CATDOLL : CATDOLL: What are the basic conditions for farming freshwater shrimp in rice fields?

1. What are the basic conditions for breeding freshwater shrimp in rice fields?

The rice field where shrimps are cultured is a common place for shrimps and rice to grow. The quality of the rice field conditions directly affects the growth of rice and shrimps, and affects the yield and benefits. Therefore, to cultivate shrimps in rice fields well, it is necessary to select rice fields and carry out rice field engineering construction in accordance with the environmental conditions required for the growth of rice and shrimps (Figure 17).

Figure 17: Farming shrimp in rice fields

(1) Water source quality conditions

The plots used for rice field shrimp farming should be located near water sources, with sufficient water and good water quality. It is best to choose concentrated and contiguous medium- and low-yield farmland, or low-lying wasteland for transformation. The basic conditions for water quality are: dissolved oxygen above 5 mg/L, pH 7-8, no industrial pollution or domestic pollution sources around, and meeting the national standards for freshwater aquaculture. (2) Soil conditions

Loam soil is the best soil for shrimp farming. This soil condition has good water and fertilizer retention performance, fertile subsoil, thick ridges, and is easy to manage water and fertilizer. Generally, sandy soil fields, leaky fields, and other fields that are difficult to retain water and fertilizer are not suitable for use. (3) Environmental conditions

The environment should be quiet, with access to water, electricity, and roads, a wide range of sources of bait and fertilizer, a good foundation for the supply of shrimp seedlings, and a self-contained irrigation and drainage system for the rice fields that is not affected by the fertilization and pesticide spraying of surrounding farmland. (4) Size of the rice fields

There is no strict requirement for the size of rice fields used for shrimp farming. In order to build standardized farmland, achieve uniformity and facilitate production management, 10 to 20 mu is generally appropriate. In order to facilitate unified seed supply, water supply, fertilization and pest control, a scientific drainage and irrigation system should be constructed, and unified planning and layout of roads, bridges, culverts, management buildings, etc. should be implemented. It is best to adopt centralized and contiguous development and unified construction.

2. What are the special requirements for the cultivation and management of rice in shrimp-raising rice fields?

Improving rice cultivation and management is another important aspect of developing shrimp farming in rice fields. We must adhere to the principle of adapting measures to local conditions and comprehensively promote high-yield rice cultivation technology.

(1) Selection of rice varieties

When choosing rice varieties, we must consider the needs of raising shrimp in rice fields and scientifically select them based on local climate, soil and other conditions. Specific requirements: First, they must be resistant to diseases and have few pests and diseases; second, they must be tolerant to fertilizers, have hard stems and are not prone to lodging; third, they must be compact, conducive to ventilation and light transmission; fourth, they must have large ears and many grains, high quality and high yield, and a long growing period. (2) Rice seedling cultivation

Usually, the following steps are mainly used to raise seedlings using dry land film:

① Fertilizer bed preparation: Choose a field that is leeward, sunny and close to water sources as a seedling bed. The seedling bed is 1.2-1.5 meters wide and 20-40 meters long, with a distance of 35-40 centimeters between beds. In early to mid-April, apply 2,500 kg of human and animal manure per mu of seedling bed, and plow and harrow the land several times. One week before sowing, apply 20-25 kg of urea, 100 kg of phosphate fertilizer, and 30 kg of potassium chloride per mu of seedling bed, and plow the land shallowly 3-4 times to promote soil maturation and build a good seedling bed.

② Sowing at the right time: Use 2.5-3.0 kg of selected rice seeds or 1-1.5 kg of hybrid rice seeds per mu of seedling bed. Soak them first, then put them into baskets and put them in the greenhouse for germination at the appropriate temperature. Sow around the beginning of summer, and drop 0.15-0.2 kg of rice seeds per square meter of seedling bed.

③ Strengthen management: After sowing, spread a layer of fine soil and some wheat straw on the seedling bed, cover it with plastic film to increase temperature and moisture, promote uniform seedling growth, and spray the seedlings once on a sunny morning or cloudy afternoon. When the seedlings grow to 2 leaves and 1 heart, apply 10-15 kg of urea per mu to promote seedling growth.

④ Prevention and control of diseases and pests: Use 1 tube of seed soaking spirit mixed with 10 kg of water, soak 6 kg of rice seeds, and prevent seedling blight and dry tip nematode disease. For the first generation of Chilo suppressalis, 25% of insecticide double can be used at the peak of egg hatching, with a dosage of 100-200 ml per mu; or 90% of insecticide single can be used at a dosage of 50-60 grams per mu, mixed with water and sprayed. For weeds in the nursery bed, 45% of dry seedling grass Ning or 60% of new Machete can be used at a dosage of 75-100 ml per mu, mixed with water and sprayed to remove weeds. (3) Transplanting seedlings

The row spacing of hybrid japonica rice is 26-30 cm, and that of conventional japonica rice is 24-26 cm, and the plant spacing is 13-15 cm. 18,000-20,000 holes are planted per acre of net rice field, with 5-6 seedlings per hole, and about 120,000 seedlings per acre. At the same time, 2 more rows can be planted beside the shrimp ditch to give full play to the advantages of the side rows. (4) Rice growth management

The main thing is to do a good job in fertilization, weeding and pest control, and water and slurry management. First, scientific fertilization, the general requirement is to apply enough base fertilizer, appropriate amount of topdressing, and appropriate ratio of nitrogen, phosphorus and potassium to fully meet the fertilizer needs of rice growth, tillering, ear increase and grain increase; second, water and slurry management, requiring shallow water planting, deep water to keep the plants alive, thin water to tiller, dehydration and baking, re-watering to grow and thicken, deep water to ear, shallow water to seed, and water-free harvesting; third, pest and disease control, high-efficiency and low-toxic pesticides should be selected, and attention should be paid to the use method, and caution should be used to avoid harm to the shrimp as much as possible.

3. The shrimp-rice field should be deep and the water level should be appropriate

Shrimp are raised in rice fields. The water level in the rice fields is 30 centimeters in winter and the ditch water is 1.8 meters deep.