Soil Moisture Sensor Installation Guide V9.0
Contents
1. soil moisture O I t and climate monitoring with certainty Moisture Sensor Installation Guide 41 Vine Street Magill South Australia 5072 p 0883329044 i f 0883329577 US Version 9 0 e mea mea com au dis s March 2015 w WWW mea com au E EB Soil Moisture Sensor Installation Guide E Notices Copyright Copyright Measurement Engineering Australia Pty Ltd 2014 All rights reserved Under the copyright laws this manual may not be copied in whole or in part by any means without the written consent of Measurement Engineering Australia Pty Ltd Design Changes Measurement Engineering Australia Pty Ltd reserves the right to change the designs and specifications of its products at any time and without prior notice Contact Measurement Engineering Australia Pty Ltd 41 Vine Street MAGILL SA 5072 Telephone 08 8332 9044 Fax 08 8332 9577 Email mea mea com au Web www mea com au Warranty MEA offers a 12 month return to factory warranty on all products The warranty applies to hardware software and system defects only The warranty does not cover acts of misuse by the user or third parties including misuse arising from failure to install or operate a system or its components in accordance with relevant system documentation or failure to seek advice from MEA regarding correct installation or operation of a system or its components EnviroPro probes have a 5 year warranty ThetaProbes have a 2 year warranty2. 11 Wet the hole 6 Pushthe sensor cable through the pipe from the bottom Hold the cable taut and use the pipe to gently push the sensor into the hole Use the marks on the pipe to ensure the sensor is at the intended depth Fig 12 Use the PVC pipe to insert the gypsum block in the hole 7 Withdraw the pipe Pour a handful of earth down the hole and gently compact with the dowel WWW mea com au Page 15 EB Soil Moisture Sensor Installation Guide 7 Di 3 8 Add the bentonite and sand mix and backfill the hole to 25 mm from the top 9 Use more earth to complete filling the hole lt gt Fig 13 Add earth and Fig 14 Add the bentonite Fig 15 Cap the hole with tamp and sand mix earth and tamp 10 Use the permanent marker to label the sensor wire with the depth installation date and sensor number a cattle tag can be used for this Fig 16 Markthe cables with the block number and depth 11 Connect the sensor to the logger or display WWW mea com au Page 16 EB Soil Moisture Sensor Installation Guide X d Installing GBLites in Shallow Root Zones In many vegetable crops the root zone is very shallow under 20 cm The active feeder roots of citrus particularly when grown in sandy soils can also be quite shallow GBLite sensors can be installed at shallow depths by laying the sensor horizontally in a hole opened up with a spade or trowel Wet th
3. Dripper line Fig 41 A pair of FullStops under drippers www mea com au Page 38 B Soil Moisture Sensor Installation Guide 5 d Sprinkler or Microjet Irrigation e Wetting patterns tend to be shallower under sprinkler irrigation than drip or furrow irrigation e Suggested depth for the shallow detector is 20cm and for the deep detector is 40 cm Note that it usually takes 20 mm or more of irrigation to activate a detector at 20cm depending on soil type and on how dry the soil is before irrigation e For sprinkler systems that apply small amounts of water each day or second day e g microjets or centre pivot depths of 15 cm and 30 cm are more suitable 5 cm and 20cm to the rim of the funnel Detectors will usually not be activated by applications under 15 mm unless the soil is quite wet before irrigation Fig 42 A pair of FullStops under sprinkler irrigation Wwww mea com au Page 39 B Soil Moisture Sensor Installation Guide ORE E Furrow Irrigation Detectors should be positioned half under the furrow and half under the bed with the extension tube rising through the shoulder of the bed Suggested depth for the shallow detector is 20 30cm and for the deep detector is 40 60cm from the base of the furrow Deep rooted crops with less frequent irrigation would require deeper placement Fig 43 FullStops under furrows Required Tools and Equipment 20cm and 5 10cm augers or shovel and trowe
