Case Study
California State University
Fresno
The objective for this project was to analyze how crop water requirements can vary based on different classifications. This specific project is comparing irrigation based off of soil moisture requirements vs. ET (evapotranspiration) requirements.
Olives
20 acres
Pump & valve automation
Project Details:
- 20 acres of 12 year old olives
- Single line drip irrigation
- Pump & valve automation
- Soil moisture sensors ranging from 6”- 42”
- Pressure transducers to show PSI within irrigation lines
- Flowmeter monitoring to help track inches of water applied
- Weather Station to monitor temperature and Et0
Infiltration rates were calculated from the depths 6”-42” based on formulas specific to the crop. It was determined that the main root zone activity was as deep as 30”, anything beyond that point will show irrigation that is going past the point of water optimization.
Analysis - Root Zone
- Soil moistures at different depths were plotted to observe the change in soil moisture
- Significant change in soil moisture was identified to be part of the root zone and layers with little to no change in soil moisture were identified to be below root zone
- No change or a fairly steady moisture level in any layer represents consistent water movement just by the soil itself
- While soil moisture is fairly steady below 30", biggest changes are observed in shallow depths. It is estimated that average maximum active root zone depth is 30"
