Abstract: Granular coated particles suitable for use alone or in combination with other fertilizer particles as an nitrogen-dispersing agricultural fertilizer, and a process for making the granular coated particles are disclosed. The granular coated particles include particles formed from at least one metal nitrate, and a first coating layer surrounding each of the metal nitrate particles. The first coating layer is formed from a mixture containing urea and at least one metal nitrate. The metal nitrate particles each is substantially free and discrete from other metal nitrate particles. The metal nitrate is preferably sodium nitrate or potassium nitrate.

Abstract: Free-flowing moisture resistant calcium-containing particles that inhibit the water absorption characteristics of calcium products, including soluble calcium products that are hygroscopic and deliquescent, by providing a moisture resistant coating. The core of the particle is a calcium-containing material, more particularly a soluble calcium-containing material. Moisture resistant or hydrophobic coatings are applied to the core to inhibit water absorption by the calcium-containing material. The coated particles may then be more easily shipped, stored and handled as a dry, anhydrous product. A core comprised of calcium chloride coated with urea is useful as both a soil conditioner and a fertilizer. Additional plant nutrients are mixed with either the core or the coating materials to improve fertilizing qualities. Additional coatings of hydrophobic materials such as a paraffinic hydrocarbon or a polymeric resin increase the water resistance of the particles.

Abstract: Solids that, untreated, have a tendency to cake are treated with distillation bottoms that are liquid at about 60.degree. C. or less and are obtained from production of an alcohol having the formula:R2-R1-OH,wherein R1 is substituted or unsubstituted, branched, straight chain or cyclic, C.sub.4 to C.sub.12 and R2 is OH or H.

Abstract: Aqueous ammoniate solutions made during the manufacture of N-hydrocarbyl thiophosphoric triamides, consisting essentially of aqueous solutions of ammonium chloride and ammonia containing a water-soluble impurity normally tending to engender corrosion of ferrous metal are rendered corrosion-resistant by dissolving therein a small corrosion-inhibiting amount (e.g., up to about 5000 ppm (wt/wt) of a water-soluble salt or oxide of zinc, aluminum, arsenic, antimony or bismuth.

Abstract: The invention relates to a stable aqueous fertilizer suspension suitable for drip irrigation, which suspension contains 5-55% by weight water and 45-95% by weight of one or several plant-nutrient containing substances, of which at least one contains water-insoluble solid particles, the particle size of the solid particles contained in the suspension being less than 50 .mu.m and the pH of the suspension being within the range 2-7. The invention also relates to a process for the preparation of this suspension.

Abstract: The present invention relates to a controlled release fertilizer having water-soluble fertilizers as nucleus and limited-soluble plant nutrient compounds as coating layers, characterized in that more than two coating layers of limited-soluble compounds are formed around the nucleus, and that the release rates of the fertilizer can be controlled by regulating the solubilities of the limited-soluble compounds. The invention also relates to a process for preparing the controlled release fertilizer.

Abstract: A particulate urea product having improved hardness, nonfriable and anti-caking properties and which is useful for either direct application to the soil or as an intermediate product for the subsequent incorporation with other fertilizer materials into solid bulk blends. The product consists of an admixture of urea and a finely divided inorganic material selected from the group consisting of calcium oxide, calcium hydroxide, cement and fly ash and is in particulate form, some examples of which are granules or prills.

Abstract: Mechanically strong, water-disintegrable agglomerates for use as a soil conditioner produced from dust particles emitted from kilns during the manufacture of cement and a process for forming such agglomerates are disclosed. The process comprises combining cement kiln dust and a water-soluble binder to produce agglomerates which are then subjected to controlled drying such that the dried agglomerates having a size ranging from -7 to +8 Tyler Standard Sieve Series exhibit an average green crush strength of at least about 2 pounds (about 0.9 kg).

Abstract: This patent describes nitrification inhibitors characterized by the fact that they contain as their active ingredients a substituted pyrazole, or a salt or metallic complex thereof, dicyanodiamide, and one of the compoundsammonium thiosulfate,biguanide, orammonium rhodanide. The combinations of the present invention are more efficacious than the individual ingredients alone and binary combinations of the same ingredients, and are thus superior to same from the ecological, phytotoxicity, and cost-effectiveness stand-points, as well as in terms of their tendencies to form undesirable residues.

