GB730464A - Improvements in or relating to a method of improving soil structure - Google Patents

Abstract

A soil-conditioning composition comprises a water-soluble polymer containing units of the formula <FORM:0730464/IV (a)/1> where n is zero or 1, X is selected from -OM, -O1/2Ca, -ONH4, -ONRH3, -ONR2H2, -ONR3H, -OH, -NH2, -OCH2NR2, -OCH2CH2NR2, -OCH2CH2NHR, -OCH2 CH2NH2,-NHCH2CH2NR2, -NHR or -NR2, M being an alkali metal and R an alkyl group having one to four carbon atoms and a major proportion of a solid carrier, e.g. a fertilizer. The polymer may be a homopolymer of acrylic acid, methacrylic acid, acrylamide, methacrylamide, a sodium, potassium, calcium or ammonium salt of acrylic or methacrylic acid, betaaminoethylacrylate or methacrylate, a beta-N-alkylaminoethyl acrylate or methacrylate, a beta-N : N-dialkylaminoethyl acrylate or methacrylate, and an alkylamine salt of acrylic or methacrylic acid or a copolymer of one of the above monomers with styrene, vinyl acetate, acrylonitrile, methacrylonitrile, butadiene, alkyl acrylates or methacrylates, vinylidene chloride, vinyl chloride, or a -methylstyrene. Specified copolymers are the sodium salt of a hydrolysed copolymer of acrylonitrile and vinyl acetate, acrylamide and acrylonitrile, methacrylic acid and dimethylaminoethyl methacrylate, the ammonium salt of acrylamide and methacrylic acid, and the ammonium salt of the acid hydrolysis product of methacrylic acid and acrylonitrile. The solid carrier may be peat moss, limestone, sand, a mixture of potassium sulphate, superphosphate and inorganic nitrogen-containing compounds, urea, processed sewage sludge, soyabean meal, guano, bone meal, animal tankage, dried blood, humus, dried cow manure or cocoa waste. The composition may also contain trace elements such as boron, manganese, magnesium, molybdenum, cobalt, or iron. Chemically reactive groups present in the polymers may combine with reactive groups in the solid carrier. In examples of the preparation of suitable polymers polydimethylaminoethyl methacrylate is made by polymerizing the methacrylate in water in the presence of glacial acetic acid and potassium persulphate; the sodium salt of a hydrolysed copolymer of acrylonitrite and vinyl acetate is made by refluxing the copolymer in the presence of sodium hydroxide and stearic acid; a copolymer of acrylamide and acrylonitrile is made by dissolving a mixture of the monomers in 50 per cent methyl alcohol and polymerizing in the presence of potassium persulphate and sodium bisulphite; a copolymer of methacrylic acid and dimethylaminoethyl methacrylate is made by polymerizing the monomers dissolved in water in the presence of potassium persulphate; and the ammonium salt of the hydrolysis product of a copolymer of methacrylic acid and acrylonitrile is made by hydrolysing the copolymer in the presence of sulphuric acid and treating the product with ammonium hydroxide. Specification 730,463 is referred to.ALSO:The physical structure of soil is changed by incorporating in it a water-soluble polymer containing units of the formula:- <FORM:0730464/I/1> Where n is zero or 1, X is selected from -OM,-0 1/2 Ca, -ONH4, -ONRH3 -ONR2H2, -ONR3H -OH, -NH2, -OCH2NR2, -OCH2 CH2 NR2, -OCH2CH2NHR, -OCH2CH2NH2, -NHCH2 CH2NR2, -NHR, or -NR2, M being an alkali metal and R an alkyl group having one to four carbon atoms (see Group IV (a)), or a composition thereof comprising a major proportion of a solid carrier (e.g) a fertilizer. The solid carrier may be peat moss, limestone, sand, a mixture of potassium sulphate, superphosphate and inorganic nitrogen-containing compounds, urea, processed sewage, sludge, soyabean meal, guano, bone meal, animal tankage, dried blood, humus, dried cow manure, or cocoa waste. The composition may also contain trace elements such as boron, manganese, magnesium, molybdenum, cobalt, or iron. Chemically reactive groups present in the polymers may combine with reactive groups in the solid carrier. The following examples of compositions are given in the Specification:-(1) polyacrylamide and a mixture of an inorganic mineral fertilizer, (2) sodium polyacrylate and a mixture of an inorganic mineral fertilizer, (3) ammonium polyacrylate, potassium sulphate and superphosphate, (4) potassium polyacrylate and inorganic fertilizer, (5) ammonium polymethacrylate and inorganic fertilizer, and (6) the sodium salt of a copolymer of acrylic acid and vinyl alcohol. Specification 730,463 is referred to.