Characterization of Porous Cups and Modified Suction Probes for the Extraction of the Soil Solution

Abstract

Techniques to evaluate the nutritional state of the crop include techniques for determination of nutrient parameters in the soil solution. A nondestructive method that allows taking of samples along the crop and obtaining the real soil solution without dilution is the suction cup, although some problems exist, including the limited sample size and possible contamination. In this work the porous cup was characterized from the chemical point of view, identifying the crystalline structures that constitute it, with x-ray fluorescence, dispersion of the wavelengths, use of certified reference patterns that guarantee the traceability of the measurements, and (from the physical point of view) determination of the total porosity and the pore-size distribution by means of the mercury intrusion technique. The design of the suction cups were also studied to obtain a robust sampler that is easy to handle, affordably priced, and able to obtain an adequate size of sample for use in commercial horticultural greenhouses. This method of measuring water and salt content of the root environment has potential applications in the greenhouse production of potted plants. Measurements obtained with this method may lead to new information on nutrient uptake by plants and the development of new strategies for managing fertility and irrigation of horticultural crops.