Calcium polysulfide, potassium polysulfide, calcium thiosulfate, and magnesium thiosulfate as urease inhibitors

1. A method for inhibiting urease activity on urea-containing fertilizer applied to soil or foliage comprising applying to the soil or foliage a urease-inhibiting quantity of a compound selected from the group consisting of calcium polysulfide, potassium polysulfide, calcium thiosulfate, magnesium thiosulfate, and blends thereof, wherein the compound is applied simultaneously with, before or after the urea-containing fertilizer is applied to the soil or foliage such that the compound is in direct contact with urea in the urea-containing fertilizer.

2. The method of claim 1 wherein the urea-containing fertilizer is in aqueous solution with the urease-inhibiting compound.

3. The method of claim 2 wherein the solution is applied to foliage.

4. The method of claim 1 wherein the urea-containing fertilizer is in homogeneous solid mixture with the urease-inhibiting compound.

5. The method of claim 1 wherein the quantity of urease-inhibiting compound is between about 1 and about 10 pounds per 100 pounds urea.

6. The method of claim 1 wherein the quantity of urease-inhibiting compound is between about 2.5 and about 10 pounds per 100 pounds urea.

7. The method of claim 1 wherein the quantity of urease-inhibiting compound is between about 5 and about 10 pounds per 100 pounds urea.

8. A method for inhibiting urease-catalyzed conversion of urea-containing fertilizer applied to soil or foliage to ammonia comprising applying to the soil or foliage a urease-inhibiting quantity of a compound selected from the group consisting of calcium polysulfide, potassium polysulfide, calcium thiosulfate, magnesium thiosulfate, and blends thereof, wherein the compound is applied simultaneously with, before or after the urea-containing fertilizer is applied to the soil or foliage such that the compound is in direct contact with urea in the urea-containing fertilizer.

9. The method of claim 8 wherein the urea-containing fertilizer is in aqueous solution with the urease-inhibiting compound.

10. The method of claim 8 wherein the urea-containing fertilizer is in homogeneous solid mixture with the urease-inhibiting compound.

11. The method of claim 8 wherein the quantity of urease-inhibiting compound is between about 1 and about 10 pounds per 100 pounds urea.

12. The method of claim 8 wherein the quantity of urease-inhibiting compound is between about 2.5 and about 10 pounds per 100 pounds urea.

13. The method of claim 8 wherein the quantity of urease-inhibiting compound is between about 5 and about 10 pounds per 100 pounds urea.

14. A method of reducing nitrogen loss from urea-containing fertilizer applied to soil or foliage comprising applying to the soil or foliage a urease-inhibiting quantity of a compound selected from the group consisting of calcium polysulfide, potassium polysulfide, calcium thiosulfate, magnesium thiosulfate, and blends thereof, wherein the compound is applied simultaneously with, before or after the urea-containing fertilizer is applied to the soil or foliage such that the compound is in direct contact with urea in the urea-containing fertilizer.

15. The method of claim 14 wherein the urea-containing fertilizer is in aqueous solution with the urease-inhibiting compound.

16. The method of claim 15 wherein the aqueous solution is applied to foliage.

17. The method of claim 14 wherein the urea-containing fertilizer is in homogeneous solid mixture with the urease-inhibiting compound.

18. The method of claim 14 wherein the quantity of urease-inhibiting compound is between about 1 and about 10 pounds per 100 pounds urea.

19. The method of claim 14 wherein the quantity of urease-inhibiting compound is between about 2.5 and about 10 pounds per 100 pounds urea.

20. The method of claim 14 wherein the quantity of urease-inhibiting compound is between about 5 and about 10 pounds per 100 pounds urea.