Saudi Arabia

Operational Implementation Plans

1. Crop identification and acreage estimation:

The Water Productivity Mapping (WPM) project was initiated on 1st January 2012 in Haradh farm of NADEC and Todhia arable  of Al-Kharj region to fulfill the
following objectives:

  1. To develop and evaluate maps of crop types, cropping intensity and crop productivity.
  2. To evaluate energy balance algorithms for mapping daily and seasonal crop water use at field, landscape and regional scales.
  3. To develop and evaluate water productivity maps of major (irrigated) crops of the region over space and time.
  4. To study accuracies and errors involved in WPM across scales, radiometry and bandwidth.

Ground truth data on crop biophysical parameters such leaf area index (LAI), NDVI and canopy temperature are being recorded for major crops (wheat, alfalfa, Rhodes grass, corn and potato) grown in these farms.

  • Normalized Difference Vegetation Index (NDVI): NDVI(G) is measured in the field on the dates of satellite pass, using the Crop Circle (Model: ACS-470) of Holland Scientific, USA. It was calibrated by configuring with a 670-nm filter in channel 1, an NIR filter in channel 2 and a 550-nm filter in channel 3 of the sensor socket for measuring NDVI(G). Map mode measurement with two samples per second was used for field data collection. To determine field data coordinates, an Omnistar GPS receiver (Model 9200-G2) is connected to the Crop Circle at a baud rate of 9600.  Field data measurements were recorded by the crop circle at 1m above the canopy.
  • Leaf area index (LAI): LAI measurements on the ground (LAI (G)) are made on the dates of satellite pass using the Plant Canopy Analyzer (Model: PCA –2200) of Licor Biosciences, USA. At each measurement location, one above canopy and five below canopy readings are recorded to compute a single LAI value. Above and below canopy measurements are made with a ‘‘fisheye’’ optical sensor with 148º angle of view. Respective geo-locations were collected using a handheld Trimble GPS receiver (Model-Geo XH 600). An azimuth mask of 180º view cap is used on PCA-2200 sensor during data collection to block the bright sky for eliminating the shadowing effect of instrument operator.
  • Crop canopy temperature (ºC): Canopy temperature measurements are made using a hand-held infrared thermometer of Spectrum Technologies, Plainfield, IL, USA. The mean of three measurements is recorded at the centre of the plot and approximately 0.5 m above the canopy with a 30 angle of view, detecting radiation in the 8–14 µm wave bands. Measurements are made between 12:00 to 16:00 hours on cloudless, bright days.
  • Growth and Yield parameters: The data on crop height and yield parameters are recorded at the time of harvest, on five randomly selected plants.


The WPM methods and protocols using remote senisng data consist of : (1) crop productivity (t/ha) maps (CPMs) involving crop type classification, crop yield
and biophysical modelling and extrapolating yields models to larger areas using remotely sensed data; (2) Actual seasonal evapotranspiration or actual ET
(WUMs) developed through SABEL / SSEB model; and (3) water productivity (kg/m3) maps (WPMs) produced by dividing raster layers of CPMs by WUMs.

  • Acquired ASTER images are subjected to radio-metric (Top of Atmosphere) correction using radiative transfer model.
  • Crop biophysical variables such as NDVI, SAVI, CWSI and ET will be assessed using ASTER images. 
  • Crop type mapping based on Spectral Mixing Analysis (SMA) and/or CART algorithms
  • ET/actual crop water use mapping using SEBAL  model.
  • Accuracy assessment will be carried out using ResourceSat-2 and World View 2 data and ground truthing.
  • Extrapolation/ up scaling of obtained to dominant agriculture areas of Saudi Arabia using MODIS.  

2.  Crop biophysical variables:

  • LAI, NDVI, CWSI, chlorophyll and nitrogen indices are computed based on field measured hyperspectral reflectance data collected by using Field Spectro radiometer (ASD Field Spec 3).

3.  Other:

  • Laboratory analysis of plant samples to determine the total nitrogen content. The current project phase is research or operational pilot (select one or both). Research as well as operational pilot project
©2015 Joint Experiment for Crop Assessment and Monitoring