Foliar fertilization method and composition
AssigneeUnion Oil Company of California
InventorDonald C. Young
Life of this patent
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Abstract
Aqueous urea solutions particularly suited for foliar fertilization are disclosed. They are characterized by low phytotoxicity, low corrosivity, and improved toxicity stability and comprise urea nitrogen and between about 0.005 and about 0.1 molar equivalents per mole of urea of a pH buffer having a buffering point between about 6 and about 7.6. Also provided are aqueous urea solutions suitable for foliar application containing mineral or organic acids, or both, in the presence or absence of a pH buffer having pH values between about 6 and 7.6. Either solution is foliarly applied at substantially non-toxic rates of at least about 10 pounds of nitrogen per acre.
Claims12
As a composition of matter in aqueous urea solution for foliar fertilization having low ammonia partial pressure, phytotoxicity and corrosivity, improved toxicity stability, and a pH of at least about 6 and less than about 7.6, comprising a nitrogen source consisting essentially of urea in an amount corresponding to at least about 1 weight percent nitrogen, and at least about 0.005 and not in excess of about 0.1 molar equivalents per mole of said urea of a pH buffer having a buffer point between about pH 6 and 7.6, sufficient to maintain (a) the pH of said solution between about 6 and about 7.6 and (b) a low free ammonia content corresponding to an ammonia concentration in the gas phase in equilibrium with said solution at a temperature of 20.degree. C. and atmospheric pressure below about 40 ppm.
As a nitrogenous foliar fertilizer an aqueous urea solution of low ammonia concentration, phytotoxicity and corrosivity, having a major nutrient content consisting essentially of urea nitrogen, containing at least about 5 weight percent nitrogen as urea and at least about 0.005 but not in excess of about 0.1 molar equivalents per mole of urea of a pH buffer sufficient to maintain the pH of said solution at a level of about 6 to about 7 and a low free ammonia concentration in said solution corresponding to an equilibrium gas phase ammonia concentration below about 10 ppm at 20.degree. C. and atmospheric pressure.
Dependencies are inferred from the claim text.