Detailed explanation of rice-shrimp co-cropping farming techniques, master the method of raising shrimp in rice fields

1. Overview

The “rice-shrimp co-cropping” model upgrades the single planting model of ordinary rice fields into a three-dimensional ecological combination of planting and breeding, that is, raising red swamp crayfish (Procambarus clarkii) during the rice growing period, with red swamp crayfish and rice growing together in the rice field. This production model can make full use of the shallow-water environment and winter fallow period of rice fields, effectively improve the economic benefits per unit area of rice fields, realize dual use of one field and double harvest from one water body, and at the same time further reduce agricultural non-point source pollution and aquaculture tailwater pollution.

2. Technical points

(1) Geographical conditions

The surrounding environment is beautiful, the roads are unobstructed, the water quality is fresh and pollution-free, water and electricity are available, and there is no worry about drought or flooding.

(2) Rice field renovation

Choose a concentrated contiguous area, separated from the surrounding ordinary farmland water system. The area of a single rice field block should preferably be 20 mu, which is convenient for management, feeding and harvesting. Along the perimeter of the rice field, dig a ring ditch 2 m to 3 m wide, 0.6 m to 0.8 m deep, with a slope ratio of 1:1.5 or more. The field ditch accounts for 10% to 15% of the rice field area. Install 80-mesh double-layer silk screen cloth at the water inlet, and a dense-mesh net cover of 40 mesh or more at the water outlet.

(3) Clearing wild species and disinfection

Use 75 kg of quicklime dissolved in water per mu, or 10 kg to 15 kg of camellia seed cake extract, and splash it over the whole pond.

(4) Fertilization

Apply 500 kg of fully fermented organic fertilizer + 15 kg of superphosphate per mu, then rotary till, burying to a depth of 10 cm to 20 cm. The fertilizer is used to cultivate aquatic plants and bait organisms, and is also the base fertilizer for rice. During the breeding process, regularly use photosynthetic bacteria and EM bacteria to strengthen bottom improvement.

Technical points of the rice-shrimp co-cropping farming model

(5) Aquatic plant planting

On the 2nd day after fertilization, transplant Elodea along the shallow-water areas of the ring ditch. Before transplanting aquatic plants, use flurenol to kill blue-green algae, and use tea saponin to kill fish eggs on the aquatic plants. When transplanting aquatic plants, use 3 to 5 plants as one cluster, with a spacing of 1 m to 2 m between clusters, and splash 25 kg of potassium dihydrogen phosphate per mu to promote growth, with aquatic plants accounting for 60% to 70% of the rice field area. In the middle and late stages of seedling rearing, amino acid biological fertilizer can be applied as a top dressing to maintain normal growth of aquatic plants and cultivate natural bait.

(6) Shrimp fry stocking

In mid-to-late March, stock 30 kg to 40 kg of juvenile shrimp of 80 shrimp/jin to 100 shrimp/jin per mu of rice field. Before the fry are put into the pond, they need to be disinfected in 3% to 5% salt water for 3 minutes to 5 minutes. Fry transportation: purchase fry nearby, transport with water and oxygen, or semi-with water, with transportation time within 2 hours.

(7) Management

Escape prevention: build an escape-prevention wall on the field ridge with netting and plastic film, 60 cm to 70 cm high, with the bottom 30 cm to 40 cm buried in the soil.

Bird prevention: after the beginning of spring there are many water birds, and in addition the rice field water level is relatively shallow, so shrimp fry are easily preyed upon. Lines can be strung in the rice field to drive away birds.

Feeding: the daily feeding amount is 3% to 5% of body weight, evenly splashed for feeding. The types of bait include wheat, corn, small trash fish, etc.

(8) Harvesting

Harvesting time: April to June (before rice planting),

Harvesting method: place shrimp cages in the ring ditch and in the middle of the field for harvesting, harvest large ones and stock small ones, alternate stocking and harvesting in turns, and change the position of the ground cages once every 2 to 3 days.

(9) Source of fry for the second year

After the crayfish that have not been fully harvested enter the ring ditch, induce reproduction through manual regulation of the water level.

(10) Rice planting

For rice, medium japonica rice should preferably be selected, using the wide-ridge double-row planting method. Planting time: from early-to-mid June to early July each year.