Shi Yuzhu (China National Green Food Corporation) 1 Introduction Wood vinegar, also called phyto acid, is a tan mixture obtained during the dry distillation of wood. It contains many organic substances such as acids, alcohols, phenols, and ketones, most of which are trace components. As a by-product of natural forest products, wood vinegar is widely used in the chemical industry, forestry, agriculture, animal husbandry, food processing and medical and health industries. With the advancement of agricultural production methods and agricultural research methods, the performance of wood vinegar has been gradually recognized and paid attention to, under the premise of focusing on environmental protection and health, and its application in agriculture has become more and more widespread. According to the production experience and related experimental research, it has been found that wood vinegar has various functions such as promoting plant growth, inhibiting bacteria, weeding, and preserving. At present, the research on wood vinegar in agriculture at home and abroad is still in its infancy, and various properties of wood vinegar are gradually being recognized, and its refining method, use method, main action components and mechanism of action need to be further studied. 2 Production of wood vinegar and its application in agriculture 2.1 Recovery and purification of wood vinegar During the process of burning charcoal, chimneys are used to condense the smoke produced during the charring of wood, and the obtained liquid is coarse with a lot of tar and other impurities. Wood vinegar, which cannot be directly applied to agricultural production, needs further refining. The refining methods of crude wood vinegar mainly include static sedimentation, charcoal (or activated carbon) refining, drug refining, simple distillation, and vacuum distillation [1]. In the application of agricultural production, generally adopt the following two methods to refine: 1 standing clear method: the crude wood vinegar placed in the container for more than 30 days, it will be separated from the three layers, remove the upper 10% light oil and The lower part contains 30% of tar and other impurities, and the middle part is the safe and effective wood vinegar ingredient, which can be applied to agricultural production. (2) Charcoal (or activated carbon) refining method: Charcoal powder is added to the wood vinegar (or the wood vinegar that has been left standing for a long time) in proportion to absorb the impurities. After mixing, stirring and filtering, the refined wood vinegar is obtained. 2.2 The status of application of wood vinegar in agriculture The use of wood vinegar in agricultural production in the United States, Japan, South Korea and other countries. In the United States, wood vinegar is mainly used in garden horticulture. In comparison, Japanese agricultural production is the most common application of wood vinegar. In Japan, about 40 million liters of wood vinegar are produced each year, about half of which are used in agricultural production, and its role is mainly to promote crop growth and control of nematodes, pathogens and viruses [2]. In our country, the research work of wood vinegar on agricultural production started not late. In 1989, Yanbian Agricultural College cooperated with relevant manufacturers and took the lead in trial production of wood vinegar based on technical data from Japan and South Korea, and carried out a series of indoor and outdoor experiments using wood vinegar to prevent diseases in crops, vegetables, and fruit trees. However, in actual agricultural production, wood vinegar as a natural alternative to agricultural chemicals has not been truly promoted. 3 Research progress of wood vinegar in agricultural production 3.1 Wood vinegar promotes the study of plant growth Wood vinegar can affect the rooting power of plants. Observation of the germination process of Japanese pear seeds in vitro showed that the addition of wood vinegar promoted the sprouting of Japanese pear roots in vitro [3]. Li Guihua and others further explored the effects of different sources and different concentrations of wood vinegar on the rooting power of rice. After repeated experiments, it was proved that the rooting power of rice cultivars of different sources and different concentrations (except 200 times) was greater than that of rice. The control has increased. Among them, 500 ~ 700 times the rice husk extracted wood vinegar and 500 times the wood extracted wood vinegar to promote rice rooting effect is best [4]. In order to investigate the effect of wood vinegar on the germination of vegetable seeds and the growth of shoots, Yang Hua selected five kinds of vegetable seeds such as Chinese cabbage, Chinese cabbage, radish, radish, and cucumber in the experiment. The culture solution was cultured in an incubator. The results showed that the wood vinegar promoted the growth of lateral roots of 5 kinds of vegetable sprouts, and the number of lateral roots increased significantly. At the same time, the wood vinegar used Chinese cabbage, radish