using weather stations to improve irrigation scheduling

Using Weather Stations to Improve Irrigation Scheduling

SMART WIRELESS SOLUTION

Ali Mah’d Al ShroufAbu Dhabi Food Control Authority

UAEAli.Alshrouf@adfca.ae

Agriculture, Climate & Water

WHY WEATHER STATIONS?

To get real-time micro-climatic information To compute Evapotranspiration To use the same data for disease models To monitor soil moisture To correlate irrigation with ETo, soil moisture, soil

salinity, precipitatin, ground water level, etc. -TO UNDERSTAND WHAT‘S GOING ON -

AND TAKE BETTER IRRIGATION DECISIONS!

Disease Solutions

• provides the grower with advice via computer regarding the optimum moment at which to use fungicides and which type of fungicide to use.

Irrigation Solution

• The right volume at the right moment.

determine the optimum time for irrigation.

• This prevents both damage due to draught stress and excessive watering.

Insect Solution

provides a grower with advice via his computer regarding the insect's current development stage. This allows the correct moment and the correct type of insecticide to be determined.

Fertilizer Solution

• Advises how much and at which point to apply fertilizer.

ADFCA AGRI-METROLOGICAL STATION

Objectives: effectiveness evaluation for using the automatic weather station in Irrigation calculation

Weather Stations for Irrigation Improvements

What is todays most important rule for irrigators?– THE RULE OF THUMB

Why do farmers irrigate the way they irrigate? „because it looks dry“ „because that‘s how I always did it“ „because it feels right“

irrigation decision is pure guesswork

Precision Irrigation

Irrigation Improvements– Just about all farmers over-irrigate - with rather detrimental

consequences:• Wash out of nutrients = increased need of fertilizers• Too much water in the soil > too little oxygen! This

– largely affects the plants „metabolism“, reduces growth,– harms micro-organisms, reduces yield.

• Pollution of ground- and surface water (nitrates!!)• Unnecessary wear and maintenance of equipment• Waste of energy (electricity, fuel) to run the pumps

Temporary slow downof daily crop water use and

growth caused by over irrigation.

Irrigation

Irrigation

3 days

45 m

m

10 days80

mm

15 mm/day

8 mm/day

Precision Irrigation

Irrigation ImprovementsSome farmers under-irrigate - with consequences as fatal:– The plant suffers excessive dry stress = reduced yield, lesser

quality crops– Water and fertilizers do not reach the active root zone =

reduced yields, lesser quality crops– Water and fertilizers that do NOT reach the active

• rootzone are 100% lost for this crop! And so is the• energy invested for their application!

An Automatic Weather station - Sensor Requirements

• at least the sensors required by the ETo Formula according to Penman-Monteith is needed.

A Weather Station‘s Sensors

• Data collection - the Sensors (evaluation criteria)– Sufficient Accuracy– Robust– Operate in wide temperature range– Low Power Consumption– Little drift over time– Simple Installation, low maintenance

Data Collection: GPRS

InternetMeasure once per minute, transmit averages every 15

minutes

GSM Provider

Weather Stations for Irrigation Improvements

• Which quality / accuracy is required?– Sufficient accuracy for the task!– Low Drift at least within the first five years– Low maintenance requirements– Remote Configuration– Low Power Consumption

Local Quality Control and Assurance

Water - the resource of the future

• Monitoring needs in the cycle of water– Precipitation– Quantity and quality of irrigation water– Irrigating• Evapotranspiration• Soil moisture (at various levels)• Wind speed and direction

QA/QC Checks

Range – within a reasonable range

Step – maximum allowable change

Persistence – minimum allowable change

Like Sensor – similar value to similar sensors

Spatial – similar value to neighboring stations (parameter dependent)

Range Checks

Three range checks1. Valid2. Suspect3. Invalid

If the data falls within the inner range then it will be marked Valid If it falls in between the outer range and the inner range it will be marked Suspect

If data falls outside the outer range it will be marked as Invalid If the data is missing it will be marked Missing and then filled

InvalidSuspect

Valid

Hourly Parameter of Interest

InvalidSuspect

Valid

Hourly Parameter of Interest

Range Checks: Solar Radiation

-0 950

Invalid

Suspect

Valid

Hourly Solar Radiation (W m-2)

• Use wave function to define when day light occurs: Daylight = f(latitude, Julian day)

Persistence Check

valid

valid

susp.susp. susp.

valid

Difference of Maximum and Minimum over n steps must begreater than y

23

Step

valid

valid

susp.

valid validvalid

Difference of maximum and minimum over n steps must be at most y

Automated Q/C

–Upper and lower limit checks on sensor data–Rate of change between consecutive readings

– Every morning, data graphically reviewed–Geographically similar stations grouped– All weather parameters reviewed– Bad data estimated or deleted–Dependent computations (ET) recomputed

25

Other Tests

• Like Sensors– Relating wind speed 2M to wind speed 10M– Relating occurrence of precipitation to humidity

• Nearest Neighbors

THANK YOU