Zizania latifolia, also known as Zizania latifolia and Zizania latifolia, has the biological characteristics of no pregnancy when the temperature exceeds 30 degrees, the market is out of stock and the price rises. This double-season water bamboo variety is extremely resistant to high temperature, and does not need a cold climate or special cultivation techniques. It can be planted from June 165438+ 10 to April of the following year and listed in April-June, or it can be planted in June-August of the Gregorian calendar and listed in June-June, ending in June-August. After the end of this variety, the conventional water bamboo (bamboo shoots) will not be listed until 6 months later. Traditional summer onion will be on the market from August to September, and our variety 10 will be on the market. This double-season water bamboo variety is an excellent opportunity for water bamboo planting.
Three. Quality characteristics (1) Nutritional components and edible value Water bamboo generally contains protein 1.4%, fat 0.3%, sugar 3.5%, crude fiber 1. 1%, and a lot of water and inorganic salts. Because the organic nitrogen exists in the form of amino acids before the water bamboo matures, the water bamboo has excellent quality and delicious taste, and is a vegetable with high nutritional value. Autumn harvest of northern water chestnut or double-season water bamboo has a certain effect on vegetables in off-season of drip irrigation regulator. There are many ways to eat Zizania latifolia in Jinan, many of which are included in Shandong cuisine recipes and become famous dishes at banquets. 1. Variety selection In the south, we should choose varieties with early harvest, high yield, strong stress resistance and good heat resistance and products that meet market demand. Second, the selection of seed plants of Zizania latifolia is propagated by ramets, and the quality of seed plants directly affects the yield, yield and quality of Zizania latifolia. Because of the difference in the invasion time, quantity and cultivation management level of smut, species often degenerate, leading to the emergence of male water chestnut and gray water chestnut, so seed plants should be strictly selected every year. The selection requirements of excellent mother plants are: neat plant shape, early pregnancy, many knots, fat meat and beautiful shape; The belt position is low and the maturity is consistent; There are no male, gray, green and deformed piers to keep seeds. Double-season water chestnut seedlings go to YEATION three times a year; 1 time: selecting the water bamboo planted in the same year at the time of harvesting, selecting excellent single plants as seeds according to the selection criteria and marking; The second time: check the selected seed plants 1 time in the spring harvest, and remove the non-standard seed plants; The third time: combined with the management of winter water field, the piers such as male plants, miscellaneous plants, gray plants, green shells and abnormal water rows were dug out in time. General planting 1 mu field needs about 250 planting piers. Third, the choice of paddy field The planting sequence of double-season water bamboo in South China is related to the control of soil layer, water layer depth and water temperature. Generally, paddy fields with high altitude will be earlier than paddy fields with low altitude, windward slopes will be earlier than sheltered low-lying areas, and paddy fields with shallow soil layers (preferably 20-27 cm) will be earlier than paddy fields with deep soil layers. Therefore, paddy fields with sufficient water, convenient irrigation and drainage, good ventilation and shallow soil layer should be selected as far as possible for planting Zizania latifolia in southern China. Fourth, plough the farmland and apply sufficient base fertilizer. Paddy fields are generally ploughed in time after rice harvest, and old fields are generally ploughed in time after autumn harvest, and the fields are fully aired and ridged to ensure that 15-20cm can irrigate the fields. During the whole field, apply 100 tons of decomposed pig manure and cowshed manure or 1000 kg of chicken manure and 50 kg of phosphate fertilizer as base fertilizer per mu, harrow and water for 2-3 cm to make the field flat, muddy and full of fat. 5. Timely planting time: South double-cropping Zizania latifolia is usually planted before the end of June-August or before the end of June-August, but it can only be harvested in autumn, and it should be planted at the end of April or August at the latest. Methods: Leave 10 cm before planting, cut off the dead leaves on the ground of the selected superior seed pier, dig out the superior seed pier, split the robust old stem seedling, and take an old stem with roots as the seedling. The planting density is wide 1m, narrow by 0.8m, and the spacing between plants is 0.6m. The planting density is about 1400 piers per mu. The planting depth should be that the white part of the old stem enters the mud (that is, the original depth). Field management of intransitive verbs (1) Management of newly planted fields 1. Irrigation: Water cannot be cut off during the whole growth period, and the water level should be adjusted with different growth stages.
