September 20, 2001

Western Australian Wheat Fares Better Than Expected 

Summary

Persistent dry early-winter conditions this season in two of Australia's wheat producing states, Queensland and Western Australia,  severely affected wheat production potential.  However, improved rainfall since mid-July has improved prospects.  Satellite data of the region reveals good winter crop conditions, with overall plant health similar to 1999 (a year characterized by above-average growing conditions).  Western Australia's northern area may be less affected by below-normal precipitation than previously anticipated.  

(Go to Data and Graphics supporting this crop condition assessment)

Late Rains May Salvage Crop Prospects

Sparse rains during planting and continued dryness until early July gave a pessimistic outlook for western Australia's winter grain season. Data from multiple weather stations in the Western Australia wheat belt show below-normal rainfall for mid-April through late-July, resulting in reduced area and yield expectations.  However, some drought-affected areas of Western Australia are faring better than expected, as near-normal rainfall since the end of July has prompted some recovery in crop prospects.   Recent satellite data confirms an improvement in crop conditions.  

Different Conditions, but Similar Plant Health in 1999

The 1999 growing season benefited from widespread positive growing conditions that resulted in above-average yields.  Conversely, 2001 experienced an unusually dry start, with conditions improving in August.  Comparing rainfall data from 1999 and 2001 shows significantly greater accumulation in 1999, particularly during the early portion of the season.  However, analysis isolating only wheat producing areas reveals similar plant health as of mid-September. 

Imagery Analysis of Worst Drought Area

Local area analysis focused on growing areas identified by Australia Bureau of Meteorology as being the driest this season, including those portions of western Australia's wheat belt experiencing as little as 50 percent of normal rainfall in August.  The remaining portion of Australia's wheat belt had higher rainfall percentages, with the notable exception of Queensland. 

Two types of satellite data were used to analyze Western Australia's mid-season conditions.  First, NOAA-AVHRR data provided information covering all of Western Australia's growing area.  The NOAA data shows relatively healthy vegetation as of September 15, 2001, as compared to the same period for 1999.  Landsat TM satellite data was used to follow up and examine specific local conditions.  

Location of:: Landsat TM  113 080 scene  (click to view image, and  sites referenced below)

This Landsat image indicates that much of the wheat area is having a favorable year, with similar vegetation health as during mid-August 1999.  It appears that areas doing poorly are the more marginal eastern areas (site 4).  However, other areas show similar planted area and vegetation health in this historically productive wheat area (sites 1, 2, 3).  

Data Sources for this Report:
Australia Bureau of Resource Economics (ABARE)
FAS- PECAD analysis and mapping of meteorological data
FAS  PECAD analysis and mapping of remote sensing data and GIS products
World Meteorological Organization – Weather Station Observations
US Air force Computer Simulated Weather Data
UN FAO GIEWS SPOT Vegetation Products

For more information, contact Jim Crutchfield  
with the Production Estimates and Crop Assessment Division, Center for Remote Sensing Analysis at (202) 690-0135.