Sulphur in the Polish fertilization diagnositcs

Over the years, researchers from Polish research centres have been improving analytical methods as well as plant and soil assays, designed to diagnose demands of crops for sulphur fertilization and to assess their supply with this element. In this article, the authors look back at the last 100 years of the Polish research on sulphur, in the context of analytical methods, soil and plant assays, and their application to assessments of crop fertilization requirements. Studies on diagnosing crops' demand for sulphur fertilization have a long-standing tradition. Back in 1903, for example, GODLEWSEI and JENTYS wrote about nutritional demands of crops and about sulphur nutrition. For over a century since then, the analytical methods have changes, soil and plant assays have been designed and parameters have been established to facilitate assessment of plant nutrient demands. Sulphur-oxidizing autotrophic microorganisms or the fungi Aspergillus niger have been used for diagnosis. Another investigated possibility was monitoring the capacity of sulphur for migration, assayed in lisymetric experiments. The 1960s were a time when modifications of earlier turbimetric methods appeared. In addition, applications of the isotope S-35 were checked as a sulphur marker enabling determination of the dynamics of this element in soil and in plants. With the passing of time, new technologies and measuring devices were developed. Some research centres implemented sulphur detection assays on soil and plant material with the following methods: ICP, GC, HPLC or XPF (x-ray fluorescent analysis). With respect to soil and plant tests, which admittedly are a very useful tool for monitoring the sulphur abundance in soil and nutritional demands of plants, it is now the time to state that they need further verification and calibration, in both pot and field experiments.