Abstract:
As one of the three primary plant nutrients, K remains critically important in crop
production. As an essential element for human nutrition, K intake today is inadequate
in the diets of most of the world’s population. The need for improved cropping
system productivity and the need for efficient use of all local resources and external
inputs, including K and inputs with which K interacts, have greatly elevated the need
to predict the capacity of specific soils to meet the K needs of specific crops. When
that capacity is found insufficient, effective guidelines for K source, rate, timing, and
placement decisions are needed. In the past few decades, the adoption of both hightech
and low-tech approaches to site-specific nutrient management has increased the
demand for accuracy and precision in K recommendations. Soil K evaluation has
increased in importance in regions of the world where long-term negative K balances
have increased the frequency of K deficiency in crops. In many areas, desired
accuracy and precision are not attainable with current K recommendation
approaches.
