Silicon is the second most abundant element in the earth's crust and soil, but so far little is known about the biological effects of silicon. Although it is currently impossible to prove that silicon is an essential element for plant growth, silicon is at least beneficial to the healthy growth of plants such as grasses. This article gives a brief discussion on the effects of silicon on plant growth and the application of silicon and calcium fertilizers. Forage Grass,Medicago Sativa,White Clover,Perennial Ryegrass Chengdu Lv Mu Tian Xia Agricultural Technology Co. LTD , http://www.cdlmtx.com
First, the role of silicon on plant growth
1. Improve the photosynthesis of crops: Silicon increases the photosynthetic efficiency of gramineous crops such as rice, wheat, and sugar cane. The mechanism is that silicon deposited in epidermal cells makes the plants upright, and the angle between leaves and stems becomes smaller and improves. The light receiving potential of plants increases the interception and utilization of light by plants.
2, to improve the activity of the roots: Silicon to increase the activity of the root performance in the silicon can increase the number of white roots in rice, increase the rice É‘-naphthylamine oxidizing roots, enhance the ability of rice roots to emit oxygen, increase root dehydrogenase activity, So as to reduce the harm of harmful and toxic substances such as Fe2+, Mn2+, H2S, etc., under anaerobic conditions to the root system.
3, to improve the lodging resistance: As the silicon deposited in the epidermal cell wall forms a silicon double layer, the mechanical strength of the stem increases, the plant pulls out, can effectively prevent the lodging of rice, wheat and other crops, in the harsh climate This effect is particularly evident in the case of typhoons.
4, to enhance disease resistance: Silicon to improve crop disease resistance is an indisputable fact. Silicon has significant resistance to three major diseases of rice (rice blast, sheath blight, and bacterial blight), leaf spot of flax, rust of wheat and head blight. Silicon-calcium fertilizer can significantly reduce the aphid damage of rice aphids, rice planthoppers and big wheat, and can improve the resistance of cucumber, melon, melon, watermelon and other cucurbits to fungal diseases such as downy mildew, pythium mildew, and powdery mildew. , To reduce the incidence of tomato umbilical rot. However, the mechanism by which silicon enhances disease resistance has not been clarified. For a long time, it has been thought that silicon deposited on the papillae, epidermis cell walls, or sites of fungal infections acts as a natural "mechanical or physical barrier" to plants, accumulates silicon, and resists disease or system diseases in host cells.
5, improve the plant's resistance to stress: Silicon significantly improve the plant's stress (such as the above-mentioned disease resistance) and abiotic stress (ie environmental stress, such as iron, manganese, aluminum and other heavy metal poisoning, salt damage, drought stress, etc.) The resistance (resistance).
6, inhibit the transpiration of crops, improve water use efficiency: the silicon deposited in the epidermal cell wall formed by the silicon layer can inhibit water transpiration, is conducive to economic water crops. It is of great significance for the development of water-saving agriculture.
7. To increase crop yield and improve quality: Gramineous crops such as rice, wheat, corn, and sugar cane; cucumber, melon, melon and melon, etc.; and crops such as tomato, soybean, strawberry, cotton, etc. More obvious reaction. Sugarcane, sugarbeet and melon can significantly increase sugar content after applying silicon-calcium fertilizer. Tomato can increase vitamin C content after applying silicon-calcium fertilizer. The mechanism of production increase should be a comprehensive effect (promote growth, increase high photosynthesis, promote the absorption of nutrients, increase the utilization of nutrients, improve resistance to lodging, disease resistance, etc.).
8. Promote absorption of nutrients and improve nutrient balance in the body: Silicon can improve the imbalance of nutrients in crops by promoting or inhibiting the absorption and transportation of certain essential nutrients by crops.
