Nutrient uptake from the soil is a seven-step process, requiring input from the plant with participating elements of the roots, energy input, and vascular tissues.

Corn and soybean take up relatively large amounts of phosphorus (P) and potassium (K), and much of this P and K ends up in the grain that is taken off the field during harvest. In order to keep soil nutrient levels from dropping over time, the amounts removed need to be replaced by applying fertilizer or manure. In order to know how much nutrient a crop removes, we need to know how much there is in a bushel of harvested grain.

Ag company agronomist believes farmers on both sides of the weather extremes are likely to have crops that need additional nitrogen, potassium and sulfur.

Global supplies of potash could outstrip demand by between 59 and 100 per cent by the end of the decade, a research report from Rabobank warns.