The International Plant Nutrition Institute discusses how variable-rate applications of phosphorus can help growers address problems with spatial variability with the nutrient in farm fields.

As 2010 gets underway and growers plan for the upcoming crop season, applying potassium (K) fertilizer may be more important than ever. According to a study released last fall by the International Plant Nutrition Institute (IPNI), 39 percent of the soils across North America were in negative balance for K, and this study didn't take into consideration the cutbacks of the 2009 growing season.