Second, the abundance of silicon in China's soil For a long time, people have been considered that the acidic and slightly acidic soils in the south have a strong desiliconization and aluminization. Therefore, there is a lack of available silicon in acidic, slightly acidic soils, brick red soil, brick-red red earth, red and yellow soils, and in the north, calcareous soils do not lack silicon. However, studies in the past decade have shown that there is also silicon deficiency in limestone in the north. The reason is that the large amount of calcium carbonate in the calcareous soil reduces the effectiveness of silicon by the adsorption and fixation of calcium silicate on silicic acid. According to rough estimates, about 200 million mu of paddy soil in China suffer from silicon deficiency. III. Diagnostic techniques for lack of silicon in soil and crops
1. The content of available silicon (PH4.0 acetic acid-sodium acetate buffer extract) content in the soil in the southern acidic and slightly acidic soil is less than 100-105 mg SiO2/kg, which indicates that silicon and calcium fertilizers in the soil may have significant yield-increasing effects. The effective silicon content in soil is 100-130mgSiO2/kg, and the application of silicon-silicon fertilizer may be effective. The content of available silicon in northern calcareous soil (pH4.0 acetate-sodium acetate buffer extraction) is less than 300mgSiO2/kg, and the application of silicon-silicon fertilizer still has significant effect.
2. Diagnosis of plants (1) According to the full-scale diagnosis of stalk SiO2, the full amount of SiO2 in stems of mature rice is less than 10%, indicating that rice lacks silicon.
(2) According to the form diagnosis: Silicon deficiency rice stems are soft, the leaves are covered, showing weeping willow, easy to lodging in case of wind, diseases such as rice blast and other fungal diseases are more serious. Sugarcane is susceptible to leaf spot disease.
Fourth, the type and application of silicon calcium fertilizer
1. The slag calcium-silicon fertilizer is currently the most commonly used silicon-calcium fertilizer at home and abroad. It is a slag silicon-calcium fertilizer made from the blast furnace slag of steelmaking ironmaking through mechanical grinding (100 mesh). The effective silicon content is related to the fineness. In countries such as Japan, South Korea, Thailand, and Malaysia, the application of slag-calcium-silicon fertilizers is also large. In other areas of China, slag-lime-silica fertilizer was also used to increase production. However, due to the large amount of application and inconvenience of rural transportation, it has not been widely applied. The slag silicon-calcium fertilizer is a slow-acting silicon-calcium fertilizer, which is generally used as a basal fertilizer. The slag-silica-calcium fertilizer is also suitable for hi-calcium, such as legumes, in addition to rice and sugarcane and other silicon-bearing crops.
2. The high-efficiency silicon chemical fertilizer was developed from the silicon-calcium fertilizer invented by Prof. Ma Tongsheng of the College of Resources and Environmental Sciences, Nanjing Agricultural University, and spray-dried with cefotaxime (water glass) as raw material. The calcium-silicon fertilizer is a fully water-soluble white powder and is a mixture of sodium disilicate and sodium metasilicate. It does not contain other auxiliary components, and its water-soluble SiO2 content is 50-56%. The amount of 6 kg per mu can be used as base fertilizer and top dressing. For top dressing before the best jointing application. However, due to the high price per ton, it failed to promote the application.
3. The new high-efficiency Si-Ca fertilizer was successfully developed by Prof. Liang Yongchao of the College of Resources and Environmental Sciences of Nanjing Agricultural University. Its raw material is also a blast furnace slag of steel-making ironmaking by-products. The blast furnace slag is chemically treated to form a chemical fertilizer. Effective silicon (SiO2) content> 20%, effective CaO> 20%, effective MgO5-10%, in addition to P, S, K, and other available trace elements. The dosage per acre is 10-30 kg. The cost is low and the effect is good. The silicon-calcium fertilizer is suitable as base fertilizer. Top dressing is best applied before jointing. This product is suitable for hi-silica crops such as peanut and other legumes, in addition to rice and sugarcane and other silicon crops.
4. Si-containing compound fertilizer is produced by compounding silicon-calcium fertilizer through granulation. The effective silicon content of the fertilizer is generally low, and the silicon-containing compound fertilizers produced by various plants have different effective silicon contents. Generally used as base fertilizer.
V. Conclusion The beneficial effects of silicon on plant growth have been increasingly valued by people and will play a greater role in the sustainable development of agriculture. Silicon increases the resistance of crops to heavy metal poisoning and enhances disease resistance of crops. It is particularly important today to join the WTO for the absence of pesticides, the development of non-toxic, non-polluting green foods and the safety of foods. significance.