393-4 Changes In Soil Test P Following Seven Consecutive Applications of High Rates of Phosphate Fertilizer.



Wednesday, October 19, 2011: 1:50 PM
Henry Gonzalez Convention Center, Room 212A, Concourse Level

Olalekan O. Akinremi, Soil Science, University of Manitoba, Winnipeg, MB, Canada
Changes in soil test phosphorus following seven consecutive applications of high rates of phosphate fertilizer.

Wole Akinremi1 C. A. Grant2, D.V. Ige1. X.Gao2, D. N. Flaten1, M. Tenuta1, S. Malhi3

1Department of Soil Science, University of Manitoba, Winnipeg, MB, Canada R3T 2N2 email: akinremi@cc.umanitoba.ca

2Agriculture and Agri-Food Canada, Brandon Research Centre, Box 1000A, R. R. #3, Brandon, MB, R7A 5Y3, Canada phone: 204 578-3570  Facsimile 204 728-3858

3Agriculture and Agri-Food Canada, Melfort Research Farm, Melfort, SK, Canada

Key words:  STP, Mehlich-3 P, Olsen-P, Water-P, phosphate fertilizer

 

The application of phosphate  (P) fertilizer is known to influence soil test P (STP). If the rate of change of soil test P following application of phosphate fertilizer can be estimated, this will help to better tailor fertilizer application to meet soil test P thresholds that are set for environmental purposes.  Also, how changes in soil test P are influenced by soil factors is difficult to predict. The study took advantage of field plots that were established in 2002 at 7 sites across the Canadian prairies to evaluate the impact of repeated applications of 0, 20, 40 and 80 kg P ha-1 applied as monoammonium phosphate (MAP) fertilizer containing 0.38, 70 or 210 mg kg-1 of Cd. The sites were planted each year, using a durum wheat-flax cropping sequence. Soil samples were taken from each site in the fall at 0-7.5 and 7.5 to 15 cm depth. Archived samples for the plots with the highest rate of P (80 kg P ha-1) from 2002 to 2008 were analyzed using Olsen, Mehlich-3 reagents and water.  The changes in STP were related to cumulative P applied using linear, quadratic and exponential functions. Changes in the parameters of these functions as related to different STP method, soil depth and site will be presented and discussed.

See more from this Division: S11 Soils & Environmental Quality
See more from this Session: Phosphorus Fate In Long-Term Fertilized/Manured Soils