Soil pore water Rhizon samplers

These methods were selected for different reasons, but mainly for their flexibility and novelty. Rhizon samplers represent the current equivalent of porous cups, widely used in the recent past centrifugation is possibly the current most widely used method because of the ease and the ready availability of the requisite equipment in most laboratories squeezing is a novel alternative, since it has been used on soils recently (Di Bonito, 2005) and has the potential to access water contained in small pores soil suspension or saturation extracts constitute a valid alternative, especially when batch experiments are carried out (Degryse et al., 2003). Furthermore, these methods are capable to perform fractionated extraction on the soil, whereby a combination of the methods can be used to provide soil water originating from a wider range of pores, which can present a variety of interactions with the soil matrix and possibly different chemistry. 

Samples collected with these devices may inadequately represent the pore water in its natural occurrence because of problems inherent in the technique (Litaor, 1988). This limitation may be additionally influenced by the complex nature of the soil, whose heterogeneity highly affects the chemical concentrations in pore water. Hence, Rhizon samplers, with their small cross-sectional area, may not adequately integrate for spatial variability (Amoozegar-Fard et al., 1982 England, 1974 Haines et al., 1982), and may represent point samples with qualitative rather than quantitative attributes (Biggar and Nielsen, 1976). 

Rhizon soil moisture samplers, centrifugation, high-pressure squeezing and soil water suspensions constitute good laboratory techniques for the recovery of pore water. The functionality, benefits and limitations of these methods can be summarized as follows ... 

---