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Research status of new fertilizers at home and abroad
The production and use of chemical fertilizers in the world has undergone three changes. Before the 1960s, the fertilizers produced were mostly low-concentration fertilizers; in the 1960s and 1980s, developed countries developed high-concentration fertilizers and compound fertilizers; in the last 20 years, developed countries began to focus on slow/controlled release fertilizers, bio-fertilizers, and organic Compound fertilizers and functional fertilizers have become the hotspots of research and development of new fertilizers.
1. Slow/controlled release fertilizer
The most important feature of slow/controlled release fertilizer is that nutrient release is synchronized with crop absorption, simplifying fertilization technology, achieving one-time fertilization to meet the needs of the crop throughout the growing season, less fertilizer loss, high utilization rate and environmental friendliness. Countries around the world have come to realize that one of the most effective measures to improve fertilizer utilization is to study new slow/controlled release fertilizers. Since the 1980s, the United States, Japan, Europe, Israel and other developed countries have shifted the focus of scientific fertilization technology to the development of new slow/controlled release fertilizers, and strive to greatly improve the utilization rate of fertilizers by changing the characteristics of fertilizers themselves. Slow/controlled release fertilizer is known as an important development direction of the fertilizer industry in the 21st century. At present, there are four main types of slow/controlled release fertilizers.
(1), coated slow/controlled release fertilizer; coated slow/controlled release fertilizer is mainly used to control the nutrient release of the coating material on the surface coating of fertilizer particles to regulate nutrient release. In 1957, the United States first studied sulfur-coated urea. In 1961, TVA carried out a small test of sulfur-containing urea (SCU) on a 1-7 kg/h plant. In 1978, a demonstration plant of 10 t/h SCU was built in the United States. In this case, studies on sodium sulphate (SCK) and thiophosphoric acid diamine (SCP) were carried out. Sulfur-containing urea is still the current leading product in the United States.
The United States is also the first country to commercialize resin-coated fertilizers. In 1967, the production of alkyd resin coated fertilizer Osmocote in California became the world's leading controlled release fertilizer brand. Japan began to study coated controlled-release fertilizers in the 1960s. After the 1970s, it focused on the research of thermoplastic-plastic resin polythene-coated fertilizers, referred to as the POCF process, by adjusting the ratio of PE to EVA, and using inorganic fillers as The pore-opening agent can produce a film controlled release fertilizer with a release period of 40 days to 360 days. The development of degradable polymer coating materials and the study of fertilizers with different nutrient release patterns represent the research direction of coated fertilizers.
Since the 1980s, Israel, Germany, the United Kingdom, Canada, Italy, India and other countries have also carried out research on coated slow/controlled release fertilizers, trying to use polymers, grass charcoal, lignin, paraffin, inorganic nutrients, etc. Wrap urea, etc., to make slow / controlled release fertilizer. In July 1991, the first ring/controlled release fertilizer seminar was held in Sheffferld, Alama, USA; in 1993, an international seminar on slow-release fertilizers was held in Israel. At present, the world's annual slow release / controlled release fertilizer consumption of 1 million tons (physical), mainly coated with fertilizers, accounting for more than half, and some countries accounted for more than 90%.
Synthetic micro-slurry slow-release fertilizers, one type of synthetic organic nitrogen compounds that are slightly soluble in water, such as urea-formaldehyde fertilizer (Ureaform), isobutylidene diurea (IDBU), butadiene diurea (CDU), etc.; The class is a slightly water-soluble or citric acid synthetic inorganic fertilizer, such as partially acidified phosphate rock (PAPR), divalent metal ammonium phosphate potassium salt and the like.
Urea-formaldehydes and released fertilizers are the condensation of urea with aldehydes, the most common being urea formaldehyde (UF). In 1924, BadisheAnilin and Ssoda~Fabrek districts obtained the first patent for the manufacture of urea-formaldehyde fertilizers. In 1955, they were put into industrial production. Germany published the process of preparation of Liao Yong acetaldehyde and urea in 1924. Japan's Mitsubishi Corporation and 1961 - 1962 proposed a patent for the reaction of urea and isobutyraldehyde to prepare isobutylidene diurea (IBDU). Since 1964, there has been a small sale in the Japanese market.
In the early 1990s, the slow/controlled release fertilizers of the century still dominated the soluble urea reactants, accounting for more than 50%. European tradition uses a slightly soluble cold urea compound slow release fertilizer. Its proportion accounts for more than 70% of slow release fertilizer sales. The release rate of nutrients due to nutrients is greatly affected by factors such as soil moisture, pH, and microorganisms, and the price is high. The demand for such fertilizers has a tendency to decline.
The chemically inhibited slow-acting fertilizer adjusts the activity of soil microorganisms by adding urease inhibitors and nitrification inhibitors, slows the hydrolysis of urea and the nitrification of ammonia nitrogen, thereby achieving the slow release of fertilizer nitrogen; in the 1960s, people began to pay attention to screening. The work of soil urease inhibitors. HQ (hydroquinone), NB-PT (N-butylthiophosphoric triamide), PPD (o-phenylphosphoryl diamine), TPTA (thiophosphoric triamide), CHPT (T-phosphate III Cyclohexylamine and the like are important soil urease inhibitors for screening studies.
Since the 1950s, the development of nitrification inhibitors has been carried out abroad. The main products studied are derivatives of pyridine, pyrimidine, thiourea, thiazole, mercury, etc., as well as bismuth potassium nitride, chlorophenyl isothiocyanate, and hexachloroethane. , sodium pentachlorophenol, and the like. Dicyandiamide (DCD) is a widely used nitrification inhibitor for high nitrogen fertilizer utilization.
Matrix compound fertilizer and adhesive slow release controlled release fertilizer, mixing fertilizer nutrients with substances that can reduce its solubility, and making fertilizers with slow release of nutrients through the functions of fitness and cementation. In particular, organic high molecular polymers, modified grass charcoal and weathered coals, organic only equals fertilizers, cementation, and changes the release rate of nutrients to produce slow-release fertilizers. At present, research work in this field is carrying out research directions on slow-release fertilizers, and the prospects are promising.
