Early Season Corn Fertility

Many folks are getting ready to start planting corn.  In fact yesterday I visited with one grower who just could not wait any longer and started planting already in northern NJ.  Early planted corn can get off to a slow start due to poor early season growing conditions and cool soil temperatures.  "Pop-up" fertilizers are often used to maximize early season fertility.  See the attached Penn State Agronomy Guide for more information. Basic Fertility Management

Stephen Komar

From Penn State Extension Agronomy Guide, Crop & Soil Management: Corn

Basic Fertility Management

Lime, phosphate (P₂O₅), potash (K₂O), and magnesium (Mg) requirements are best determined by soil testing. Soil test recommendations take into account the yield goal or the crop yield potential for the soil type, the fertility level of the specific soil, and projected crop nutrient removal. Nitrogen (N) fertilizer recommendations are based on the yield potential of the crop and the contribution of previous legume crops. On manured fields, sidedress nitrogen requirements also can be estimated using the presidedress nitrogen soil test. For a more detailed discussion of basic soil fertility management, see Section 1.2, “Soil Fertility Management.”

Adjusting Recommendations

To determine the amount of commercial fertilizer required to produce a corn crop:

• Determine total nutrient requirements from soil test recommendations or, in lieu of a soil test, from Table 1.2-5.
• Adjust the recommendations for manure applications using Tables 1.2-13, 1.2-14, and 1.2-15. (See Table 1.4-2 for an example.)
• If you did not check the appropriate previous legume crop on your soil test questionnaire, adjust the nitrogen recommendations using Table 1.2-8. (For an example, see Table 1.4-3.)
• Determine the amount of N-P₂O₅-K₂O to be applied as row (starter) fertilizer and subtract this amount from the adjusted recommendation to determine broadcast or plowdown requirement. (For examples, see Tables 1.4-2 and 1.4-3.)