4. suitable for use where soil moisture levels are to be tightly controlled and in critical applications such as hydrology soil stability studies soil water profiling pollution monitoring water leakage detection from pipes and dams ground truthing and forestry ThetaProbes can be used with e MEAS MAX soil moisture loggers for continuous monitoring and viewing of data on a PC e HH2 Reader to provide spot measurements that can be downloaded to a PC WWW mea com au Page 18 EB Soil Moisture Sensor Installation Guide Sensor Site Selection Please see Sensor Site Selection on page 9 Although this section deals with the placement of gypsum blocks under different types of irrigation the considerations apply equally well to ThetaProbe sensors Required Tools and Equipment Surface Installation Soft ground no tools are required Hard ground a ThetaProbe insertion kit and a hammer Buried Installation Spade or trowel for shallow installation 45 mm Auger MEA2192 for deeper installation 32mm 174 PVC pipe or similar 300mm longer than the deepest installation depth 12mm dowel 100mm longer than the PVC pipe Active Gel Bentonite civil grade eg Unimin Active Gel 150 MEA2197 Dry builder s sand 4 times the quantity of bentonite Tape measure notebook tags permanent marker or tape for marking WwWwW mea com au Page 19 EB Soil Moisture Sensor Installation Guide mt aH How to Install ThetaPr
5. 46 EnviroPro WINING reete reete er E da esc qusa 46 POMOC NECK WIKING REPRE EO 47 WWwW mea com au Page4 E Soil Moisture Sensor Installation Guide E Introduction Thank you for purchasing a soil moisture sensor from MEA This guide tells you how to install your soil moisture sensor correctly For information on how to install operate and maintain other components of your soil moisture monitoring system please refer the User Manual or System Document that was supplied with your system WWW mea com au Page 5 EB Soil Moisture Sensor Installation Guide E How to Use Scotchloks Many but not all of the soil moisture sensors discussed are connected to measuring equipment using low voltage irrigation connectors 3M 316IR Scotchloks can be used for this purpose If you have not used Scotchloks before the following notes will be of use e Use one Scotchlok per join There are three holes use one for a sensor wire and one for a measurement equipment wire leave the third hole unused e Don t strip the insulation from the wires to be joined The metal plates inside the connectors work by displacing the insulation Stripping the insulation will result in a poor connection 1 Pushone wire from the sensor cable and the relevant coloured wire from the logger or field station into the connector as far as they will go The connectors are translucent on the side opposite the black button so you will be able to see when the wires are all t
6. 5 EPEC12 v Y Y 12 126 5 EPEC16 v Y v 16 166 5 Sensor Site Selection Please see Sensor Site Selection on page 9 Although this section deals with the placement of gypsum blocks under different types of irrigation the considerations apply equally well to EnviroPro sensors Required Tools and Equipment e 36 mm Auger MEA2189 e Tape measure e Permanent marker or tape for marking WWwW mea com au Page 27 B Soil Moisture Sensor Installation Guide E The Probe Must Be Installed in A Slurry EnviroPro sensors are installed in over sized holes and a slurry mix must be used to ensure good sensor to soil contact The two type of slurry recommended are e A soil slurry made of soil obtained from the hole itself and surrounds e Aslurry made of a bentonite clay and fine sand How to Prepare a Soil Slurry You will need e About 1 kilogram of clean soil to install two 80 cm probes e About 1 litre of clean water per kilo of soil e A means of sieving out rocks and organic matter from the soil e Abucketto mix the soil and water together in e Afunnelto pour the mixture down the hole Method 1 Passthe soil through a sieve to remove any rocks and organic material 2 Gradually mix in enough water to form a creamy paste WwWwW mea com au Page 28 EB Soil Moisture Sensor Installation Guide X E How to Prepare a Bentonite Sand Slurry If the local soil is not suitable for the preparation of a slurry as described above the EnviroP
7. add salinity measurement at each depth are available Soil moisture readings are temperature compensated and can be salinity compensated The internal electronics are fully protected making the probes reliable consistent and very stable The EnviroPro comes with a five year warranty Each probe is supplied with 5 m of cable Designed to be completely buried the EnviroPro is out of the way when slashing spraying and harvesting Moisture profiling at 100 mm intervals allow you to track the movement of water through the root zone and optimise irrigation events Following the movement of nutrients through the root zone by tracking changes in salinity allows you to optimise fertiliser applications and only apply leaching irrigations when needed EnviroPros can be used with e Plexus for continuous monitoring and the display of data on smart devices e MAX for continuous monitoring and viewing of data on a PC WWwW mea com au Page 26 EB Soil Moisture Sensor Installation Guide E Which Probe to Use The choice of probe will be determined by the depth of the root zone or profile depth to be monitored and the parameters to be measured All EnviroPro probes can measure soil moisture and soil temperature EC equipped models also measure electroconductivity EC at each depth Moisture Temp Sensing Points Length cm EP04 Y Y 4 46 5 EPO8 Y v 8 86 5 EP12 v Y 12 126 5 EP16 v v i 16 166 5 EPECO4 V v Vx 4 46 5 EPEC08 v v v 8 86