In addition, the slow release fertilizers of different types and different release rates are passed through the "heterogeneous shifting", so that the nutrient release rhythm of the fertilizer is maximized and the crop absorption is synchronized, which is highly valued in the research and application of slow release fertilizer.
At present, the annual consumption of slow/controlled release fertilizers in the world is about 1 million tons, including 600,000 tons (about 60%) in the United States and Canada, 200,000 tons (months to 20%) in Japan, and 150,000 tons in Western Europe and Israel. About 15%, other countries have more than 50,000 tons per month, which is significantly higher than the seasonal fertilizer growth rate. Currently, the most important issue affecting the development of slow/controlled release fertilizers is the price issue. Due to the high price, in addition to Japan, 90% of the controlled release fertilizers in the United States and Western Europe are used in non-agricultural markets such as lawns and nurseries. Reducing production costs and moving to the field is an important direction for the development and production of slow/controlled release fertilizers.
China's research on slow/controlled release fertilizer started late. In the 1970s, the Nanjing Institute of Soil Science of the Chinese Academy of Sciences conducted the development of long-acting ammonium bicarbonate. In the 1980s, especially in recent years, with the large amount of chemical fertilizers, low utilization rate, chemical fertilizers, agricultural products and environmental problems, the pace of research on domestic slow/controlled release fertilizers has accelerated. Beginning in 1983, Zhengzhou Institute of Technology and other countries took the lead in systematically developing materials to use nutrient guessing to develop packaged controlled release fertilizers, and successively developed calcium magnesium phosphate coated urea (1983), phosphate rock partially acidified urea (1991), and two prices. Metal ammonium phosphate potassium salt Baoguo urea (1995) 3 categories of continuously upgraded products, nutrient control release time of more than 95 days, breaking through the key technology of nutrient material nutrient release control control at home and abroad. Developed an industrialized production line with an annual production capacity of 10,000 tons. The registered brand of the product is Luxacote, which is exported to the United States, Australia, Singapore, Japan and other countries, and is the same as Osmocote, MEISTER and Nutri-cote. At present, under the support of the National 863 Program, research is underway to further reduce costs, focusing on the development of special controlled-release fertilizers for field crops. The products are widely demonstrated in corn fields in Henan and Shandong, with an increase of more than 10%. The utilization rate has increased by more than 10 percentage points.
The development of resin coated controlled release fertilizer, China mainly learn from Japanese experience. Since 1992, the Beijing Academy of Agricultural and Forestry Sciences has taken the lead in systematically researching resin-coated urea. On the basis of drawing on Japanese technology, there have been major improvements and breakthroughs in solvents, coating materials and equipment. The research screened out low-toxic solvents with a recovery rate of over 98%; developed a continuous production equipment to apply for national invention patents. The coating material is made of inexpensive polyacrylamide and modified for degradation. At present, a resin package with an annual production capacity of more than 3,000 tons has been built into a urea production line to produce a series of coated ureas with controlled release of nutrients for 30 to 200 days or longer. The products are classified into linear and S-type release models. With coated urea as the masterbatch, the N, P, K composite controlled release fertilizers were prepared by the heterogeneous shifting technology, and large-scale demonstrations were carried out on rice, corn and other crops in Beijing, Northeast, Shandong, Guangdong and other places. Received good results. The product was awarded the National Key New Product Certificate in 2002.
Soil and Fertilizer Institute of China Academy of Agricultural Sciences, South China Agricultural University, etc. in matrix compounding, cementation controlled release, coating material research, especially the use of industrial and agricultural waste to develop coating materials, as well as in film forming process, mechanism, organic compounding, water retention A lot of work has been done on the development of multi-functional controlled release fertilizers such as disease prevention. Invented the reaction film-forming technology, using the normal temperature equipment to produce coated controlled-release materials, the matrix composite and water-retaining controlled-release fertilizers were developed on a large scale in the corn, Shandong and Xinjiang vegetables and cotton crops in Shandong. The Shenyang Institute of Applied Ecology has also done a lot of work on the development of slow-release fertilizers using urease inhibitors and nitrification inhibitors. The products have been demonstrated on field crops.
In addition, China Agricultural University has conducted a lot of research on the controlled release mechanism and evaluation of controlled release fertilizers. The Institute of Soil and Fertilizer, Chinese Academy of Agricultural Sciences, “The Long-term Monitoring Base for Soil Fertility and Fertilizer Efficiency of the National Brown Soil†has taken the lead in the long-term positioning of slow-release fertilizers in China. This is the long-term positioning experiment of common chemical fertilizers, which will promote the fertilizer efficiency of slow-release fertilizers. Basic research such as evolution and environmental assessment is of great value.
Although the research on slow/controlled release fertilizer in China started late, the research features are obvious. The products and processes such as resin coating, nutrient material wrapping, matrix compounding, cement controlled release, and enzymatic inhibition are all blooming. Especially in recent years, national and local governments have attached great importance to the research and industrialization of slow/controlled release new fertilizers. The Agricultural Fertilizer Research Institute of China Academy of Agricultural Sciences, China Agricultural University, South China Agricultural University, Zhengzhou University, Beijing Academy of Agriculture and Forestry, and other five units jointly undertake the national “10th Five-Year Plan†863 Program “Environmentally Friendly Fertilizer Development and Industrialization†(2001AA246023) With the goal of controlling release fertilizers to field crops, more than 10 related invention patents have been obtained and declared, and more than 50 products on different levels of industrialization, pilot test and small test have been developed, and the production of nutrient materials can be realized. There are 3 production lines with over 10,000 tons of controlled release fertilizers for wrapping, resin coating and matrix compounding. The cost of products is only 1/4 or lower of similar foreign products. It has been widely demonstrated in rice, corn, vegetables, cotton and other crops in Northeast China, Beijing, Shandong, Henan, Xinjiang, Guangdong, etc. Some products have been exported to the United States. Japan, Singapore, Australia, etc.
