Abstract:
Phosphate enriched, potassium supplemental manure product and method of production including reaction of manure with a solution of alkali metal acid phosphate salt in orthophosphoric acid, in some cases with prolonged reaction at elevated temperatures to hydrolyze manure protein to free amino acids.

Description:
BACKGROUND OF THE INVENTION 
     A phosphate enriched manure fertilizer is prepared by reaction of manure with an acid phosphate reactant comprising phosphoric acid such as orthophosphoric acid and an acid phosphate salt such as and particularly monopotassium acid phosphate. 
     In particular embodiments the invention further relates to the mineral supplementation of manure fertilizers by the addition of phosphate and by the addition of potassium. 
     In further embodiments of the invention, the reaction of phosphoric acid with manure is continued at elevated temperatures and for a prolonged period and in the presence of a buffering quantity of alkali metal acid phosphate salt, effecting hydrolysis of the protein content of the manure and the generation of free amino acids. 
     The invention further relates to method for production of phosphate enriched manure, potassium enriched manure, and free amino acid containing manure fertilizer products. 
     PRIOR ART 
     Mineral and element supplementation of manures is known. A variety of materials have been used including in some instances phosphoric acid and alternatively in the prior art phosphate salts. Among the patents known to applicants are U.S. Pat. No. 173,621 to Griffith, U.S. Pat. No. 129,739 to Loewenstein, U.S. Pat. No. 1,703,504 to Walton et al, U.S. Pat. No. 47,610 to Baugh, U.S. Pat. No. 517,661 to Powter, U.S. Pat. No. 673,167 to Giffen, and U.S. Pat. No. 1,420,596. 
     SUMMARY OF THE INVENTION 
     The invention has for its purpose the preparation of an improved fertilizer material, one comprising manure as the basic ingredient and having provision for supplementation of the manure with mineral and elemental materials specifically phosphate and potassium known to be beneficial to plant life and as well in certain embodiments the provision of free amino acids which, as is known, are directly assimmiable into the plant structure and which therefore are extremely efficient in the soil in plant nutrition. 
     In accordance with the purposes of the invention there is provided method for the production of phosphate enriched high organic content fertilizer comprising manure, including the steps of reacting the manure with at least one part by weight of an acid phosphate reactant per one part of manure, the reactant comprising a mixture of one part by weight of an alkali metal acid phosphate and from one to eight parts by weight of orthophosphoric acid, and recovering the product. In preferred embodiments the salt is monopotassium phosphate but the acid phosphate salt may have the formula MeH 2  PO 4  wherein Me is an alkali metal selected from potassium, sodium, lithium and cesium. In other embodiments the acid phosphate salt may have the formula Me 2  HPO 4  in which the metal is an alkali metal as mentioned. The orthophosphoric acid may be used as an aqueous solution containing about 85 percent by weight of the acid i.e. commercial orthophosphoric acid. 
     In certain embodiments it is preferred that the manure be first slurried in water prior to effecting reaction with the acid phosphate reactant. 
     Accordingly and in preferred carrying out of the invention there is provided method for the production of phosphate enriched high organic fertilizer comprising manure, including the steps of slurrying manure in up to five parts by weight of water per part of manure, mixing an acid phosphate reactant solution of one part by weight of monopotassium acid phosphate in from one to four parts of orthophosphoric acid with the manure slurry in an amount of one to four parts by weight of the acid phosphate reactant per part of manure and recovering the product. 
     In further embodiments of the invention three amino acids are generated within the enriched manure fertilizer product. In this respect the invention provides a method of producing free amino acids in the fertilizer product produced as above by heating the product at an elevated temperature above about 75° C for several hours and recovering the product. Typically, heating is continued for not less than 4 hours and preferably heating is carried out at about 90° C. 
     Accordingly, in a preferred form of the process there is provided method for the production of free amino acid-containing phosphate-enriched high organic content fertilizers comprising manure, including slurrying manure in up to five parts by weight of water per part of manure, mixing acid phosphate reactant solution of one part by weight of monopotassium acid phosphate with from one to four parts of orthophosphoric acid with the manure slurry in an amount of one to four parts by weight of the acid phosphate reactant per part of manure, heating the resulting mixture at about 90° C for not less than 4 hours to hydrolyze proteinaceous material in the manure into free amino acid, and recovering as product a manure fertilizer containing free amino acid, and enriched with phosphate and potassium. 
     The invention further relates to the products obtained by the foregoing methods. 
