Key Techniques for Fish Culture in Lotus Field with High Yield by Lotus and Fish Cropping

The co-cultivation of lotus and fish refers to the technology of planting lotus root and raising fish in the same water body, and fish lotus live together for a long time or short time to realize the high yield of fish lotus. In lotus field, a large number of aquatic weeds, aquatic insects and benthos compete with lotus root for water, fertilizer and glory, which affect the growth of lotus, but they can be used as fish bait. Fish culture in lotus field can not only weed lotus field and control lotus field diseases and insect pests, but also reduce soil bulk density, increase soil porosity and improve soil fertility.

Fish culture in lotus root field

First, symbiotic engineering design. The "back" project is adopted, that is, ditching around the lotus root field, with a width of 2.5 meters, a depth of 1.5 meters and a height of 1.5 meters, leaving a road about 3 meters wide to enter the field. The area of the ditch accounts for about 10% of the total area of the lotus field. The advantage of this project is that the water level in the ditch will not change greatly due to the change of the water level in the lotus field, which can meet the water environment needed for the growth of fish and ensure the growth of fish. In addition, due to the ditching around, the dike is higher, which can reduce the loss of lotus root during the storm.

2. Selection of varieties:

1. Fish species selection. It is appropriate to put fish fry in lotus root field with 35-45 kg per mu, generally according to the proportion of 60% of common carp, crucian carp, 20% carp, 15% silver carp and grass carp, 5% of herring, and a small number of other species of fish, such as catfish, snakehead, etc. The stocking quantity of herbivorous fish should be strictly controlled, otherwise it is harmful to the growth of lotus root.

2. Variety selection of lotus root. It is appropriate to select late-maturing varieties of lotus root, such as "Baoying Beauty Red", "Suzhou slow Lotus" and so on.

(3) putting in fish fry, planting lotus root, feeding bait and fertilizing:

1. Fish fry release. The release of fish fry should be carried out half a month after the excavation and disinfection of the project, usually from the first and middle of March to the middle and late April. The specification of fish fry is generally 30-50 grams per tail, for herbivorous fish fry, if sufficient green fodder can be ensured, the dosage can be increased appropriately; for omnivorous fish fry, the dosage can be increased according to feed supply. Crucian carp fry can be released according to 300-500 fish / mu, leather-bearded catfish can be released according to 100-200 fish / mu. But it is best not to exceed the total amount of 50 kg / mu.

2. Planting lotus root. The planting time of lotus root is from March to May. The amount of seed used should be slightly less than that of conventional cultivation, generally about 200 kg / mu. During cultivation, the terminal bud of the lotus root species connected with the inner lotus root around the lotus root field should be toward the center of the field, more than 1 meter away from the ridge.

3. Fish bait. A large number of aquatic weeds, insects and benthos in lotus root fields can be eaten by fish, such as coarse culture, but not feed. In order to achieve high yield, a certain amount of feed should be put in from the end of March, and each feed should account for 10-20% of the total fish.

4. Fertilization. The basic fertilizer of lotus root should be applied early and re-applied. Generally, 2500 kg of organic fertilizer and 30 kg of urea are applied during soil preparation. The topdressing of lotus root is mainly urea, and the amount of topdressing can be reduced by about 50% compared with general cultivation conditions. In order to prevent the effect of fertilization on fish, half of the fertilizer can be applied first, and then half of it, with an interval of 1-2 days, so that the fish have room for manoeuvre.

Fourth, water level management. A week before transplanting the lotus root, the lotus root field stores 5 cm of water, and the water in the fish ditch is separated from the lotus root field; after the lotus root transplanting, the water level of the lotus root field is maintained at 3-6 cm, until a large number of floating leaves appear in the lotus root growth, and then gradually deepen the water level, allowing the fish to feed in the lotus root field. From August to September, the water level should be above 40 cm, and the water should be changed once every 3-4 days.