China's controlled release fertilizer technology is generally inferior to the level of developed countries, especially in terms of industrialization. At present, China's annual consumption of slow/controlled release fertilizer is about 20,000 tons (in-kind). The main brands on the market are Osmocote, Osmocoteplus, Japan's MESTER, Nutricote, Israel's Multicote and other coated controlled-release fertilizers. More than 10,000 yuan per ton. China's current slow/controlled release fertilizer industrialization production capacity has exceeded 100,000 tons, but the operating rate is low.
Biological fertilizer
Bio-fertilizer is a microbial living product that is heterogeneous and microbial life activity and its products cause the crop to obtain a specific fertilizer effect. It has low production cost, good effect, and no need to let the environment not only increase production after application, but also improve the quality of agricultural products and reduce the amount of chemical fertilizer. It plays an important role in the sustainable development of agriculture.
The world's first microbial fertilizer was the “Nitragin†Rhizobium inoculant launched in Germany in 1895. By the 1930s and 1940s, the United States, Australia, the United Kingdom and other countries had a rhizobium inoculant industry, which developed rapidly. At least 70 countries have their own microbial fertilizer production enterprises, product technical standards and quality supervision systems.
Microbial fertilizers In the past, the main variety was Rhizobium fertilizer. Until now, Rhizobium fertilizer is still an important variety. The focus of research in developed countries such as Europe and the United States is mainly on how to overcome the strong competition of low-efficiency rhizobium in soil, as well as the selection of high-efficiency nitrogen-fixing strains and legume hosts. At present, genetically engineered bacteria with competitive nodulation have been obtained. And applied to the field on a large scale. With the emergence of chemical fertilizer problems and the development of pollution-free agriculture, bio-fertilizers have developed rapidly in the past 20 years, and the research field has been continuously expanded. New products of microbial fertilizers such as phosphorus and potassium are continuously introduced. In particular, the research on vocal and disease prevention of PGPR has become a research hotspot in the past 10 years. Its research mainly focuses on Pseudomonas, which can inhibit a variety of plant diseases, especially soil-borne diseases. The research scope mainly includes effective colonization, antibiotic resistance, rhizosphere nutrition competition, enzymes leading to Wu Kangxing and secretory degradation of pathogenic microorganisms. In the application of PGPR preparations and composite microbial preparations, Canada has developed "Rhizobium + PG-PR" compound fertilizer, and Brazil's PGPR preparation is an important fertilizer for crops such as wheat and corn. With the infiltration of molecular biology, the genetic traits of sound and disease prevention have been improved by genetic engineering. The countries that have expressed the Prn gene have been successfully constructed in the United States and the United States, and the HCN gene cluster has been successfully introduced to improve the biocontrol activity. Strains. In addition, the research and development industry of new straw rot fungi, soil and environmental pollution repairing agents has developed rapidly. It is estimated that the current microbial fertilizer production in the world exceeds 10 million tons. In addition to being widely used in legumes, the application area of ​​vegetables and food crops is also expanding.
The research, production and application of microbial fertilizers in China have a history of nearly 50 years, and the development has been several times. In the 1960s and 1970s, the research and production of microbial fertilizers developed rapidly. In the 1960s, the "5406" antibiotic fertilizer was a microbial fertilizer with compound functions of disease resistance, sound promotion and nutrition. According to statistics in 1975, the area of ​​“5406†antibiotics and fertilizers used in the country reached hundreds of millions of mu, and it has applications in crops such as grain beans and fruits and vegetables. Rhizobium inoculant had played a very important role in China's agricultural production in the 1970s, but it was not developed quickly. Around the 1980s, due to the influence of unfavorable propaganda, misunderstanding, technical reasons and market chaos, the research and development of microbial fertilizer in China was greatly affected, causing adverse effects among the masses. In the past 10 years, a new situation has emerged in the research and development of microbial fertilizers in China (Table 3). Significant progress has been made in the use of biotechnology to construct highly efficient engineered bacteria and PGPR preparations. A number of engineered Rhizobium strains with nitrogen-fixing properties have been improved in China; a number of high-efficiency rhizobium and growth-promoting and nodulation PGPR strains that have been applied or modified for use in legumes have been developed and screened in soybeans and peanuts. The crops have achieved good demonstration results; the application of PGPR preparations on wheat, corn and other crops has also achieved yield and disease resistance. The overall status of research and application of microbial fertilizers in China: 1) The basic microbial fertilizer industry has been formed, and 11 types of products have been registered with the Ministry of Agriculture. There are currently about 450 microbial fertilizer companies in the country with an annual output of more than 2 million tons, which has gradually become an important member of the fertilizer family. 2) The types of edible fungi of microbial fertilizers are constantly expanding. The strains used are not limited to rhizobium. Currently, more than 80 species of bacteria are used. 3) The application effect of microbial fertilizers, such as increasing production, improving quality, reducing the amount of chemical fertilizers, and preventing diseases, have gradually been recognized by farmers, and the application area has been continuously expanded, with a cumulative total of nearly 5 million hectares. 4) The quality awareness is improved and the quality inspection system is initially formed. In 1996, the Ministry of Agriculture incorporated microbial fertilizers into the national inspection and registration management, and supervised the production, sales, application and publicity of microbial fertilizers. 5) A small number of products have begun to enter the international market.
In addition to the engineering bacteria construction technology, key fermentation equipment and technology, China's microbial fertilizer research is not low, and the overall level is not low. The state has given certain support to the development of the microbial fertilizer industry in the industrial policy, and the investment in scientific research and the construction of industrial demonstration projects have been continuously strengthened. China's microbial fertilizer industry is entering a virtuous circle and is developing in a healthy and orderly direction.
