History of Plant Tissue Testing.

Plant analysis, sometimes referred to as leaf analysis, has a considerable history dating back to the early 1800’s.  Chemist working on the composition of plant ash recognized that a relationship existed between yield and nutrient concentrations in plants.  However, it was not until the work of Macy in1936 that quantitative methods for interpreting these relationships were developed in a manner that could be used for assessing the plant nutrient status.  Goodall and Gregory (1947) were among the first to relate the nutrient element composition of a plant to its nutritional status and grouped work done prior to 1947 into four categories: (1) investigations of nutritional disorder made manifested by definite symptoms, (2) interpretation of the results of field trials, (3) development of rapid testing methods for use in advisory work, and (4) use of plant analysis as a method of nutritional survey.  These categories are still applicable today in terms of research as well as plant analysis utilization in crop production decision making.

In the early 1960’s some state, commercial, and privately operated soil testing laboratories began offering plant analysis services.  Initially, the volume of samples received by the laboratories for row crops was not very high.  This was due in part to slow turn-around-time and the grower not always being able to make corrective treatment for the sampled crop.  However, with the introduction of spark emission spectrographs, x-ray spectrometers, inductively coupled plasma spectrographs (ICP), nitrogen and sulfur analyzers and microwave digestion turnaround time in the laboratories has been reduced considerably.  Improvements in laboratory equipment, computer generated interpretations and recommendations coupled with the internet now make it possible to process the sample and have the results and recommendations available for the grower within 24 to 36 hours.