Abstract: Non-corrosive nitrogen containing fertilizer solutions are provided which contain effective levels of corrosion inhibitors which are monocarboxylic acids or polycarboxylic acids, or their salts, or mixtures thereof.

Abstract: The essence of the invention resides in that in production of a solid product obtained in a reactor (1) by way of synthesis from source components and serving as a raw material for preparing a solution of salt and/or fertilizer, a pulp is obtained and then loaded in a container (2) at fixed temperatures corresponding to crystallization of the product to a hydraulically compacted state of preset degrees. The same container (2) is used for transportation and storage of the hydraulically compacted crystals. The solution of salt and/or fertilizer is prepared within preset concentration and dosage just before its application by the user (4), and the crystals are dissolved in the same container (2). If required the product is transferred into another container.

Abstract: The present invention describes a protein guarantor composition and its application, in particular to improving the protein content of cereals. The protein guarantor composition containing urea as nitrogen source and incorporating deacylated chitin proves noteworthy, by virtue of the increase in the protein content of the grain. This composition does not cause harmful scorching of the foliage and its apparent use coefficient for nitrogen is much better than that of the nitrogen fertilizers applied to the soil.

Abstract: Plant growth stimulants containing compounds which increase intracellular carbon dioxide as the main active component and optionally supplemented with specific nutrients have been found to enhance productivity of plants. Exemplary compounds include lower alcohols, such as methanol, ethanol, propanol and butanol, and amino acids, such as glycine, glutamate, and aspartate. Such growth stimulation appears to result, in part, from inhibition of stress induced photorespiration according to a previously unrecognized photosynthetic pathway. Exposure of the plants to sunlight or other sufficient illumination following treatment with the compositions results in enhanced fixation of carbon dioxide and turgor. Stimulant compositions may comprise from 5% to 50% by volume aqueous solutions of methanol or 0.1% to 10% by weight amino acids and are preferably applied by foliar spraying of plants and plant shoots.

Abstract: A process for the removal of oxides or hydrated oxides of carbon or sulfur from an acid waste gas stream in which a bed of moist particulated solid waste material is formed, the bed particles are coated with alkaline earth oxides or alkaline earth carbonates and a catalyst to promote the reaction of the oxides or hydrated oxides of carbon or sulfur with the alkaline earth oxides or alkaline earth carbonates in the presence of the moisture and in which the bed is contacted with the waste gas stream whereby the oxides or hydrated oxides or carbon or sulfur react with the alkaline earth oxides or alkaline earth carbonates in the presence of the moisture and are absorbed on the bed particles. The bed particles resulting from the process may be used as agricultural soil amendments alone or in combination with fertilizers and the like.

Abstract: Ionene polymers having biologically-active organic and/or inorganic anions are described. Methods to prepare the ionene polymers, compositions containing them and their methods of use are also described.

Abstract: A machine system and process for producing attrition resistant, controlled release fertilizer is described. In the process, a prewet solution is used to initially coat the plant nutrient to be coated followed by the separate application of the individual components used in the coating. The machine system provides an improved means for uniformly applying a single layer or multiple layers of polymer coatings to the plant nutrient.

Abstract: Urea increases the solute content of a fertilizer comprising water and at least two different nitrate-containing compounds selected from the group consisting of ammonium nitrate, alkali metal nitrates, and alkaline earth metal nitrates. In addition, urea enhances plant uptake of alkaline earth metals. Particularly favored are quaternary aqueous solutions containing urea, calcium nitrate, and ammonium nitrate.

Abstract: Solid compound fertilizers for dissolving into stock solutions advantageously employing urea phosphate as a phosphorous source. The use of urea phosphate makes it possible to have calcium present as well as nonchelated trace metals without precipitation.

Abstract: Improved release profiles which can, for the first time, be customized to match requirements of systems including crop nutrient uptake are realized by providing a plurality of heterogeneous particles comprised of water-soluble constituents set in a matrix of water-insoluble materials, and further providing a continuous homogeneous barrier of same, or a different water-insoluble material, juxtaposed the peripheral surface of each such heterogeneous particle. A first alternate embodiment includes forming in situ reaction products to reduce the specific gravity of such heterogeneous particles. In a second alternate embodiment, there is substituted for all, or a portion of such water-soluble material, organic media comprised primarily of composted poultry litter wherein soluble iron values remain available for substantial periods of time without incorporating or utilizing expensive conventional synthetic chelating agents.