and water. The growth of vegetable rhizome such as radish and cucumber has a good promoting effect [5]. Different organics contained in wood vinegar have different effects on the growth of different plants. Eight kinds of alcohol substances and eight phenolic substances contained in wood vinegar were added to the medium to observe their effects on the germination and growth of vegetables such as radish, Chinese cabbage, and indigo, and the results showed that most of the alcohol substances Can promote the growth of vegetables, and most of the phenolic substances have an inhibitory effect on vegetable growth [6]. Shen Fengshan et al. separated the wood vinegar and obtained the wood vinegar of different main components. After that, it conducted tests on the effects of rice vinegar on the germination and seedling growth of rice. The test results showed that the wood vinegar liquor removed aldehydes and ketones. The remaining liquid (mainly containing phenols, acids and their derivatives) has the most obvious effect on rice germination and seedling growth [7]. In the actual agricultural production, Japan has conducted a series of experiments on the development and application of wood vinegar, among which the effect on the growth of strawberry is the most significant. After the wood vinegar was mixed with the bark charcoal, it was applied to the soil at a dosage of 500 g/m2. The growth and development status of the strawberry plants in the test area, the status of soil pest control, the harvested amount of the strawberry, and the sugar content were all significantly better than the control area. Among them, the amount of strawberry harvested increased by 31.6%, sugar content increased by about 0.4 [1]. It can be seen that wood vinegar has great potential for agricultural production. In the process of using wood vinegar, attention should be paid to the relationship between biological activity and concentration. Many experimental results show that if the concentration of wood vinegar is too high, it will show inhibitory effects on plant growth. Therefore, the use of wood vinegar in agricultural production requires a good concentration. 3.2 Wood vinegar to promote the growth of edible fungi In addition to promoting plant growth, wood vinegar can also promote the growth of edible fungi. The addition of different concentrations of wood vinegar to the edible medium (sawdust) will promote the growth of edible mycelium and fruit bodies. When 0.05 to 0.25 ml of wood vinegar per kilogram of the medium is contained, The promotion of the growth of edible fungi is best [8]. Further studies have found that the addition of 3,5-dimethylphenol, butyric acid and other components to the culture medium of edible fungi can also promote the growth of edible fungi. Adding 0.1 to 6% of wood vinegar stock solution to the medium can make Practical bacteria increase 21 to 42%; adding a certain concentration of butyric acid or 2-methoxyphenol, edible fungi will also have different rates of increase in production [9]. 3.3 Antibacterial effect of wood vinegar The use of wood vinegar as a bacteriostatic agent is relatively widespread. In traditional agricultural production, Japanese farmers generally use wood vinegar to prevent crop or fruit tree diseases, with significant effects [10]. In 1994, Japan carried out studies using wood vinegar to suppress soil-borne diseases and tested its inhibitory effects on various pathogens such as Pythium, Penicillium, Rhizoctonia, Sclerotium, and Fusarium.[11] , 12]. Production practices and many scientific experiments have confirmed that different concentrations of wood vinegar show different effects on pathogenic microorganisms such as bactericidal, inhibiting and promoting. From 1991 to 1994, Yanbian Agricultural College carried out a series of indoor and outdoor experiments using wood vinegar to prevent diseases in crops, vegetables, and fruit trees. The four-year experimental results showed that: 1 wood vinegar liquid stock control effect on apple rot disease is better than commonly used drugs "corbiqing"; 2 wood vinegar control effect of rice bacterial blight is obvious, and before its broadcast or after broadcast The watering effect of the seedlings was the same at one leaf stage, and the effect of 200 times liquid wood vinegar on controlling watermelon wilt was better than the commonly used drug "thiophanate-methyl", but if the wood vinegar was mixed with thiophanate-methyl, the effect was better. 4 Use wood vinegar 200 to 300 times to control cucumber downy mildew, the control effect is higher than the commonly used drugs "B phosphorus aluminum" [13]. In order to seek the main components and mechanism of wood vinegar from inhibiting bacteria, Lu Jinglan et al. conducted in-depth research on the antibacterial effects of wood vinegar. The experimental results show that the raw materials of wood vinegar extracted from different materials all have strong antibacterial effect; the antibacterial effect of several different substances obtained by column chromatography of wood vinegar was also tested, and it was found that only the wood Vinegar has the most prominent effect in inhibiting pathogenic bacteria. Therefore, Lu Jinglan et al. concluded that the single component contained in the wood vinegar does not have the ability to inhibit bacteria, but that the wood vinegar liquor has an excellent effect in inhibiting the pathogen [14]. 