Industrialized organic fertilizer
Organic fertilizers have an incomparable role in chemical fertilizers in improving soil fertility and improving crop quality, especially in improving the quality of flavored foods. The development of organic agriculture and pollution-free agriculture at home and abroad places great emphasis on the application of organic fertilizers. Domestically, the development of green food standards stipulates that AA and green foods are only allowed to apply organic fertilizers and microbial fertilizers. However, due to the large volume, low nutrient concentration, and dirty odor, traditional organic fertilizers have gradually declined in fertilizer status with the emergence of chemical fertilizers. The proportion of nutrients provided by organic fertilizers in China dropped from 99.9% in 1949 to 49.0% in 1980, up to the current 30%. However, the problems of good waste resources and environmental pollution have become more and more prominent. Straw incineration and large-scale livestock and poultry farms have entered the water bodies in large quantities, causing serious environmental pollution. It is an important direction for new fertilizer research at home and abroad to upgrade traditional organic fertilizer products, develop alternative products, and improve the utilization level of organic waste resources.
There are fewer relatives in foreign countries, most of the crops are cooked once a year, the scale of production is large, and large-scale mechanized operation. In addition to being used as forage, crop straw treatment is mainly for direct field change, and there is less burning in the field.
Developed countries attach great importance to the research and treatment of livestock and poultry manure technology, including rapid fermentation technology, deodorization technology, fermentation nutrient preservation technology, fermentation equipment, organic fertilizer production process equipment and technology. In Japan, the composting of livestock and poultry manure has been realized, and the horizontal brick type and vertical multi-layer rapid composting device developed by the company have a fermentation time of 1-2 weeks, which has the characteristics of small land occupation, fast fermentation and excellent texture. The organic fertilizer fermentation device developed in Russia has a productivity of 100 tons of organic fertilizer per day. The US BIOTEC 2120 high temperature composting system consists of 10 large rotating bioreactors, which can process 1000 tons of livestock manure or garbage in 72 hours through microbial flying feet, making it a high quality organic fertilizer. This method has special for high humidity materials. The role of the system was patented in 1993 and recognized by the United Nations International Environmental Protection Organization. American BEARD-ABT dynamic high-temperature composting is carried out in a closed large fermentation tower and has an assembly function. The air spray gun distributed in the fermentation tower can automatically perform ventilation and induced air conversion according to the needs of the composting process to achieve the overall optimal biological reaction. effect. The trough-type spiral agitation fermentation system developed by Korea has the characteristics of low cost, low operating cost, continuous fermentation, etc. It belongs to a more advanced practical organic material hair gel system. In addition, foreign microbial deodorization technology has made great progress, but it is still dominated by traditional control methods such as water washing, acid absorption, and alkali neutralization. The volatilization loss of nutrients during fermentation is large. Developed countries use a variety of methods to control nitrogen loss and reduce nitrogen volatilization. However, these methods are mainly used in the storage and transportation of livestock and poultry manure, but less control in the composting process. Process and technology for nitrogen loss.
In general, foreign countries have become more and more perfect in organic fertilizer fermentation technology, technology and equipment, basically reaching the scale and industrialization level, but the equipment cost is high, the running cost is high, and it is difficult to directly promote and apply it in China. On the basis of introduction, digestion and absorption, we must form a commercial organic fertilizer production process, equipment and complete sets of technology suitable for China's characteristics.
China is a big country in the production and use of traditional organic fertilizers. But the real systematic study of organic fertilizer began in the 1930s. In the 1950s and 1960s, the technical characteristics were to summarize the traditional experience of farmers and improve the technology of organic fertilizer, system, insurance and use. The research focuses on the first, the fermentation conditions of high-temperature compost, the second is the accumulation method of manure, and the third is the organic fertilizer of tanning and grass pond mud. In the 1970s and 1980s, the research focus was on biogas fermentation, and the second was to apply a lot of basic research on the fertilizer effect of organic fertilizer and inorganic fertilizer. It is affirmed that the combination of organic fertilizer is the basic policy of fertilization technology in China. Since the end of the 1980s, China's agricultural production situation and methods have undergone great changes. Every year, 200 million tons of crop straw remains unmanageable, and the development of large-scale livestock and poultry farming is extremely rapid. Organic fertilizer research has begun to explore the road of scale, industrialization and commercialization. The focus of the research is on the direct return of straw technology to the field; the second is to produce commercialized organic-inorganic compound fertilizer technology for livestock and poultry manure.
At present, some compound fertilizer manufacturers in China have begun to produce organic compound fertilizers. The raw materials are mainly grass charcoal and weathered coal. The actual implementation of factory-treated straw livestock and poultry manure waste produces less commercial organic fertilizer. The production scale is small and the efficiency is small. Low, the pollution is more serious. China's commercial organic fertilizer production technology is still in its infancy, and fermentation technology, ugly technology, and key equipment have yet to be improved.
Multifunctional fertilizer
One of the important directions of new fertilizers in the 21st century is to research and develop multifunctional fertilizers that combine crop nutrition with other factors that limit the high yield of crops. Their production meets the requirements of ecological fertilizer technology, and their fertilization technology will condense agronomy and soil science. Relevant advanced technologies in the fields of informatics and so on. These functional fertilizers mainly include: fertilizers with improved water use efficiency, high-yield fertilizers, fertilizers for improving soil structure, fertilizers for adapting to excellent varieties, fertilizers for improving crop lodging resistance, fertilizers for controlling weeds, and Fertilizers with anti-fungal functions.
There is not much work done at home and abroad on the research and development of functional fertilizers. . With the continuous development of research and application of water retention agents, people began to study water-retaining functional fertilizers. South China Agricultural University and other pioneered research on water-retaining controlled release fertilizer, using high-water-absorbent resin (HWAR) coated urea and coated controlled-release fertilizer to make water-preserving controlled-release fertilizer. The product was tested in arid areas of Xinjiang and achieved good results. . The research products are currently entering the pilot stage. Other aspects of functional fertilizer research, only sporadic reports, far from the industrialization requirements.