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In carrying out the invention use is made of manure i.e. animal excrement widely found in rural areas where fertilizer is most important. While manure is a natural fertilizer, it is desirable to augment its action in fertilizing plants by the addition of mineral and elemental supplements. It is to this purpose that the invention is directed. Specifically the invention provides for reacting manure with phosphoric acid in the first instance, but only in the presence of an acid salt of phosphoric acid whereby the reaction conditions are ameliorated to an extent permitting the effective reaction of phosphoric acid with the manure fertilizer. In addition, particularly where the acid phosphate salt is the monopotassium or dipotassium acid phosphate salt there is further added to the soil a quantity of potassium which is a necessary nutrient for plants. 
     As the phosphoric acid reactant we prefer to use orthophosphoric acid particularly in its commercial form i.e. 85 percent H3PO4 in aqueous solution. 
     As the acid phosphate salt reactant we prefer to employ an alkali metal i.e. potassium, sodium, lithium, or cesium metal, mono- or di- acid salt as the salt reagent in the process. 
     In practice the manure is slurried in water to facilitate mixing of the manure and acid phosphate reactant. Typical proportions are for each part of manure from one to eight parts and preferably up to five parts by weight of water. 
     Following slurrying of the manure the acid phosphate reactant is prepared. Typically, this is accomplished by dissolving in phosphoric acid the particular salt e.g. and for illustrative purposes monopotassium phosphate. The ratio of monopotassium salt as an illustration to phosphoric acid is in the range of, for each part of monopotassium acid phosphate salt, from one to four parts of orthophosphoric acid. In general, from one to four parts by weight of the acid phosphate reactant material comprising both the phosphoric acid and the acid phosphate salt is employed in the range of from one to four parts of the acid phosphate reactant per part of manure in the slurry. 
     The reaction is generally effected at room temperature and proceeds nicely in an aqueous slurry of manure with the concentrations of acid phosphate reactant set out. After reaction, the reaction product is dried and may be applied directly as fertilizer for an improved result in plant nutrition and soil supplementation. 
     As noted above, the invention further provides for the production of free amino acids within the modified fertilizer product prepared as just described. For this purpose, the proteinaceous material within the manure is hydrolyzed under particular conditions leading to the generation of free amino acid. It is believed, while not wishing to be bound to any particular theory, that the hydrolysis of proteinaceous material within manure produces usable free amino acids in the product while apparently similar processes do not, by virtue of the conjoint presence of both phosphoric acid and a complimentary phosphate salt such that the pH of the acid is buffered to approximately 25 percent to 50 percent higher than the acid per se whereby hydrolysis proceeds even at the elevated temperatures and for the prolonged heating periods recommended herein in such manner as to provide by virtue of the buffered hydrolysis such amino acids as cuistein phosphate, arginine phosphate, alanine phosphate, glycine phosphate, and histadine phosphate, and others. 
     It is noteworthy that in view of the buffered condition of the reaction system, amino acids generated are not destroyed and are thereby retained for use by the plant. It is known that amino acids may be directly assimilated by the plants and therefore the nutritional effect is immediate and remarkable. 
    
    
     The invention will be further described as to illustrative embodiments in the following examples in which all parts and percentages are by weight. 
     EXAMPLE 1 
     Cow manure, one part by weight, was slurried with water, five parts by weight, and thereto there was added one part by weight of an acid phosphate reactant comprising 0.5 part by weight of monopotassium acid phosphate and 0.5 part by weight of orthophosphoric acid. The slurry and acid phosphate reactant solution were stirred together and the product recovered by drying. 
     EXAMPLE 2 
     The reaction conditions of Example 1 were duplicated with the generation of free amino acids by heating the reaction product at 75° C for 4 hours. There was produced a reaction product, which exhibited a positive test for free amino acids. 
     EXAMPLE 3 
     Example 1 is duplicated employing four parts by weight of the acid phosphate reactant per part of manure. 
     EXAMPLE 4 
     Example 1 is duplicated employing as the acid phosphate reactant solution one containing 0.5 part of monopotassium acid phosphate and two parts of orthophosphoric acid. Results were equivalent. 
     EXAMPLE 5 
     Example 1 is duplicated employing eight parts by weight of water per part of manure in slurrying the manure. Results were equivalent. 
     EXAMPLE 6 
     Example 1 is duplicated employing as the acid phosphate reactant an also phosphoric solution of an alkali metal acid salt selected from sodium, lithium and cesium, mono- and dihydrogen acid phosphate salts. Results were equivalent. 
     EXAMPLE 7 
     Example 2 is duplicated using 90° C as the reaction temperature and heating for 4.5 hours. The reaction product tests positively for free amino acid. 
     The products of Examples 1 through 7 are tested for fertilizing efficiency in a truck garden by blending into the soil at the level of one bale per 1000 square feet the fertilizer products obtained. Garden vegetables are grown in the area and the results observed. It is noted that the plants are healthy, rapid growing and heavy bearing of fruit, the amino acid containing fertilizer areas having somewhat swifter results.