Although farmers have achieved yield increases over the past several years, new data suggest that the trend of soil nutrient removal rates are outpacing fertilizer application rates in most states. PotashCorp's eKonomics program released an in-depth, state-by-state analysis of the 2015 soil test levels in North America issue by the International Plant Nutrition Institute (IPNI). eKonomics combined IPNI data from 2005, 2010 and 2015 and presented it alongside nutrient balance data.

With another year of large crops and expected high yields during a down economy, ag retailers will have a hard time convincing farmers not to cut their fertilizer budgets. However, maintaining or building their soil fertility program could go a long way toward building their land's future profitability.

The analysis focused on the declining nutrient balance levels of potassium and phosphorus, according to Robert Mullen, Ph.D., PotashCorp's director of agronomy. Harvests have removed a significant amount of nutrients from the soil in recent years, but fertilizer application rates have not increased to sufficiently replace the nutrients that have been removed, the data found.

From the IPNI data, the most significant decline in soil test levels for potassium was seen in the Midwest, Southeast and Mid-Atlantic regions of the U.S. as the median soil test levels for potassium have declined an average of 18 ppm in 26 states since 2010. For phosphorus, under-fertilization was more widespread geographically – the median soil test levels for 22 states declined an average of 9 ppm and the median soil test level for 21 states increased by an average of 8 ppm.

“If you happen to be a farmer producing crops on soils that have slipped below the established critical level, you are likely not producing as many bushels as you could, nor are you generating the maximum return from your farming operation,” said Mullen. “The best course of action is to reevaluate your fertility program and invest your dollars in those nutrients that are limiting your production potential.”

In addition, Mullen advises farmers to look beyond the soil test results and to consider the productivity levels they are experiencing. Shorting this year’s crop from necessary nutrients will mean lost revenue and a continued decline in soil test levels. Declining soil test levels translate into a greater fertilizer need down the road as the nutrient balance deficit continues to grow.

The 2015 IPNI soil test summary is the esteemed organization’s most extensive to date, including results from more than 7.5 million samples from U.S. states and Canadian provinces. To view the in-depth state-by-state analysis, please visit the eKonomics site at and join the discussion on Twitter @eKonomics_PCS.