Using modern sensor technology to improve water usage ... - adagio

» 

Sensor Technology for improved water efficiency - 

selection criteria and the 10 most common mistakes 

BOKU, June 2009 

© by Adcon Telemetry GmbH 

© 2009 by Adcon Telemetry GmbH

» Sensor Technology to improve Water efficiency 

3 accepted technologies: 

- Weather Stations 

- Soil Sensors 

- Plant Sensors 



Weather Stations: 

- Calculating Evapotranspiration ETo / ETc 

according to 

- FAO-56 (P.M.) 

- Shuttleworth-Wallace 

th ll 

- Priestley-Taylor 

- Hargreaves, 

- etc. 



Soil Sensors to monitor 

- Soil Moisture 

- Soil Conductivity 

- Soil Salinity 

it 

- Soil Temperature 



Plant Sensors to monitor 

- Shrinkage and Expansion of trunk, branches 

and fruits (dendrometers) 

Best if used in conjunction with other methods, in 

particular with soil moisture sensors. 


» The Process of Selection - Installation - Operation 

Bad Data in - Bad Data out. 

Before taking any decision follow this 7 step process: 

Step 1: Definition of the purpose of the equipment 

Step 2: Risk Assessment 

Step 3: Select equipment according to the results of Steps 1 and 2 

Step 4: Site Selection 

Step 5: Installation 

at Step 6: Ongoing Maintenance 

Step 7: Replacement 


» Step 1: Defining the Purpose of the Equipment 

a) What is the equipment needed for? 

• General Meteorology 

• Agro-Meteorology 

Disease modeling 

Evapotranspiration 

Soil and Plant Monitoring 

• Hydro-Meteorology 

• Airport Meteorology 

• Wind energy site testing 

• Roadside Weather 

• A combination of the above 

• ....? 


» Step 1: Defining the Purpose of the Equipment 

b) Which requirements exist for the respective application? 

b1) Legal requirements 

Informal requirements – recommendations, rules, standards 

b2) Requirements as to 

• sensor accuracy – e.g. WMO recommendations 

• logger accuracy 

• mechanical characteristics – orifice, sun shield, ventilation, 

heating, .. 

• installation method and location – distance to soil surface, 

distance from each other, distance to nearby objects, etc. 

• data collection method – number of samples, averaging 

methods, frequency of measurement,.. 

• transmission intervals 


» Installation scheme according to WMO 


» Step 2: Risk Assessment 

Choose the equipment according to the purpose, e.g. 

- a3-year research project 

- a valuable crop 

- food security 

Questions to be answered: 

• What's at stake? 

• What are the potential benefits? 

• What are the potential damages? 

• What happens if ...? 

• Will my insurance accept data from my equipment? 


» Step 2: Risk Assessment 

Examples: 

1) 25 hectares of grapes, 14 avg. sprays at Euro 40/ha. 

Potential saving of 5 sprays = € 5.000,00 p.a. 

2) 200 hectares of potatoes, 6 avg. sprays at USD 40/ha. 

Saving only 1 spray = USD 8.000,00 p.a. 

3) 50 ha of grapes, average yield per ha: Euro 15.000. Total: € 750.000000 

Irrigating too little or too late, spraying too late, resulting in a loss of 

only 

1% of crop quantity of quality ranking amounts to € 7.500,00 

4) 1000 hectares of corn, average yield per ha: 10mt@USD158/mt - 

2 stress days due to late or low irrigation = up to 10% lower yield > 

loss of USD 158.000,00 ! 


» Step 3: Select Equipment acc. to steps 1 and 2 

Specification of technical characteristics of loggers and 

each sensor according to 

• The required installation methods 

• The required accuracy 

• The cost / risk ratio 

• The insurance companies assessment 


» Installationsdiagramm nach WMO 

1. Temp. ventilated, t 200cm 

2. Temp. ventilated, 20cm 

3. RH, 200cm 

4. Wind, 250cm 

5. Solar radiation 

6. Leaf Wetness 

7. Soil Temp. in 5cm 



10. Heated Rain Gauge 

11. Bird Protector 

12. Ventilation for Air Temp. 

13. Data Logger 

14. Communications Cable 

15. 220V Power Supply 

(c) Bayr. LA f. Landwirtschaft, Weihenstephan 






» Step 4: Site Selection 

The site has to meet the requirements of the application. 

