April 2007 New soil moisture sensors Enable high performance SWAT Controllers Mike van Bavel, President Dynamax Inc. - Our Mission Combine science and technology to produce advanced & affordable soil moisture irrigation control solutions for efficient water management and water conservation. Delta-T Devices (UK)} sensor design and production Dynamax Inc (Houston) } system design, controls manufacturing, USA sales / support

April 2007 Background - Portable Moisture Probes Multiple soil moisture readings Battery operated hand held recorder & display – HH2 ThetaProbe soil moisture sensors Portable Sensors - Surface readings - -or inserted in access tubes - -Profile Probes Irrigation system audits, test application, and soil surveys for salinity (EC) – electrical conductivity

April 2007 New Conservation Controllers vs Plain Old Timer There are 2 basic conservation controller types: –Soil Moisture Sensor: Uses actual soil conditions for irrigation start / stop points. Uses real-time information on soil moisture conditions for irrigation. Regulates a Timer according to water needs. –ET (Evapotranspiration): Uses historical / pre-programmed water usage, or actual ET from a local station or the controller, updated manually or automatically. Regulates a timer according to estimated water use. The plain old timer has no feedback on the actual soil or the weather conditions.

April 2007 Why Soil Moisture ? Properly applied soil moisture irrigation scheduling is the most accurate and efficient conservation method! most accurate, when you use accurate and proven sensors.Both technologies work for water conservation but soil moisture is the most accurate, when you use accurate and proven sensors. The answer is: soil moisture is what the plants use and people intuitively understand how it works.

April 2007 SM200 Introduction Low cost Good accuracy Excellent temp stability Excellent salinity response Durable Buriable Compact for limited space applications Patented design Proven Delta-T technology

April 2007 SM200 specifications Water tight connector ½” Thread For conduits 2.5mm pins 50mm long Stainless steel – indefinite lifespan Durable plastic body Shaped pin termination

April 2007 SM200 Specifications Power5 to14 typically, low power Output0 to 1.2V full scale, easy to read Range 0 to 40% accuracy  3% Range 0 to 60% accuracy  5% Add. Temp errors  0.01%/  C over 0 to 40%, 0 to 60  C Add. Salinity errors  3.5% over 0 to 40%, to 500mSm -1

April 2007 Why are Delta-T SM200 Soil Moisture Sensors Accurate and Reliable? Developed by Scientists and produced for scientists (since 1996). Wide range of applications needed for research. The first FDR probe with a single voltage output - ThetaProbe patented technology. FDR - (Frequency Domain Reflectometer) Measures soil dielectric with a microwave signal. Wide moisture range 0-60%. Operates with a wide range of soils, and includes a calibration built into each and every sensor. Salinity and temperature instability are designed out, and have limited effects.

April 2007 Soil Moisture Control – Set Point Requirements Set Point

April 2007 Moisture Control theory and requirements A closed-loop controller (C) uses feedback (-) from sensors to control states or outputs of a dynamical system (y). The reference values ( r +) are set by the user to a desired beneficial level. A operational controller must also have: Stability, Controllability, and Observability. Sensor feedback that has error in excess of the desired control function feedback (e), causes uncontrollability and problems with observability.

April 2007 Closed Loop Controllers- The good news: Advantages over open loop, ex. timers: disturbance rejection guaranteed performance even with model uncertainties, when the model structure does not match perfectly the real process and the model parameters are not exact unstable processes can be stabilized reduced sensitivity to parameter variations improved reference tracking performance

April 2007 What Sensor Accuracy do We need ? Stress Level < 7% Irrigation Start (7%) Stress Level < 33% Deficit Irrigated ClaySand 0% 10% 30 % 40 % 50% Field Capacity (10%) WIlting Point 4% Over Irrigated Optimum Growth Moisture Range Optimum Moisture Range Wilting Point 22% Dead Plants - No Production Wasted Water & Fertilizer Irrigation Start Point (33%) Field Capacity (45%) Over Irrigated 20% 60% Maximum Error Allowable +/ – 3 % Wasted Water

April 2007 Real Time Example - Seattle

April 2007 CIT SWAT Testing protocol - Results What does the test result show us? A correlation between a soil simulator drying out and a soil moisture sensor reading in the top 4 inches. (not a calibration for the sensor) The soil drying trend will show a correlation to the soil sensor in a single installation to be accurate enough for control purposes. If there are poor correlations due to salinity effects or temperature operating range changing the sensor characteristics.

April 2007

CIT SWAT Test Results

April 2007 The range of 95% confidence, (2*SD) = +/-1.4%. Well within the minimum accuracy needed to control moisture in sandy soils.

April 2007 Advanced Moisture Level Control IL200-MC How does it work? –Set desired initial Irrigation Start Point (% Vol) by soil type chart. –The output relay triggers when below the set point. Or use a learning curve –Determine site specific field capacity one day after irrigation. –Adjust the moisture to the ISP, about 0.9 * field capacity.

April 2007 IL200-MC Irrigation System Applications Satellite and Standard Timer Upgrade Scheduling: IL200-MC controls the water for 5-8 zones grouped together. The moisture sensor, SM200, is buried in most critical zone. Valve power is enabled when moisture is below the irrigation set point.

April 2007 Moisture Clik TM Setup The setup is fairly simple. There are only three connections to be made after the box is mounted. The basic steps are: –Connect the power lead. –Connect the sensor leads. –Connect the output / control wires from the relay to the sensor input. –Other applications Direct Valve Control Common Interrupt line Alarms to central control

April 2007 Set the Dial for the Irrigation Start Set by Soil Type Directly, or Irrigate and adjust by Soil Field Capacity - Timer Program - Short cycles, with multiple start times: Repeat water & soak so all zones are the same soil moisture.

April 2007 New - Advanced Irrigation Control with SM200, GP1 Precision Moisture control and monitor with recordings: Soil moisture, water used, rainfall, temperature

April 2007 Conclusions Accurate water conservation control solutions with soil sensors are available. Smart water solutions may be successful with tested sensors. Next: Develop the protocol to measure savings and water efficiency certification. Thank you for attending, Dynamax appreciates your time and interest!