Detailed Explanation of Key Techniques for High-Yield Field Cultivation of Water Chestnut
Water chestnut (pinyin: bí qi; English: water chestnut scientific name: Eleocharis dulcis), also known as horseshoe, water chestnut, shao, fuzi, wuyu, puji, dili, is a species in the genus Eleocharis of the family Cyperaceae. It is a shallow-water perennial herb in the genus Eleocharis of the family Cyperaceae, and its corms are eaten as a vegetable. In ancient times it was called fuzi (fuzi), commonly known as horseshoe, also called dili, because its shape resembles a horseshoe and it also looks like a chestnut. Calling it horseshoe refers only to its appearance; saying it resembles a chestnut refers not only to its shape, but also to the fact that its nature, flavor, composition and functions are similar to those of chestnuts, and because it sets fruit in the mud, it is called dili.
Characteristics of water chestnut
Water chestnut originated in our country and is an aquatic vegetable suitable for shallow-water cultivation. Its underground corms are eaten, either raw or cooked, and can also be used to make starch or for medicinal purposes. Water chestnut is a perennial herbaceous plant propagated by corms. After the corms are planted, inconspicuous shortened stems emerge from the corms, and slender fibrous roots can grow from the basal stem nodes, without root hairs. From the shortened stem, green leaf-like aerial stems emerge upward. The leaf-like stems are tubular, erect, hollow, and clustered, and can carry out photosynthesis. Stolons emerge around the shortened stem and grow horizontally in the soil. Some stem nodes can produce roots and buds, and when the buds extend out of the ground they become new plants, called branch-type stolons. The tips of some stolons can swell into corms, called corm-type stolons. The corms are oblate, with a smooth surface, and when mature are dark chestnut-colored or date-red, with 3-5 rings. The corm enlargement period is about 70 days. Water chestnut grows vigorously and is easy to cultivate. When cultivated in shallow water with deep soil, rich in organic matter, and fertile and soft, the corms are numerous and plump, with a red, lustrous color. The water depth should not exceed 30 cm, otherwise the aboveground part will grow too vigorously and affect corm formation. It has a relatively high demand for phosphorus and potassium fertilizers, and excessive nitrogen fertilizer must be prevented. For temperature, 15-20 degrees is suitable in the early stage, 25-28 degrees is suitable during the tillering stage, and 10-20 degrees is suitable during the corm formation stage.
High-yield field cultivation techniques for water chestnut
1. Select good varieties, sow at the right time, and plant at reasonable density.
At present, the main excellent water chestnut varieties promoted in Zhangzhou City include “Guilin Horseshoe”, “Minhou Weili”, etc. They belong to early-to-mid-maturing varieties, with plant height 90105 cm, single fruit weight 18-20 grams, red-brown color, crisp and tender quality, sweet taste and abundant juice, excellent quality, and are suitable for processing and canning. For water chestnut seed corms, choose corms with strong buds, uniform size, and no disease or rot. Before raising seedlings, first soak the water chestnut seed corms in water for 24 hours. From late June to early July, choose a garden plot that is easy to keep moist and shade for the germination seedbed. First loosen the seedling plot with a hoe, break up the soil clods and level them, then arrange the seed corms, with a grain spacing of 1 cm, and cover with a layer of semi-dry, semi-moist light loam or decomposed farmyard manure, with a thickness suitable for covering the water chestnuts. If the covering soil or fertilizer is too dry, strengthen water management and water frequently to keep the soil in a moist state. After 15-20 days of germination, the shoots emerge 810 cm. When roots grow from the buds, promptly move them into late rice seedling fields for seedling raising. The plant and row spacing is 12 cm×12 cm. During the seedling period, apply 1-2 times of 30% dilute urine water, and spray-irrigate 12 times with 1000-fold carbendazim solution to prevent stem blight. In late July and early August, when the shoots are more than 25 cm tall and the seedling field raising period is 16-18 days, the seedlings can be pulled up with roots and transplanted to the main field. Corms that have already sprouted can also enter the seedling field for seedling raising; in the early stage, manage water to keep it moist, and if conditions permit, build a shed for shade.
