The reason for the formation of duckweed is that the plant is triangular and floats on the water. The recumbent stem is short and slender, with pinnate branches, roots under it and lobules on it. Leaves are small, scaly, alternate, and there are two rows of herpes zoster on the stem. Each leaf is divided into two overlapping lobes, and the upper leaf is reddish brown or green, which has photosynthetic function and often contains nitrogen-fixing cyanobacteria (ANABAENA). The lower leaves are submerged in water, membranous and sporocarp-bearing. Short growth period and fast reproduction.
Morphological characteristics of duckweed A small floating plant that grows in paddy fields or ponds. The plant is triangular, green when it is young, grows rapidly, and often grows into a piece on the water. Autumn and winter
In season, its leaves contain a lot of anthocyanins, which are red, so it is called red duckweed. The individual is very small, with a diameter of about 1cm, and is triangular, rhombic or quasi-circular. Rhizomes are slender, procumbent, pinnately branched, and fibrous roots hang down into the water. Ye Xiaoru scales, fleshy, arranged in two rows on the stem, alternate; Each leaf is deeply divided into two petals: the upper petal is fleshy, floating on the water, green, and turns red after autumn, which can be used for photosynthesis; Lower petal, born obliquely in water, without pigment; Spores are born in pairs on submerged leaves at the base of branches. Duckweed is usually associated with Anabaena, a blue-green algae that can fix nitrogen in the atmosphere. Therefore, duckweed can be used as high-quality green manure for rice and feed for fish and livestock.
Red duckweed is also called? Red apples and green apples? . Ferns, azaleas. Plants are small and triangular, floating on the water. The roots are overgrown. The leaves are small and fleshy, arranged in two rows, and Chun Lv is red in autumn, forming a large red water landscape, which is very spectacular, hence the name Red Duckweed. Breeding fast, born in paddy fields or lakes and marshes, widely distributed in southeast and southwest China. Whole grass can be used as feed for fish and livestock, and also as medicine. Cercospora often occurs, which has nitrogen fixation and is an excellent green manure.
The control strategy of duckweed should adopt the method of combining agronomic measures with chemical weeding.
(1) Agronomic measures mainly include: first, establishing a rice production environment with smooth ridges and furrows, good water retention and free irrigation; Secondly, weed seeds are eliminated by combining seed treatment with ploughing and soil preparation; Third, implement regular paddy-upland rotation to reduce the occurrence of weeds; The fourth is to improve the quality of sowing, sowing the whole seedling at one time, and pressing the grass with seedlings.
(2) Chemical weeding. At present, one-time enclosure is used in most places, that is, within 1-3 days after sowing (accelerating germination), with 40% per mu? Live green? 60 grams of wettable powder, mixed with 40-50 kilograms of water, is sprayed evenly, and the field remains moist when applying the medicine. After 3 days, normal irrigation and field management were resumed. After chemical weeding, if there is still a certain amount of weeds in the later stage, targeted methods can be used to supplement weeding.
For example, in a field dominated by barnyard grass and Euphorbia fischeriana, 50 ml of 10% Euphorbia fischeriana emulsion and 30 kg of water can be used at the 3-5 leaf stage of weeds, and the stems and leaves can be sprayed by a targeted method. Water must be drained in the field one day before application, and normal management should be resumed two days after application.
For example, in a field dominated by sedges and broad-leaved weeds, about 30 days after sowing, 20 g 10% mercury wettable powder and 150 ml 20% dimethyl tetrachlorohydrin were mixed and 30 kg water was sprayed. Cement slurry management as above.
If there are all kinds of weeds in the field, 75- 100 ml of 48% bentazon solution can be mixed with 20% dimethyl carbon tetrachloride solution 150 ml, and sprayed by targeted methods.
Feeding value of duckweed Red duckweed can directly provide a large number of natural high-quality green feed for herbivorous fish in spring and autumn. As a feed crop, duckweed has a crude protein content of 25.00%, which is higher than alfalfa. The crude fiber content is 1 1.50%, which is only half of alfalfa. The annual output of fresh grass per unit surface in Longdong area can reach 540t/hm2, which is equivalent to 1 1 and 250kg/hm2, which is 8 times that of alfalfa. According to the air-drying analysis of duckweed by relevant scientific research units, duckweed has high nutritional value, with crude protein 2 1%, crude fat 2.57%, crude fiber 14.6% and nitrogen-free extract 50.97%. In addition, duckweed is moderate in size and can be directly fed to fish, especially grass and Polygonum hydropiper.
In ponds, lakes, reservoirs and other fishery ecosystems, duckweed community is conducive to the proliferation of food resources of herbivorous economic fish, promoting its growth and increasing its yield. If duckweed fresh grass or dry powder is used to replace part of concentrated feed as a part of compound feed, a large amount of feed grain can be saved every year, thus reducing the breeding cost and improving economic benefits.
economic value
Duckweed not only has good feed value, but also has high economic value if it can be used reasonably. Based on duckweed, built in lakes and reservoirs? Ping? Chicken? Fish? The integrated supporting technology of ternary material production and circulation and the sustainable ecological model with high efficiency, low consumption and low pollution established in rice fields have shown good economic benefits in production and application.
Ecological value
Purify water quality
Red duckweed fern has high water use efficiency; It can reduce the salinity of water, adjust the pH value of water, purify water and enrich potassium.
nitrogen fixation
Duckweed is not only a high-quality green manure and forage for fish and livestock, but also an excellent aquatic nitrogen-fixing plant, with an annual nitrogen-fixing capacity of 249-300 kg/hm2.
Enrich metal elements
The strong adsorption of heavy metal ions such as chromium, cadmium, copper, manganese and zinc by duckweed and the volatilization of selenium.
The main functions of duckweed are sweating, expelling wind, penetrating rash and diuresis.
1. Treat exogenous fever, rheumatalgia, wind itching, urticaria, measles, dysuria and excessive leucorrhea [1]. Decocting: 3 ~ 9g.
2. Treat burns and scalds, grind and apply oil.
See how the red duckweed is formed, and see:
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