8. Soil Moisture Sensor Installation Guide da GDot Switch Box Wiring Gypsum Switch Box Connector Blocks Red Blue 1 Green 2 Yellow White Black 3 Brown 4 Violet ThetaProbe Wiring 4 Pin Connector Function Colour 1 Signal Yellow 2 Signal Ground Green 3 Power Ground Blue 4 Power Supply Red EnviroPro Wiring Function Plexus Cable EP preOct 2013 EP post Oct 2013 12V Red Brown Red Data Blue Blue Blue GND Green Green Yellow Black not used Yellow Yellow To connect an EnviroPro to systems other than Plexus please consult the User Manual or wiring diagram that came with your system www mea com au Page 46 EB Soil Moisture Sensor Installation Guide E AquaCheck Wiring Function Plexus Cable AquaCheck 12V Red Brown Data Blue Blue GND Green Green Yellow not used Yellow To connect an AquaCheck probe to systems other than Plexus please consult the User Manual or wiring diagram that came with your system WWW mea com au Page 47
9. Support If you have questions or problems that cannot be resolved using the information in this manual contact MEA technical support using the details above If phoning ask for technical support and explain the issue Your issue will be referred to a technician for action at the earliest opportunity Quoting your MEA Job Reference Number will enable us to quickly locate your details Charges may apply for support other than warranty support Phone support is generally available Monday to Friday between 9 am and 5 pm Central ie South Australian Standard or Summer Time Site visits will incur charges for labour travel time and where applicable accommodation and meals MEA technicians can only offer support for issues relating directly to the operation or maintenance of products supplied by MEA WWwW mea com au Page2 EB Soil Moisture Sensor Installation Guide Contents Introd tio u iin ken DX MENS x ERN QUE UMIM OIM PR EDGE How to Use Scotchloks ssss A Note on Augering Tolerances Gypsum Blocks rene tere tenen nu rtntnns Which Type of Gypsum Block is Suitable 1 8 Sensor Site Selection Required Tools and Equipment How to Install Gypsum Blocks sessesss Improving the Sensor to Soil Contact ThetaPro
10. bes fe Sensor Site Selection iiec ttd ec Required Tools and Equipment How to Install ThetaProbes sse l7 e E Which Probe to Use a Sensor Site Selection 1 Required Tools and Equipment The Probe Must Be Installed in A Slurry How to Install EnviroPro Probes How To Extract an ENVIO O uuu au auqa sassa AquaCheck Sub surface Probe Which Probe to Use ass Sensor Site 5el ctloft eiie eiii iab esa idesaRuds How to Install AquaChecks sss www mea com au Page3 EB Soil Moisture Sensor Installation Guide E FullStop Wetting Front Detectors 11 37 Sensor Site Selection sss nennen 38 Required Tools and Equipment 40 How to Install FullStops sss 41 WET Sensors ciiin sen asini ania pecu tran buccina aaraa taaa 44 How to Install WET Sensors eter et en eet rte en 44 LII ECIID T 45 GBug Wiring Diagram ioter cr tt ed aa 45 GI B g Wiring Dlagtarm iere teeth ine ete ki pa en key Pac 45 BDot Switch BOX WINN g seseris irrisoria ane 46 Th taProb Wiring ere Sterben iniii ii ia tadini aia
11. ble in the trench to provide strain relief if the cable is snagged by machinery or stretched due to compaction of the ground 8 Where the cable leaves the ground consider placing it in protective conduit to prevent damage from animals or machinery 9 Tiethe cable to the post supporting the logger or Plexus unit using zip ties www mea com au Page 32 B Soil Moisture Sensor Installation Guide x 4 How To Extract an EnviroPro EnviroPro probes can be extracted using a purpose built probe removal tool available through MEA or using multi grips or vice grips Extraction Using a Probe Removal Tool 1 If the soil is dry extraction can be made easier by pre wetting the soil the day before attempting extraction 2 Useatrowel or small spade to carefully remove the soil around the head of the probe down to a depth of 15 cm 3 Clamp the probe removal tool to the probe body 10 mm below the cable Fig 40 Placement of the probe removal tool 4 Grip the handles of the probe removal tool Rotate the probe clockwise and anti clockwise until you can rotate the probe approximately a quarter turn A Make sure the removal tool does not interfere with the probe cable 5 You should now be able to work the probe free of the soil by pulling upward while continuing the rotating motion A Ensure you lift the probe vertically Off vertical force can damage the probe Www mea com au Page 33 B Soil Moisture Sensor Instal
