Patent ID: 7569091

Claim:
A method for producing a compound fertilizer by supplementing irrigation water with at least two nutrients, said method comprising the steps of: (11a) determining the ambient concentration of an index nutrient, Nu i in the irrigation water; (11b) determining a desired final concentration, [Nu i ] f ; of Nu i ; (11c) adding a sufficient quantity of exogenous Nu i to a volume, V, of the irrigation water to achieve substantially [Nu i ] f ; (11d) determining a desired concentration, [y], of an additional nutrient, y, wherein [y] is determined by applying a predetermined index ratio, R i , representing a desired ratio of [Nu i ] f to [y]; and, (11e) adding a sufficient quantity of y to V to achieve substantially [y] as determined at Step (11d), whereby the ratio of [Nu i ] f to [y] in the supplemented irrigation water is substantially equal to R i .