The production and use of chemical fertilizers in the world has undergone three changes. Before the 1960s, the fertilizers produced were mostly low-concentration fertilizers; in the 1960s and 1980s, developed countries developed high-concentration fertilizers and compound fertilizers; in the last 20 years, developed countries began to focus on slow/controlled release fertilizers, bio-fertilizers, and organic Compound fertilizers and functional fertilizers have become the hotspots of research and development of new fertilizers.
1. Slow/controlled release fertilizer
The most important feature of slow/controlled release fertilizer is that nutrient release is synchronized with crop absorption, simplifying fertilization technology, achieving one-time fertilization to meet the needs of the crop throughout the growing season, less fertilizer loss, high utilization rate and environmental friendliness. Countries around the world have come to realize that one of the most effective measures to improve fertilizer utilization is to study new slow/controlled release fertilizers. Since the 1980s, the United States, Japan, Europe, Israel and other developed countries have shifted the focus of scientific fertilization technology to the development of new slow/controlled release fertilizers, and strive to greatly improve the utilization rate of fertilizers by changing the characteristics of fertilizers themselves. Slow/controlled release fertilizer is known as an important development direction of the fertilizer industry in the 21st century. At present, there are four main types of slow/controlled release fertilizers.
(1), coated slow/controlled release fertilizer; coated slow/controlled release fertilizer is mainly used to control the nutrient release of the coating material on the surface coating of fertilizer particles to regulate nutrient release. In 1957, the United States first studied sulfur-coated urea. In 1961, TVA carried out a small test of sulfur-containing urea (SCU) on a 1-7 kg/h plant. In 1978, a demonstration plant of 10 t/h SCU was built in the United States. In this case, studies on sodium sulphate (SCK) and thiophosphoric acid diamine (SCP) were carried out. Sulfur-containing urea is still the current leading product in the United States.
The United States is also the first country to commercialize resin-coated fertilizers. In 1967, the production of alkyd resin coated fertilizer Osmocote in California became the world's leading controlled release fertilizer brand. Japan began to study coated controlled-release fertilizers in the 1960s. After the 1970s, it focused on the research of thermoplastic-plastic resin polythene-coated fertilizers, referred to as the POCF process, by adjusting the ratio of PE to EVA, and using inorganic fillers as The pore-opening agent can produce a film controlled release fertilizer with a release period of 40 days to 360 days. The development of degradable polymer coating materials and the study of fertilizers with different nutrient release patterns represent the research direction of coated fertilizers.
Since the 1980s, Israel, Germany, the United Kingdom, Canada, Italy, India and other countries have also carried out research on coated slow/controlled release fertilizers, trying to use polymers, grass charcoal, lignin, paraffin, inorganic nutrients, etc. Wrap urea, etc., to make slow / controlled release fertilizer. In July 1991, the first ring/controlled release fertilizer seminar was held in Sheffferld, Alama, USA; in 1993, an international seminar on slow-release fertilizers was held in Israel. At present, the world's annual slow release / controlled release fertilizer consumption of 1 million tons (physical), mainly coated with fertilizers, accounting for more than half, and some countries accounted for more than 90%.
Synthetic micro-slurry slow-release fertilizers, one type of synthetic organic nitrogen compounds that are slightly soluble in water, such as urea-formaldehyde fertilizer (Ureaform), isobutylidene diurea (IDBU), butadiene diurea (CDU), etc.; The class is a slightly water-soluble or citric acid synthetic inorganic fertilizer, such as partially acidified phosphate rock (PAPR), divalent metal ammonium phosphate potassium salt and the like.
Urea-formaldehydes and released fertilizers are the condensation of urea with aldehydes, the most common being urea formaldehyde (UF). In 1924, BadisheAnilin and Ssoda~Fabrek districts obtained the first patent for the manufacture of urea-formaldehyde fertilizers. In 1955, they were put into industrial production. Germany published the process of preparation of Liao Yong acetaldehyde and urea in 1924. Japan's Mitsubishi Corporation and 1961 - 1962 proposed a patent for the reaction of urea and isobutyraldehyde to prepare isobutylidene diurea (IBDU). Since 1964, there has been a small sale in the Japanese market.
In the early 1990s, the slow/controlled release fertilizers of the century still dominated the soluble urea reactants, accounting for more than 50%. European tradition uses a slightly soluble cold urea compound slow release fertilizer. Its proportion accounts for more than 70% of slow release fertilizer sales. The release rate of nutrients due to nutrients is greatly affected by factors such as soil moisture, pH, and microorganisms, and the price is high. The demand for such fertilizers has a tendency to decline.
The chemically inhibited slow-acting fertilizer adjusts the activity of soil microorganisms by adding urease inhibitors and nitrification inhibitors, slows the hydrolysis of urea and the nitrification of ammonia nitrogen, thereby achieving the slow release of fertilizer nitrogen; in the 1960s, people began to pay attention to screening. The work of soil urease inhibitors. HQ (hydroquinone), NB-PT (N-butylthiophosphoric triamide), PPD (o-phenylphosphoryl diamine), TPTA (thiophosphoric triamide), CHPT (T-phosphate III Cyclohexylamine and the like are important soil urease inhibitors for screening studies.
Since the 1950s, the development of nitrification inhibitors has been carried out abroad. The main products studied are derivatives of pyridine, pyrimidine, thiourea, thiazole, mercury, etc., as well as bismuth potassium nitride, chlorophenyl isothiocyanate, and hexachloroethane. , sodium pentachlorophenol, and the like. Dicyandiamide (DCD) is a widely used nitrification inhibitor for high nitrogen fertilizer utilization.
Matrix compound fertilizer and adhesive slow release controlled release fertilizer, mixing fertilizer nutrients with substances that can reduce its solubility, and making fertilizers with slow release of nutrients through the functions of fitness and cementation. In particular, organic high molecular polymers, modified grass charcoal and weathered coals, organic only equals fertilizers, cementation, and changes the release rate of nutrients to produce slow-release fertilizers. At present, research work in this field is carrying out research directions on slow-release fertilizers, and the prospects are promising.
