Water Management Methods for Schisandra (Schisandra chinensis) Plantations

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

Schisandra is most sensitive to water during the budbreak stage, the rapid shoot growth stage, and the rapid berry enlargement stage. Water deficiency in the early growth stage will cause uneven budbreak, short and small new shoots and leaves, and a reduced fruit-setting rate, seriously affecting the yield of that year. Water deficiency in the early stage of rapid berry enlargement often has an adverse effect on continued berry enlargement and can cause severe fruit drop. Slight water deficiency during the fruit ripening stage can promote berry ripening and improve fruit quality, but severe water deficiency 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. In general, irrigation can be carried out with reference to the following main periods:

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

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

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

2. Drainage In the various provinces of Northeast China, July to August is the rainy season, with abundant and concentrated rainfall. In mountainous Schisandra orchards, soil and water conservation work should be done well and attention should be paid to drainage. In flatland Schisandra orchards, drainage work should be arranged even more carefully to avoid waterlogging damage to the plants or excessive humidity causing widespread spread of diseases.

In locations 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 within the orchard for drainage. In mountainous areas, drainage ditches should preferably lead to a water storage pond (or reservoir) for use in irrigation during droughts.

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

(4) Removal of suckers and underground creeping stems

Schisandra is a special tree species. The underground creeping stem is an important organ for asexual reproduction. The underground creeping stems grow especially large amounts each year and produce a large number of suckers, which not only cause considerable nutrient competition and waste, but also, because of their strong growth vigor, climb over the surface of the trellis and cause deterioration of the light conditions on the trellis surface. Therefore, the removal of underground creeping stems and suckers must be carried out every year.

1. Removal of underground creeping stems The underground creeping stems of Schisandra 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 after leaf fall and before the ground freezes, or during the budbreak period after bleeding stops. When removing the creeping stems, because the Schisandra root system is relatively shallow, care should be taken to protect the roots. In addition, because the underground creeping stems of Schisandra have adventitious roots and can continue to grow and form new plants after being cut from the parent plant, they must be thoroughly removed from underground to avoid causing trouble for future operations.

2. Removal of suckers During each year's growing season, the underground creeping stems of Schisandra produce large numbers of suckers. The timing of sucker removal should be determined according to specific circumstances, and they should be removed whenever found, so as to benefit the normal growth of Schisandra and facilitate trellis management. When removing suckers, for relatively weak plants, care should be taken to retain vigorous sucker branches as replacement main vines; they should not all be removed, otherwise it will be unfavorable for the renewal of the main vines.