A New Approach for Determining Fertilizer Application Rates.

The use of fertilizers has contributed to drastic increases in crop yields during the last 40-50 years, which have brought about numerous benefits including increased commodity supplies and improved on-farm income potential.  However, wide-scale, high-rate fertilizer use has also contributed to accelerated water resource degradation, increased fossil fuel consumption (to manufacture fertilizers), and indirect commodity price reduction pressure.  Critics might argue that fertilizer rates are not excessive; however, published studies, anecdotal accounts, and state and federal agricultural statistics consistently show that annual fertilizer rates are determined with the goal of achieving the highest yield under ideal growing conditions.  The problem is that near-ideal growing conditions are rare (on the range of 1 year in 10-20 years).  In the past when fertilizer prices were low, this over-fertilization mindset has been used as “insurance” to maximize yields and thus profits in ideal years, but this may not maximize annual average profit in the current economic climate with considerable input costs.  Thus, a new approach is needed to ensure agricultural productivity, improve on-farm profitability, and minimize agriculture’s contribution to water quality degradation.  We propose that fertilizer be applied at rates that are determined based on the total amount of plant available nutrients in the soil for a given crop with a proven yield potential.  This is certainly not “no fertilizer input” farming.  It is not even “low fertilizer input” farming.  It is “optimal fertilizer input” farming.  The proposed approach may sound similar to the traditional fertilization programs; however, upon further examination, it is a radical change with the potential for dramatic environmental and socio-economic benefits.