Corn and Soybean Response to Starter and Foliar Application of Macro and Micronutrients.

The use of starter and foliar fluid fertilizers in high-yield corn and soybean environments is frequently used by producers, but are they needed?  The objectives of this study are to quantify corn and soybean response to starter and foliar fertilizer, and evaluate soil and tissue analysis as diagnostic tools to identify potential crop responses. Field research was conducted in 2010 at two pivot-irrigated locations in north-central Kansas (two sites with corn and two sites with soybeans). The experimental design was a factorial arrangement in a randomized complete block design with three replications. Starter and foliar factors contained three treatments each; control, NPK, and NPK plus micronutrients (B, Cu, Fe, Mn, & Zn).  Starter fertilizer rates were 4, 11, 11 kg/ha of NPK and 0.6 kg/ha of each micronutrient.  The foliar fertilizer rates were 2 kg/ha of each N, P, and K, and 0.2 kg/ha of each micronutrient.  Starter fertilizer was dribble applied over the row. Soil samples (0-15 cm) were collected from each experimental unit prior to planting. Plant tissue samples were collected from each experimental unit prior to foliar application at V8 in corn and R1-R2 in soybeans.  Early growth in corn (g plant^-1), determined from a composite sample of five plants, was not significantly improved by the application of NPK or NPK plus micronutrient starter over the control.  A low-P soil, 11 ppm Mehlich-3 P, at one site still did not elicit a significance response in early growth in corn in 2010.  Additional responses and variables are still being assessed.