Corn and Soybean Response to Starter and Broadcast Fertilization.

Optimum fertilizer placement and application method can substantially affect yield response, crop profitability, and potential nutrients loss. The objective of this study was to evaluate the effect of combined starter and broadcast fertilizer application on corn and soybeans in a typical corn-soybean rotation in Kansas. The experiment was completed at four locations during 2011 and 2012 in Kansas. Treatments were a factorial combination of starter and broadcast including an unfertilized control, 15-21-21 (N-P-K) dribble starter, broadcast MAP and the combination of starter and broadcast. Soil samples and plant tissues were collected and analyzed for P and K concentration. Corn early growth was measured at V6-V7 stages. Grain yield was determined by harvesting the two center rows of each plot. Corn early growth was increased with fertilization at both sites; however this was not an indicative of higher grain yield. No significant effect in yield response was found for soybeans. Corn tissue P concentration and P uptake, and soybean tissue P was positively correlated with soil P test levels. Broadcast alone or with starter significantly increased the P uptake on corn at V6-V7 stage and increased P concentration in soybeans at R2 over the control and starter alone. Corn and soybeans grain yield did not respond to fertilization or placements methods. These results with no yield response may be due a very dry condition during the years of the experiment and/or soil test levels were not low enough to show fertilizer response. Plant tissue P and K concentrations and P uptake generally were affected by placement and by fertilization.