Key Points of Water Management Techniques in Schisandra chinensis Orchards

1. Irrigation The root system of Schisandra chinensis is relatively shallow, and drought has a considerable impact on its growth, flowering, and fruiting. In Northeast China, spring rainfall is scarce, making drought conditions likely and highly unfavorable to the early growth of Schisandra chinensis. If irrigation can be carried out promptly throughout the year according to climate changes and the plant's water requirements, it will have an extremely significant effect on improving the yield and quality of Schisandra chinensis.

Schisandra chinensis is most sensitive to water during the bud break stage, the rapid shoot growth stage, and the rapid berry enlargement stage. Water shortage in the early growth period can cause uneven bud break, short and small shoots and leaves, and a reduced fruit set rate, seriously affecting the yield of that year. Water shortage in the early stage of rapid berry enlargement often has an adverse effect on continued berry enlargement and can cause serious fruit drop. Slight water shortage during the fruit ripening stage can promote berry ripening and improve fruit quality, but severe water shortage will delay ripening and reduce berry quality.

The timing, frequency, and amount of each irrigation often vary depending on the cultivation method, soil depth, soil properties, climatic conditions, and so on, and should be flexibly managed according to local conditions. Generally, irrigation can be carried out with reference to the following main periods:

① Irrigate once after thawing and before bud break. This irrigation can promote uniform bud break in the plants and is beneficial to the rapid early growth of new shoots.

② Irrigate 1-2 times before flowering, which can promote the rapid growth of new shoots and leaves and increase the fruit set rate.

③ From after flowering to before berry coloring, irrigate 2-4 times depending on the amount of precipitation and soil conditions. Irrigation during this period is beneficial to berry enlargement and improving the quality of flower bud differentiation. Since Schisandra chinensis is a traditional Chinese medicinal material, the irrigation water should meet the farmland irrigation water quality standards (well water and rainwater, etc. can be regarded as sanitary and suitable irrigation water).

2. Drainage July to August is the rainy season in the northeastern provinces, with abundant and concentrated rainfall. In mountain Schisandra chinensis orchards, soil and water conservation work should be done well, and attention should be paid to drainage. In flatland Schisandra chinensis orchards, drainage work should be arranged even more carefully to avoid damage to the plants from waterlogging or the widespread spread of diseases caused by excessive humidity.

In places with a high groundwater table and low-lying terrain, drainage ditches about 0.5-1.0 m deep can be dug every 25-50 m in the orchard for drainage. In mountain areas, the drainage ditches should preferably lead to a water storage pond (or reservoir) for use in irrigation during drought.

Seedlings in nurseries and young trees are prone to excessive vegetative growth and delayed maturity, so drainage should be given even more attention.

(4) Removal of Suckers and Underground Horizontal Rhizomes

Schisandra chinensis is a special tree species. The underground horizontal rhizome is an important organ for asexual reproduction. The annual growth of underground horizontal rhizomes is particularly large, and they produce a large number of suckers, which not only causes considerable nutrient competition and waste but also, because of their strong growth

vigor, clings to the surface of the trellis, worsening the light conditions on the trellis surface. Therefore, the removal of underground horizontal rhizomes and suckers must be carried out every year.

1. Removal of underground horizontal rhizomes The underground horizontal rhizomes of Schisandra chinensis are distributed relatively shallowly, mainly concentrated in the soil layer 5-15 cm below the surface, and are relatively easy to remove. The removal period is from after leaf fall to before the ground freezes, or during the bud break period after bleeding stops. When removing horizontal rhizomes, since the root system of Schisandra chinensis is shallowly distributed, care should be taken to protect the roots. In addition, because the underground horizontal rhizomes of Schisandra chinensis have adventitious roots, they can continue to grow and form new plants after being cut from the parent plant, so they must be thoroughly removed from the ground to avoid causing trouble for future operations.

2. Removal of suckers During each year's growing season, the underground horizontal rhizomes of Schisandra chinensis produce a large number of suckers. The timing of sucker removal should be determined according to specific circumstances, and they should be removed whenever found, so as to facilitate the normal growth of Schisandra chinensis and the management of the trellis surface. When removing suckers, for weaker plants, attention should be paid to selecting and retaining vigorous sucker branches as reserve main vines, and they should not all be removed, otherwise it will be unfavorable for the renewal of the main vines.