In addition, the slow release fertilizers of different types and different release rates are passed through the "heterogeneous shifting", so that the nutrient release rhythm of the fertilizer is maximized and the crop absorption is synchronized, which is highly valued in the research and application of slow release fertilizer.
At present, the annual consumption of slow/controlled release fertilizers in the world is about 1 million tons, including 600,000 tons (about 60%) in the United States and Canada, 200,000 tons (months to 20%) in Japan, and 150,000 tons in Western Europe and Israel. About 15%, other countries have more than 50,000 tons per month, which is significantly higher than the seasonal fertilizer growth rate. Currently, the most important issue affecting the development of slow/controlled release fertilizers is the price issue. Due to the high price, in addition to Japan, 90% of the controlled release fertilizers in the United States and Western Europe are used in non-agricultural markets such as lawns and nurseries. Reducing production costs and moving to the field is an important direction for the development and production of slow/controlled release fertilizers.
China's research on slow/controlled release fertilizer started late. In the 1970s, the Nanjing Institute of Soil Science of the Chinese Academy of Sciences conducted the development of long-acting ammonium bicarbonate. In the 1980s, especially in recent years, with the large amount of chemical fertilizers, low utilization rate, chemical fertilizers, agricultural products and environmental problems, the pace of research on domestic slow/controlled release fertilizers has accelerated. Beginning in 1983, Zhengzhou Institute of Technology and other countries took the lead in systematically developing materials to use nutrient guessing to develop packaged controlled release fertilizers, and successively developed calcium magnesium phosphate coated urea (1983), phosphate rock partially acidified urea (1991), and two prices. Metal ammonium phosphate potassium salt Baoguo urea (1995) 3 categories of continuously upgraded products, nutrient control release time of more than 95 days, breaking through the key technology of nutrient material nutrient release control control at home and abroad. Developed an industrialized production line with an annual production capacity of 10,000 tons. The registered brand of the product is Luxacote, which is exported to the United States, Australia, Singapore, Japan and other countries, and is the same as Osmocote, MEISTER and Nutri-cote. At present, under the support of the National 863 Program, research is underway to further reduce costs, focusing on the development of special controlled-release fertilizers for field crops. The products are widely demonstrated in corn fields in Henan and Shandong, with an increase of more than 10%. The utilization rate has increased by more than 10 percentage points.
The development of resin coated controlled release fertilizer, China mainly learn from Japanese experience. Since 1992, the Beijing Academy of Agricultural and Forestry Sciences has taken the lead in systematically researching resin-coated urea. On the basis of drawing on Japanese technology, there have been major improvements and breakthroughs in solvents, coating materials and equipment. The research screened out low-toxic solvents with a recovery rate of over 98%; developed a continuous production equipment to apply for national invention patents. The coating material is made of inexpensive polyacrylamide and modified for degradation. At present, a resin package with an annual production capacity of more than 3,000 tons has been built into a urea production line to produce a series of coated ureas with controlled release of nutrients for 30 to 200 days or longer. The products are classified into linear and S-type release models. With coated urea as the masterbatch, the N, P, K composite controlled release fertilizers were prepared by the heterogeneous shifting technology, and large-scale demonstrations were carried out on rice, corn and other crops in Beijing, Northeast, Shandong, Guangdong and other places. Received good results. The product was awarded the National Key New Product Certificate in 2002.
Soil and Fertilizer Institute of China Academy of Agricultural Sciences, South China Agricultural University, etc. in matrix compounding, cementation controlled release, coating material research, especially the use of industrial and agricultural waste to develop coating materials, as well as in film forming process, mechanism, organic compounding, water retention A lot of work has been done on the development of multi-functional controlled release fertilizers such as disease prevention. Invented the reaction film-forming technology, using the normal temperature equipment to produce coated controlled-release materials, the matrix composite and water-retaining controlled-release fertilizers were developed on a large scale in the corn, Shandong and Xinjiang vegetables and cotton crops in Shandong. The Shenyang Institute of Applied Ecology has also done a lot of work on the development of slow-release fertilizers using urease inhibitors and nitrification inhibitors. The products have been demonstrated on field crops.
In addition, China Agricultural University has conducted a lot of research on the controlled release mechanism and evaluation of controlled release fertilizers. The Institute of Soil and Fertilizer, Chinese Academy of Agricultural Sciences, “The Long-term Monitoring Base for Soil Fertility and Fertilizer Efficiency of the National Brown Soil†has taken the lead in the long-term positioning of slow-release fertilizers in China. This is the long-term positioning experiment of common chemical fertilizers, which will promote the fertilizer efficiency of slow-release fertilizers. Basic research such as evolution and environmental assessment is of great value.
Although the research on slow/controlled release fertilizer in China started late, the research features are obvious. The products and processes such as resin coating, nutrient material wrapping, matrix compounding, cement controlled release, and enzymatic inhibition are all blooming. Especially in recent years, national and local governments have attached great importance to the research and industrialization of slow/controlled release new fertilizers. The Agricultural Fertilizer Research Institute of China Academy of Agricultural Sciences, China Agricultural University, South China Agricultural University, Zhengzhou University, Beijing Academy of Agriculture and Forestry, and other five units jointly undertake the national “10th Five-Year Plan†863 Program “Environmentally Friendly Fertilizer Development and Industrialization†(2001AA246023) With the goal of controlling release fertilizers to field crops, more than 10 related invention patents have been obtained and declared, and more than 50 products on different levels of industrialization, pilot test and small test have been developed, and the production of nutrient materials can be realized. There are 3 production lines with over 10,000 tons of controlled release fertilizers for wrapping, resin coating and matrix compounding. The cost of products is only 1/4 or lower of similar foreign products. It has been widely demonstrated in rice, corn, vegetables, cotton and other crops in Northeast China, Beijing, Shandong, Henan, Xinjiang, Guangdong, etc. Some products have been exported to the United States. Japan, Singapore, Australia, etc.
