Rhizon Systems for Soil pore Water Sampling
Rhizon samplers can extract small volumes of pore water from soil and sediments, in an easy, non-destructive, repeatable way. They can be used for sampling water from unsaturated soils as well as from saturated zones and the extract can be used for the measurement of dissolved compounds such as nutrients, dissolved organic carbon or pollutants. In addition, specialized Rhizon Irrigators can be used for irrigation experiments. Thus, Rhizons in their various forms are an perfect match to the VSI Rhizoboxes and are made to be used with RhizonBoxes. Rhizons are manufactured by Rhizosphere Research Products (RRP).
Three major types of Rhizons for soil pore water extraction and manipulation are available for Rhizonboxes / Rhizoboxes / small pots:
1) MicroRhizons,
2) Rhizons, and
See bottom of page for characteristics of the Rhizon microfiltration membrane, and some details on the sampling procedure.
MicroRhizon Samplers
RRP-MicroRhizon samplers are mainly used in RhizonBoxes and agar tests. They consist of two parts: a porous part (i.e. microfiltration membrane) of 8 mm with an outer diameter of 1 mm, and PEEK tubing (0.6*0.4 mm; 12 cm long) with a connector fit to a syringe. The mean pore size of the porous part is 0.15 µm, hence no filtering of samples before analysing is required. The yield of MicroRhizons is up to 2 ml (depending on pore water availability). As the tubing of MicroRhizons consists of PEEK and a special glue, it is possible to steam-sterilise them. All Rhizon samplers are sold in sets of 10. Access manufacturer homepage.
Table 1 MicroRhizons and accessories for soil pore water sampling in RhizonBoxes
| RRP product number | Length, porous part [mm] | Length, tubing [cm] | Description of Product |
| 19.21.81 | 8 | 12 | MicroRhizon, 8 mm porous, glued on 12 cm PEEK tube, 10x |
| 19.21.83 | 8 | 12 | MicroRhizon, 8 mm porous, glued on 12 cm PEEK tube, with silicone sleeve, silicon connector for syringe with tip, 10x |
| 19.21.84 | - | - | Accessory - PEEK tubing, 1.6 mm OD, guide tubing to push your MicroRhizon into agar or other media, 5 cm |
| 19.21.85 | - | - | Accessory - PEEK extension tubing 0.6 x 0.4 mm, (including silicon connectors), 30 cm |
| 19.21.88 | - | - | Accessory - Syringe PP set [Syringe PP, 5 ml, Luer tip, with wooden retainers 5 cm,], 10x |
| VSI custom | - | - | Accessory - RhizonBoxes |
Rhizon Samplers
RPP-Rhizon samplers are used for (un-)disturbed soils (see types below), and are thus ideal to be positioned in Rhizoboxes and RhizonBoxes. Especially RhizonBoxes can be equipped with special openings on the side wall (e.g. at different depth) to insert special Rhizon samplers (with sleeve to prevent leakage of water from the RhizonBox) before or after soil filling. They can be used to collect water from larger zones (length of porous parts: 5 cm or 10 cm) for analyzing macro and micro elements, dissolved organic carbon (DOC) and dissolved gases. Using Rhizons with a 10 cm porous part, maximum yield of water is approximately 4 ml per minute. See below for the four types of Rhizon samplers:
Rhizon SMS. For installation in disturbed soils, lab, greenhouse, and in upper layer in the field. For analysing macro elements, not suitable for analyzing metals and DOC. SS 316 strengthener wire can be bent permanently.
Rhizon MOM. For installation in disturbed soils, lab and greenhouse. For analysing macro and micro elements, dissolved gases and DOC. MOM samplers have a tip with a bulb (2.8 mm) and need several hours or days to achieve a good contact between soil and sampler. Strengthener is a a glass fibre wire.
Rhizon CSS. For direct sampling in cores and undisturbed soils. For analysing macro and micro elements, dissolved gases and DOC. CSS samplers have a flat tip (2.5 mm) of the diameter of the porous part. The direct contact between the soil and the porous part makes CSS samplers suitable for immediate sampling. Strengthener is a a glass fibre wire.
Rhizon Flex. For disturbed soils, only fit to be positioned during the filling of Rhizo(n)boxes or pots. For analysing macro and micro elements, dissolved gases and DOC. Strengthener is a a nylon wire.
Each Rhizon type is available in 6 varieties:
- with a 5 cm or 10 cm porous part
- with a male luer lock - suitable for creating a vacuum with needles + vacuum tubes, or with a female luer lock - suitable for creating a vacuum with syringes
- with 0.15 µm or 0.60 µm pore size.
See Table 2 for details. Please make sure to ask for silicon sleeve versions (i.e RRP product number + S) during ordering (if required) as they cannot be retrofitted!
