Over the past few months, producers have purchased a large portion of their fertilizer needs; however, it may not be enough. Fertilizer in many cases is the largest crop input and needs careful management.  Historical trends suggest an imbalance in application to crop requirements.

Canadian producers purchase approximately $4 billion of fertilizer annually, typically allocated as follow: 72% nitrogen, 18% phosphate and 10% potash.  Historical trends shows that usage rates of nitrogen fertilizer are six times larger today than in 1970; in comparison, phosphate and potash usage has remained unchanged.  This usage pattern would indicate that phosphorus and potassium application levels are not keeping up with increasing yields and are resulting in declining soil test levels.

A good place to start evaluating fertilizer requirements is to review available soil test results by field.  Using historical tests allow trends to be determined by nutrients over time.  If nutrient levels by field are being maintained or are increasing, only small adjustments to application rates may be required.  However, if levels are decreasing over time, more attention to those fields is required.  Matching soil nutrient trends with historical crop yield provides a great strategy.

Advocating increased fertilizer application should follow the 4R principle created by the Canadian Fertilizer Institute – Right Source; Right Rate; Right Time; Right Place.  The 4R principle was developed to provide “growers with sustainable economic returns while protecting the environment and providing people the nutrients they need” (Canadian Fertilizer Institute). Producers should take the opportunity to apply fertilizer to match plant uptake and ensure minimal nutrient loss prior to plant uptake.

Agriculture should be commended for its more efficient use of fertilizer in crop production.  However, declining soil test levels and past usage patterns suggest nutrients are being removed more quickly than they are being replenished.  I would encourage producers to take some time to examine their fertilizer purchases to date to ensure a successful 2015 crop.

Shawn Winter, CCA-ON, Maizex Seeds Product Development Manager
Twitter: @SWinter_Maiz 

Source: Canadian Fertilizer Institute. https://www.cfi.ca/elibrary/