Soil Moisture Monitoring Soil Moisture Monitoring for Irrigation Schedulingfor Irrigation Scheduling

T.E. Harms Irrigation ManagementT.E. Harms Irrigation ManagementAAF, Brooks AB.AAF, Brooks AB.

Soil Moisture Instrument Soil Moisture Instrument EvaluationEvaluation

4 year study that is still continuing 4 year study that is still continuing informally.informally.Criteria for Soil Moisture InstrumentsCriteria for Soil Moisture Instruments

Cost Effective (~$1000 Cost Effective (~$1000 CdnCdn))PortablePortableReasonable AccuracyReasonable AccuracyEasily Understood Visual DisplayEasily Understood Visual DisplayImmediate DisplayImmediate DisplayNo Special TrainingNo Special Training

COMPARISON OF VARIOUS MODES OF PROBE

INSTALLATION FOR PROFILING

Moisture•Point C Probe

PF-1

Single segment TDR and Capacitance Access Tube Probes

TDR and Capacitance Forks and Buried Type Probes, Gypsum Blocks

Neutron Probe for Access Tube, RF Sensor

Gravimetric Method

Soil Auger

Soil Moisture Instruments Soil Moisture Instruments Evaluated for Irrigation SchedulingEvaluated for Irrigation Scheduling

Pros and ConsPros and Cons

Pros and cons with all sensorsPros and cons with all sensorsCPN 503 DR is the standard but its storage, CPN 503 DR is the standard but its storage, use, certification is strictly regulated.use, certification is strictly regulated.Capacitance sensors are sensitive to soil Capacitance sensors are sensitive to soil salinity and change based on soil bulk salinity and change based on soil bulk density.density.Soil potential probes have limited range up to Soil potential probes have limited range up to ––200 200 cbarscbars..They all work and the choice depends on the They all work and the choice depends on the application desired.application desired.

RomComm Kelowna

Brooks

Soil Moisture Sensor, Pivot in Lethbridge, AB

10-May 20-May 30-May 9-Jun 19-Jun 21-Jul 31-Jul 10-Aug0

20

40

60

80

100

120Av

ailab

le W

ater

Con

tent

(%)

Date

Turn Pivot On

Turn Pivot Off

ZimmaticZimmatic’’ss New New GrowSmartGrowSmartTechnologyTechnology

Irrigation StrategiesIrrigation Strategies

0-15”

20”

30”

1 weekRoot zone full

Allowable depletion

Limited Adoption of Soil Moisture Limited Adoption of Soil Moisture Sensors for Irrigation SchedulingSensors for Irrigation SchedulingExpense is not worth the information provided.Expense is not worth the information provided.Too complicated Too complicated -- installation, learning curve for installation, learning curve for use, interpretation.use, interpretation.Effort is not worth the result.Effort is not worth the result.Point measurement in field.Point measurement in field.Time consuming.Time consuming.No local support.No local support.Interest and use primarily by consultants and Interest and use primarily by consultants and industry field personnel.industry field personnel.

ET Based Irrigation SchedulingET Based Irrigation Scheduling

Alberta Irrigation Management Model Alberta Irrigation Management Model (AIMM)(AIMM)

DesktopDesktop

Irrigation Management Climate Information Irrigation Management Climate Information Network (IMCIN)Network (IMCIN)

WebWeb--basedbased

AdvantagesAdvantages

Many irrigators are farming increased area and are Many irrigators are farming increased area and are not as not as ““intimateintimate”” with individual fields.with individual fields.Daily information regarding the soil moisture status Daily information regarding the soil moisture status of your fields.of your fields.Can prioritize time to concentrate on the fields Can prioritize time to concentrate on the fields requiring irrigation.requiring irrigation.Anticipate irrigation need rather than react to soil Anticipate irrigation need rather than react to soil moisture shortage or crop stress.moisture shortage or crop stress.Assists decision making for efficient and effective Assists decision making for efficient and effective irrigation scheduling.irrigation scheduling.

Information can be provided as:Information can be provided as:

Pull Pull –– require user to request information (How require user to request information (How most automated pivot systems work most automated pivot systems work –– how IMCIN how IMCIN works).works).Push Push –– deliver information to the user (Increasing in deliver information to the user (Increasing in use with consultants, producer groups use with consultants, producer groups –– most most attractive option for irrigators).attractive option for irrigators).Plug Plug –– allow user to maintain handsallow user to maintain hands--on contact with on contact with data source (AIMM data source (AIMM –– desktop application).desktop application).

((MagareyMagarey et al., 2002)et al., 2002)

Example of Graphical Output from Example of Graphical Output from AIMMAIMM

Example of Information from Example of Information from IMCIN WebsiteIMCIN Website

ConclusionsConclusions

Soil moisture sensors for irrigation scheduling Soil moisture sensors for irrigation scheduling ––limited adoption in Southern Alberta.limited adoption in Southern Alberta.Advanced features supplied by pivot manufacturers Advanced features supplied by pivot manufacturers for continuous soil moisture measurement and for continuous soil moisture measurement and information information –– no adoption that presenter aware of no adoption that presenter aware of in Southern Alberta.in Southern Alberta.ET based scheduling tools ET based scheduling tools –– estimated about 15% of estimated about 15% of irrigated area in Southern Alberta using AIMM for irrigated area in Southern Alberta using AIMM for irrigation scheduling.irrigation scheduling.IMCIN increasing in utility and use IMCIN increasing in utility and use –– developing developing disease forecasting and urban watering.disease forecasting and urban watering.