Detailed Explanation of Key Techniques for High-Yield Lotus Seed Cultivation

Lotus Field Selection and Preparation

For the lotus field, it is best to choose winter fallow fields or green manure fields with irrigation conditions, abundant sunlight, deep soil layers, and medium-to-upper fertility. Loam, clay loam, and clay soils are suitable; sandy loam with convenient irrigation is also acceptable. The soil pH should be between 6.5 and 7. Barren sandy fields, year-round cold-waterlogged fields, and rust-water fields are not suitable for planting. Lotus field preparation requires intensive cultivation to achieve appropriate depth, loose soil, a level field surface, and sufficient basal fertilizer. For winter fallow fields, deep plowing and sun-drying of ridges should be carried out in winter, with 2000 kg of barnyard manure applied per mu. In early spring, irrigate and carry out two plowings and two harrowings to level the field surface and await transplanting. Green manure fields are generally given two plowings and two harrowings in late February. After the first plowing, 25 kg of lime is applied per mu to promote the decomposition of green manure. If green manure yield exceeds 2000 kg, no additional barnyard manure is needed; if the yield is too low, some barnyard manure must be supplemented.

Selection of Varieties and Seed Lotus Rhizomes

The quality of seed lotus rhizomes directly affects the yield and quality of lotus seeds. First, the appropriate variety should be selected according to needs. For seed lotus production, Shilihe No. 1, Taikong No. 36, and Taikong No. 3 are suitable choices. Second, for the selection of seed rhizomes, it is required that the variety be pure and true, that the previous year's per-unit yield was high, and that the seed rhizomes come from seed fields free of disease. Select and dig at the same time, choosing rhizomes that possess the characteristics of the variety, have fresh color, thick and robust rhizome bodies, short internodes, no disease spots, no damage, and intact terminal buds. Main rhizomes with three or more nodes and secondary rhizomes with two or more nodes should be used as seed.

Planting Density

In conjunction with lotus field preparation, apply 2000 kg of barnyard manure per mu, and apply 25 kg of lime to green manure fields. One day before transplanting, apply 20-25 kg of ammonium bicarbonate and 25 kg of superphosphate per mu as a surface fertilizer to ensure sufficient basal and surface fertilizer. Timely transplanting is an important step for increasing per-unit yield and ensuring high yield. Generally, transplanting is best when the local temperature stabilizes above 12 degrees C, that is, in early to mid-April. Planting density is generally 120-150 seed rhizomes per mu. Early planting should be sparse; late planting should be dense. High-fertility fields should be sparse; medium- and low-fertility fields should be dense. Planting Requirements: From transplanting to the closing of lotus leaves over the field, 2-3 rounds of field weeding and cultivating are needed. Begin cultivating when the main stem of the lotus sends out its first standing leaf, then cultivate once every 10-15 days until the lotus leaves close over the field. Before cultivating, drain the water first, keeping only a thin film of muddy water. During cultivation, pull out all weeds and bury them in the mud to achieve the requirements of soft mud, level surface, and no weeds. Combine topdressing with cultivation so that fertilizer can be applied deep and fertilizer efficiency improved. Lotus is particularly sensitive to herbicides, so the use of herbicides in lotus fields is generally not recommended.

Scientific Fertilization

Lotus has a long growth period and consumes a large amount of fertilizer, while its root system has weak fertilizer-absorbing capacity. Fertilization should emphasize applying sufficient organic fertilizer, increasing phosphorus and potassium fertilizer, applying topdressing in small amounts but many times, and appropriately supplementing micronutrients. For field topdressing of lotus, the total fertilizer per mu is equivalent to about 40 kg of urea, 20 kg of potassium chloride, and 2.5 kg of borax. When fertilizing, adhere to the principle of "light seedling fertilizer, heavy flower fertilizer, complete seed fertilizer" and apply in stages and multiple times. After the first standing leaf emerges (seedling stage), combine with the first cultivation to apply seedling fertilizer, using 5 kg of urea and 2.5 kg of potassium chloride per mu, applied in spots around the lotus seedlings. Cultivate immediately after fertilization. At the beginning of the flowering stage, apply heavy flower fertilizer when the first flower bud appears, applying 7.5 kg of urea plus 4 kg of potassium chloride per mu, spread evenly over the whole field. Do not scatter fertilizer onto lotus leaves or flowers, and maintain a 3-5 cm water layer in the field. At the early pod-setting stage, apply seed-strengthening fertilizer, using 5 kg of urea, 2.5 kg of potassium chloride, and 0.5 kg of borax per mu, with the same application method as above. After that, apply topdressing once every 10-15 days (each fertilizer amount reduced by 10%), for a total of 5-6 times throughout the whole period.