Nutrient Removal

There are nutrients required by crops that are not accounted for in a simple nutrient balance accounting for kg applied and kg exported in grain.

This is partially due to the following:

1. The remaining stubble contains high quantities of nutrients that are not translocated into the grain (especially in the case of K and S). Depending on the fate of the stubble, these nutrients may, or may not be, returned to the soil for use by future crops or pastures.
2. The soil, organic matter and atmosphere can contribute differing amounts of some required nutrients (N, S and some trace elements).
3. There may be a low plant availability of applied nutrients due to sorption by soil and organic matter particles (P and trace elements).
4. Soil applied nutrients may be unavailable due to dry conditions.
5. Nutrient concentrations in final product can vary greatly. These are averages however can vary up to 50% under differing conditions.