(1): After planting Zizania latifolia, the field should be kept in shallow water of 2-4 cm for overwintering. When Zizania latifolia seedlings begin to grow in spring, the water level should be kept shallow, about 2-3 cm, which is beneficial to the increase of ground temperature and the promotion of germination and tree growth. Later, as the plants grow, the water level will gradually deepen.
(2) Before and after 50 days of planting, the field can be baked once according to the tillering situation of Zizania latifolia (the degree of baking depends on the crack of chicken feet), and then water with the depth of 10- 15 cm can be poured to control the ineffective tillering.
(3): During pregnancy, the water level can be controlled at 20 cm, but it can't exceed the white eyes, so as to prevent the water pipe from rising. After mid-March, the temperature rises gradually, so it is necessary to change water frequently, and it is best to use running water for irrigation, which is beneficial to pregnancy in spring.
(4): After harvesting, the water level drops to about 6 cm; After harvest, the water level drops to 3-4 cm. Stay in shallow water for 2-4 cm when hibernating.
(5): Put shallow field water before each fertilization, fertilize and cultivate the soil, drain the field water before irrigation. 2. Top dressing: Top dressing should be done sooner rather than later in southern double-cropping water bamboo to promote early seedling development and early pregnancy. Combined with aquifer management, it can promote effective tillering in the early stage, control ineffective tillering in the later stage, promote pregnancy and improve yield and quality. Zizania latifolia has a long growth period, tall plants and a large amount of fertilizer. In addition to applying sufficient base fertilizer, topdressing must be timely. (1) If base fertilizer is not applied to the newly planted farmland, it should be supplemented within 15 days.
(2) When the old stems germinate, apply 30 kg ammonium bicarbonate or urea 10 kg per mu.
(3) Planting for about 30 days (early tillering stage), applying 45% compound fertilizer 30-50kg per mu.
(4) In the spring water chestnut harvesting process, appropriate topdressing can be carried out according to the growth of water chestnut seedlings.
(5) After harvesting in spring, 20-30 kilograms of 45% compound fertilizer can be applied per mu to facilitate the growth in autumn. 3. Tillage and weeding: In the water bamboo field, iron harrows or manual ploughing can be used between the rows of water bamboo to achieve the purposes of intertillage, loosening soil and weeding, and can increase the soil temperature and accelerate the decomposition of fertilizer. Generally, plow 2-3 times, the first time when the plants start to turn green, and then every 15 days. 4. Remove the ashes: The ashes cannot be bound, and should be removed at any time. The empty space removed can be supplemented by seedlings with more tillers on the normal pier. 5. Stripping dead leaves and pulling yellow leaves: Stripping dead leaves and pulling yellow leaves, removing dead leaves and improving ventilation and light transmission conditions among plants. Generally, in the late spring harvest, according to the growth of plants, the dead leaves are stripped, and the requirements are not to pull out, and the pulled yellow leaves are stepped into the ground as fertilizer. 6. Sparse seedlings and replenish seedlings: When the tillers of double-season Zizania latifolia planted in the south reach more than 15/pier, the seedlings should be thinned, and the over-dense small tillers should be removed, leaving about 15-20 effective tillers/pier. After thinning, a piece of mud should be pressed in the middle of the pier to make the plants evenly distributed and ventilated. (2) Management of old farmland. Dead leaves should be removed before 65438+February, leaving 10 cm old stems to cut off residual plants on the ground, digging out male plants, gray plants, miscellaneous plants, green plants and abnormal plants in the shell, digging seedlings from superior plants, replanting in shallow water, applying more organic fertilizer, and so on. Top-dressing 30 kg ammonium bicarbonate or 10 kg urea per mu in early February, and top-dressing 30-50 kg 45% compound fertilizer per mu in mid-March. When thinning seedlings, leave about 20 trees per pier. Other management such as water level is the same as that of new farmland. Seven, pest control in South China, high temperature resistant pests and diseases are mainly flax leaf spot, rust, rice planthopper, stem borer and so on. 1) Fungal diseases of flax leaf spot: (Hemimycotina). It can occur in the whole growth period of Zizania latifolia. 1. Symptoms: yellow-brown spots appear on the leaves at the initial stage, which gradually expand into oval sesame-sized brown spots (there are often yellow halo around the diseased spots); Late stage: the edge of the lesion is brown, and the middle is yellowish brown or grayish white. In severe cases, the diseased spots are connected into irregular large spots, and dark gray to black mildew spots are formed on the surface when the humidity is high. The damaged leaves dry down from the tip of the blade, which often leads to half or all of the leaves dying in the later stage, resulting in reduced production. 2. Infection process: hyphae and conidia overwinter on the residual leaves of Zizania latifolia and spread with airflow or rain. 3. Environmental factors: the soil is acidic, the potassium and zinc are deficient, the fields are poorly managed or weak, and the condition is serious after long-term deep-water irrigation and hypoxia. In hot and humid weather, excessive application of nitrogen fertilizer is futile, poor ventilation and light transmission in the field, and the disease is aggravated. 4, prevention and control methods:
(1) In combination with stubble clearing before winter, collect diseased old leaves and burn them centrally, so as to reduce bacterial sources.
