Three-dimensional polyculture of fish, shrimp and shellfish generally adopts tilapia, prawn and SINONOVACULA constricta for three-dimensional culture, which is a comprehensive culture mode that makes full use of the water in shrimp ponds and increases economic benefits. The basic method is to raise a certain number of tilapia and SINONOVACULA constricta under the normal production conditions of shrimp culture, so as to form a benign ecological environment in the shrimp pond.

The technical points are as follows:

(1) The preparations for pond repair, dredging and leveling should be done well as soon as possible. Generally, the pond should occupy 1/3 ~ 1/2 of the whole shrimp pond area.

(2) According to China shrimp culture standard, the pond was cleaned by sowing razor clam seedlings in the pond. When the medicinal properties fail, sow the seedlings of razor clam at the bottom, and choose natural seedlings with uniform size, such as 4000-5000/kg, 80-100kg every 667m2. Remember to sow them evenly.

(3) Feed water and fertilize to cultivate basic bait, then feed water and apply basic fertilizer in time. At this time, we should pay attention to the reasonable combination of nitrogen and phosphorus to maximize the proliferation of zooplankton in water, that is, to maximize the primary productivity of water. It is suggested that the ratio of nitrogen to phosphorus (effective concentration) is 5∶ 1. Please note that phosphate fertilizer should not be used with alkaline substances such as lime.

(4) After feeding the fish and shrimp fry for a period of time, the water is yellow-brown or yellow-green. At this time, the shrimps and fry can be released. Generally, the release specification is 2.5 ~ 3.0cm, with 208,000 ~100000 shrimps per 667m and 2 150 tilapia larvae per 667m.

(5) The transparency of water management should be controlled within 20 ~ 30cm. In the future, phosphate fertilizer should be added frequently to promote the growth of phytoplankton, which is beneficial to purify water, increase dissolved oxygen, inhibit the growth of pathogenic bacteria, and also play a role in shading. It is suggested that water should not be changed during culture, and only the leaked and evaporated water should be added.

(6) Special attention should be paid to the use of disease prevention drugs: do not destroy the microecological balance of water bodies, and it is best to use oral drugs or make drug bait. This polyculture model organically combines the characteristics of fish, shrimp and shellfish. The residual bait and fish and shrimp feces make the water in the shrimp pond too fat, so Sinonovacula constricta uses the fat water to promote its own growth. At the same time, it also improves the water quality, reduces the discharge of sewage, and achieves the purpose of biological water purification. The cave life of SINONOVACULA constricta increased the permeability of sediments, accelerated the decomposition of organic matter at the bottom of the pond, and further improved the organic pollution at the bottom of the pond. In addition, SINONOVACULA constricta's respiration and food filtration also promoted the flow of bottom water and accelerated the exchange of water, thus relatively increasing the dissolved oxygen in the bottom water. In addition, tilapia can feed on benthic organic debris and phytoplankton, especially cyanobacteria. Because of its unique digestive ability, it absorbs and digests microorganisms and bacteria in water at the same time, which plays a good role in purifying water and killing bacteria. In a word, because of their complementary characteristics, combining them is conducive to the formation and development of a virtuous circle, but also promotes the growth and development of shrimp, fish and shellfish, and increases economic benefits.

The content of this article comes from: China Agricultural Development Report by China Agricultural Publishing House.