12. e bottom of the hole and carefully backfill with moist soil gently compressing the soil to remove air pockets Fig 17 Sensor laid on its side to monitor shallow rooted crops GTBug Temperature Sensor The temperature sensor should be installed between 100mm and 150mm where daily fluctuations in surface temperature are minimised This sensor can simply be placed in a hole of the correct depth and backfilled gently compacting the soil as you go Improving the Sensor to Soil Contact In reactive clay soils and in light sands the installation procedure can be modified to improve soil to sensor contact This avoids problems with clay soils shrinking away from the sensors or with sandy soils drying down faster than the sensor can respond Before installing the sensor 1 Make a 50 50 slurry of water and clay loam sourced from elsewhere on site if available 2 Coatthe sensor in a thin layer of slurry then install Www mea com au Page 17 EB Soil Moisture Sensor Installation Guide a ThetaProbes ThetaProbes are a type of soil moisture content sensor The probe consists of a waterproof housing containing electronics with an array of stainless steel electrodes at one end for direct insertion into undisturbed soil and a power signal cable at the other ThetaProbes measures soil moisture content with an accuracy of 1 over the range of 0 to 60 of volumetric soil moisture content This level of accuracy makes the probe
13. e tape measure to check the depth after the auger is extracted to ensure that part of the hole wall has not collapsed or that other material has not fallen into the hole A Z Z Z 2 Fig 35 Augerthe hole Fig 36 Check the depth WWW mea com au Page 31 EB Soil Moisture Sensor Installation Guide Ee E Pour slurry into the hole until it is half full 4 Pushthe probe into the hole until the top is 35 mm below the soil surface Apply a maximum of 15 kg of force to the probe Avoid causing sharp bends in the cable where it enters the probe Hint Assess the thickness of your slurry Some resistance should be encountered when pushing the probe into the hole If the probe is very difficult to push in the slurry is too thick Add 596 more water mix and test If the probe goes in too easily the slurry is too thin Add 596 more bentonite sand mix thoroughly and leave for fifteen minutes before testing Repeat this procedure until you are satisfied with the consistency 5 Theslurry should ooze up around the instrument and slightly overflow the hole If you do not see any slurry carefully extract the instrument mix up some more slurry and add to the hole 6 Backfill to cover the probe Fig 37 Fillthe hole half Fig 38 Insertthe Fig 39 Capthe hole with full of slurry EnviroPro extracted earth 7 Trench the cable in to a depth of 100 mm or deeper to protect it Leave a loop of ca
14. ee that will get the hot afternoon sun Fig 5 Placement of gypsum blocks under furrow irrigation Centre Pivot or Linear Lateral Move Irrigation Place the blocks at locations down the length of the pivot between towers just ahead of the start point Fig 6 Placement of gypsum blocks under pivot irrigation WwWwW mea com au Page 11 EB Soil Moisture Sensor Installation Guide Required Tools and Equipment 25mm Auger MEA2193 Masking tape or electrical tape 13mm PVC pressure pipe 1 2m in length or about 300mm longer that the depth of the deepest block you are going to install 12mm dowel about 100 mm longer than the PVC pipe Trowel Bucket amp water Two small funnels Bentonite civil grade eg Unimin Active Gel 150 MEA2197 2kg pack will cover 15 20 sensors Hint Use only powdered active gel bentonite Bentonite is also sold in granulated form granulated bentonite is unsuitable for sensor installation Fine dry builder s sand eg Unimin AFS85 grade 8 kg to mix with 2 kg of bentonite Tape measure notebook tags amp permanent marker WWW mea com au Page 12 B Soil Moisture Sensor Installation Guide E How to Install Gypsum Blocks 1 Poura couple of litres of clean water into the bucket and place the gypsum blocks in to soak Hint If the blocks are GB Heavies remove the foil wrapping first A It is enough to soak the blocks for
