Evaluating rhizon soil solution samplers as a method for extracting nutrient solution and analyzing media for container-grown crops

Abstract

The rhizon soil solution sampler (RSSS) currently is being used for in situ extraction of the soil solution for nutrient analysis of mineral soils used to produce field-grown crops. In this study, laboratory and greenhouse experiments were conducted to test the effectiveness of the RSSS for in situ solution extraction from soilless container root media and to compare an RSSS extraction method for measuring root-medium pH, electrical conductivity (EC), and NO3-N and K concentrations with that measured with the saturated media extract (SME) method. A near 1:1 correlation was found between the pH, EC and NO3-N and K concentrations measured in the extracted solution of the RSSS and SME method in media without plants and in media from ten species grown using three water-soluble fertilizer concentrations applied by subirrigation. More testing is needed with the RSSS, perhaps using composite samples from several pots for analysis. The RSSS shows promise for nutrient extraction in container-grown crops because it is fast, nondestructive, simple, economical, and has minimal effect on the nutritional status of the medium in the pot.