Abstract: Polymer topcoated sulfur coated fertilizer compositions are provided which exhibit slow release characteristics and are abrasion resistant, free flowing, non-smearing and essentially dustless products.

Abstract: A precipitate free concentrated aqueous stock solution formed from a dry solid fertilizer mixture and containing from about 0.1% to 50% by weight of dissolved solid fertilizer. The stock solution contains phosphorus and calcium and is prepared by bringing together the dry fertilizer mixture and water to make up a concentrated stock solution. The dry solid fertilizer mixture comprises 1% to 95% by weight of dry urea phosphate as the principal phosphorus source and 0.2% to 70% by weight of dry calcium phosphate in the form of monocalcium phosphate, dicalcium phosphate, tricalcium phosphate and mixtures thereof to contribute a desired amount of phosphorus and calcium for fertilization purposes.

Abstract: A method of preparing liquid nonpolymeric controlled release nitrogen plant food composition by the condensation reaction of about one molecule ammonia, about two molecules of urea, and about three molecules of formaldehyde in base buffered aqueous solution at a minimum pH of 7 and a temperature of about 100.degree. C. and concentrating by evaporation until nitrogen concentration is between 20 and 30 percent before formation of polymers containing more than 3 urea moieties occurs. The new nonpolymeric aqueous liquid controlled release nitrogen plant food composition prepared exhibits high storage stability, low phytotoxicity, high nitrogen availability to plants, and contains less than 6 percent unreacted urea nitrogen, less than 1 percent unreacted ammonia nitrogen, and contains large amounts of 5-methyleneuriedo-2-oxohexahydro-s-triazine.

Abstract: The present invention relates to a fertilizer composition comprising solution or dispersion of nutrient compounds and method for its manufacture. The solution/dispersion constitutes the discontinuous phase of a water-in-oil type (w-i-o) emulsion having a volume phase ratio, discontinuous phase: total volume in the range of 0.80-0.95. The fertilizer composition may additionally contain 0-60 weight % solid nutrient salts and/or urea. The oil or hydrocarbon component of the w-i-o emulsion comprises mineral, vegetable or animal oils, wax or mixture of these, and the emulsion comprises at least one w-i-o emulsifier. The hydrocarbon component may also contain 0.5-6 weight % of elastomer, preferably polyisobutylene. The method comprises dissolving or dispersing the nutrient compounds at a temperature of 5.degree.-15.degree. C.

Abstract: Urea increases the solute content of a fertilizer comprising water and at least two different nitrate-containing compounds selected from the group consisting of ammonium nitrate, alkali metal nitrates, and alkaline earth metal nitrates. In addition, urea enhances plant uptake of alkaline earth metals. Particularly favored are quaternary aqueous solutions containing urea, calcium nitrate, and ammonium nitrate.

Abstract: The method relates to the production of phospho-nitrogenous products soluble in neutral ammonium citrate and wherein free urea does not remain in significant amount in such products. Most of the free urea is involved in a ureic combination of calcium sulphate. Tricalcic phosphate is reacted with a reactant obtained by mixing sulfuric acid and urea. The process is particularly useful for the manufacture of fertilizers.

Abstract: Solid compound fertilizers for dissolving into stock solutions advantageously employing urea phosphate as a phosphorous source. The use of urea phosphate makes it possible to have calcium present as well as nonchelated trace metals without precipitation.

Abstract: A trace amount of a molybdate is disclosed for inhibiting corrosion by concentrated urea-ammonium nitrate fertilizer solutions (UAN) in contact with ferrous metal piping and equipment surfaces. From 10 to 200 ppm of sodium molybdate are blended in a UAN solution containing 20-50 weight percent water for effectively inhibiting corrosion. The corrosion-inhibited UAN solution is non-sludging, non-foaming and essentially free of precipitates.

Abstract: A machine system and process for producing attrition resistant, controlled release fertilizer is described. In the process, a prewet solution is used to initially coat the plant nutrient to be coated followed by the separate application of the individual components used in the coating. The machine system provides an improved means for uniformly applying a single layer or multiple layers of polymer coatings to the plant nutrient.