2. Field cultivation techniques.
1. Sow early at the right time. Water chestnut is transplanted to the field from Major Heat to the end of July, and sets corms at the end of September, thereby extending the corm enlargement period and increasing the proportion of large corms. Transplanting seedlings should be 2025 cm tall. When the main clump has 10-15 leaf-like stems, lift the seedlings with soil, bring them to the field with pesticide treatment, pull them carefully and place them gently, to prevent breaking the stems and roots.
2. Choose the field well. Water chestnut itself is not strict about soil requirements. However, for townships located in plains, the field should be selected as follows: first, choose black mud fields, black dike fields, or gray dike fields that are convenient for irrigation and drainage and have fertile soil, which is favorable for achieving high yield and high quality; second, implement contiguous planting to facilitate unified management; and third, divide into blocks for rotation to prevent continuous cropping and reduce disease.
3. Plant moderately deep. The planting depth should be 12-15 cm, and in principle the corms should be kept 35 cm from the plow pan. For dense planting specifications, generally transplant at a plant and row spacing of 50 cm×50 cm, with 2500-2600 clumps per mu.
4. Balanced fertilization. In fertilization, the principle of “stable in the front, controlled in the middle, and pushed in the later stage” should be grasped.
① Fertilization during the bud and seedling growth period can stabilize growth and promote strong stems. First apply base fertilizer, mainly organic fertilizer, applying 2000-3000 kg of soil and miscellaneous fertilizer per mu. For fertile fields, 2-4 days before transplanting to the main field, deeply apply 75 kg of ammonium bicarbonate plus 25 kg of superphosphate per mu. 7-10 days after planting, broadcast 10 kg of urea per mu, and maintain a water layer, combined with 1 intertillage. After 20 days, apply 10 kg of urea to promote row closure.
② Fertilization during the vigorous growth period can strengthen the plant and control excessive growth. Mainly apply phosphorus and potassium fertilizers, broadcasting 10 kg of calcium magnesium phosphate plus 20-25 kg of potassium sulfate or potassium chloride per mu, or broadcasting 25 kg of potassium chloride compound fertilizer per mu, to promote the stem color to turn lighter and lay the foundation for producing plump corms.
③ Fertilization during the corm enlargement period should promote large corms. Mainly grasp timely fertilization according to seedling condition, and mainly apply nitrogen and potassium fertilizers. When the water chestnut corms reach 2 cm, apply 10 kg of potassium sulfate or 20 kg of potassium chloride compound fertilizer plus 10 kg of urea per mu for the first corm-strengthening fertilizer; after 10-15 days, apply another round as appropriate according to seedling condition, and there should be a water layer when fertilizing. During the entire field growth period, the applied ratio of nitrogen, phosphorus, and potassium fertilizers is 1:0.40:1.03.
5. Maintain a water layer. Water chestnut is an aquatic crop and should maintain a shallow water layer, especially in the early growth stage when sufficient water should be ensured. Specifically, during the seedling stage maintain a shallow water layer of 35 cm, and during the vigorous growth period maintain a water layer of 69 cm, not exceeding 10 cm, to prevent excessive growth. After the clump number closes the rows, until the late flowering stage, it can be managed with moisture. 20 days before harvest (around Frost's Descent), cut off the water and let it dry, so the leaves begin to turn yellow and gradually dry up, in preparation for digging.
6. Timely control of diseases and insect pests: the main diseases and insect pests of water chestnut are stem blight, rust, and white rice borer, etc. Spraying with 40% DuPont Fuxing emulsifiable concentrate 10000-fold solution or 68.75% DuPont Yibao wettable granules 1500-fold solution plus 90% DuPont Keling wettable powder 2000-fold solution has a very good control effect.
7. Harvest and retain seed. After draining and drying in mid-November, when the soil no longer sticks to the hoe, it can be dug. Water chestnuts intended for seed use are required to be large (single fruit weight more than 18 grams), with a short navel, round and complete, and undamaged. Water chestnuts can be stored for up to one year. The method can be building a pool (cellar) for sealed storage, or heap storage, loose-pack storage, or stacked storage. Generally, after the water chestnuts are dug out, remove the soil and dry them in the air, then store them in clean urea bags or feed bags with an inner lining, then stack them evenly bag by bag, cover the surface with a layer of fine sand, and seal the heap with agricultural film for the winter, leaving them for use as seed the following year.