July 19, 2000

WHEAT ESTIMATES REVISED FOR RUSSIA AND UKRAINE

The USDA has increased its estimate of 2000/01 Russia wheat production from 33.0 to 34.0 million tons, up from 31.0 million last year, and reduced the Ukraine estimate from 13.0 to 12.0 million, down from 13.5 million last year. The revisions are based on generally favorable weather throughout June in European Russia, and the persistent dryness in southern Ukraine. Comparison of output from the CERES (Ritchie) yield-simulation model for June 30, 1999 and June 30, 2000 shows the impact of drought in southern Ukraine and Moldova and the substantial year-to-year improvement in crop conditions in the Volga Valley and Central Black Earth region. AVHRR satellite imagery from May is largely consistent with the results of the yield models, and reflects the overall year-to-year decline in crop conditions throughout Ukraine.

Total 2000/01 grain production for Russia is estimated by the USDA at 61.7 million tons, including roughly 1.5 million tons of pulses and miscellaneous grains, up from 54.8 million last year. Conditions have been good in most production regions, but significant planting delays will likely have a negative impact on spring-grain yield potential and will increase the risk that a larger-than-usual portion of the crop will remain in the field in the event of unfavorable harvest weather. Ukraine output is estimated at 23.0 million tons, against 24.4 million last year.

A note on yield-model and vegetative-index interpretation: The yield-simulation models used by PECAD provide an semi-quantitative indicator of the location and relative severity of weather-related stress. The models estimate the impact of weather events only, and assume adequate soil fertility and proper pest management. Non-weather factors, such as reduced fertilizer application and yield loss attributed to harvest delays, must be examined separately. The normalized difference vegetation index (NDVI), derived from the AVHRR satellite imagery, is a widely-used indicator of crop conditions and yield potential. The NDVI offers an advantage over weather-based models, in that it integrates the impacts of both weather conditions and crop management. In May, winter wheat typically is advancing through reproductive stage in southern Russia and most of Ukraine; this is when the vegetative index reaches its peak and imagery provides the best indicator of yield potential in the prime winter-wheat zone.

For more information, contact Mark Lindeman with the Production Estimates and Crop Assessment Division on (202) 720-0888.