Abstract: An improved fluid urea-containing fertilizer composition is disclosed; the composition is essentially comprised of an aqueous solution of urea, ammonium nitrate, N-(n-butyl)thiophosphoric triamide (NBPT), dicyandiamide (DCD), and may optionally also contain a clay as a suspending agent. The fluid fertilizer composition can be applied to a field crop in a single application and will nevertheless supply sufficient nitrogen to the plants throughout their growth and maturing cycles. As a result, the improved composition increases the nitrogen uptake efficiency of plants, enhances crop yields, and minimizes the loss of nitrogen from the soil.

Abstract: An improved homogenous granular fertilizer composition is disclosed; the composition is comprised primarily of urea, N-(n-butyl)thiophosphoric triamide (NBPT), and dicyandiamide (DCD). The composition of this invention can be applied to a field crop in a single surface application and will nevertheless supply sufficient nitrogen to the plants throughout their growth and maturing cycles. The new improved composition increases the nitrogen uptake by plants, enhances crop yields, and minimizes the loss of both ammonium nitrogen and nitrate nitrogen from the soil.The NBPT is incorporated into the homogenous granular fertilizer composition of this invention by blending a concentrated solution of NBPT in a solvent selected from the group consisting of liquid amides, 2-pyrrolidone, and N-alkyl 2-pyrrolidones directly into molten urea prior to its granulation; the DCD may be added to the urea melt as a solid or in dissolved form along with the NBPT.

Abstract: A method for increasing the yield of rice crop plants by foliar application to the plants during the plant growth stage a granular fertilizer consisting essentially of urea and ammonium sulfate in a urea/ammonium sulfate. The granular fertilizer has a urea/ammonium sulfate weight ratio of about 4/1 and contains at least 40% nitrogen and at least 4% sulfur. The relatively high N-S fertilizer is applied at relatively high rates of about 100 to 150 pounds per acre to ensure that the fertilizer nutrients are always available to the rice plants at several stages of their growing period.

Abstract: A method of preparing a new granular homogeneous metal ammonium phosphate-alkylene urea buffered fertilizer, containing slow releasing water insoluble nitrogen of two types which provide sustained nitrogen release. The method is based on the discovery that a strong metal ammonium phosphate matrix may be formed to homogeneously contain fine particles of alkylene urea compounds. The new buffered fertilizer provides concentrated slow release nitrogens, and phosphate, and buffering amounts of metal nutrients. The alkylene urea may be formed in-situ from liquids concommittantly with the formation of the metal ammonium phosphates, or it may be admixed as finely divided alkylene urea solids. The preferred alkylene ureas are methylene ureas and polymers, isobutylene diurea, and crotonylidene diurea. The metal nutrients are divalent and are preferably magnesium, manganese, zinc, and iron reacted as oxides, hydroxides, or carbonates.

Abstract: A new method of preparing a new aminoureaformaldehyde fertilizer composition which exhibits high cold water insoluble nitrogen (CWIN) levels and high Availability Indices (AI). The method utilizes the discoveries that ammonia compounds, usually ammonium salts, inhibit the urea-formaldehyde polymerization reaction and decrease the formation of hot water insoluble nitrogen (HWIN), and that the ammonium compounds take part in the reaction to form controlled release compounds which are both cold water soluble and insoluble. The process is carried out at elevated temperatures between 60 and 125.degree. F., so that it may be completed in an order of magnitude less time than either the dilute or concentrated conventional commercial ureaform processes, requiring between 2 and 20 minutes for completion. In the process, between 3 and 25 percent of the total nitrogen is supplied as ammonia nitrogen with the remainder from urea, respective formaldehyde to urea to ammonia mol ratio is 1.0, between 1.0 and 2.

Abstract: A nitrification-inhibiting agent is described which is characterized in that it comprisesa) dicyandiamide andb) guanylthiourea and/or ammonium thiosulphate and/or ammonium phosphate.This agent is distinguished by an increased activity compared to the individual components and by its low toxicity.

Abstract: Solid compound fertilizers for dissolving into stock solutions advantageously employing urea phosphate as a phosphorous source. The use of urea phosphate makes it possible to have calcium present as well as nonchelated trace metals without precipitation.

Abstract: Process of furnishing slow release nitrogen to field soil comprising inserting and distributing in the soil in particulate or granular form melamine, ammeline, ammelide, cyanuric acid, mixtures thereof, their salts, and mixtures thereof.

