The combination of rice and shrimp rotation and breeding is believed to be familiar to many farmers. Now the win-win situation of this joint work is very common in rural areas. The symbiosis of rice and shrimp is the model of symbiosis and mutual benefit between rice and crayfish. Let's study the technical methods of symbiotic breeding of rice and shrimp in the Dongting Lake area for reference.
1 Rice field transformation
1.1 Basic measures for rice field transformation
Raise the reinforcement of the field and excavate the shrimp ditch and the trench.
1.2 Basic requirements for rice paddy transformation
Tian Hao must be tight and compact; Tian Yukuan is 2.0 to 2.5 m, the height of the levee is 1.0 to 2.0 m, the slope ratio is (1:2) to (1:3), and the field is required to be 0.6 to 0.8 m above the surface of the field. The depth is 1.5 m and the width is 3 to 4 m. The unit area is larger than (100×667) m 2 , and the “Ten†or “well†type trench is to be excavated in the field. The depth of the trench is 0.8-1.0 m. The width is 1.0-1.5 m, and the trench is set along the short side. The trench is also one of the essential shrimp ditch in the rice shrimp field. Like the dry soil, the unit area is less than (50×667) m 2 or the unit area is larger. Large rice shrimp fields, after excavating the "Ten" word ditch and "Jing" word ditch, must be opened at 2.0 m (planting rice on the car), the groove width is 0.3-0.4 m, and the depth is 0.2-0.3 m. Generally, the total area of ​​the shrimp ditch is 10% to 20% of the unit area, and the rice paddy field with a large unit area has a large shrimp ditch area.
1.3 The role of shrimp ditch
1) Preserving rainfall, reducing farmland discharge, reducing water and fertilizer loss, and purifying public water bodies.
2) Planting water plants, purifying water quality, creating a high quality habitat for crayfish and providing a quality food source.
3) Provide crayfish shelters when handling agricultural techniques in rice production.
4) Coordinate the ecological environment such as rice, water, fertilizer, gas and heat, and promote rice yield and income.
5) Improve the quality grade and yield of crayfish, and change the fishing (spring) to two fishing (spring and autumn), which greatly improves the efficiency of shrimp farming.
2 anti-escaping natural enemies
Basic measures: Set up anti-evasion walls around the perimeter, set up anti-escape nets in the water inlet and outlet, erect straw scarecrows, and poison the rats; the first breeding must also apply lime to kill aquatic natural enemies.
The anti-evasion wall can be erected with cement tile, composite plate and buried plastic film. The base is required to be buried in the field 0.2 to 0.3 m (under normal water level), and the upper field is 0.1 to 0.2 m, and wood is used every 1.0 to 1.5 m. Supporting materials such as piles and bamboo poles are supported and reinforced; an encrypted wire mesh or barrier is set up at the inlet and outlet.
Frogs, water snakes, scutellaria, loach, carnivorous fish, water mice and waterfowl are the main natural enemies of crayfish. The first stocking of crayfish requires 50-75 kg of quicklime per 667 m 2 (the amount of mud feet must be increased) to kill jaundice, carnivorous fish, snake eggs and frog eggs. Inlet water must be filtered with a 20 mesh gauze net to prevent the intrusion of fish, the peak of water mouse activity or the crayfish hole breeding period, the poison bait poisonous mice, erecting scarecrows and ribbons, threatening to drive water birds.
3 kinds of grass bait, regulate water quality
3.1 Basic requirements
Planting aquatic plants is the key to the success of shrimp farming. The basic requirements for planting grass are the combination of upper, middle and lower, and the combination of ups and downs, sparse and uniform. The water grass accounts for about 60% of the water body area. The water grass is 60% of the submerged water grass and about 40% of the suspended water grass. The suspended water grass must be fixed with bamboo frame, and the water grass should be too dense and timely, and the plant should be replanted in time. Delivery.
3.2 Selection of aquatic plants
Commonly used submerged grasses include Hydrilla verticilla (Lanna algae), Elodea (Osmanthus fragrans), Ceratophyllum algae, Vallisneria (flat grass), and commonly used suspended water grasses have water peanuts (revolution grass).
3.3 The role of planting water plants
1) Provide botanical bait for growing crayfish and animal bait (culture microbes).
2) Adsorption and absorption of water-rich nutrients, purification of water quality, regulation of water environment.
3) absorbing sunlight for photosynthesis, increasing the amount of dissolved oxygen in the water, which is conducive to the metabolism of crayfish.
