A lot of farmers have already pre-paid for starter fertilizer in 2014 but some serious thought needs to be given to what starter product fits the need. When corn was over $5 per bushel it was easy to justify some of the micronutrients in a starter mix. However, often times a lot of these ‘extra’ nutrients may or may not provide a yield response. With the profitability margin getting closer we need to take a long look to determine what nutrients are needed in a starter blend. The best place to start is with soil testing. Starter fertilizer blends should be based off of recent soil test.
Know and understand what the critical soil test levels are for each nutrient. The critical level is the nutrient concentration that indicates the division between a crop being responsive and non-responsive to applications of fertilizer. For example, the critical soil test level for P is 20 ppm. For soils with a P soil test greater than 20 ppm a response to P fertilizer is unlikely. This is not to say that I would eliminate P from a starter mix in corn but you definitely can reduce the rate if your soil test P is greater than 20 ppm.
After you get a soil test back, consider your fertility needs and calculate the price per pound of N and P for several products. For example, 10-34-0 may have a $0.55 per pound of P, while a similar mix with Zn may bring the cost of P to $0.80 per pound of P. If the Zn is needed but if not it is expensive P.
One example of a nutrient that is often not needed every year in a starter mix is Zinc. The critical value for soil test Zinc is 1.0 ppm. If your soil test is above this level your crop is unlikely to respond to Zinc fertilizer. Pay attention to the soil test levels. If nothing is needed based on the soil test levels I would recommend just focusing on N and P for your starter.
Starter fertilizer is simply what the name infers; it is fertilizer to get your crop off to a quick start. When it comes down to it the nutrients most likely needed early in the season are N, P, and sometimes S. However, you still need to keep in mind the nutrient removal by the crop to help maintain productive soil but reduce or eliminate the unneeded nutrients in your starter mix.