China's controlled release fertilizer technology is generally inferior to the level of developed countries, especially in terms of industrialization. At present, China's annual consumption of slow/controlled release fertilizer is about 20,000 tons (in-kind). The main brands on the market are Osmocote, Osmocoteplus, Japan's MESTER, Nutricote, Israel's Multicote and other coated controlled-release fertilizers. More than 10,000 yuan per ton. China's current slow/controlled release fertilizer industrialization production capacity has exceeded 100,000 tons, but the operating rate is low.
Biological fertilizer
Bio-fertilizer is a microbial living product that is heterogeneous and microbial life activity and its products cause the crop to obtain a specific fertilizer effect. It has low production cost, good effect, and no need to let the environment not only increase production after application, but also improve the quality of agricultural products and reduce the amount of chemical fertilizer. It plays an important role in the sustainable development of agriculture.
The world's first microbial fertilizer was the “Nitragin†Rhizobium inoculant launched in Germany in 1895. By the 1930s and 1940s, the United States, Australia, the United Kingdom and other countries had a rhizobium inoculant industry, which developed rapidly. At least 70 countries have their own microbial fertilizer production enterprises, product technical standards and quality supervision systems.
Microbial fertilizers In the past, the main variety was Rhizobium fertilizer. Until now, Rhizobium fertilizer is still an important variety. The focus of research in developed countries such as Europe and the United States is mainly on how to overcome the strong competition of low-efficiency rhizobium in soil, as well as the selection of high-efficiency nitrogen-fixing strains and legume hosts. At present, genetically engineered bacteria with competitive nodulation have been obtained. And applied to the field on a large scale. With the emergence of chemical fertilizer problems and the development of pollution-free agriculture, bio-fertilizers have developed rapidly in the past 20 years, and the research field has been continuously expanded. New products of microbial fertilizers such as phosphorus and potassium are continuously introduced. In particular, the research on vocal and disease prevention of PGPR has become a research hotspot in the past 10 years. Its research mainly focuses on Pseudomonas, which can inhibit a variety of plant diseases, especially soil-borne diseases. The research scope mainly includes effective colonization, antibiotic resistance, rhizosphere nutrition competition, enzymes leading to Wu Kangxing and secretory degradation of pathogenic microorganisms. In the application of PGPR preparations and composite microbial preparations, Canada has developed "Rhizobium + PG-PR" compound fertilizer, and Brazil's PGPR preparation is an important fertilizer for crops such as wheat and corn. With the infiltration of molecular biology, the genetic traits of sound and disease prevention have been improved by genetic engineering. The countries that have expressed the Prn gene have been successfully constructed in the United States and the United States, and the HCN gene cluster has been successfully introduced to improve the biocontrol activity. Strains. In addition, the research and development industry of new straw rot fungi, soil and environmental pollution repairing agents has developed rapidly. It is estimated that the current microbial fertilizer production in the world exceeds 10 million tons. In addition to being widely used in legumes, the application area of ​​vegetables and food crops is also expanding.
The research, production and application of microbial fertilizers in China have a history of nearly 50 years, and the development has been several times. In the 1960s and 1970s, the research and production of microbial fertilizers developed rapidly. In the 1960s, the "5406" antibiotic fertilizer was a microbial fertilizer with compound functions of disease resistance, sound promotion and nutrition. According to statistics in 1975, the area of ​​“5406†antibiotics and fertilizers used in the country reached hundreds of millions of mu, and it has applications in crops such as grain beans and fruits and vegetables. Rhizobium inoculant had played a very important role in China's agricultural production in the 1970s, but it was not developed quickly. Around the 1980s, due to the influence of unfavorable propaganda, misunderstanding, technical reasons and market chaos, the research and development of microbial fertilizer in China was greatly affected, causing adverse effects among the masses. In the past 10 years, a new situation has emerged in the research and development of microbial fertilizers in China (Table 3). Significant progress has been made in the use of biotechnology to construct highly efficient engineered bacteria and PGPR preparations. A number of engineered Rhizobium strains with nitrogen-fixing properties have been improved in China; a number of high-efficiency rhizobium and growth-promoting and nodulation PGPR strains that have been applied or modified for use in legumes have been developed and screened in soybeans and peanuts. The crops have achieved good demonstration results; the application of PGPR preparations on wheat, corn and other crops has also achieved yield and disease resistance. The overall status of research and application of microbial fertilizers in China: 1) The basic microbial fertilizer industry has been formed, and 11 types of products have been registered with the Ministry of Agriculture. There are currently about 450 microbial fertilizer companies in the country with an annual output of more than 2 million tons, which has gradually become an important member of the fertilizer family. 2) The types of edible fungi of microbial fertilizers are constantly expanding. The strains used are not limited to rhizobium. Currently, more than 80 species of bacteria are used. 3) The application effect of microbial fertilizers, such as increasing production, improving quality, reducing the amount of chemical fertilizers, and preventing diseases, have gradually been recognized by farmers, and the application area has been continuously expanded, with a cumulative total of nearly 5 million hectares. 4) The quality awareness is improved and the quality inspection system is initially formed. In 1996, the Ministry of Agriculture incorporated microbial fertilizers into the national inspection and registration management, and supervised the production, sales, application and publicity of microbial fertilizers. 5) A small number of products have begun to enter the international market.
In addition to the engineering bacteria construction technology, key fermentation equipment and technology, China's microbial fertilizer research is not low, and the overall level is not low. The state has given certain support to the development of the microbial fertilizer industry in the industrial policy, and the investment in scientific research and the construction of industrial demonstration projects have been continuously strengthened. China's microbial fertilizer industry is entering a virtuous circle and is developing in a healthy and orderly direction.