4) Provide crayfish with habitat, shelling and shelter from the enemy to prevent damage.
5) Prevent the sun from drying in the hot season and cool down in summer.
3.4 Water quality control
The visibility of water body is 0.3-0.4 m, which is clear and moderate. It is the best growing environment for crayfish. It is not conducive to the growth of crayfish by over-clearing, over-green, over-black and over-turbid. If the water body is too clear, the water is too thin, the nutrients and microbes are too small, the food source is lacking, the water level should be appropriately lowered, the water body temperature and photosynthetic efficiency should be increased, the organic fertilizer should be added, and the amount of feed should be increased; if the water body is green, the water level is opposite. Too shallow, fertilizer nutrient excess, too much bait, organic dirt accumulation, need to kill cyanobacteria, raise the water level, add new water, reduce the amount of feed properly; water quality is turbid, because the water is too little, water The layer is too shallow, or affected by temporary rainfall, it is necessary to increase the suspended water grass, increase the water level, and apply the medicine symptomically; the water body is too dark, which is caused by the decay of the high temperature season and the weeds in the field or excessive feeding and excessive excretion. It shall be treated with water exchange and combined application of modified substrate.
4 feeding
The method of placing prawn in the symbiotic breeding mode of rice and shrimp is divided into autumn and spring according to time; according to the method of seedling, the prawn is placed and the shrimp is placed. Among them, the broodstock can be divided into male and female with broodstock and female prawn.
4.1 Fall delivery mode
The autumn delivery mode is mainly based on broodstock. The crayfish enters sexual maturity at the end of July, and enters the mating peak in September. The female prawn holds eggs in October. According to this rule, it is generally recommended to put 30 to 60 kg of broodstock with a specification of 5 to 10/kg per 667 m2 from August to September, in which the ratio of male to male is 3:1. Moreover, it is required that the male and female do not choose from the same population to exert their hybrid advantage. It is also possible to directly deliver female prawn in mid-to-late October, with a dose of 10 to 15 kg per 667 m 2 . The advantage is that it does not need to be matched with male shrimp, and its reproductive rate is higher than that of stocking male and female. The autumn delivery mode uses winter idle feeding to increase the fattening time. From April to June of the next year, it can be launched early and arrested, which can reduce costs, increase production, and catch up with market prices and increase production value and efficiency.
4.2 Spring delivery mode
The spring delivery mode is mainly based on shrimp seedlings, and the juveniles with a specification of 50-75 tails/kg are stocked, generally 40-70 kg per 667 m2. It should be released from March to April, and it should be sooner rather than later. It will be arrested from May to June. When fishing, catch large and stay small.
Two types of rice-shrimp fields with standard shrimp ditch can be caught twice a year, that is, April-June and August-September.
4.3 Feeding Management
The juvenile shrimp are mainly fed with animal feed and juvenile shrimp compound feed; the animal feed includes fish gills, minced screw meat, and scraps of the slaughterhouse, and the daily feed amount is 5% to 8% of the total mass of the juvenile shrimp. Feed 3 times a day, and allocate 20% in the morning, 20% in the afternoon, and 60% in the evening. The feeding of adult shrimp is mainly from March to June. When the water temperature rises to 12-15 °C, the shrimps start to feed. The water plants and feeds should be properly replenished. The water grass should be placed once every 2 weeks, and the dosage should be 100 per 667 m 2 . ~150 kg, one animal feed per week, the amount of feed is 2% of the amount of shrimp, one artificial feed (cake, bran, rice bran, bean dregs) is given every evening, and the amount of shrimp is The amount is 2% to 5%, and the feeding amount is adjusted according to the foraging situation of the shrimp.
5 crayfish disease prevention
Crayfish disease prevention and control work should adhere to the principle of "preventing prevention, combining prevention and treatment". Common diseases are viral diseases, bacterial diseases, parasitic diseases and stress reactions. Mainly through regular water transfer, bottoming, health care drug prevention and other prevention and control measures to reduce disease occurrence, to maximize the benefits of farming.
5.1 Bacterial diseases (carapace ulcer disease)
In the initial diseased shrimp, some dark spots appeared in the shell, and then the edge of the spot festered, and the cavity was necrotic.
The main control methods: avoid damage, cultivate water plants, make the habitat empty, prevent food and pile up, and use 2 to 3 g·m -3 of deep white powder water for spilling.
