Is It Feasible to Raise Crayfish in Lotus Root Ponds? Methods, Profits and Precautions

In recent years, as the markets for other aquaculture species have been unstable, the crayfish, a popular consumer item, has performed well, with prices remaining relatively stable and profits fairly good. Currently, crayfish farmers in various places are also exploring new farming models, so can crayfish be raised in lotus root ponds? How are the profits? What are the methods and precautions for intercropping crayfish in lotus root ponds?

I. Can crayfish be raised in lotus root ponds? How are the profits from intercropping crayfish in lotus root ponds?

Crayfish can indeed be raised in lotus root ponds. For example, a farmer in Lingcheng District, Dezhou, Shandong, has explored a model of intercropping crayfish in lotus root ponds over the past two years and achieved success. In a trial of raising crayfish in a 30-mu lotus root pond, the yield of crayfish per mu was 300 jin, with an average selling price of 18 yuan; the lotus roots harvested from this three-dimensional ecological farming had fewer diseases, and their improved quality and price brought good market demand and considerable profits.

This intercropping model has low requirements for pond conditions, and generally any fish-lotus pond can be used as a farming pond. Before stocking, the pond needs to be cleared and disinfected, and aquatic plants planted. In early April, about 6,000 crayfish fry of 3—5 cm in size can be stocked per mu, and they can be fed with zucchini, pumpkin vines and fruits, potatoes, corn feed, etc. The key is to properly adjust water quality and water level, maintain aquatic plants, prevent and control pests and diseases, and harvest by catching the large and leaving the small.

II. What are the methods and precautions for intercropping crayfish in lotus root ponds?

Intercropping crayfish in lotus root ponds——Pond conditions

1. Pond preparation

Choose an old pond with relatively thick silt, so that the pond is rich in organic matter, which is not only suitable for planting lotus roots but also produces lotus roots that are tender, crisp and good to eat. Along the perimeter of the pond, dig a ring-shaped crayfish trench with a top width of 120 cm, a bottom width of 90 cm and a depth of 80 cm. A “cross”-shaped trench between the pond sections should also be dug in the middle of the pond, and the inter-pond trench should connect with the surrounding trench and the pond. Its total area should account for about 10% of the total pond area. Set the inlet and outlet diagonally opposite each other, and seal them with 60-mesh stainless steel mesh. Use 60 cm high calcium-plastic boards around the pond as fencing facilities, bury the calcium-plastic boards 10-15 cm into the soil and tamp them firm, and drive a wooden stake every 80 cm to fix the calcium-plastic boards, ensuring that the crayfish do not escape.

2. Fertilization

Before planting lotus roots, apply sufficient base fertilizer, preferably organic fertilizer, with the amount accounting for more than 60% of the annual total. In June, apply 50 kg of high-quality compound fertilizer per mu; in July, apply 50-75 kg of urea per mu; when the lotus leaves have basically covered the pond surface, apply an additional 30 kg of urea per mu to ensure sufficient fertilizer for the lotus roots. When fertilizing, be careful not to burn the lotus leaves.

Intercropping crayfish in lotus root ponds——Lotus root planting and management

1. Selection of lotus root seed

For seed lotus roots, it is best to choose whole lotus roots with 3-4 nodes, requiring complete branches, intact terminal buds, thick and strong seed lotus roots, tender and crisp buds without damage, and free of pests and diseases, among other high-quality traits.

2. Planting of lotus root seed

Around Qingming or Guyu, when the water temperature in the outer pond remains at 12°C, the whole pond can be planted with seed lotus roots, with reasonable close planting at 600-700 plants per mu. Place the seed lotus roots flat and bury them in the mud at a depth of about 10 cm, with the tail section slightly tilted upward (5 cm into the mud). When planting the lotus root seed, soak it in carbendazim for 30 minutes.

3. Water level regulation

The principle of water level management in lotus root ponds is shallow, deep, shallow. Starting from a shallow water level of 10 cm, gradually add water as the temperature rises, increasing the water level to 20 cm, and reasonably adjust the water depth to facilitate normal photosynthesis and growth of the lotus roots. In June, the water level reaches 1.2-1.5 m. After the weather turns cool, gradually lower the water level. From mid-September to the end of October, maintain a water depth of 30 cm; during the overwintering period, maintain shallow water of 5 cm or keep the soil moist for overwintering. During the farming period, flexibly let water in and drain it according to climate and water temperature.

4. Lotus root harvesting

After the terminal leaf of the lotus root appears, when the back of the terminal leaf is slightly red and the edges of the upright leaves at the base begin to turn yellow and wither, it proves that the lotus root is mature, and it can be harvested at the appropriate time according to market demand. Generally, alternate-row harvesting is practiced to leave seed lotus roots.

Intercropping crayfish in lotus root ponds——Stocking and management of crayfish seedlings

1. Stocking river snails

Stocking river snails can not only supplement animal-based feed for the crayfish but also help purify the substrate. At the beginning of the year, stock 250 kg of live river snails per mu to let them reproduce naturally and provide certain palatable feed for the crayfish.

2. Stocking crayfish seed

To prevent inbreeding, purchase male and female brood crayfish from other places. On August 16, 2016, stock brood crayfish with a size of 20-30 individuals per kg, at a female-to-male ratio of 3:1, and a density of 24 kg per mu.

3. Feed feeding

Since natural feed in lotus root ponds is relatively abundant, after the crayfish are put into the lotus root pond, generally not much feeding is needed. The appropriate amount of bait can be based on the abundance of natural feed in the lotus root pond, feeding some compound feed. The feeding points should mainly be areas with shallower water and where crayfish are concentrated. The feeding amount should be determined as appropriate based on leftover bait, weather and other conditions. The general principle is “little at the beginning, more in the middle, and little in the later stage.”

4. Crayfish disease prevention and control

Adhere to the policy of “prevention first, combining prevention and control.” Before stocking the crayfish seed, soak them in about 3% salt water for 3-5 minutes. During the growth period of the crayfish, every 15-20 days use 10-15 kg of quicklime dissolved in water and splash it over the whole pond once to prevent disease.

5. Crayfish harvesting

Crayfish begin to be gradually harvested from March to April. When harvesting, crayfish cages with a mesh size of more than 2 cm can be placed in the ring trench every evening, adopting the method of catching the large and leaving the small and gradually bringing them to market. In early May, when the lotus roots have just grown small leaves, all crayfish should be caught clean when the lotus roots begin normal growth, so as not to affect the growth of the lotus roots.

Intercropping crayfish in lotus root ponds——Harvesting and sales

From mid-to-late March to early May is the season for harvesting and selling crayfish. At this time, crayfish have not yet reached the period of large-scale market supply, so prices are relatively high, while lotus roots are sold in large quantities during the Mid-Autumn Festival and Spring Festival. In this way, by staggering farming and sales, better economic benefits can be achieved.