15. he way in 2 Holding the wires in place use pliers or multi grips to push the black button on the connector all the way down rid Repeat for all remaining connections B After all the blocks are connected ensure that the end of the logger cable is off the ground and pointing downward so that water is not able to collect in the cable For added protection you can wrap the end of the cable or the join itself in waterproof tape lt www mea com au Page6 B Soil Moisture Sensor Installation Guide 4 A Note on Augering Tolerances Augered holes need to be slightly larger than the sensor installed in them to allow the insertion of the sensor However holes should not be too large or air gaps can exist between the sensor and the surrounding soil Sensor to soil contact can be improved by the use of slurries to fill the gaps In the case of the bentonite clay and fine sand slurry recommended for some probes in this manual too much slurry can negatively affect the quality of the readings The following method may help you create a clean tight fitting hole that minimises air gaps and minimises the amount of slurry required 1 Remove the topsoil at the installation site using a post hole auger shovel or other tool Neatly pile the topsoil nearby 2 Use an under sized auger eg a gypsum block auger in the case of EnviroPro or AquaCheck installation to drill a pilot hole to the required depth 3 Finish the ho
16. l to check that it reaches the required depth Make sure the extension tubes are vertical Fill the funnel with soil from the same layer and lightly firm it down Break up the sides of the hole before returning more soil as smooth sides can restrict the growth of roots and the movement of water Pack soil around the sides and under the funnel to keep it firmly in place hold the outlet tube out of the way the deeper narrow hole does not need to be packed with soil Fig 47 Check the Fig 48 Fillthe funnel Fig 49 Pack under the depth with soil funnel with soil Wwww mea com au Page 42 EB Soil Moisture Sensor Installation Guide m ese 10 Return the rest of the soil to the hole in the layer order in which it was extracted 11 Soil should be firmed down by hand but not compacted 12 Use the trowel to break up the top edge of the hole 13 All the soil should be returned to the hole leaving a slight hump which should settle after rain or irrigation After settling check that the soil is level so that water does not run away from or toward the detector 14 Push the tubing stake supplied with the FullStop into the end of the outlet tube this will prevent insects and soil from entering and blocking the tube and use it to position the tube away from the detector Fig 50 Backfill the hole Fig 51 Fitthetubetothe Fig 52 Install the tubing tubing stake stake For more infor
17. l if you don t have access to the augers Tape measure Portable EC Meter MEA2272 for monitoring salinity levels Nitrate and nitrite test strips MEA2273 and MEA2274 for monitoring nutrient levels WWwW mea com au Page 40 EB Soil Moisture Sensor Installation Guide X E How to Install FullStops Following are instructions for installing the FullStops using augers Hint If you do not have the required augers a shovel can be used instead of the larger auger and a trowel instead of the small auger 1 Assemble and test the FullStops according to the instructions that came with them Check for leaks and make sure the float indicator can move freely through the extension tube s Attach as many extension tubes as required for the installation depth 2 Makea hole with the large Auger This will accommodate the wide part of the funnel Hint If the soil texture changes with depth keep the different soil layers separate 3 When the hole is deep enough use the small Auger to make a hole for the bottom of the FullStop 4 Addthe filter sand supplied with the FullStops to the detector until it covers the locking ring by at least 1 cm Mu Fig 44 Digthelarge Fig 45 Digthe small Fig 46 Add the filter hole hole sand to the funnel Www mea com au Page 41 EB Soil Moisture Sensor Installation Guide E E 5 Place the detector in the hole and measure the distance to the rim of the funne
18. lation Guide E Extraction Using Multi Grips or Vice Grips If a probe removal tool is not available multi grips or vice grips can be used for extraction The method and precautions are the same as that for extraction using a probe removal tool see above Hint To avoid damage to the probe body cushion the jaws of the multi grips or vice grips with heavy duty heatshrink electrical or duct tape or rubber WWW mea com au Page 34 B Soil Moisture Sensor Installation Guide 4 AquaCheck Sub surface Probe AquaCheck probes provide reliable soil moisture and temperature measurement in all soil types Multiple sensor clusters per probe allow the monitoring of moisture and temperature at each sensor depth Soil moisture readings are temperature compensated The internal electronics are fully protected making the probes reliable consistent and very stable Each probe is supplied with 5 m of cable Designed to be completely buried the AquaCheck is out of the way when slashing spraying and harvesting Moisture profiling at 100 mm intervals allow you to track the movement of water through the root zone and optimise irrigation events Following the movement of nutrients through the root zone by tracking changes in salinity allows you to optimise fertiliser applications and only apply leaching irrigations when needed AquaChecks can be used with e Plexus for continuous monitoring and the display of data on smart device
