Project title: Soil test phosphorous target levels for corn
Duration: 1973-1985
1985-1990
1990-
Present
Funding: HATCH Funding
Contact:
Charles Shapiro Northeast Research and Extension Center, Haskell Agricultural Laboratory, UNL, 57905 866 Road, Concord, NE 68728-2828, (402) 584-2803, cshapiro1@unl.edu
Project
description:
This
site was one of the original sites for the Soil Test Comparison study initiated
by Professor Olson et al in 1973.
Treatments were discontinued in 1986 and a residual phase of nitrogen
only applications were conducted until 1990.
During this time soil build up of phosphorus on several treatment units
was allowed to be drawn down. In 1990 a new phase was initiated. Target levels of soil phosphorus as measured
by Bray 1 extractant were chosen at 15, 30 and 45 ppm. In addition a no phosphorus control and an
application of phosphorus at removal rates was included. For experimental units with soil levels
below the target area P was applied at a rate of 20 lbs P2O5 per 1 ppm addition
in soil P levels desired. Annual soil
samples determine the soil P levels and if subsequent P needs to be applied.
Key
results: In progress
Publications: None