• Evaluate which application is of highest significance. 

• WMO – disease models – ETo differ in their requirements. 

• Disease models: old models – station outside of crop 

• recent models – stations inside the 

crop 

• ETo: 1ha of short-cut grass 

• Soil moisture sensors: installation site must be typical for 

soil 

type, crop type, crop age, irrigation system, ... 



Permanent installation or temporary? 

• If installation is permanent evaluate a site on a timeline – 

what will it look like in 10 – 15 – 20 years? 

• Are trees nearby ? Variety? Max. size? Can they be cut? 

• Are water bodies nearby? Flooding areas? 

• Zoning of the area – construction work to be expected? 


» 

Weather Stations for Irrigation Improvements 

• What is todays most important rule for irrigators? 


» 

Weather Stations for Irrigation Improvements 

• What is todays most important rule for irrigators? 


» 

Proper Installations 

• ETo as it should be in Chile 


» 

Proper Installations 

• A good example for leaf wetness from Styria 








» Step 5: Site Selection - Sensor Positioning 

Moisture Zones in Drip Irrigation 

Sand Loam Clay 

Access Tubes 

To wet 

To dry 

Soil Moisture Optimum 


» Step 5: Installation 

Good equipment - great site - bad installation? 

• Pole well anchored in the ground and perfectly vertical 

• Guy wires if necessary (soft soil, strong winds) 

• Solar panel facing South 

• Wind direction facing North 

• Orifice of Rain gauge g and pyranometer must be absolutely 

horizontal 

• Sensors must not influence each other 

• Keep sensors away from hot surfaces (esp. Temp., RH, 

Leaf 

wetness, pyranometres!) 

• Take a picture of the installation and note the GPS 


» Step 6: Installation - What‘s this- disease or ETo ? 


» Step 6: Ongoing Maintenance 

The best equipment will have a short lifetime and little 

reliability if no proper maintenance is being performed! 

• Clean the solar panel, pyranometer, rain gauge once per 

month 

• Visually check all sensors for damage, dirt, foreign objects 

once per month / every visit 

• Check cables for nicks and animal bites. 

• Make sure all connectors are seated well. 

• If applying chemicals cover sensors before spray or 

clean them thereafter. 

• Check sensor readings in the field with reference sensor 



The best equipment will have a short lifetime and little 

reliability if no proper maintenance is being performed! 

• Replace the humidity sensor every 3 – max. 5 years. 

• Depending on the application recalibrate a e sensors so s every e 1 – 5 years 

• Calibrate spare sensors in the lab and only replace in the 

field. 


» Maintenance is key! 


» Maintenance - why birds love rain gauges 


» Maintenance - expect the unexpected! 



Keep an eye on your data! Much can be told from the office. 

• Check patterns of moisture: RH - rain - leaf wetness 

• Check RH sensor diurnal fluctuations 

• Check for regularly occurring errors. 



Keep an eye on your data! Much can be told from the office. 

• Check patterns of moisture: RH - rain - leaf wetness 

• Check RH sensor diurnal fluctuations 

• Check for regularly occurring errors. 


» Step 7: Replacement 

Even the best equipment, well maintained, i doesn’t live forever. 

Make appropriate accruals for replacement of certain 

components after x years. 

X will depend on quality level of equipment, maintenance, 

environmental conditions, etc. 

• Leaf Wetness: every 2 - 3 years 

• Data loggers: 10 - 15 years (aging of electronics, voltage 

references, oscillators, ADC, etc.) 

• Wind speed and direction: 10 years (bearings) 

• Pyranometers: 10 - 20 years 

• Rain gauges: 10 years depending on model (min. reed 

switches) 


» 

Thank you for your attention!

Using modern sensor technology to improve water usage ... - adagio

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