19. le using the auger recommended on the Required Tools and Equipment list for the relevant sensor 4 Install the sensor 5 Carefully replace the topsoil Firm the topsoil down to remove air pockets WWwW mea com au Page7 B Soil Moisture Sensor Installation Guide E Gypsum Blocks Gypsum blocks are a type of soil moisture tension sensor They report soil moisture in kilo pascals kPa Gypsum blocks can be used with e Plexus radio networks for continuous monitoring and viewing of data on your PC or smart device e MAX soil moisture loggers for continuous monitoring and viewing of data on your PC e GDotfor spot monitoring GBLites only MEA s GBHeavy measures over the range of 50 to 500 kPa the range found in heavy soils having a high clay content The GBLite also known as the Watermark measures over the range of 10 to 200 kPa sand to sandy clay loam Which Type of Gypsum Block is Suitable if moisture levels are to be kept in the range where it is readily available to the plants use the GBLite regardless of soil type Where the crop is going to be pushed into deficit use the GBHeavy in soils with a substantial clay content and the GBLite in sandy soils The GBHeavy sensor also makes an inexpensive drainage detection sensor when used below a set of GBLites WWwW mea com au Page8 EB Soil Moisture Sensor Installation Guide X j 4 Sensor Site Selection The following section relates specifically to the
20. mation please visit www fullstop com au WWW mea com au Page 43 B Soil Moisture Sensor Installation Guide 4 WET Sensors The WET Sensor measures water content electrical conductivity and temperature in soils composts and other artificial growing media In five seconds the probe can provide a measure of water content over the range of 0 to 8096 pore water conductivity from 0 to 600 mS m and temperature over the range of 0 to 40 C The WET sensor is used with e HH2 Reader which needs to be loaded with the sensor s unique calibration Data can be viewed on the Reader and downloaded to a computer How to Install WET Sensors If the WET sensor is to be installed in a fixed location remember that although the sensor housing is waterproof the connector used to attach it to a HH2 Reader is not You will have to find some means of ensuring that water does not enter the connector Installation equipment procedures and considerations are the same as for ThetaProbes Please see ThetaProbes on page 18 or refer to the WET User Manual WWW mea com au Page 44 EB Soil Moisture Sensor Installation Guide 4 Wiring Guides GBug Wiring Diagram Gypsum GBug Connector Blocks Red Blue 1 Green 2 Yellow White Black 3 Brown 4 Violet GTBug Wiring Diagram Gypsum GTBug Connector Blocks Red Green Yellow Oe White Black Brown CON Temp Violet LO sewer a WWW mea com au Page 45 B
21. monitor a particular part of the root zone can require a buried installation Even with a shallow installation it might be preferable to bury the probe to provide protection for it ThetaProbes can be installed either horizontally or vertically depending on the depth of installation and installation equipment available How to Install a ThetaProbe Horizontally The probes may be installed horizontally in shallow sites The sensor should be inserted into undisturbed soil on the face of the trench 1 Atthe monitoring site excavate a trench down to 10cm below the intended sensor depth Clean off the face of the hole at the required depth 2 Pushthe rods into the side of the hole until the soil comes in contact with the probe body 3 Route the sensor cable out of the hole to the surface it can be sheathed in conduit to protect it against damage 4 Carefully backfill under and around the sensor Fig 22 ThetaProbe installed horizontally WWwW mea com au Page 22 B Soil Moisture Sensor Installation Guide X E How to Install a ThetaProbe Vertically 1 Usethe marker or tape to mark the auger and the PVC pipe with the installation depth s Fig 23 Mark the auger and pipe with the installation depths Hint When marking the PVC pipe remember to allow for the length of the sensor 2 Make a dry 1 part bentonite to 4 parts sand mix Venonte Fig 24 Mix the bentonite and sand
