Farmers don't have the luxury of simplicity when it comes to replacing nutrients in the field, particularly following a drought. As a general guide, the industry has adopted a model to help producers think of fertilization as a process, not just a chore. They call this guide 'The 4R's' and while the elements of the 4R's may seem obvious, soil quality is much too important to be taken lightly. As growers look forward to spring applications, think through the 4R's before you mount up.
Right Nutrient is the first of the four. Soil testing is highly recommended in a year like this simply because nutrient uptake in fields is heavily dependent on rainfall. A lot of rain can deplete certain nutrients quickly while scant rain may leave reserves in the soil for the next round of crops. This ties in neatly with the second R...
Right Rate refers to how much to apply. Again, soil testing will tell you how much of each nutrient must be applied. In some cases, growers may be able to skip a particular nutrient if drought has left a surplus in the soil. Keep in mind, too much fertilizer is just as damaging as too little and corn yeilds have exhibited a treminal response to excessive N applications. In other words, piling on nitrogen does not add up to piling on bushels.
Right Time is the third R. Timing can mean the difference between maximizing exposure and wasting time and money on nutrient only to watch early spring rains erode profits. Nitrogen is particularly time sensitive. The following graphic from cropphysiology.cropsci.illinois.edu illustrates the timing of N&P uptake in corn throughout its life cycle.
Right Place rounds out the 4R approach. This is where your specialized planter attachments earn their keep. The 2x2 method is the preferred right place for starter fertilizers. Nitrogen is not recommended for foliar application as corn does not absorb much Nitrogen through foliage, and it may burn the leaves. The 2x2 approach is not generally recommended for Phosphorous (P), however, as P does not move once in the soil. In addition, if you have not had your local agronomist grid-map your soil, we highly recommend you consider it. The data gathered here can help target problem areas in your plots and improve application efficiency.
Good education yields good farmers, and with the 4R's in mind, growers can maximize profits while eliminating waste by efficiently targeting specific deficiencies in cropland soil.