② Strengthen fertilizer and water management, apply wax fertilizer in winter, apply seedling fertilizer in spring, spray foliar fertilizer in time, and pay special attention to supplement phosphate fertilizer, potassium fertilizer and zinc fertilizer to enhance the disease resistance of plants.
③ Chemical control: Before May and at the initial stage of the disease, spray 600 times of 50% chlorpheniramine suspension, 500-600 times of 50% polysulfide wettable powder or 500 times of 20% tricyclazole, and use alternately for 2-3 times continuously. Use with caution during pregnancy. 2) Fungal diseases of rust (Basidiomycotina) harm leaves and leaf sheaths. 1. Symptoms: During the onset, yellow-brown convex microspores will appear on the front and back of leaves. After the microspore is broken, the rust stain will disperse. The lesions are scattered and irregularly arranged. In severe cases, leaves will die or plants will become short. 2. Infection process: hyphae and spores overwinter on the diseased plant residues, spread by airflow, high temperature and high humidity, and local application of nitrogen fertilizer are beneficial to the disease. (Beat the old yellow leaves in time) 3. Prevention and control methods:
① Remove diseased plants and weeds in the field.
② Increase the application of phosphate fertilizer and potash fertilizer to avoid partial application of nitrogen fertilizer.
(3) Proper irrigation in high temperature season can reduce water temperature and soil temperature and control diseases.
④ Chemical control: spray 800 ~ 1000 times of 15% triadimefon wettable powder, 500 times of 50% sulfur wettable powder or 200 times of 67% sodium dichloride wettable powder every 7 ~ 10 days. Use with caution during pregnancy. 3), plant hopper control method:
(1) Remove the residue of Zizania latifolia in winter and reduce the number of overwintering eggs.
(2) Peeling dead leaves and pulling yellow leaves in time will increase ventilation and light transmission in the field, which will cause unfavorable living environment for adults.
③ Chemical control: 10% imidacloprid wettable powder 1500 times solution or 3000-4000 times solution of 90% DuPont Wanling wettable powder can be used for control. 4) Control methods of stem borers:
(1) Reduce the population base of overwintering insects, remove the disease and disability of Zizania latifolia when cutting piers before winter, and remove weeds in fields and ditches in spring to eliminate overwintering larvae.