22. nit An indicator flag is fitted to an extension tube which protrudes above ground When water collects in the base of the funnel floats within the extension tube cause the indicator flag to pop up to show that the wetting front has arrived The indicator flag is held up with a magnetic latch and must be pushed down to reset it If the soil is still very wet the flag will pop up again An outlet tube at the base of the FullStop allows water collected in the funnel to be extracted using a syringe and tested for EC and nitrate levels Unlike the other sensors in this guide the FullStop requires no power source Readers Loggers or software WWwW mea com au Page 37 EB Soil Moisture Sensor Installation Guide X E Sensor Site Selection FullStops are sold and generally used in pairs with one unit at one third of the root depth and the second at two thirds of the root depth Drip Irrigation e The detector must always be placed directly under a dripper Suggested depth for the shallow detector is 30cm and for the deep detector is 60 cm e Deeper placement is required for widely spaced drippers or long irrigation intervals Shallower placement suits closely spaced drippers frequent irrigation or shallow rooted crops e Itis common for detectors to respond quickly under drip because all the water is being concentrated around the dripper with dry soil between drippers In such cases less water should be applied more often
23. obes Surface Measurement e For surface measurement the stainless steel rods can just be pushed into undisturbed soil Rods fully TECNI Fig 18 Surface measurement with a ThetaProbe Hint Make sure the stainless steel rods are completely covered If any part of the rods are uncovered soil moisture readings will not be accurate e Ifthe probe is going to be left in place it is a good idea to insert it at a slight angle eg 10 20 so that water running down the outside of the probe is less likely to pool around the rods e Try to ensure there are no air pockets or stones around the electrodes as this will reduce the quality of the measurements A Take care not to bend the rods Do not handle the probe by its cable Repairs can be costly and time consuming WWwW mea com au Page 20 EB Soil Moisture Sensor Installation Guide r a e Inhardground use of the ThetaProbe Insertion Kit is recommended Place the guide block on the ground at the sampling location Place the preparation rods into the holes in the guide block and gently tap them into the soil until the heads contact the guide block e Withdraw the guide block and preparation rods and insert the probe Fig 19 Fitthepinstothe Fig 20 Hammerthepins Fig 21 Push the probe guide block in into the holes WWwW mea com au Page 21 B Soil Moisture Sensor Installation Guide mt a Buried Installation The need to
24. one to five minutes Do NOT soak the blocks for long periods eg overnight as this will shorten their usable life 2 Make adry 1 part bentonite to 4 parts sand mix Two kilograms of bentonite mixed with eight kilograms of sand will make approximately enough to install sixteen gypsum blocks depending on the installation depths and augering tolerances Fig 7 Soak the blocks Fig 8 Mix the bentonite and sand Hint The bentonite sand mix forms a plug that prevents water running down the disturbed soil in the hole and making the blocks wetter than the surrounding soil WWwW mea com au Page 13 EB Soil Moisture Sensor Installation Guide 3 3 Markthe auger and the PVC pipe with tape at the installation depths Treat the mid point of a gypsum block as the sensing point when working out depths Fig 9 Mark the auger and pipe with the installation depths Hint When marking the PVC pipe remember to allow for the length of the sensor 4 Auger the first hole Remove the auger to clean the flukes frequently Hint Put the soil removed from the hole in its own pile You will use it to help seal the sensors WWW mea com au Page 14 EB Soil Moisture Sensor Installation Guide E 5 Pour half a cup of water down the hole to ensure correct seating of the sensors Soil removed 125ml from hole J Fig 10 Auger a hole Fig
25. placement of gypsum block sensors under different types of irrigation but the principles will apply more broadly to other types of soil moisture sensor Drip Irrigation Install the sensors at the edge of a 10 15 cm radius centred under the dripper Dripper line 50mm 150m 1 m Fig 1 Place the blocks ina circle around Fig 2 Place the blocks through the the dripper as shown wetting onion The deepest block serves asa drainage sensor Hint If you have more than one gypsum block install each block in its own hole Stacking sensors in the same hole can lead to leakage down the hole and makes it impossible to replace deeper blocks if later required WWW mea com au Page9 B Soil Moisture Sensor Installation Guide X aH Sprinklers Install the sensors in a straight line 10cm apart in a location where the sprinklers are delivering their rated output Under tree crops place the blocks under the drip line of the canopy Fig 3 Gypsum blocks under sprinklers Fig 4 Under sprinkler irrigated tree crops place the blocks under the drip line of the canopy WWwW mea com au Page 10 B Soil Moisture Sensor Installation Guide X E Furrow or Flood Irrigation Locate the sensors about 2 3 of the way down the run just ahead of the tail or backup water This is the area where water penetration is usually the poorest With tree crops locate the sensors on the side of the tr
