Agronomic and Economic Assessment of Variable Rate

Determine the agronomic information required to choose the optimum nutrient rates and assess the economic the benefits of variable rate fertilization.


Farm operators in Saskatchewan typically manage quarter-sections of land as a single unit, with constant rates of fertilization and seeding over the entire 160 acres; yet it is well know by producers and researchers alike that soil and productivity conditions can differ widely throughout the quarter-section of land. These differences in conditions are most pronounced on no-level land, where the topography itself introduces a major, but easily-accounted for, source of variability. Read more

Year of initiation:1995
Year of completion:1998

Interpretive Summary

Agronomic and Economic Assessment of Variable Rate Fertilization, 1998 Farmers in the Canadian Prairies are interested in variable rate fertilizer application, but don’t know the best way to manage it. The rolling topography typical of the prairies lends itself to variable rate technology because the re-distribution of water results in variable crop yields between upper, mid and lower slope soils.

Agronomic and Economic Assessment of Variable Rate Fertilization, 1997 The potential for variable rate fertilizer application in the rolling landscapes of prairie soils is great. Topography, because of its effect on moisture re-distribution, has a major impact on crop productivity. After two years, this study has demonstrated that landscape can readily separated into management units based on slope position and that slope positions respond differently to N and P.

Agronomic and Economic Assessment of Variable Rate Fertilization, 1996 A precision farming study was initiated on rolling terrain in central Saskatchewan to evaluate variable rate fertilization based on landscape position. Part of the study involves developing mapping tools to separate the landscape into differing management units (i. e. knolls, mid- and lower slopes). First year results have been very encouraging using this approach.

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Updates & Reports


1998 Annual Report


Project Description







Project Leader

Dan Pennock, University of Saskatchewan

Project Cooperators


IPNI Staff

Adrian Johnston


Americas \ Northern America \ CAN \ Saskatchewan


4r place, 4r rate, 4r time, nutrient management

barley, rapeseed (canola), wheat

Nitrogen (N), Phosphorus (P)