Iron-supplemented fertilizer

1. A liquid fertilizer composition consisting essentially of:

(a) a slow-release nitrogen-containing fertilizer, wherein the slow-release nitrogen-containing fertilizer is selected from the group consisting of triazone, urea-triazone, isobutylidene-diurea (IBDU), and a combination thereof;

(b) iron chelated to an aminopolycarboxylic acid or a polycarboxylic acid; and

(c) optionally water,

wherein a pH of the liquid fertilizer composition comprises a pH of about 7.5 to about 9.5, and the liquid fertilizer composition does not include potassium.

2. The liquid fertilizer composition of claim 1 , wherein the slow-release nitrogen-containing fertilizer comprises urea-triazone.

3. The liquid fertilizer composition of claim 1 , comprising iron chelated to an aminopolycarboxylic acid, and wherein the aminopolycarboxylic acid comprises one or more of ethylenediamine tetraacetic acid (EDTA); diethylenetriamine pentaacetic acid (DTPA); N-(2-hydroxyethyl)ethylenediamine triacetic acid (HEDTA); cyclohexane-1,2-diamine tetraacetic acid (CDTA); ethylenediamine-N,N′-bis(o-hydroxyphenylacetic acid (o,o-EDDHA); ethylenediamine-N-(o-hydroxyphenylacetic)-N′-(p-hydroxyphenylacetic) acid (o,p-EDDHA); ethylenediamine-N,N′-bis(2-hydroxy-4-methylphenylacetic) acid (EDDHMA); ethylenediamine-N,N′-bis(5-carboxy-2-hydroxyphenylacetic) acid (EDDCHA); ethylenediamine-N,N′-bis(2-hydroxy-5-sulfophenylacetic) acid (EDDHSA); N,N′-bis(2-hydroxyphenyl)ethylendiamine-N,N′-diacetic acid (HBED); or ethylenediamine-N,N′-disuccinic acid (EDDS).

4. The liquid fertilizer composition of claim 1 , comprising iron chelated to an aminopolycarboxylic acid and wherein the aminopolycarboxylic acid comprises six or more coordination bonds.

5. The liquid fertilizer composition of claim 1 , comprising iron chelated to an aminopolycarboxylic acid, and wherein the aminopolycarboxylic acid comprises diethylenetriamine pentaacetic acid (DTPA).

6. The liquid fertilizer composition of claim 1 , comprising iron chelated to a polycarboxylic acid and wherein the polycarboxylic acid comprises one or more of citric acid, oxalic acid, succinic acid, malonic acid, or tartaric acid.

7. The liquid fertilizer composition of claim 1 , wherein the pH of the liquid fertilizer composition comprises a pH of about 8 to about 9.

8. The liquid fertilizer composition of claim 1 , wherein the liquid fertilizer composition is contained in a spray bottle.

9. The liquid fertilizer composition of claim 1 , wherein the slow-release nitrogen-containing fertilizer comprises from about 1% to about 99% nitrogen by weight.

10. The liquid fertilizer composition of claim 1 , wherein the slow-release nitrogen-containing fertilizer comprises from about 20% to about 70% nitrogen by weight.

11. The liquid fertilizer composition of claim 1 comprises from about 0.1% to about 10% of elemental iron by weight.

12. The liquid fertilizer composition of claim 1 comprises from about 1% to about 40% of the iron chelated to an aminopolycarboxylic acid or polycarboxylic acid by weight.

13. The liquid fertilizer composition of claim 1 further comprises a fast-release nitrogen-containing fertilizer.

14. The liquid fertilizer composition of claim 13 , wherein the fast-release nitrogen-containing fertilizer comprises one or more of urea, urea ammonium nitrate, ammonium, or nitrate.

15. The liquid fertilizer composition of claim 13 , wherein the fast-release nitrogen-containing fertilizer comprises from about 1% to about 99% nitrogen by weight.

16. The liquid fertilizer composition of claim 13 , wherein the fast-release nitrogen-containing fertilizer comprises from about 20% to about 50% nitrogen by weight.

17. A method of fertilizing plants comprising: applying the liquid fertilizer composition of claim 1 to plants.

18. A method of greening turfgrass comprising:

supplying a liquid fertilizer composition consisting essentially of a slow-release nitrogen-containing fertilizer, wherein the slow-release nitrogen-containing fertilizer is selected from the group consisting of triazone, urea-triazone, isobutylidene-diurea (IBDU), and a combination thereof, iron chelated to an aminopolycarboxylic acid or a polycarboxylic acid, and optionally water, wherein a pH of the liquid fertilizer composition comprises a pH of about 7.5 to about 9.5, and the liquid fertilizer composition does not include potassium; and

applying the liquid fertilizer composition to turfgrass to cause greening in about 3 days or less; and

wherein greening is an increase in the dark green color index (DGCI) value of the turfgrass as compared to turfgrass not treated with the liquid fertilizer composition.

19. A liquid fertilizer composition consisting of:

(a) a slow-release nitrogen-containing fertilizer, wherein the slow-release nitrogen-containing fertilizer is selected from the group consisting of triazone, urea-triazone, isobutylidene-diurea (IBDU), and a combination thereof;

(b) iron chelated to an aminopolycarboxylic acid or a polycarboxylic acid;

(c) optionally water; and

(d) optionally a fast-release nitrogen-containing fertilizer,

wherein a pH of the liquid fertilizer composition comprises a pH of about 7.5 to about 9.5.