26. ro should be installed using a fine sand and bentonite slurry The quantities and method described below will make enough slurry for the installation of two 80 cm probes You will need e One MEA2014 Bentonite and sand pack e 1L clean water e Small bucket with lid e Funnel e Two litre plastic bottle with lid Method 1 Mix 100gm of bentonite and 1 kg sand together in a bucket BeMrone Fig 30 Mix the bentonite and sand WWwW mea com au Page 29 EB Soil Moisture Sensor Installation Guide E 4 2 Pourthe dry mix through a funnel into a two litre plastic bottle Pour 750 ml of clean water into the bottle 4 Put the lid on and shake until thoroughly mixed Allow 15 minutes for the bentonite to swell The resulting mix should be a creamy consistency Mix 2 litres Fig 31 Pour the dry Fig 32 Add the water Fig 33 Shake until mix into the completely container mixed Hint Always shake the mixture before application the sand might settle in storage Wwww mea com au Page 30 E Soil Moisture Sensor Installation Guide A E How to Install EnviroPro Probes 1 Measure the length of the probe Use the tape measure and the adhesive tape to mark the auger 3 5 cm longer than the probe to be installed Fig 34 Mark the auger 3 5 cm longer than the length of the EnviroPro 2 Auger a hole 3 5 cm deeper than the probe to be installed Use th
27. s e MAX for continuous monitoring and viewing of data on a PC WWW mea com au Page 35 EB Soil Moisture Sensor Installation Guide E Which Probe to Use The choice of probe will be determined by the depth of the root zone or profile depth to be monitored Standard sensor depths for the sub surface model as at July 2014 are listed in the table below Probe Model 60 cm 80 cm 100 cm 120 cm 10 10 10 20 20 20 20 40 Sensor Depths 30 30 40 60 Ga 40 40 60 80 50 60 80 100 60 80 100 120 Sensor Site Selection Please see Sensor Site Selection on page 9 Although this section deals with the placement of gypsum blocks under different types of irrigation the considerations apply equally well to AquaCheck probes How to Install AquaChecks The tools methods and considerations for the installation of AquaCheck probes are the same as those for EniviroPro probes Please refer to EnviroPro on page 26 WWW mea com au Page 36 EB Soil Moisture Sensor Installation Guide 4 FullStop Wetting Front Detectors The FullStop provides a cost effective method of assessing whether too much or too little irrigation is being applied to detect water logging and to monitor nutrient and salt levels in the soil The heart of the FullStop is a funnel shaped collector which is buried in the soil As moisture moves through the soil profile a wetting front it converges in the funnel and collects in a reservoir in the base of the u
28. www mea com au Page 23 B Soil Moisture Sensor Installation Guide OE E 3 Auger a hole Hint It is recommended that the hole be augered approximately 10 off vertical to help prevent water pooling at the rod array 4 Thread the probe cable and connector if fitted through the PVC pipe and use this to push the sensor down the hole pushing the rods into the undisturbed earth at the bottom of the hole Take care not to bend the rods Soil removed from hole Y Fig 25 Augera hole Fig 26 Usethe PVC pipe to insert the ThetaProbe into the hole WwWwW mea com au Page24 EB Soil Moisture Sensor Installation Guide x 5 Pourahandful of earth down the hole and gently compact with the dowel 6 Fill the hole to 25 mm below the surface with the dry bentonite and sand mix gently tamping as you go Use more earth to complete filling the hole Do not overfill as this will form a surface cap which will shed water away from the sensor I Fig 27 Add earth and Fig 28 Add the bentonite Fig 29 Cap the hole with tamp and sand mix earth and tamp WwWwW mea com au Page 25 B Soil Moisture Sensor Installation Guide 4 EnviroPro EnviroPro probes provide reliable soil moisture and temperature measurement in all soil types Multiple sensor clusters per probe at 100mm spacings allow the monitoring of moisture and temperature at each sensor depth Models which
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