Nutrient Budgets and Balances




Nutrient management planning has directed the attention of many crop advisers and retail input dealers to nutrient balances. A balance of nutrient supply in comparison to crop removal has been advocated by many as the solution to nutrient overloading and resulting impairment of water quality. It is critical to understand the chemical nature of a nutrient and the processes that influence nutrient loss to water before deciding whether a surplus is indeed a peril to water quality.

Plants require at least 17 elements as essential nutrients. Each of the 17 is equally crucial to the plant's survival, but some are more likely to become deficient to crops than others. Supplies of the three primary nutrients, nitrogen (N), phosphorus (P) and potassium (K), most often need to be managed to ensure adequate quantities of each for crop growth. To understand why they may be deficient, or in excess, the soil inventory of each, their transformations when added to soil, and the common types of flows that add or remove them must be considered.

The links below provide estimates of regional nutrient balances:

Update: Ontario Crop Nutrient Balance, 1950-2007

Eastern Canada NPK Balances (data prepared by PPI Northeast Director TW Bruulsema)

Mid-Atlantic States N&P (U.S. Land Grant Colleges and Universities' Mid-Atlantic Regional Water Program)

Nutrient Budgets in North America (PE Fixen and AM Johnston)

NUTRIENT BALANCE IN THE WESTERN U.S. (RL Mikkelsen)

Nutrient balance in the Great Plains region (WM Stewart)


These links provide instructions on farm level nutrient budgets:

How to Estimate Farm-level Nutrient Budgets (TS Murrell)

PKalc: Nutrient Budget Estimator


Nutrient Use in Ontario Crop Production and its Impacts on Water Quality

This paper was prepared for the Ontario Farm Environment Coalition by the Water Quality Technical Group, and released 9 February 2004. It contains an agricultural Nitrogen and Phosphorus balance for the province of Ontario from 1930 to 2003.