Detailed Explanation of the Latest Cultivation Techniques for Shallow-Water Lotus Root

I. Lotus Field Land Preparation 

Choose clay loam with deep, fertile soil and strong water retention. Applying more compost can reduce rust spots on the lotus root. Apply 30000-45000 kg of farmyard manure per hectare, or 60000 kg of green manure. 

II. Seed Selection and Planting 

Planting is generally done from Qingming to Guyu, and harvest begins from late July to early August, continuing until around Qingming of the following year. Select whole lotus roots or daughter lotus roots with the characteristics of the variety and a relatively short rear node for seed use. For early lotus, the row spacing is 166 x 133 cm, with 3000 holes per hectare, that is, 3000 seed lotus roots with 3-4 lotus heads each are planted; for late lotus, the row spacing is 250 cm square, with 1650 holes per hectare planted with seed lotus roots bearing 3-4 lotus heads each. If daughter lotus roots are used, plant 2 per hole. Generally, 2250-3750 kg of large lotus roots or 1875 kg of small lotus roots are needed per hectare. 

When planting field lotus, first arrange the seed lotus roots on the field surface according to the specified plant spacing and the direction of the lotus runners, then bury the lotus heads 10-12 cm into the mud, and leave the nodes slightly above the water surface. Whether for field lotus or pond lotus, when planting, the lotus heads on all four sides must face inward to prevent the lotus runners from extending beyond the field ridges. 

III. Strengthen Lotus Field Management 

1. Weeding, leaf removal, and flower bud breaking: If flower buds appear, bend the flower stalks. 

2. Water level regulation: During the sprouting and growth stage, maintain a shallow water layer of 3-5 cm to raise soil temperature and promote germination; during the vigorous growth stage of lotus leaves and lotus runners, maintain a water layer of 12-15 cm; at the beginning of lotus root formation, shallow water is suitable, 3-5 cm; when strong winds blow, the water layer should be deeper to protect the lotus leaves; one month before harvest, maintain a shallow water layer. 

3. Timely topdressing: Base fertilizer is primary, accounting for 70% of the total fertilizer amount, and topdressing accounts for 30%. Apply topdressing twice during the vigorous growth of lotus leaves and at the beginning of lotus root formation, applying 30000-45000 kg of human manure per hectare. Before each fertilization, drain the water shallowly so the fertilizer is absorbed into the soil, then refill to the original depth. 

4. Turning lotus runners: When curled leaves are 1 m from the field edge, turn the lotus runners back toward the field at any time. Turning lotus runners should be done at noon when the stems and leaves are soft to prevent breakage. 

5. Pest and disease control: The main disease is rot disease. Preventive methods include doing one's utmost to avoid continuous cropping, reducing nitrogen fertilizer application, and using lime for disinfection, applying 2250-3000 kg per hectare.           The main pests are aphids and tobacco cutworms. For aphids, spray 40% dimethoate emulsion at 1500-2000 times dilution, or spray 50% wettable aphid powder at 1000-1500 times dilution. For tobacco cutworms, spraying with 1000 times dilution of Lailinghuang gives good results. 

IV. Harvesting and Storage 

When harvesting tender lotus roots, the leaves are still green, so generally the field water is not drained, and they are dug out by hand; when harvesting mature lotus roots after the leaves have withered, drain the lotus field and dig them out with a spade. After being dug out, lotus roots generally do not store well; in cold weather they can be stored for one month, while in early autumn and late spring they can only be stored for 10-15 days. Lotus roots for storage should be mature, with intact nodes, and the root body should carry mud and be undamaged; broken parts should be sealed with mud. During storage and transport, they should not be piled too thickly or packed too tightly. Cover them with lotus leaves and water grass, water frequently, and always maintain a cool and moist environment.

V. Key Points

1. Select excellent seed lotus roots. Choose excellent varieties suitable for shallow-water cultivation as seed lotus roots, such as the early-maturing variety Elian No. 5 and the mid-late-maturing variety Elian No. 2. Seed lotus roots should be selected for being thick and strong, with vigorous buds, free of pests and diseases, and undamaged.

2. Choose fertile clay loam fields. Because shallow-water lotus roots have underdeveloped roots and no root hairs, they have relatively strict soil requirements. It is advisable to choose clay loam with deep, fertile soil rich in organic matter.

3. Cultivation method. When sowing, tilt the top end of the seed lotus root downward at a 30-degree angle, with the rear end slightly exposed above the soil surface. Appropriate dense planting has the effect of early maturity and increased yield. Generally, the density for early-maturing varieties is: row spacing 2 m, hole spacing 0.7 m. Late-maturing varieties should be appropriately sparsely planted, with a density of: row spacing 2-2.5 m, hole spacing about 1 m.

4. Scientifically regulate the water level. The general principle of water layer management for shallow-water lotus root is shallow at the front, deep in the middle, and shallow at the back. During the germination and growth period, the water layer should be shallow, preferably 4-7 cm. During the vigorous growth period of stems and leaves, the water layer should be deeper, preferably 12-15 cm. During the lotus root formation period, the water layer should be shallow, preferably 4-7 cm.

5. After the soil is prepared, sufficient base fertilizer needs to be applied. The base fertilizer for shallow-water lotus root is mainly organic fertilizer. There are many types of organic fertilizer, including crop straw, humic acid fertilizer, microbial fertilizer, farmyard manure, compound fertilizer, and so on. If farmyard manure and compound fertilizer are used, 4000 to 5000 kg of decomposed farmyard manure and 100 kg of ternary compound fertilizer can be applied per mu.

6. Harvest in a timely manner. After the terminal leaf appears in lotus root, when the back of the terminal leaf is slightly red and the edge of the upright leaf at the base begins to turn yellow, the lotus root is fully mature. At this time, it can be dug up and sold on the market.