Abstract: The present invention utilizes inexpensive, low-quality by-product ammonium sulfate (AS) characterized as having poor storage, handling, and use properties and normally unsuitable for use as a solid fertilizer because crystals thereof are very fine and of a undesirably high-moisture content. This invention involves production of high-quality, long-storing suspension intermediates directly from AS slurries or AS crystals, followed by storage of the resulting suspensions as intermediate raw materials, and further followed by production of solution fertilizers from such suspension intermediates.

Abstract: A storage-stable dispersion providing melamine in the form of a concentrated liquid for effective use as an end product or as an ingredient for conversion into other products. The dispersion contains melamine particles finer than about 50 microns in diameter, admixed with a chemically inert suspending liquid, having a specific gravity between 0.9 and 1.3 grams per milliliter, containing between 0.03 and 0.20 percent of a chemically inert thickening agent, which interacts physically with the suspending liquid to increase viscosity to between 250 and 3000 centipoise, thereby substantially maintaining the melamine particles in a stable dispersion and preventing their settling. The dispersion composition is an effective form of melamine for accurate dispensing as an agricultural, pulp and paper, or fire-retardant ingredient. Effective thickening agents include xanthan gums, carrageenans, polyacrylamide, chemically treated cellulose, and clays.

Abstract: A process for producing fertilizer granules containing urea and ammonium sulphate by granulation in a fluidized bed of particles is described. Ammonium sulphate particles are introduced into a fluidized bed and urea is applied to the particles in the fluidized bed by spraying an aqueous urea-containing liquid with a urea concentration of 70-99.9% by weight. Preferably, the aqueous urea solution contains a granulation additive and/or ammonium sulphate.

Abstract: A carrierless granular slow release fertilizer composition is prepared by spraying a urea-formaldehyde resin composition having a U/F molar ratio ranging from 2.4 to 13.3 onto finely divided solid particulate raw materials and cooling the resulting sprayed product to solidify the resin composition providing a matrix within which the solid particulate raw materials are bound. The fertilizer composition is characterized by having desired physical and chemical properties in regard to chain length of nitrogen polymers in the product, nitrogen release patterns, hardness and dust free nature of the product and the dispersibility characteristics of the product. The product has an abrasion index of about 0.800-1.000.

Abstract: An agricultural fertilizer material is provided which is resistant to agglomeration, powdering and burning of plant life and which is made up of lightweight blast furnace slag having a water content in the range of about 3% to 5% and mixed with about 10% to 35% by weight of a mixture of nitrogen, phosphoric acid and potash as conventional nutrient salts, said salts and nitrogen being present in amounts sufficient to provide at least 1% by weight of nitrogen on the total mix and said slag having a CaO equivalent of about 20% to 25%.

Abstract: Useful fertilizer solutions of high nitrogen and high sulfur content can be prepared from ammonium sulfate, ammonium nitrate and urea in water. By selecting proper ratios, low salt-out temperatures can be achieved to use optimum amounts of inexpensive urea.

Abstract: Unusually high-analysis low-temperature-stable solution-type fertilizers are produced by mixing urea and phosphoric acid with urea-ammonium nitrate solution (UAN). The ratio of P.sub.2 O.sub.5 to total nitrogen and the ratio of CO(NH.sub.2).sub.2 --N(nitrogen) to NH.sub.4 NO.sub.3 --N(nitrogen) must be maintained within broad specified parameters in order to ensure the production of the instant high-analysis clear-liquid fertilizers which are stable at temperatures as low as 0.degree. C. For example, to produce a 35 percent total plant nutrient (TPN) product, the weight ratio for P.sub.2 O.sub.5 :N (total) must be within the range of about 0.316 to about 0.538, the weight ratio of urea-N to NH.sub.4 NO.sub.3 --N+P.sub.2 O.sub.5 must be in the rang of 1.41 to 1.59, and the weight ratio of CO(NH.sub.2).sub.2 :NH.sub.4 NO.sub.3 must be in the range of 15.25 to 3.75. Similar solutions may be produced by dissolving solid urea and ammonium nitrate in pure or impure phosphoric acid or by utilizing urea.H.sub.3 PO.

Abstract: Low molecular weight urea-formaldehyde reaction products are provided. Such products exhibit cold water solubility. They find use as a sustained nitrogen-release source for animals and plants. A three-stage process is provided for preparing the reaction products. The first stage comprises reacting urea and formaldehyde in an alkaline, alcoholic solution. Then the solvent is distilled off to form a melt. In the final stage the melt is polymerized to form the cold water soluble, low molecular weight reaction product.

