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fertilizer,organic or inorganic material containing one or more of the nutrients—mainly nitrogen, phosphorus, and potassium, and other essential elements required for plant growth. Added to the soil or other medium, fertilizers provide plant nutrients that are naturally lacking or that have been removed by harvesting or grazing, or by physical processes such as leaching or erosion. Organic fertilizers include animal and green manuremanure,
term used in the United States to refer to excreta of animals, with or without added bedding; also called barnyard manure. In other countries the term often refers to any material used to fertilize the soil.
..... Click the link for more information. , fish and bone meal, and compostcompost,
substance composed mainly of partly decayed organic material that is applied to fertilize the soil and to increase its humus content; it is often used in vegetable farming, home gardens, flower beds, lawns, and greenhouses.
..... Click the link for more information. (see also humushumus
, organic matter that has decayed to a relatively stable, amorphous state. It is an important biological constituent of fertile soil. Humus is formed by the decomposing action of soil microorganisms (e.g.
..... Click the link for more information. ). Microorganisms in the soil decompose organic material, making its elements available for use by plants. Inorganic or artificial fertilizers (also called chemical or mineral fertilizers) are formulated in appropriate concentrations and combinations for various crops and growing conditions. The most popular inorganic fertilizers include: anhydrous ammonia, a gas that is 82% nitrogen; urea, a solid compound containing 46% nitrogen; superphosphate; and diammonium phosphate, containing 18% nitrogen and 46% phosphate. Fertilizers may be spread over the soil surface or plowed under, drilled into deep or shallow layers of the soil, applied in bands under the rows where the seeds are to be sown, drilled into the bands at the time of planting, applied in small doses (micro-dosing) to the seeds at the time of planting, or side-dressed between planted rows. Nitrogen fertilizer washing from farms into surface waters promotes overgrowth of aquatic vegetation, which degrades water quality and can cause eutrophication. Use of inorganic nitrogen suppresses nitrogen-fixing soil bacteria, making agriculture increasingly dependant on artificial fertilizer. See nitrogen cyclenitrogen cycle,
the continuous flow of nitrogen through the biosphere by the processes of nitrogen fixation, ammonification (decay), nitrification, and denitrification. Nitrogen is vital to all living matter, both plant and animal; it is an essential constituent of amino acids,
..... Click the link for more information. .
See publications of the U.S. Dept. of Agriculture.
an organic or inorganic substance that contains plant nutrients or that activates nutrients present in soil. According to their chemical composition, fertilizers are divided into organic fertilizers and inorganic, or mineral, fertilizers. Organic fertilizers include manure, compost, and green manure. Mineral fertilizers include nitrogenous fertilizers, phosphorus fertilizers, potassium fertilizers, mixed fertilizers, lime, and micronutrient fertilizers. According to their effect on plant nutrition, fertilizers are said to be either direct or indirect. There also are bacterial fertilizers. Fertilizers obtained directly on farms are called local fertilizers, whereas those produced by chemical plants are called industrial fertilizers.
Fertilizers increase soil fertility by altering nutrient, water, heat, and aeration conditions. They also improve the chemical, physicochemical, physical, and microbiological properties of soil. The repeated addition of large quantities of fertilizers and other farming practices (tilling, sowing of grasses) can alter the soil-forming process and give rise to new soil subgroups— anthropogenic soils—of high fertility. Through the use of fertilizers, man intervenes in the natural cycle of matter and creates, in particular, a positive nutrient balance. Correctly used, fertilizers have a beneficial effect on plant growth and development and, ultimately, on crop yields and quality. The efficiency of fertilizers varies with the biological characteristics of the crops, with the nutrient and moisture content of the soil, and with the reaction of the soil solution. Fertilizers elicit a substantial increase in yield under irrigated conditions. A combination of fertilization and irrigation also encourages a more economical consumption of water and nutrients by plants.
The supply of fertilizers per hectare (ha) of sown area is one of the main indexes of the intensification of agriculture. Approximately 50 percent of the total increase in yield is believed to be due to fertilizers. The increase in yield of the principal crops of the USSR after the use of fertilizers is shown in Table 1.
