Fertlizer Notes

Click HERE for University of Georgia Dryland Corn Recommendations which is 120-80-80 assuming yield 100 bu/acre. Conditions in Georgia are quite different since average annual precipitation is 50 inches so rates need to be adjusted for yield. The following fertlizer rates should be adjusted by Fertilizer-Rate X Bushels-Expected-Yield / 100. We use a little more K20 than recommended.

For N the following resource Comparison of Nitrogen Use Efficiency Indices for Corn Fertilized with Commercial Urea & Poultry Litter - Alabama Cooperative Extension System is useful. Phosphate recommendations are 60-165lbs per acre. Potash recommendations are 100-200lbs per acre. * Mangnesium should be 50-100lbs per acre and is less than recommended because Magnesium absorption is higher at high pH and the local fertilizer rep. says local soil Mg is sufficient.

Most sites say a minimum of 80lbs of K20 per acre so N+K20 will easily exceed 80lbs per acre. Another site says if K20 is needed, starter N + K2O should be limited to no more than 80-100 lbs/acre in the fertilizer band to prevent salt injury. This difference in recommendations may depend on the reference's local soil conditions or because it is placed in-band. I am not putting fertilizer in band (for those who do not know this is putting fertilizer in the planting row next to the seeds rather than broadcasting fertilizer evenly). Broadcasting fertilizer is less efficient especially if row spacing is wide (like corn at 4ft apart) but I don't have equipment for in-band placement. Also my new research shows that Hopi corn need much more space and hence roots reach farther and should be accessing broadcast fertlizer over a larger area. Remember that fertlizer rates should be adjusted for yield/acre which is lower for dryland corn grown with less than 10 inches of precipitation.