Detailed Explanation of Key Cultivation Techniques for the Chinese Medicinal Herb Lotus Seed

Site Selection and Land Preparation

The selection of the lotus pond should be based on the lotus's habits of loving light, moisture, and water while fearing wind. Choose a spot that is sheltered from wind and faces the sun, with an abundant water source, slow water flow, a silt layer of about 15cm, and water quality free from excessive pollution. The water level of the pond should generally be relatively stable, with a water depth not exceeding 1m, no sudden rises and falls in summer, and no drying up in winter; alternatively, choose a paddy field with strong water and fertilizer retention capacity, sheltered from wind and facing the sun, with an abundant water source. Before planting lotus rhizomes or sowing seeds, first drain the water to make it shallow and apply sufficient base fertilizer. The base fertilizer is generally mainly manure such as pig manure, cow manure, and chicken manure, applied at 4000-5000kg per mu. At the same time, the soil should be plowed and harrowed so that the pond soil or field soil is smooth, level, fine, and soft.

Planting Methods

Lotus propagation is usually mainly by division of rhizomes, which has the advantage of maintaining the excellent genetic traits of the parent plant and allowing flowers to be viewed and rhizomes and lotus seeds to be harvested in the same year. When using lotus seeds for sexual reproduction, the seedlings are small in the year after sowing and cannot bloom or bear fruit; it takes 2-3 years for them to fully grow. Moreover, sexual reproduction produces greater variation, and the harvested rhizomes are uneven, so it is generally not used in production. However, sometimes sexual reproduction is needed to cultivate new varieties.

1. Division propagation: Around Qingming, the terminal buds of the rhizomes begin to sprout, and this is the most suitable time for division. Select robust-growing rhizomes, cut the main rhizome or secondary rhizome with intact terminal buds into sections retaining 2-3 nodes, and keep the tail node to prevent mud from entering the rhizome holes and causing rot. When planting, hold the rhizome body with the left hand, grasp the top node of the rhizome with the right hand, and use the middle finger to protect the terminal bud. Insert the lotus shoot upward into the pond soil at an angle of 20°C-30°C, at a depth of about 10-15cm, leaving the tail node tilted and exposed above the mud surface. The shoot heads should all face the center of the pond to facilitate the development of underground rhizomes and prevent the lotus runners from crossing the pond ridge. After planting, press down lightly to prevent floating after irrigation. The planting density varies with pond and field conditions and varieties. Early-maturing varieties and lean land should be denser, while late-maturing varieties and fertile pond fields should be sparser. Generally, the plant spacing is 1-1.5m, the row spacing is 1.5-2m, and 500-800 seed rhizomes are used per mu.

2. Sowing propagation: Before sowing, select fully mature seeds and carry out scarification treatment. First, use spring scissors or wire pliers to break a small opening at the recessed end of the lotus seed, exposing the seed coat without damaging the embryo. Put the cut lotus seeds into water to soak, with the water depth just enough to submerge the lotus seeds. If too shallow, the lotus seeds cannot obtain the water needed for germination; if too deep, oxygen in the water is insufficient, which is unfavorable for germination. When the lotus seeds grow 2-3 young leaves, they can be sown. Both spring sowing and autumn sowing are acceptable.

Field Management

1. Provide sufficient light: Lotus is a light-loving plant. In cultivation and management, sufficient light should be ensured. Under strong light, lotus grows and develops quickly and blooms early; under weak light, it develops slowly and blooms late. If cultivated under shady conditions, it will cause the lotus leaves to lose green color and the flower buds to die.

2. Properly control moisture: Although lotus is a plant that loves moisture and fears dryness, its water requirements differ at different growth stages. When planting lotus rhizomes separately, the water should be shallow, which can raise soil temperature and facilitate the growth of lotus seedlings and seed rhizomes. At the same time, do not irrigate too much at once, so as to avoid a sudden drop in soil temperature that affects the growth of lotus seedlings and seed rhizomes. As the floating leaves and standing leaves grow, the water level should be gradually raised, and the height of the water level should be kept such that the floating leaves and standing leaves remain exposed above the water. In summer, when temperatures are high, special attention should be paid to maintaining the water in the lotus pond, strictly preventing death of the lotus caused by water shortage. In late autumn and early winter, after new rhizomes form, the lotus enters dormancy. At this time, the water level in the pond should be lowered and kept shallow; in winter, the water level in the pond should also be maintained to preserve the soil temperature under the water, prevent freezing, and help the lotus overwinter in the open field.

3. Rational fertilization: In lotus cultivation, sufficient base fertilizer is the main approach, supplemented by topdressing. About half a month after planting, when standing leaves have grown, topdressing should be applied, with about 1000kg of fully decomposed manure or about 15kg of nitrogen fertilizer per mu. Before rhizome formation, apply a compound fertilizer of nitrogen, phosphorus, and potassium once. When fertilizing, do not contaminate the leaves to prevent damage. Finally, when the flowers and fruits are nearing maturity, a mixed fertilizer mainly of phosphorus and potassium fertilizer with slightly lower nitrogen fertilizer can be applied as topdressing, at 30-40kg per mu.

4. Frequently remove weeds, duckweed, and water moss: After lotus rhizomes are newly planted in the lotus field, weeds such as barnyardgrass and nutsedge are especially likely to grow, directly affecting the growth and development of the lotus. Therefore, throughout the entire growth cycle, weeding must be carried out 2-3 times. For water moss, duckweed, algae, and the like, they should be pulled out and scooped up at any time to avoid consuming water and fertilizer and to promote the normal growth of the lotus. About 1 month after planting, the floating leaves gradually turn yellow and withered, and they should be removed promptly so that sunlight can penetrate into the water and raise the soil temperature. For weeds, herbicides can be applied. Commonly used agents are nitrofen or nitrofen plus diuron, with the dosage per mu being: 25% nitrofen 500g + 25% diuron 50g. Only when used in mid-to-late May, when the water temperature is stable above 20°C, do herbicides show good results.