Early papers on precision farming focused on variable rate fertilization and variable spraying technology (Roberts, 1996).  The adoption of this 1^st round of precision farming was acknowledged to be a “dead horse” (Mangold, 2000).  These authors put forward the notion that farmers needed better tools to decide if the intensive management of fertilizer would result in a significant reduction in input costs, or a significant increase in crop yields.  Western Ag Innovations Inc. has taken a significant step forward in quantifying the net returns that result from fertilizer decisions with the commercial adaptation of the Plant Root Simulator (PRS^TM) technology.   Delivery of this technology to farmers has hinged upon the use of a Decision Support System called the PRS^TM Nutrient Forecaster.  This Knowledge-based computer tool has been utilized by growers in the Northern Great Plains for over 10 years, allowing them to assess the cost-benefit of a particular fertilizer and/or cropping decision on a field-by-field basis.  The simulation engine in the PRS^TM Nutrient Forecaster was used to optimize individual nutrient applications across many sites within a field.  Analysis of the logistics required to deliver straight N, P, K, and S products to the 80 million acres of the Northern Great plains, crystallized the true limitation to variable rate or Precision Farming, the economic relating to fertilizer logistics. 

This research paper squarely addresses logistics optimisation.  Our work focused on an Intelligent Solution (IS) optimisation using a simulated annealing algorithm with the test for accuracy being the Forecaster simulation output deviations from the optimum yield on each site considering independent fertilizer nutrients.  Field application of the technology indicated that finding a compromise in logistics using two best blends to re-blend in the field, resulted in more yield potential being realized that the straight rate controls, meanwhile simplifying the fertilizer handling.