Abstract: An improved aqueous nitrogen fertilizer has been developed that increases first-year nitrogen uptake efficiency to plants. It is also a nitrogen with features to minimize exposure to nitrogen loss. It is a nitrogen fertilizer consisting of urea, ammonium nitrate, dicyandiamide, ammonium thiosulfate, and a phosphate compound which is preferably an ammonium phosphate compound. This composition can contain a herbicide and/or various micro nutrients. This aqueous fertilizer solution can be applied to a field crop in a single application and is available to the growing plant throughout its growth and maturing cycle. The aqueous fertilizer composition is conveniently prepared by the addition of a slurry containing dicyandiamide, ammonium thiosulfate and the phosphate compound to a urea-ammonium nitrate solution wherein the nitrogen content has been adjusted to account for the nitrogen that will be supplied by the slurry.

Abstract: The invention is directed to the fumigation of soils, enclosed spaces, agricultural products and other commodities, etc., using compositions which decompose to form carbon disulfide and certain other biocidal materials. Such fumigation can be used to control bacteria, fungi, insects, nematodes, rodents, nitrification, and weeds.Fumigant compositions are described herein as "thiocarbonates," including, without limitation, salts of trithiocarbonic acid and tetrathiocarbonic acid, compositions having empirical formulae intermediate to these acids salts (such as MCS.sub.3.7, wherein M is a divalent metal ion), and compositions containing substances in addition to thiocarbonates, such as a stabilized ammonium tetrathiocarbonate which contains ammonium sulfide, i.e., (NH.sub.4).sub.2 CS.sub.4 (NH.sub.4).sub.2 S.The compositions are generally water soluble and can be prepared, stored, and used in aqueous solutions.

Abstract: A foliar fertilizer specifically for iron deficient plants which contains a complex of various ingredients such as citric acid admixed/reacted with ferrous sulfate previously converted at-least predominantly to ferric sulfate by oxidation at about 90 degrees or more centigrade or a neutralizing amount of ammonium ion, to a pH ranging from about pH 6 to about pH 7, the ferrous sulfate being typically produced by reaction of iron metal with sulfuric acid, excluding the presence of any phosphate salt, neutralized with NH.sub.4 OH, then admixed with urea and/or ammonium nitrate, the total mixture critically having a nitrogen-to-iron ratio of not less than (i.e., at least) 3/1, preferably within a range of about 4/1 to about 5/1, in aqueous solution, and the method including using the above-noted fertilizer complex as a source, diluting with water such that the source as a percentage ranges from about 5% to about 40%, followed by foliar spraying onto plant foliage, up to an application of about 5 lbs.

Abstract: A process for preparing suspension fertilizers wherein nutrient material and at least one crystal growth inhibitor are mixed, potassium chloride is added, the resultant slurry mixed and subsequently a suspending aid, for example a clay, is added with mixing.

Abstract: An improved aqueous nitrogen fertilizer has been developed that increases first-year nitrogen uptake efficiency to plants. It is also a nitrogen fertilizer with features to minimize exposure to nitrogen loss. It is a nitrogen fertilizer consisting of urea, dicyandiamide, ammonium thiosulfate, and optionally a phosphate compound which is preferably an ammonium phosphate compound. This composition can contain a dye and/or various mineral micronutrients. This homogeneous granular fertilizer can be applied to a field crop in a single application and is available to the growing plant throughout its growth and maturing cycle. The homogeneous granular fertilizer composition is conveniently prepared by the addition of a dicyandiamide, and a solution of ammonium thiosulfate to molten urea. A phosphate compound and preferably ammonium polyphosphate, would be added along with these components.

Abstract: A one-step method of preparing coated particulate plant nutrients wherein a polyfunctional coupling agent is applied to a mobile mass of plant nutrient particles containing functional groups which are chemically reactive with the functional groups of the coupling agent, while simultaneously applying a second reactive material containing functional groups also reactive with the functional groups of the coupling agent, maintaining the mobile mass at a temperature between 30.degree. C. and 300.degree. C. until a strong, water-insoluble particle. The product of the one-step method is a controlled-release plant nutrient having excellent attrition resistance.