Table 2 Rhizon types for soil pore water sampling in RhizonBoxes and Rhizobox studies. See Table 3 for Rhizon sampler accessories.
| RRP product number | Length, porous part [cm] | Length, tubing [cm] | Description of product |
| 19.21.01 | 10 | 12 | Rhizon, SMS (for macro elements, not suitable for metals & DOC), 0.15 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire (can be bent permanently), male luer, 10 per set |
| 19.21.83 | 10 | 12 | Rhizon, SMS (for macro elements, not suitable for metals & DOC), 0.15 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire (can be bent permanently,) female luer, 10 per set |
| 19.21.05 | 5 | 12 | Rhizon, SMS (for macro elements, not suitable for metals & DOC), 0.15 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire (can be bent permanently), male luer, 10 per set |
| 19.21.05F | 5 | 12 | Rhizon, SMS (for macro elements, not suitable for metals 6 DOC), 0.15 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire (can be bent permanently), female luer, 10 per set |
| 19.60.01F | 10 | 12 | Rhizon, SMS (for macro elements, not suitable for metals), 0.6 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire which can be bent permanently, female luer, 10 per set |
| 19.60.05F | 5 | 12 | Rhizon, SMS (for macro elements, not suitable for metals), 0.6 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, samplers have a SS 316 strengthener wire (can be bent permanently), female luer, 10 per set |
| 19.21.21 | 10 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.15 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), male luer, 10 per set |
| 19.21.21F | 10 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.15 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), female luer, 10 per set |
| 19.21.22 | 5 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.15 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), male luer, 10 per set |
| 19.21.22F | 5 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.15 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), female luer, 10 per set |
| 19.60.21F | 10 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.6 µm pore size, 10 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), female luer, 10 per set |
| 19.60.22F | 5 | 12 | Rhizon, MOM (for macro & micro elements, dissolved gases and DOC), 0.6 µm pore size, 5 cm porous part, glued on 12 cm PVC/PE tube, glass fiber wire as strengthener, tip with bulb (bulb diameter 2.8 mm), female luer, 10 per set |
| 19.21.25 | 10 | 60 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.15 µm pore size, 10 cm porous part, glued on 60 cm PVC/PE tube, nylon wire as strengthener, male luer, 10 per set |
| 19.21.25F | 10 | 60 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.15 µm pore size, 10 cm porous part, glued on 60 cm PVC/PE tube, nylon wire as strengthener, female luer, 10 per set |
| 19.21.26 | 5 | 30 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.15 µm pore size, 5 cm porous part, glued on 30 cm PVC/PE tube, nylon wire as strengthener, male luer, 10 per set |
| 19.21.26F | 5 | 30 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.15 µm pore size, 5 cm porous part, glued on 30 cm PVC/PE tube, nylon wire as strengthener, female luer, 10 per set |
| 19.60.25F | 10 | 60 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.6 µm pore size, 10 cm porous part, glued on 60 cm PVC/PE tube, nylon wire as strengthener, female luer, 10 per set |
| 19.60.26F | 5 | 30 | Rhizon Flex (for macro & micro elements, dissolved gases and DOC in disturbed soils), have to be positioned during the filling of pots or cylinders, 0.6 µm pore size, 5 cm porous part, glued on 30 cm PVC/PE tube, nylon wire as strengthener, female luer, 10 per set |
If the standard Rhizons do not meet the requirements of your experiments, RRP develops and produces custom made Rhizons - get in contact. See Table 3 (below) for Rhizon accessories.
Table 3 Accessories for soil pore water sampling with Rhizon samplers
| RRP Product number | Description of Product | |
| 19.21.02 | Needle 40 mm, diameter 0.8 mm, with protecting cap, 10x | |
| 19.21.03 | Vacuum tube 9 ml, plastic, 50x | |
| 19.21.04 | Syringe set 10 ml female-female, [10ml syringe + female-female Luer lock connector + wooden retainer 7 cm], 10x | |
| 19.21.08F | Female-female connector, 10x | |
| 19.21.08M | Male-Male connector, 10x | |
| 19.21.09.7 | Wooden retainer 7 cm, for syringe 10 ml, 10x | |
| 19.21.09.8 | Wooden retainer 8.5 cm, for syringe 20 ml, 10x | |
| 19.21.09.10 | Wooden retainer 10 cm, for syringe 30 ml, 10x | |
| 19.21.09.12 | Wooden retainer 12 cm, for syringe 50 ml, 10x | |
| 19.21.10 | Connector/Retainer set, [Luer lock connector 2*female + wooden retainer 7 cm], 10x | |
| 19.21.13 | Silicone tubing, 1 m, 6 * 2 mm (+ guide wire), slips over and seals tubing outside diameter 2.5-3.2 mm, for about 30 connections | |
| 19.21.14 | PE Extension tubing, semi rigid, black, 3.2 *1.0 mm, 50 m | |
| 19.21.16 | PVC/PE extension tubing, flexible, transparent, 2.5 * 1.0 mm, 50 m | |
| 19.21.18 | Luer lock stopcock 2-way, for sampler flushing without vacuum loss, 10x | |
| 19.21.19 | Luer lock stopcock 3-way, for sampler flushing and removal of O2, 10x | |
| 19.21.44 | Extension tubing PVC/PE with Luer lock connectors, 10 x 1 m | |
| 19.21.45 | Extension tubing PVC/PE with Luer lock connectors, 10 x 0.5 m | |
| 19.21.48 | Syringe set 10 ml, [Syringe 10 ml, Luer lock, with wooden retainers 7 cm], 10x | |
| 19.21.46 | Syringe set 20 ml, [Syringe 20 ml, Luer lock, with wooden retainers 8.5 cm], 10x | |
| 19.21.49 | Syringe set 30 ml, [Syringe 30 ml, Luer lock, with wooden retainers 10 cm], 10x | |
| 19.21.47 | Syringe set 50 ml, [Syringe 50 ml, Luer lock, with wooden retainers 12 cm], 10x | |
| VSI custom | RhizonBoxes | |
| VSI custom | Rhizoboxes | |
| VSI | Evacuator for vacuum tubes |
Microfiltration Membrane - CHARACTERISTICS
The microfiltration membrane of (Micro-)Rhizon samplers is made of an hydrophilic, inert polymer with no ion exchange properties. Rhizons have very small diameters and low dead volumes and are easy to handle; once installed for an experiment, they can be used frequently.