② Chemical control: During the whole incubation period, spray control with 5% Regent rubber suspension/0/000 times solution or 50% acetaminophen EC/0/000 times solution. 5) The symptoms and characteristics of smut of Zizania latifolia mainly infringe on underground stems (bamboo shoots) of plants. The infected Zizania latifolia plants grew weaker, their leaves widened, their leaves were dark green and their sheaths were black. Digging and inspecting underground stems (bamboo shoots), it was found that underground stems became shorter, and some of them were inspected for meat quality, and it was found that the meat quality turned black and showed short strips (spores with immature bacteria) or scattered with black powder (spores with mature bacteria). Pathogenic bacteria and pathogenic characteristics The pathogenic bacteria are basidiomycetes subfamily, smut. Pathogens lurk in underground stems in the form of mycelium. When a new bud germinates, hyphae invade the bud from the mother stem and develop synchronously with the bud growth point. The metabolism of pathogenic bacteria produces a hormone substance called indoleacetic acid, which stimulates the tender stem of Zizania latifolia to expand into a spindle shape, and the pathogenic bacteria spread vertically and horizontally in the expanded underground stem (bamboo shoot), forming a winter spore pile from vegetative growth period to reproductive growth period. At this time, there are many short black stripes on the tender stems of Zizania latifolia. A large amount of black powder (winter spore mass) is released when the winter spore pile matures. Sick stems can't bloom. If plants have too many tillers, or lack of fertility, or improper irrigation, diseases are often very serious. There is still a lack of investigation on the difference of disease resistance among varieties. Among the 16 varieties of Zizania latifolia introduced in China in recent years, 8602 and 8937 cultivated by Wuhan Vegetable Branch have strong resistance and adaptability, but whether they are resistant to head smut needs further observation and determination. The control method (1) selected no strains. (2) Strengthen management. In spring, the old pier should be cut and pressed to reduce the tillering node position of plants; When the old pier germinates, the over-dense tillers are removed to promote orderly germination; Manage the water layer well, lightly irrigate before tillering, bask in the sun in the open field in the middle period, and irrigate deeply in the high temperature period to inhibit tillering in the later period; Rational fertilization, on the basis of adequate basal fertilizer, timely topdressing in early stage to promote tillering growth, appropriate topdressing in high temperature stage to control and inhibit late tillering, and timely removing yellow leaves in summer and autumn to improve plant permeability. 6) Symptoms and characteristics of soft rot of Zizania latifolia. Soft rot of Zizania latifolia mainly occurs during the transportation, sale and storage of bamboo shoots after harvest. At first, the infected bamboo shoots were nearly round to amorphous and semi-transparent water-stained spots, then the diseased spots expanded rapidly, the infected tissues were soft and rotten, and the smell was unpleasant. Finally, some or most of the bamboo shoots rotted and could not be eaten. The symptoms of the affected part are generally not obvious, and there is a sticky feeling when touching. Pathogenic bacteria and disease characteristics The pathogenic bacteria are bacteria, which belong to the pathogenic type of carrot. Carotovora (Jones) Bergey et a 1. ], which is the same as the pathogen of soft rot diseases such as cabbage. The pathogen has a wide host range, which not only harms cruciferous vegetables, but also infects vegetables such as Solanaceae, Liliaceae, Umbelliferae, Compositae and Gramineae. Pathogens overwinter in the form of bacteria in sick plants in the field and seed plants in the cellar, or in soil or soil miscellaneous fertilizers or even pests with sick residues, and spread through rainwater, irrigation water and fertilizers with bacteria and insects, and invade from the wounds of the host to cause diseases. In the process of transportation and sales, bamboo shoots are mainly infected through the contact between diseases and healthy tissues. The author first discovered this disease by accident from bamboo shoots sold in food stalls in the market. At that time, there were also a few strains of soft rot in Chinese cabbage sold in food stalls, and it was believed that the source of the pathogen was Chinese cabbage infected with soft rot in food stalls. The author once brought diseased bamboo shoots indoors, and contacted the leaves and petioles of Chinese cabbage with diseased bamboo shoots and healthy bamboo shoots or diseased bamboo shoots, and kept them moist for a period of time (about 24 hours). As a result, healthy bamboo shoots and healthy Chinese cabbage leaves are sick. It shows that the diseases of bamboo shoots in the sales process are caused by contact infection. Prevention and control methods Bamboo shoots are edible products of water bamboo plants after harvest. In order