Project title: Soil Test Phosphorous Target Levels for Corn
Principal investigators: Charles Shapiro, Richard Ferguson, Gary Hergert, Timothy Shaver, Charles Wortmann
Duration: 1990- Present
Funding: HATCH Funding; Nebraska Legislature
Charles Shapiro Northeast Research and Extension Center, Haskell Agricultural Laboratory, UNL, 57905 866 Road, Concord, NE 68728-2828 (402) 584-2803, firstname.lastname@example.org
Response to applied P was evaluated in 34 high yield corn trials during 2002 to 2004.
In another study, the effect of soil test P levels on corn yield is being evaluated. The targeted levels of Bray-1 soil phosphorus are 15, 30 and 45 ppm. In addition a no-phosphorus control and an application of phosphorus at removal rates are included.
Key results: Bray-1 P critical levels of 20 ppm for corn following corn and 15 ppm for corn following soybean were determined.
In the study with targeted Bray #1 P levels, yield has been slightly more with P applied at the removal rate (Bray-1 P = 24 ppm) compared with the Bray #1 P target of 15. Applying P for target levels of 30 and 45 ppm Bray-1 has been the least economical options.
Wortmann, C.S., A.R. Dobermann, R.B. Ferguson, G.W. Hergert, C.A. Shapiro, D.D. Tarkalson, D. Walters. 2008. High yield corn response to applied phosphorus, potassium, and sulfur in Nebraska. Agron. J. 101 546-555.
Shapiro, C.A., R.B. Ferguson, G.W. Hergert, and C.S. Wortmann. 2009. Fertilizer suggestions for corn. University of Nebraska Extension EC 117.