Paul O. Johnson, South Dakota State University Extension agronomy field specialist, Watertown, S.D., lists the top 10 ways to save money on nitrogen:
1. Take credit for carryover soil nitrate. The two-foot soil nitrate test can accurately measure the carryover amount. This is very important this year.
2. Take credit for legumes. The recommended credit for soybeans is 40 pounds per acre regardless of previous soybean yield.
3. Take credit for manure applications. Sampling manure for both organic and inorganic N should be done so accurate credits can be taken. Manure with significant inorganic N content should be knifed below the soil surface or immediately incorporated to prevent volatilization losses of ammonia. Accurate spreading is also a must.
4. Take credit for N applied with phosphorus and other N containing fertilizers. Sixty pounds of phosphorus applied as DAP supplies almost 25 pounds of N.
5. Do not apply N in fall until soil temperatures fall below 50 degrees to prevent conversion to nitrate and possible leaching from snowmelt and early spring rains.
6. Do not apply N in fall on sandy or any coarse textured soil.
7. Side dress N on corn to minimize early season leaching or denitrification. This is especially important on sandy soil, irrigated land or areas that may pond water after heavy rains.
8. Incorporate urea within two weeks of applications to minimize volatilization losses if there is not rainfall. Avoid winter urea since studies show significant volatilization losses can occur.
9. Set reasonable yield goals. Setting yield goals which may be reached only one or two years out of 10 will result in over application of N the other eight or nine years out of 10.
10. Make sure P, K, and zinc levels are adequate for the yield goal. If these levels are too low adding more N may have little benefit.