Spatial Variability of Nutrient Requirements in Fields of the South Peace River Region, Alberta

Abstract Site-specific fertilizer application is pertinent only if there is a significant sub-field variability in nutrient requirements. The variability in soil test recommendations for nitrogen (N), phosphorus (P), potassium (K), and sulfur (S) was measured, along transects across three fields in the South Peace River region of Alberta. Depending on the field and intended crop, site-specific fertilizer application would: (1) increase fertilizer inputs by 4–10 kg ha−1, (2) reduce fertilizer inputs by 5–30 kg ha−1, or (3) redistribute the same amount of fertilizer required for uniform application, differently among nutrients and across the field. Fields with extreme topography are more likely to benefit from site-specific fertilizer application, however, slope position alone would be inadequate to stratify fields for this purpose. Requirements for K were the most sensitive to sub-field variability, followed by those for S, P, and N. Producers in the region may not consider site-specific application becaus...