own in the Wheat Corn Rice 
Image Date Ground Image Date Ground Measurement Image Date Ground 
Measurement Date Measurement Date 
Date 
liy Treigation 2010/09/06 2010/09/08 2010/11/02 2010/11/02 2010/12/27 2010/12/21 
tralia (Figure 2010/09/22 2010/09/27 2010/11/18 2010/11/18 2011/01/05 2011/01/10 
tralia's most 2010/10/24 2010/10/22 2010/12/04 2010/12/04 2011/01/28 2011/01/20 
65% of total 2010/11/02 2010/11/05 2010/12/27 2010/12/27 2011/02/06 2011/02/09 
NCID, 2005) 2010/11/18 2010/11/18 2011/01/05 2011/01/05 2011/03/01 2011/02/28 
e, bes 2010/12/04 2010/12/06 2011/01/28 2011/01/28 2011/03/26 2011/03/17 
ER 2011/02/06 2011/02/06 2011/04/02 2011/04/04 
pproximately 2011/03/01 2011/03/01 
ce water is 
gee River at Table 1: Landsat 5 TM image acquisition dates and ground measurement dates of wheat corn and rice crops in CIA 
ipitation and 
d 1677 mm 2.1 Reflectance measurements 
Sensor Name 467 485 550 560 650 [660 830 855 [1240 1640 1650 
ta for NDVI 
rémentsamere Centre wavelength (nm) |467.5 4905 [550.3 5612 [652 [662 832.7 [8555 [12407 [16416 [1669 
- and winter Half Peak Bandwith (nm) [8.5 66 8.9 718 Ha 3 1456 [96 [103 14.9 195 
matey Pass Band (nm) (range) [463-472 [458-524 |546-555 525-597 [646-658 [633-691 [760-906 [851-860 [1236-1246 [1634-1649 [1572-176 
nt ataeesr Transmission 46 78 57 89 55 89 77 57 53 52 84 
rable weather Satellite Equivalent |MODIS Band |Landsat 5 |MODIS Band |Landsat 7 |MODIS |Landsat 7 |Landsat 5 |MODIS |MODIS |MODIS |Landsat 7 & Landsat 5 
free satellite 3 Band 12 Band8 |Band! |band3  |Band4 |Band2 |Band5 |Band6 |Band$ 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
(Table 1). 
Table 2: Filters fitted to the CROPSCAN MSR 
Reflectance is measured using a hand-held Multi- 
Spectral Radiometer (MSR) (CROPSCAN, 1995). This 
instrument is fitted with 11 filters. The filter bandwidths 
are similar to selected MODIS and Landsat 5 TM and NDVI — Pa-Puis (1) 
Landsat 7 ETM+ bands (Table 2). Field surveys were PRTPNIR 
conducted to capture spectral signatures for three 
irrigated crops in the study area. These surveys were 
planned to acquire crop reflectance data using MSR and 
collected data was checked and cleaned for bad readings 
2.2 LAI measurements 
LAI-2000 Plant Canopy Analyser was used to collect 
LAI measurements in different paddocks of three crops 
in the CIA. LAI-2000 measures the diffuse sun light at 
five zenith angle ranges with midpoints of 7°, 23°, 38°, 
53° and 67° simultaneously. By taking measurements at 
above and below the canopy of vegetation, the 
attenuation can be obtained and it can be used to obtain 
the amount of foliage (LAI). Normally a number of 
below canopy readings is obtained to increase the 
In row crops, satellite values will include crop and soil 
reflectance. In this study, for row crops such as corn, 
three scans per GPS point were made and taken the 
average values. The three scans were taken, one scan 
directly above the plant, another one half plant half inter- 
row space and the third directly above the inter-row 
space. This way sampling bias is removed and a more 
  
  
  
P accurate representation of the reflectance was gathered. accuracy of LAL 
y 
; : 
= MSR measurements were taken along two parallel hr this study Ae LA meas e se vas vn Ia 
transects (>30m apart), at 50 sample GPS points in the GVCICdSt Coneitions witd a, siligle sensor modeand a 
N com field with a 30m interval between consecutive Sequericesof, onc above and four below. Mostif ihe 
sample points. Similarly, reflectance was measured in measurements were taken usine à 25 view cap at dusk 
Wheat farms with 15 sample points along a single or dawn or the sensor was covered if the measurements 
transect. A 30m gap distance was maintained in both Wem à gkem under direc Sunlight fo avald‘ possible 
farms, to avoid mixed vegetation class effect on spectral reflections of Ihe sun +0 avold EironcouS results. TAI 
data of the Landsat 5 TM satellite images (30m spatial measurements also taken as the same way Bs MSR 
-— ) resolution). The coordinates of all the sample points were Douche ent taken Qu (hic samo MR ssumple poitits in 
collected using a hand held GPS in GIS file format the corresponding corn, rice and wheat farms .In addition 
during the field work crop heights were also taken at same sample points on 
; corresponding dates. The programme FV 2000 was used 
Ground based NDVI (NDVI) was calculated from the to download the collected LAI-2000 data files and to 
\ combination of red (band 6, central wave length 662 nm) analyse them, The programme was fur her ü Sed to 
and near infra-red (band7, central wave length 832.7 nm) recompute the downloaded data by eliminating bad 
reflectance values of MSR using equation 1. readings, changing rings and canopy models.