The addition of 1 ton of manure ensures the following additional yields the first year: grain, 0.2–0.3 quintals; potatoes, 1–1.5 quintals; and corn fodder, 3–4 quintals. The efficiency of mineral and organic fertilizers with an equal quantity of nutrients in a crop rotation is the same. On coarse soils the maximum increase in yield is obtained from the combined application of organic and mineral fertilizers. Organic fertilizers also enrich the soil with humus, thereby creating the preconditions for increasing the amount of mineral fertilizers. This is very important when growing varieties that consume large quantities of nutrients.
In prerevolutionary Russia fields were fertilized mainly with manure, liquid manure, and poultry manure. Mineral fertilizers, mostly imported, were used on some estates. At the beginning of the 20th century there were only 13 factories and other enterprises for the production of superphosphates. The first superphosphate factory began operation in 1860 in Kaunas. In 1913, 129,000 tons of superphosphate—39 percent of the amount required—were produced.
A great deal of attention was devoted to fertilizer production in the early years of Soviet power. In 1918 the Central Committee for Mineral Fertilizers was established. In 1919, V. I. Lenin signed the document On the Transport of Fertilizers by Railroad, which stated that fertilizers have equal priority with grain during shipment and should be treated as first-class freight. The creation of a chemical industry, including a mineral fertilizer industry, during the years of the first five-year plan made it possible to boost the production of mineral fertilizers 13-fold compared to 1913. By the end of the second five-year plan (1938) production increased 54-fold compared to 1913. A number of plants were built, including the Berezniki Nitrogen Fertilizer Plant, the Novomoskovsk Chemical Combine, the Voskresensk Chemical Combine, and the Solikamsk Potassium Plant. After the war fertilizer production continued to increase.
A program for the development of the mineral fertilizer and herbicide industries was outlined at the March 1965 plenary session of the Central Committee of the CPSU. It called for greatly increased capacity, greater diversification of crops, and improved crop quality. Of great importance for the application of chemistry to agriculture was the decree On Measures for Increasing the Efficiency of Use of Mineral Fertilizers, Reducing Losses During Transport, Storage, and Application, and Improving Agricultural Chemistry Servicing to Kolkhozes and Sovkhozes, which was issued in 1976 by the Central Committee of the CPSU and the Council of Ministers of the USSR. Mineral fertilizers delivered to farms totaled 1,261,000 tons in 1950 and 10,362,000 tons in 1970. Fulfillment of the ninth five-year plan (1971–75) with respect to fertilizer production helped to increase the quantities delivered to farms in 1975 to 17,200,000 tons (calculated on the basis of 100 percent nutrient content). The application of industrial chemistry to agriculture will intensify during the tenth five-year plan (1976–80). The development of livestock production and an increase in peat extraction boosted the use of organic fertilizers to 348 million tons in 1950, 428 million tons in 1960, 422 million tons in 1965, 468 million tons in 1970, and 626 million tons in 1974.
An agrochemical service with a network of zonal chemical laboratories directed by the Central Institute of Agricultural Chemistry Servicing was organized in the USSR to ensure the most efficient use of fertilizers. Agricultural chemists study the influence of fertilizers on yields and on the chemical processes that take place in soil and plants. A network of research organizations, for example, the Institute of Fertilizers and Soil Science and the Institute for Fertilizers, Insecticides, and Fungicides, studies the effect of fertilizers (quantities, methods and times of application) on yields. Research on fertilizers is also done at the department of agricultural chemistry and soil science at the K. A. Timiriazev Moscow Agricultural Academy and the department of agricultural chemistry at Moscow State University, as well as in many institutes and at experimental stations. General guidance for research on the application of chemistry agriculture is provided by the agriculture and chemistry division of the V. I. Lenin All-Union Academy of Agricultural Sciences. Extensive research on soil chemistry made possible the compilation of an agrochemical map of the USSR that shows the efficiency of fertilizers in the various natural and climatic zones of the country. Fertilizers are also studied in accordance with the program of the Council for Mutual Economic Assistance. The USSR is a member of the International Center for Mineral Fertilizers.
REFERENCESSee references under MINERAL FERTILIZERS and ORGANIC FERTILIZERS.
V. G. MINEEV