to facilitate short-term storage or transportation to surrounding areas, water bamboo products often keep the leaf sheath of water bamboo meat, so that the water bamboo meat can be stored for 5-7 days without turning yellow. When this kind of Zizania latifolia product enters the wholesale market and is distributed to food stall operators, the leaf sheath is removed to expose Zizania latifolia (that is, bamboo shoots can only be stored for 1 ~ 2 days) and supplied to the market on the spot. In view of the fact that soft rot of Zizania latifolia mainly occurs in this link, the following points should be paid special attention to in the prevention and control of this disease: (1) When the leaf sheath of Zizania latifolia is peeled off, the suspected diseased bamboo shoots should be removed and treated separately to avoid contact and infection. (2) Be careful not to stack and sell bamboo shoots with cruciferous vegetables such as large and small cabbages to prevent or reduce the contact infection of soft rot. If an individual or a small amount of cabbage is found to be infected with soft rot, it should be handled thoroughly and properly in time to avoid the spread of the disease and cause greater losses. (3) According to the experience of Wuxi, soaking the base of Zizania latifolia in alum powder or in 1% ~ 2% alum water for a while can prolong the storage time of Zizania latifolia products at room temperature (about l0 days). Based on this, the author suggested that l2% soluble agricultural streptomycin sulfate powder (4000 ~ 5000 times solution) should be added to alum solution in areas or food stalls where soft rot of Zizania latifolia often occurs, which could reduce contact infection and inhibit the spread of soft rot. Similarly, if soft rot of cabbage vegetables often occurs, streptomycin sulfate (the same concentration as above) can also be tried for treatment. VII) Symptoms and characteristics The disease of Zizania latifolia, also known as Zizania latifolia disease, mainly affects leaves. Leaf lesions can be divided into three types: acute, chronic and brown spot. The acute spots are punctate and dark green, and the gray-green mildew symptoms (conidia and conidia) on the back of the spots are obvious, which is a precursor to the epidemic of Zizania latifolia. Chronic plaque is nearly spindle-shaped, resembling a bull's eye, with reddish-brown periphery and gray-white center. There are often long or short necrosis lines at both ends of the lesion. This symptom is transformed from acute plaque, and its appearance shows that the disease in the field has changed from acute to remission, and the symptoms of spot back disease are not obvious. Brown spots are brown spots, which are similar to those of water bamboo, but there is no yellow halo outside the spots, which are more common in old leaves and occur in high temperature and dry weather conditions. Pathogenic bacteria and disease characteristics The pathogenic bacteria is [Pyriculariazizaniae Hara]. Pathogen overwinters on old plants or diseased residues with hyphae and conidiophore, and conidia is the inoculum of primary infection and reinfection, which spreads through the epidermis after wind and rain. High temperature and high humidity weather, especially when the rain is continuous and the sunshine is insufficient, is conducive to the occurrence of this disease. When nitrogen fertilizer is applied, the growth of plants is too strong or the canopy is too dense. The difference of disease resistance among varieties has not been investigated, and whether some new varieties with strong stress resistance, such as 8602, 8937, 860l, Yang Jing L, 83- 1, Zhejiao No.2 and No.5, are also resistant to this disease needs further observation and determination. Control method (1) Select disease-resistant varieties according to local conditions. (2) Combined with pier cutting before winter, collect sick and disabled materials and burn them, so as to reduce the source of bacteria in the coming year. (3) Strengthen fertilizer and water management. Formulated fertilization to avoid biased application of nitrogen fertilizer; Managing the water layer well, avoiding long-term deep irrigation, paying attention to timely and moderate sun exposure, improving root activity and enhancing plant stress resistance are helpful to alleviate diseases. (4) Spraying drugs as early as possible to prevent and control diseases. In the peak tillering stage of plants, according to the requirements of disease-free early prevention and early treatment, inspection should be strengthened, and selective treatment or comprehensive treatment should be decided according to seedling conditions, weather and disease (whether it is onset or not, disease spot type, etc.). ). This pesticide can be sprayed with 20% tricyclazole wettable powder 1000 times, or 40% isoprothiolane (Fuji 1No.) EC 1000 times, or 50% Vantorin SC (pesticide plant, Jiangmen, Guangdong) 600-8000 times. VIII) Symptoms and characteristics of sheath blight of Zizania latifolia. The sheath blight of Zizania latifolia mainly occurs in the field and invades the leaf sheaths and leaves of plants. At first, dark green oval spots appeared on the leaf sheath near the water