5.2 Viral diseases
In the early stage, the shrimps were weak and slow, and they were slow to move on the surface of the grass and shallow water in the field. After the dissection, a small amount of shrimp was found to have black sputum. The common expression showed no food in the intestine, and the hepatopancreas was swollen. Occasionally, there was bleeding (a few heads) There are white patches on the lower edge of the breastplate. There is yellow water in the chest of the diseased shrimp.
The main prevention and treatment method: use drugs to spill. 1) Sprinkle with povidone iodine so that the concentration of the drug in the water is 0.3-0.5 g·m -3 . 2) The quaternary ammonium salt is used to complex the iodine and the concentration of the drug in the water is 0.3-0.5 g·m -3 . 3) Dissolve 100 g of the unit chlorine dioxide in 15 kg of water and pour 667 m 3 of water. Povidone iodine and unit chlorine dioxide can be used interchangeably. Each drug can be used twice in a row, with an interval of 2 to 3 days per administration.
5.3 Parasitic ciliate disease
The typical condition is that ciliates are attached to the limbs of the shrimps, juveniles, or the surface of the fertilized egg to form a thick layer of hair.
The main control method: disinfection with quicklime before breeding to kill the pathogen. During the culture, the disease was found to be controlled by quaternary ammonium complex iodine.
6 water level control
The water level control of rice shrimp fields is very important. The production practice proves that the crayfish quality level is positively correlated with the water level depth during the cuckoo season from April to June and August to September. Therefore, the management of water level must meet the growth needs of crayfish, and also meet the growth requirements of rice. The conventional water level regulation methods are as follows.
1) From March to early April: In order to improve the water temperature of rice paddy fields and promote crayfish out of the hole for food, the water level should be lowered. The water level in the field is controlled at 0.1-0.2 m, and the water level in the shrimp ditch is controlled at 0.4-0.5 m.
2) From mid-April to early June: the temperature rises and the water temperature in the paddy field rises gradually. The water storage capacity of the rice paddy field should be increased, which is beneficial to the reproduction of microbes, aquatic plants and other foods, as well as improving the environmental quality of the water body and benefiting the crayfish. Growth, paddy field water storage 0.3 ~ 0.4 m, shrimp ditch water storage 0.6 ~ 0.7 m.
3) In the middle and late June: the fishing is over, the ridges are used as the cultivating rice, the live mud is thrown, the shallow water is live, and the paddy water level is kept 2~3 cm to promote the rice rooting.
4) July: The rice is in the period of regreening to jointing stage. In the early stage, the appropriate water storage is 0.1-0.2 m, so that the crayfish can enter the field foraging. In the later stage, the rice field is taken into account and the rice field control requirements are taken into consideration, which is conducive to rice growth.
5) August-September: Rice enters the booting stage and flowering stage, which can increase the water storage depth, and the field water level can be stored to 0.3-0.4 m. When the rice enters the milk ripening period in September, the water level can be gradually lowered to expose the field, forcing the crayfish to enter the shrimp ditch to prepare for rice harvesting.
6) October-November: After harvesting the rice, the water level can be appropriately deepened, but the rice blast must be exposed to a water surface of about 0.1 m, which can regenerate some rice blasts, provide fresh crayfish forage, and avoid flooding and rot due to rice blast. To the water quality, excessive stress and lack of oxygen affect the growth of crayfish.
7) From December to February of the next year: During the wintering period, the crayfish should be raised in the paddy field, and the water storage should be 0.3-0.4 m. The deep-water insulation will help the crayfish to survive the winter safely.
7 Rice pest control
Crayfish are sensitive to many pesticides and should not be used if they are not used, especially insecticides and herbicides. Under normal circumstances, crayfish can eat weeds, eggs and adult larvae of locusts and mites, and effectively control pests. When controlling diseases such as sheath blight, blight, rice blast, etc., the surface water layer should be drained and the diseased plant parts should be sprayed in a targeted manner. In order to ensure the health of crayfish and reduce the cost of rice production, it is necessary to appropriately improve pest control indicators, reduce the amount of drugs used and the number of drugs used, and use high-efficiency, low-toxic and low-residue pesticides and biological pesticides. The main indicators and medicaments for rice pests and diseases are listed in Table 1.
Table 1 Control indicators and agents for four major rice pests and diseases
The above is all the content of today, the source is the headline number Jishan Huayao, the favorite farmers can pay attention, is there any better experience about the rice-shrimp symbiosis rotation?
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