4 Development prospects for the application of wood vinegar in agricultural production The research, development and utilization of wood vinegar have not received sufficient attention in the country. At present, only a few research institutes conduct research on it and it is in agricultural production. The application is almost blank. In fact, wood vinegar has a broad application development prospects. Wood vinegar as a natural agricultural production data, its main features and advantages are: 1 from natural materials, does not pollute the environment, no toxic side effects on humans and animals, is an ideal substitute for agricultural chemicals; 2 is a by-product of charcoal production , can also be used rice husk, coconut shell, straw and other waste production, processing and refining method is simple, energy conservation, low cost, turning waste into treasure, considerable economic benefits; 3 complex composition, significant effect, wide range of uses, can be used High value. China has a traditional carbon-making process, which can be modified and transformed to produce wood vinegar at the same time as carbon; China has abundant raw materials, bark, rice husk, bamboo, straw and other raw materials are readily available. All of them are renewable resources; China's traditional agriculture has rich connotations and provides ample space for the application of wood vinegar. The development and application of wood vinegar has so many favorable conditions in our country, so there must be a broad prospect for development. Japan has many successful experiences in the research and development and application promotion of wood vinegar, and it is worth learning from. We should increase the depth and intensity of the development of wood vinegar and its related products, and promote and apply it vigorously to make it an industry that can truly play its due role in agricultural production in China. Main references: [1] Gao Shangyu, Qian Huijuan (compilation). Wood vinegar refining and application research in Japan. Forest Products Chemical Communications, 1994, 6: 36-37 [2] Yoshimoto T, Huang Sheng Chung (ed) .), Liu_DahJiang(ed), et al. Present status of wood vigegar studies in Japan for agricultural usage. Toward enhanced and sustainable agricultural productivity in the 2000's:breeding research and biotechnology, Proceedings of the 7th International congress of SABRAO and WSAA symposium held At Academia Sinica, Nankang, Taipei, Taiwan, 16-20 Nov. 1993, Volume III. Special Publication Taichung District Agricultural Improvement Station. 1994, 35: 811-820 [3] Kadota M, Hirano T, Irnizu K, et al. Pyroligneous acid improves in vitro rooting of Japanese pear cultivars. The American Society for Horticultural Science, 2002, 37 (1) :194-195 [4] Li Guihua, Quan Mingdao, Cui Yilong. Effects of different plant acids on rooting ability of rice. Yanbian Journal of the college of agriculture, 1998, 20 (2) : 93-95[5] Yang Hua. Sprouting and bud roots of vegetable seeds from wood vinegar Effect of growth effects. Liaoning Urban and Rural Environmental Science and Technology, 1998, 17(3): 79-81[6] Yatagai M, Unrinin G. By-products of wood carbonization VI. Germination and growth effects of wood vinegar components and their homologs on plant Seeds - alcohols and phenols. Journal of the Japan Wood Research Society, 1989, 35(11), 1021-1028[7] Shen Fengshan, Lu Jinglan, Tai Junzhe. Studies on the wood vinegar in the germination and growth of rice. Yanbian University Agronomy Journal of 2002,24(1):26-29[8] Ohta A, Zhang LiJun, Zhang L J. Acceleration of mycelial growth and fruiting body production of edible mushrooms by wood vinegar fractions. Journal of the Japan Wood Research Society, 1994 , 40(4), 429-433[9] Yoshimura H, washio H, Yoshida S, et al. Promoting effect of wood vinegar compounds on fruit-body formation of Pleurotus ostreatus. Mycoscience, 1995, 36 (2): 173- 177[10] Luo Fenglai. Some methods and experiences of rice cultivation in Okinawa, Japan. Fujian Agricultural Science and Technology, 2001, 3: 38-39[11] Numata K, Ogawa T, Tanaka K. Effect of pyroligneous acid (wood vin Egar) on the several soilborne diseases. Proceedings of the Kanto Tosan Plang Protection Society, 1994, 41:107-110[12] Numata K, Ogawa T, Tanaka K. Effect of pyroligneous acid (wood vinegar) on the several soilborne diseases. (2). Proceedings of the Kanto Tosan Plang Protection Society, 1995, 42: 75-77[13] Quan Shunzi, Li Zongtie, Yu Detian, et al. Study on the application of wood vinegar to control disease. Journal of Yanbian Agricultural College, 1994,16(2) ): 113-116 [14] Lu Jinglan, Shen Fengshan, Li Taiyuan, et al. Extraction of wood vinegar and its antibacterial effect. Journal of Agricultural Sciences Yanbian University, 2002, 24(1): 30-33