surface, and then expanded and connected with each other to form moire or tiger spots. The edge of the spot is dark brown, and the boundary between the diseased part and the healthy part is clear. The middle of the spot is light brown to grayish white. The lesions spread from bottom to top, extending to the leaves, causing moire spots on the leaves. When the disease is serious, the leaf sheath leaves die early, and the fleshy stem of Zizania latifolia is also damaged, resulting in the shriveled meat and loss of edible value. At the initial stage of the disease, the symptoms are spider silk (hyphae of pathogens), and at the later stage, radish-like nuclei (sclerotia wrapped by hyphae). The young sclerotia is white to milky white, and the old sclerotia is brown. Rough surface, spongy or honeycomb, easy to fall off. Pathogen and pathogenic characteristics of sheath blight of Zizania latifolia Bunge. The pathogen of sheath blight of Zizania latifolia Bunge is fungi. The asexual generation belongs to Rhizoctonia; Its sexual generation belongs to the genus Phanerochaete of basidiomycetes. )ju = pellicularia Sasakii (Shir。 ) ITO]. The asexual generation of pathogenic bacteria in the field is common, and the sexual generation is occasionally produced under high humidity conditions, which is not common. Even if it does, its role in the annual cycle of the disease is not important. Pathogenic bacteria mainly survive and overwinter in soil in the form of sclerotia, or overwinter in field sick residues or host crops such as weeds. Sclerotinia sclerotiorum will spread with irrigation water, float on the water surface, and gather at the edge or corner of the field in the downwind direction. When the sclerotia floats and attaches to the water bamboo plant, under suitable temperature and humidity conditions, the mycelium germinates and invades from the leaf sheath near the water surface, causing disease. After the onset of the disease, the spider silk hyphae formed in the affected area can expand the infection harm through climbing contact. Sclerotinia sclerotiorum has strong viability. Sclerotinia sclerotiorum left in the surface or even deep soil can survive for at least 1 ~ 2 years. Pathogen has many characteristics and its host range is very wide. In addition to gramineous crops and weeds, there are dozens of naturally infected hosts in 10 families. Both pathogen development and sclerotium formation like high temperature and high humidity (the optimum temperature is 28 ~ 32℃ and the relative humidity is above 96%). The occurrence and harm of diseases are affected by many factors, such as sclerotium, meteorological conditions, field ecology, plant nutrition and so on. The number of sclerotium residues in soil is closely related to the severity of early diseases in the field. Last season or last year, there were many sclerotia residues, and the incidence of early plants was also high. However, the development of field diseases was greatly influenced by field ecology and plant nutrition. In the year and season with high temperature and humidity, the disease develops rapidly; Long-term deep irrigation in the field, neglect of sun exposure, or over-dense planting, poor permeability between plants, or excessive application of nitrogen fertilizer, and high content of free ammonia nitrogen in plants are all conducive to the development of the disease and aggravate it. There is still a lack of research on the difference of disease resistance among Zizania latifolia varieties. Comprehensive control measures should be taken to eliminate the residual sclerotia in the field as far as possible before planting, reduce the source of pathogens, reasonably plant closely during and after planting, strengthen the management of fertilizer and water, and apply pesticides in time to control diseases. Specifically, we should pay special attention to the following links: (1) Try to remove the bacteria source before planting. In areas and fields with severe sheath blight, after ploughing and harrowing, the sclerotia mixed in "wave residue" can be salvaged and collected by using tools such as cloth nets or dense dustpans, so that it can be taken out of the field for burning or burying deeply, which can reduce the source of germs and alleviate the early diseases of plants. If this work can be done well, the effect is obvious. (2) Reasonable close planting, combined with management, removing sheath leaves at the base of plants as far as possible, improving the permeability between plants, and helping to reduce the incidence. (3) Do a good job in fertilizer and water management, create a field ecological environment suitable for the growth of Zizania latifolia and not conducive to the spread of diseases, control the horizontal and vertical spread of diseases and reduce the harm. In the application of fertilizer, the fertilization strategy of promoting (tillering) first, controlling (ineffective tillering) and supplementing (promoting fertilization and promoting pregnancy) is adopted, and the fertilization formula is formulated, sufficient base fertilizer is applied, and appropriate topdressing is carried out at the right time to promote the plants to grow early and grow fast, strong