Some problems to be paid attention to in the cultivation of shrimps and crabs in rice fields (6.28)

OA show ('918 '); 1 In order to meet the needs of the complex ecological environment of rice field, the newly raised crabs will crawl around the rice field or ditch system in the new environment, which will have a certain destructive effect on the seedlings of barley Therefore, it is necessary to excavate a temporary pond with a depth of 1.2m (slope of 1:2.5) at the water inlet during the field engineering design, which accounts for 8-10% of the rice field area It can not only ensure the adaptability of young crabs to the environment, but also facilitate the intensive cultivation (especially the early propagation of larva in that year, and the cultivation of young shrimps) to improve the listing specifications and survival rate At the same time, the seedlings were put into the rice field after living, so as to reduce the surface or inverted appearance of the seedlings which were collapsed by the young crabs As the saying goes, the size of a crab depends on the water In order to simulate the natural ecological environment of shrimps and crabs, it is necessary to transplant water plants such as bitter grass and round leaf black algae in the ring ditch and field ditch in time after field cleaning and disinfection (peanuts can be released in the temporary pond due to the low water temperature in the early season), so as to create a suitable environment for shrimps and crabs The ecological environment is not only conducive to the exuviation and habitat of shrimps and crabs, but also to the shade and cool in summer, as well as to the prevention of over fertilization of water quality (the water level of rice cultivation is shallow, the water temperature in summer is high, the fertilizer water in rice field is fast after topdressing, and the water quality is thick) At the same time, it plays a role of concealment (the local tea tree is added as the nest of shrimps and crabs, the effect is very good, and it is convenient for blue shrimps to copy under the nest and round catch on the market in normal times), so as to reduce the enemy attack Including the attack of the same kind and the attack of crabs and prawns, it also meets the needs of shrimp and crabs to feed on the tender leaves and roots of aquatic plants With the increase of crab's food intake, paddy field and ditch system water grass will gradually reduce It is necessary to manually add duckweed, Waihe river water grass and other plant baits to ensure that the paddy field is rich in aquatic plants and reduce the harm of crab to seedlings The coverage of water and grass in the ditch system of shrimp and crab cultivation in rice field is about 30%, not more than 50% Too much water will affect the shrimp yield (poor light, less plankton, too clear water quality, large-scale propagation of moss and attached algae) 3 Fertilization problem: the base fertilizer of rice field should be sufficient, mainly the rotten organic fertilizer (cake fertilizer 200-300kg), which should be applied into the cultivation layer one time before transplanting, so as to achieve the long-term purpose, so as to avoid that the water quality is difficult to control due to excessive topdressing, resulting in water anoxia Top dressing should be done a few times Fertilizer harmful to shrimp and crab (such as ammonia water and ammonium bicarbonate) is forbidden Generally, top dressing is once a month, with urea of 5kg / mu and compound fertilizer of 10kg / mu, which has no adverse effect on shrimp and crab Fertilization should avoid the period of crabs exuviating 4 Problems in application of Medicine: the seedlings should be of high fertility, low lodging and high yield, especially those with few diseases and insect pests, such as 95 Series, Shanyou 63, Nanyou 6, liuyou 1, Wuyujing 2, 3 and Yanji 187 Shrimp and crab are sensitive to many pesticides In order to use as little or not as possible, we should apply 1-2 times of high-efficiency delivery of marriage medicine before transplanting seedlings If it is necessary to use it after transplanting, high-efficient and low-toxic pesticides should be selected and sprayed on the rice leaf surface, not into the water as much as possible It is better to use them in different areas To control rice borer, 200 ml 18% insecticide and water 75kg spray were used to control rice planthopper Acacia, 50 grams 25% buflindol wettable powder and water 25kg spray; control rice stripe disease and rice blast, 50% grams of carbendazim 40 grams plus water spray; control rice sheath blight and rice false smut, increase the efficiency of Jinggang mycin 250 ml water spray Spray water should be carried out in the afternoon Most rice leaves are absorbed on rice because of dry leaves in the afternoon At the same time, add water to 20cm in the field before spraying, and change water in time after spraying The application of the medicine should avoid the period of large amount of molting 5 The problem of field shelving: the field should be lightly roasted, not completely dehydrated, and the water level should be reduced to the surface of the field, and the time should be short It is better to bake the shrimp and crab once before they enter the rice field 6 Water quality regulation: the water level of paddy field is shallow, especially in summer, the water quality should be kept fresh and the dissolved oxygen should be sufficient If the water level is too shallow or the water quality is too rich (after fertilization), water should be injected and changed in time Generally, water should be added at 10-11 a.m when the water temperature of the outer river is close to the water temperature of the rice field; irrigation should be conducted at the same time of drainage, so as to ensure that the water level is relatively stable and the temperature difference is small At the end of June, change water 1 / 5-1 / 4 a week, 3-4 times a week in July and August, preferably once a day (or micro running water), change water 1 / 3; after September, change water every 5-10 days, change water 1 / 4-1 / 3 every time The transparency in high temperature season is 40 cm, generally 25-30 cm The temporary pond and ring ditch shall be sprinkled with quicklime regularly once every 15-20 days, 5-10kg per mu 7 Enemy problem: there are many enemies in shrimp and crab breeding in rice fields (such as frogs, toads, water snakes, loaches, eels, water rats, etc.) In addition to thorough pond clearing, water intake and drainage of 40-80 mesh double screen silks, it is very important to remove the enemy organisms in the field The general enemy can be captured by conventional methods or eliminated by applying 10 ppm concentration of tea seed cake If the harm of water rat is great, we can use the combination of rat medicine, rat cage, rat clip and other methods to control China feed industry information network EKV (author:)