Functional and Chemical Calibrates of Ceramic Cup Water Samplers in Forest Soils

Abstract

A study was conducted to assess the properties of a tension porous-ceramic cup soil-solution sampler and its usefulness in extncting soil solutions in selected forest soils (haplic Umbrisols) at "Sierra De Gata'' Mountains, CWSpain. The main characteristics of the sampler evaluated were hydraulic c&ductivity, the time requircd to obtain the soil-water sarnple, and the volume of water uptake for optimum calibration prior to analysis of the chemicaI composition of the soil water solution. Hydraulic conductivity values were not substantially modified dunng the sampling (two hydrologic cycles). The time required to obtain the samples was relatively short (mem value 2 h) and the sphere of sarnpling influence was small (radii ranging from 6 to 15 cm), both depending on the size of the sampler. The chemical analyses obtained after calibrating the ceramic cup sarnpler pointed to: a) an effect of light acisorption by the ceramic cup, involving PO, 3-, DOC, major and minor catbns (Na' , K+, caz", M~~+ , ~e~+ ,A? +, ~n~+ , and 2n2+), Relatively low pH values (the pH of these acid forest soils is 5.1-6.2) favor the adsorption of anions and DOC, the latter also increasing the exchange capacity and cation adsorption of the cup. The results point LO a generaljzcd tendency of the ceramic cup to adsorb DOC, cations and anions (with the exception of chlorides), H4Si04, by contrast, being releascd.

Electrical Conductivity and Chemical Composition of Soil Solution: Comparison of Solution Samplers in Tropical Soils

“…A big problem of a ceramic sampler is its capacity to adsorb anions and release cations, such as Ca 2+ , Mg 2+ and Al 3+ (Litaor, 1988). Adsorption of ions (Menendez et al, 2003;Kiggundu et al, 2010) and even increased release of Ca 2+ and Mg…”

Comparison of Ceramic and Polytetrafluoroethene/Quartz Suction Cups for Sampling Inorganic Ions in Soil Solution

“…Several possible explanations exist for the underestimation observed in most cases in this experiment. The first process that can influence the Al 3þ concentration in the sample is simple adsorption (or cation exchange) on the cup material (Menéndez, Gallardo, and Vicente 2003). In this experiment, adsorption onto the cup wall seems not to be the main process because the discrepancy in Al 3þ concentration between bulk test solution and sample did not tend to diminish, and no increase in concentration of any other cation was observed.…”

“…Recoveries during the high concentration run are of the same order of magnitude for both cup types: 78% with ceramic cups and 79% with the PTFE/quartz cups. Also, Menéndez, Gallardo, and Vicente (2003) and Nagpal (1982) found a marked adsorption (15 resp. 30%) of K þ ions onto ceramic cups.…”

Soil P availability along a catena located at the Sierra de Gata Mountains, Western Central Spain

“…It has been stated that the element input by mineral weathering is almost negligible in soils of the ''Sierra de Gata'' Mountains, being the litter decomposition the main process for nutrient replenishment in these soils (Menéndez et al, 2003). As soil formation proceeds, the P availability becomes increasingly dependent from mineralization of the P o forms (Stewart and Tiessen, 1987).…”