but not prosperous, stable but not prosperous, and improve their own stress resistance. In the management of water slurry, according to the different requirements of irrigation depth in different growth stages of Zizania latifolia, the strategies of shallow before (germination stage and tillering stage), medium sun (controlling ineffective tillering) and shallow after (promoting pregnancy) were adopted, and the temperature was adjusted by water and the fertilizer was adjusted by water. Pay attention to drainage in typhoon and rainstorm season, put shallow field water before topdressing every time, and irrigate the field water moderately after the fertilizer is absorbed by the soil. During pregnancy, dry and wet alternate, so as to keep the root activity and the leaves turn normal. (4) Spraying drugs in time to prevent diseases. Horizontal transmission of controlling diseases by spraying drugs before and after tillering peak period. In the middle and late stage of plant growth, the vertical spread of diseases is controlled by spraying drugs, so that the plant can retain enough functional leaves, which is beneficial to pregnant bamboo shoots and improve bamboo shoot yield. It can be sprayed with 400-500 times of 5% Tianan aqueous solution (initial stage), 500-700 times of 28% carbendazim jinggangmycin suspension, 800-1000 times of l6% buprofezin jinggangmycin suspension, 300-400 times of 22% double well water solution, or 300 times of 2000. Eight, water bamboo must be harvested in time, which is an important link to ensure the yield and quality of water bamboo. If the harvest is too early, the water bamboo is too tender and the yield is low; But if the harvest is too late, the pork will turn blue, the texture will be rough, the fiber will increase and the quality will deteriorate. The criteria for timely harvesting are as follows: the heart leaves become shorter, the joint between the three tight leaves and the leaf sheath is obviously waist-shaped, the middle part of the pseudostem is obviously expanded, and one side of the leaf sheath is slightly cracked and exposed, and the exposed part is less than 1- 1.5 cm. However, due to the high temperature at harvest time, water chestnut is easy to turn blue and get old in summer, and there can be no cracks. Only when wrinkles appear in the middle of the leaf sheath should you harvest it immediately. Most of the water bamboo is harvested in multiple times, usually once every 2-3 days, and the good variety can be harvested for 2-4 times. The less the harvest times, the more concentrated the yield and the better the variety. Harvesting method: break the stem at the base of the stem, tie it tightly with leaves of Zizania latifolia, put it on the head of the field when harvesting above 10, cut off the leaves, cut off the residual stem and beard, and keep the length of Zizania latifolia varying from 40 to 50 cm. Mixed cropping and rotation of freshwater crayfish and cash crops in South China. Mixed cropping of freshwater crayfish and cash crops means that both freshwater crayfish and cash crops are cultured in the same pond or paddy field. The available aquatic cash crops are Zizania latifolia, rice, water chestnut, arrowhead, cress and so on. Lotus root and Euryale ferox can also be selected, but attention should be paid to prevent shrimp from damaging the buds of lotus root and Euryale ferox. Taking Zizania latifolia as an example, this paper introduces the mixed cropping of freshwater crayfish and aquatic cash crops. Preparation of planting site.
The field with flat terrain, deep soil layer, rich organic matter and good water retention performance is selected as the water bamboo field. Dig an annular ditch with a width of 1.5 ~ 2.0m and a depth of 0.8 ~ 1.5m along the inside of the ridge, and dig a ridge with a width of 0.5 ~ 1m and a depth of 1m in the middle of a large ridge. Combined with ditching, heightening, widening and tamping the ridge, the ridge was closed with 70-80cm high mesh along the ridge, the bottom of the mesh was bent 90 degrees, and the horizontal piece was about 10-20cm, and buried in the field. The vertical piece is 50 ~ 70 cm high and 45 ~ 50 cm above the ground. The upper end of the net should be wrapped with a plastic film with a width of 20 ~ 25cm to avoid the entry of pests and the escape of crayfish in the future. Before planting Zizania latifolia from 1 1 to April of the following year in southern China, 500 ~ 1 000 kg of decomposed pig and cow dung were applied as base fertilizer per mu, turned into the soil layer, and then soaked in water to soften the soil, making the field smooth, muddy and beautiful. Cultivation of Zizania latifolia.
Eleocharis tuberosa is planted by asexual propagation method, and in June-April or June-August, plants with neat growth, strong white and many tillers are selected as seed plants. Rootstock is transplanted with tillering seedlings, each plant is equipped with old stems and stolons, with 3-5 tillering seedlings, and the plant row spacing is 1m× 1m ... After planting, irrigation is carried out, and the water depth is 3-5 cm. The planting technique of Zizania latifolia is the same as above (double cropping Zizania latifolia planting technique)