Comparison of Different Methods to Extract Soil-Water from Containerized Substrates

The purpose of this research was to use low tension lysimeters (Porous Cup - PC) to extract nutrient solution or water-soil from containers or soil without destructing plants. PC is a quick and easy nutrient sampling technique used in greenhouse which could help growers to prevent nutritional problems. In previous researches PC have been normally used to monitor nitrate and or other nutrients leaching in open field with bare soil or with cover crops. This research has been focused on sampling nutrient solution of containerized substrates. Studies were conducted comparing PC method with PourThru (PT), Saturated Media Extract (SME) and 1:2 method (Adapted from Dole and Wilkins, 1998). Calibration curves were calculated in order to compare/convert values between PC and PT values. Correlation coefficients ranged from 0.845, 0.813 to 0.832 for N, P and K respectively. The pretty good correlation between the 2 different extraction procedures indicate that PT and PC are reliable and consistent methods for monitoring substrate nutrients without disturbing plants. PC provide a simple and direct method to collect water samples in the unsaturated zone helping to monitor the nutrient status of the crop.