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.

IPNI-1995-CAN-SK17

31 Aug 2001

Justification

    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. The application of constant rates throughout the quarter-section lead to differences in fertilizer uptake and benefit to the crop; to differences in water-use efficiency; and to variations in the maturity of the crop throughout the field, all of which complicate subsequent farming operations and lead to wide variations in yield throughout the quarter-section.

    The current generation of seeding and fertilizer delivery equipment under development by major Saskatchewan equipment manufacturers such as Flexi-Coil (a cooperator on this project) allow producers to choose different rates for fertilizer delivery and seeding rate from a limited range of choices from within the cab during farm operations; however what is currently lacking is both the basic agronomic information required to choose the optimum rates and the economic assessment of the benefits of variable rate fertilization.