Industrialized organic fertilizer
Organic fertilizers have an incomparable role in chemical fertilizers in improving soil fertility and improving crop quality, especially in improving the quality of flavored foods. The development of organic agriculture and pollution-free agriculture at home and abroad places great emphasis on the application of organic fertilizers. Domestically, the development of green food standards stipulates that AA and green foods are only allowed to apply organic fertilizers and microbial fertilizers. However, due to the large volume, low nutrient concentration, and dirty odor, traditional organic fertilizers have gradually declined in fertilizer status with the emergence of chemical fertilizers. The proportion of nutrients provided by organic fertilizers in China dropped from 99.9% in 1949 to 49.0% in 1980, up to the current 30%. However, the problems of good waste resources and environmental pollution have become more and more prominent. Straw incineration and large-scale livestock and poultry farms have entered the water bodies in large quantities, causing serious environmental pollution. It is an important direction for new fertilizer research at home and abroad to upgrade traditional organic fertilizer products, develop alternative products, and improve the utilization level of organic waste resources.
There are fewer relatives in foreign countries, most of the crops are cooked once a year, the scale of production is large, and large-scale mechanized operation. In addition to being used as forage, crop straw treatment is mainly for direct field change, and there is less burning in the field.
Developed countries attach great importance to the research and treatment of livestock and poultry manure technology, including rapid fermentation technology, deodorization technology, fermentation nutrient preservation technology, fermentation equipment, organic fertilizer production process equipment and technology. In Japan, the composting of livestock and poultry manure has been realized, and the horizontal brick type and vertical multi-layer rapid composting device developed by the company have a fermentation time of 1-2 weeks, which has the characteristics of small land occupation, fast fermentation and excellent texture. The organic fertilizer fermentation device developed in Russia has a productivity of 100 tons of organic fertilizer per day. The US BIOTEC 2120 high temperature composting system consists of 10 large rotating bioreactors, which can process 1000 tons of livestock manure or garbage in 72 hours through microbial flying feet, making it a high quality organic fertilizer. This method has special for high humidity materials. The role of the system was patented in 1993 and recognized by the United Nations International Environmental Protection Organization. American BEARD-ABT dynamic high-temperature composting is carried out in a closed large fermentation tower and has an assembly function. The air spray gun distributed in the fermentation tower can automatically perform ventilation and induced air conversion according to the needs of the composting process to achieve the overall optimal biological reaction. effect. The trough-type spiral agitation fermentation system developed by Korea has the characteristics of low cost, low operating cost, continuous fermentation, etc. It belongs to a more advanced practical organic material hair gel system. In addition, foreign microbial deodorization technology has made great progress, but it is still dominated by traditional control methods such as water washing, acid absorption, and alkali neutralization. The volatilization loss of nutrients during fermentation is large. Developed countries use a variety of methods to control nitrogen loss and reduce nitrogen volatilization. However, these methods are mainly used in the storage and transportation of livestock and poultry manure, but less control in the composting process. Process and technology for nitrogen loss.
In general, foreign countries have become more and more perfect in organic fertilizer fermentation technology, technology and equipment, basically reaching the scale and industrialization level, but the equipment cost is high, the running cost is high, and it is difficult to directly promote and apply it in China. On the basis of introduction, digestion and absorption, we must form a commercial organic fertilizer production process, equipment and complete sets of technology suitable for China's characteristics.
China is a big country in the production and use of traditional organic fertilizers. But the real systematic study of organic fertilizer began in the 1930s. In the 1950s and 1960s, the technical characteristics were to summarize the traditional experience of farmers and improve the technology of organic fertilizer, system, insurance and use. The research focuses on the first, the fermentation conditions of high-temperature compost, the second is the accumulation method of manure, and the third is the organic fertilizer of tanning and grass pond mud. In the 1970s and 1980s, the research focus was on biogas fermentation, and the second was to apply a lot of basic research on the fertilizer effect of organic fertilizer and inorganic fertilizer. It is affirmed that the combination of organic fertilizer is the basic policy of fertilization technology in China. Since the end of the 1980s, China's agricultural production situation and methods have undergone great changes. Every year, 200 million tons of crop straw remains unmanageable, and the development of large-scale livestock and poultry farming is extremely rapid. Organic fertilizer research has begun to explore the road of scale, industrialization and commercialization. The focus of the research is on the direct return of straw technology to the field; the second is to produce commercialized organic-inorganic compound fertilizer technology for livestock and poultry manure.
At present, some compound fertilizer manufacturers in China have begun to produce organic compound fertilizers. The raw materials are mainly grass charcoal and weathered coal. The actual implementation of factory-treated straw livestock and poultry manure waste produces less commercial organic fertilizer. The production scale is small and the efficiency is small. Low, the pollution is more serious. China's commercial organic fertilizer production technology is still in its infancy, and fermentation technology, ugly technology, and key equipment have yet to be improved.
Multifunctional fertilizer
One of the important directions of new fertilizers in the 21st century is to research and develop multifunctional fertilizers that combine crop nutrition with other factors that limit the high yield of crops. Their production meets the requirements of ecological fertilizer technology, and their fertilization technology will condense agronomy and soil science. Relevant advanced technologies in the fields of informatics and so on. These functional fertilizers mainly include: fertilizers with improved water use efficiency, high-yield fertilizers, fertilizers for improving soil structure, fertilizers for adapting to excellent varieties, fertilizers for improving crop lodging resistance, fertilizers for controlling weeds, and Fertilizers with anti-fungal functions.
There is not much work done at home and abroad on the research and development of functional fertilizers. . With the continuous development of research and application of water retention agents, people began to study water-retaining functional fertilizers. South China Agricultural University and other pioneered research on water-retaining controlled release fertilizer, using high-water-absorbent resin (HWAR) coated urea and coated controlled-release fertilizer to make water-preserving controlled-release fertilizer. The product was tested in arid areas of Xinjiang and achieved good results. . The research products are currently entering the pilot stage. Other aspects of functional fertilizer research, only sporadic reports, far from the industrialization requirements.
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