Soil testing and plant analysis: Building a future on our legacy

Soil testing and plant analysis have been used as diagnostic tools for assessing fertilizer needs of crops for more than 50 years. During that time, considerable progress has been made in developing a plethora of improved extraction procedures and analytical techniques, forming a considerable legacy on which to build in the future. However, as laboratories grew and methods became entrenched, a reluctance to change methodologies has caused a certain degree of stagnation and in many cases has resulted in poor prognostic precision. Examples in the realm of soil testing are presented to show what might be gained by implementing improved technology that measures parameters that are the primary yield-determining factors. In addition, attention is focused on precision agriculture, where an urgent need exists to develop real-time assays of nutrient levels in the soil and plants so that the appropriate rates and types of fertilizer can be applied to increase yield uniformity within a field. With the increased disposal of organic residues on land, nutrient management plans for farms are now required. Because of the associated regulations, laboratories will have to introduce protocols for analyzing soil, tissue, and water appropriate to the purpose at hand accompanied by stringent quality assurance/quality control (QA/QC) systems to meet the legal requirements. No doubt, within a short time these constraints will be applied to normal crop land being fertilized with inorganic fertilizers as the green lobby grows and applies more pressure for a cleaner environment. The implications of these changes for the future is assessed.