Evaluating Traditional and Modern Laboratory Techniques for Determining Permanent Wilting Point

The permanent wilting point is often considered the lower limit for plant available water and can be measured in laboratory using a pressure plate apparatus (traditional method) or dewpoint potential meter (modern method). However, recent evidence suggests substantial discrepancy between soil moisture at points derived from these two techniques. This preliminary study investigated magnitude of traditional modern techniques concomitant effects on estimations. For analysis, total 21 undisturbed samples were collected top 20 inches profile 18 locations Kansas Mesonet. content was 22% higher clay loam soils 25% than values obtained meter. When apparatus, resulting capacity (PAWC) 33% 57% compared to PAWC estimated Only minor discrepancies about 8 9% observed both silt sandy soils.