- Microfiltration membrane with nominal pore sizes of either 0.12 - 0.18 µm (mean pore size 0.15 µm) or a mean pore size of 0.6 µm
- Hydrophilic membrane composed of a blend of polyvinylpyrrolidine and polyethersulfone
- Structure is asymmetric/microporous
- High performance and a very good anti-fouling behaviour
- Suitable for filtration outside-in and inside-out
- pH range: 2-12
- Temperature range: 1°C to 90°C
- Pressure range: -300 to +300 kPa
- Very high resistance against acids, bases, and oil. High resistance to aliphatic alcohols and aliphatic hydrocarbons
- Not suitable for organic esters, ketones, ethers, halogenated hydrocarbons, aromatic hydrocarbons and polar organic solvents
Store in a dry, normally ventilated place, away from sources of heat, ignition and direct sunlight. Store between 0 and 50°C (32 - 122F). The membranes should not be subjected to any freezing.
Sampling Procedure
For sampling rhizosphere pore water, you need a (Micro-)Rhizon sampler and accessories to create a (partial) vacuum.
- MicroRhizon samplers need a syringe and a silicone connector
- Rhizon samplers with a female luer lock need a syringe
- Rhizon samplers with a male luer lock need a needle and a vacuum tube (evacuated vial) OR a female-female-connector and a syringe
If you use syringes to create a vacuum, wooden retainers can be used to block the plunger -which keeps the vacuum. If you use vacuum tubes, you can buy them pre-evacuated or prepare them yourself - using the VSI Vial Evaculator.
Application Note: If you are interested to test the reaction of specific roots of rhizosphere compartments to changes in the soil environment (e.g. pollutants), you might consider to use MicroRhizons (plus syringe and silicone connector) for injecting a solution into the soil (next to a specific root) instead.
Selected readings on Rhizons and other Microsuction cups
- Argo, W.R., Weesies, B.J., Bergman, E.M., Marshal, M. & Biernbaum, J.A. (1997). Evaluating rhizon soil solution samplers as a method for extracting nutrient solution and analyzing media for container-grown crops. HortTechnology, 7, 404-408.
- Frantz, J., Jeong, K. & Nelson, P. (2010). Comparison of Rhizon Soil Moisture Sampler, Pour-through, and Saturated Media Extract Extractions of Container Root Substrate. In: XXVIII International Horticultural Congress on Science and Horticulture for People (IHC2010): International Symposium on 927, pp. 981-987.
- Göttlein, A., Hell, U. & Blasek, R. (1996). A system for microscale tensiometry and lysimetry. Geoderma, 69, 147-156.
- Jeong, K., Nelson, P. & Frantz, J. (2012). Comparison of Rhizon soil moisture sampler, pour-through, and saturated media extract extractions of container root substrate. Acta Horticulturae, 981-987.
- Kölling, M., Seeberg-Elverfeldt, J. & Schlüter, M. (2005). Rhizon - an excellent pore water sampler for low maintenance collection and filtration of small volume samples. In: EGU General Assembly. EGU Vienna, Austria.
- Liu, H., White, P.J. & Li, C. (2016). Biomass partitioning and rhizosphere responses of maize and faba bean to phosphorus deficiency. Crop and Pasture Science, 67, 847-856.
- Seeberg-Elverfeldt, J., Schlüter, M., Feseker, T. & Kölling, M. (2005). Rhizon sampling of porewaters near the sediment-water interface of aquatic systems. Limnology and Oceanography: Methods, 3, 361-371.
- Wang, Z., Göttlein, A. & Bartonek, G. (2001). Effects of growing roots of Norway spruce (Picea abies [L.] Karst.) and European beech (Fagus sylvatica L.) on rhizosphere soil solution chemistry. Journal of Plant Nutrition and Soil Science, 164, 35-41.