can be sprayed appropriately to promote leaf photosynthesis. By late May, the root system has already produced a large number of absorbing roots, and the plant also has a certain accumulation of nutrients; therefore, the upper new shoots begin to grow rapidly, and the shoots that had formed terminal buds sprout secondary shoots again. This is the key period for management, and fertilizer and water management need to be strengthened. Each plant can be topdressed with 5 to 10g of urea or diammonium phosphate. To promote full maturity of the Schisandra chinensis branches, phosphorus fertilizer and potassium fertilizer can be topdressed in early and mid-August, with 100g of superphosphate and 10 to 15g of potassium sulfate per plant; or spray 0.3% potassium dihydrogen phosphate on the leaves.

Irrigate in case of drought, and pay special attention to drainage during the rainy season. Standing water must be removed in time, otherwise it can easily cause seedling death.

1.3.2 Plant management

1.3.2.1 New shoot management The growth amount of Schisandra chinensis in the year of planting is greatly related to seedling quality and management measures. On the premise of ensuring seedling quality, plant management must be strengthened. Generally, in the slow growth period after seedling sprouting, the new shoots do not need to be treated. After the new shoots begin to grow rapidly from late May to early June, when the new shoots reach about 50cm in length, according to different cultivation models, 1 to 2 vigorous main vines can be selected and retained per plant, and timely guided onto the trellis. Bamboo poles or polyethylene resin ropes can be used as supports. For other new shoots, pinching can be used to inhibit their growth, promote nutrient production, and ensure rapid plant growth. When the plant grows beyond 2m, it needs to be pinched in time to promote branch maturity. If secondary shoots are produced, overly dense secondary shoots need to be thinned, generally keeping the spacing between secondary shoots at 15 to 20cm, and pinching at about 30cm in length of the secondary shoots to promote full growth of the secondary shoots and plump buds.

1.3.2.2 Pest and disease control Schisandra chinensis seedlings generally rarely suffer from insect pests or infections, but inspection must be strengthened. Because 1-year-old seedlings are relatively weak and small, once pests or diseases occur, they will have a great impact on plant growth. In particular, observation of Schisandra chinensis black spot disease and powdery mildew should be strengthened, and early control should be achieved. Using 50% mancozeb wettable powder 500 to 600 times solution, 10% difenoconazole water-dispersible granules 1500 times solution, or myclobutanil 25% emulsifiable concentrate 4000 to 6000 times solution, sprayed once every 7 to 10 days for 2 to 3 consecutive sprays, has a relatively good control effect on Schisandra chinensis black spot disease; using 25% triadimefon wettable powder 800 to 1000 times solution or thiophanate-methyl wettable powder 800 to 1000 times solution, sprayed once every 7 to 10 days for 2 to 3 consecutive sprays, has a very good control effect on powdery mildew.

2 Planting and management of current-year green seedlings

Due to the shortage of finished seedlings or the need for replanting, in recent years people have explored the method of using current-year green seedlings for planting and orchard establishment. This method has a short recovery period, high survival rate, relatively good plant root system, and strong growth vigor in the second year. As a supplement to orchard establishment with finished seedlings, it is indeed a good method.

2.1 Planting period and seedling quality

In most areas of Liaoning and Jilin, planting is generally carried out in early and mid-August. The seedlings are required to have more than 10 leaves and a base stem diameter of more than 3.0mm. The seedling source should preferably be relatively close to the planting site to reduce seedling dehydration and root damage caused during transport; if long-distance transport is required, attention should be paid to shading, moisture retention, and cooling of the seedlings during transport, and planting should be done as early as possible.

2.2 Planting and post-planting management

Planting of seedlings is best carried out on cloudy days. If planting on sunny days, it is advisable to do so after 14:00. The planting method is the same as for finished seedlings. After green seedlings are planted, they can still grow for nearly 2 months before the early frost arrives. During these 2 months, fertilizer and water management should be strengthened so that the leaves produce more nutrients to supply the plant and root system, promoting root growth and nutrient accumulation in the tree body. In the early period after planting, 1% to 2% urea can be sprayed once a week for 1 to 2 consecutive sprays, and then 0.3% potassium dihydrogen phosphate can be sprayed 2 to 3 times; in case of high temperature and drought, irrigation should be strengthened to keep the soil moist. Before winter, leave 3 to 5 plump buds for heading, and give the plant one thorough watering, then mound soil 20 to 30cm on the plant, covering the entire plant in soil, and remove the covering soil mound before sprouting the following spring. In the second year of management, because no recovery period is needed, each plant can be topdressed with 5 to 10g of urea or diammonium phosphate before the plant begins to grow, to promote plant growth as quickly as possible. Other management is basically the same as for planting finished seedlings.