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Production
Estimates and Crop Assessment Division |
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Production
Estimates and Crop Assessment Division |
October 20, 2003
A combination of spring drought on the North China Plain and excessive rainfall in central China had a negative effect on this year's wheat crop. China’s 2002/03 wheat production is estimated at 94.0 million tons (winter wheat, 87.0 million; spring wheat 7.0 million), down 2 million or 2 percent from last month but equal to last year. The estimated yield of 3.76 tons per hectare is similar to last year's drought-reduced crop and below the 5-year average. Total wheat area is estimated at 25.0 million hectares, unchanged from last month but down slightly from last year, based on data from an area survey conducted this spring by China's National Bureau of Statistics. Winter wheat area has been declining since 1998 for several reasons, including low prices, water shortages and increasing irrigation costs, and shifts to winter rapeseed, cotton, or cash crops. Spring wheat area is also expected to drop again this year in response to low prices and poor demand, but the weather has been generally favorable and production is expected to increase in 2002/03.
Winter wheat production is concentrated on the North China Plain and the Sichuan Basin, while spring wheat is grown primarily in Heilongjiang and Inner Mongolia. Both crops are produced in Gansu, and Xinjiang provinces in western China. (Map).
It was drier than normal during the 2002/03 winter wheat planting season (September - October 2001), but widespread precipitation in December provided adequate moisture for emergence before the crop went into dormancy. The weather was unusually warm and dry from January through March 2002 and the crop broke dormancy several weeks earlier than normal. Growing conditions in March varied sharply by region. The southern part of the North China Plain (southern Henan, Anhui, and Jiangsu) had timely rainfall and mild temperatures, benefiting vegetative winter wheat. In the Yangtze River Basin (Hunan, Hubei, and Jiangxi), abnormally warm and wet weather encouraged rapid vegetative growth but set the stage for above-normal pest and disease problems, according to reports from the Ministry of Agriculture and local sources. Meanwhile, persistently warm and dry weather in the Yellow River Basin led to warnings that a spring drought could strike the region for the third consecutive year. Soil moisture was seriously depleted and non-irrigated winter wheat suffered from stress, especially in Hebei and Shandong provinces. Despite the mixed weather conditions, AVHRR satellite imagery (April 21, 2002) and vegetation indices derived from imagery (see below) indicated that the crop was growing well as it approached the heading/flowering stage in mid-April. There was no visible sign of drought, a common occurrence in northern China during the spring, and crop development appeared to be ahead of schedule.
The situation changed dramatically in mid-April, as a series of cold fronts brought 30 days of widespread rainfall and much colder temperatures to eastern Chinas. The heaviest rainfall occurred in the Yangtze Basin, where the rapeseed and winter wheat crops reportedly suffered from excessive wetness, cold temperatures, and lack of sunshine. In the southern plains, heavy rain and below-normal temperatures likely slowed wheat development and lowered grain quality. However, the rain was very welcome in the north, where it replenished soil moisture and brought total seasonal rainfall close to normal. Local government officials in Shandong, Henan, and Hebei provinces reported that freezing temperatures in late April caused widespread frost damage to winter wheat in the flowering stage, but the extent of the possible damage could not be determined.
Much drier and warmer weather returned to eastern China after mid-May. Conditions were nearly ideal for the maturing winter wheat crop, especially in the soggy Yangtze Basin and southern plains. However, the drier weather came too late to help the waterlogged winter rapeseed and barley crops, which were already being harvested by the middle of the month. In the Yellow River Basin, very hot temperatures (95 to 101 F.) and extremely low soil moisture may have created additional stress for rain-fed crops which had already suffered from drought earlier in the season. In general, however, farmers welcomed the dry weather because it will allow fieldwork to proceed quickly, reduce post-harvest losses from mold and sprouting, and increase the protein content of the grain.
The wheat harvest is now in full swing across the North China Plain and should be complete by the end of the month. On June 9, moderate to heavy rain (1-2 inches) covered the North China Plain and Northeast China. The rain will delay harvest progress for a short time but should have little impact on yield or crop quality unless it continues for several more days. On the other hand, the rainfall will vastly improve growing conditions for vegetative spring crops and boost soil moisture for summer crop planting, which begins immediately after the winter wheat harvest.
China's spring wheat crop is grown primarily in western China (Xinjiang and Gansu) and the Northeast (Heilongjiang and Inner Mongolia). In the 1990's, spring wheat production ranged from 10 to 14 million tons, but production dropped significantly after 1999 due to lower planted area and drought-reduced yields. Planting for the 2002/03 crop took place in April under mixed conditions. The weather was unfavorably cool and wet for planting in northern Xinjiang this spring. According to local officials, emergence was poor in some areas and some crops had to be replanted. In the Northeast, planting was initially hampered by very low soil moisture, but timely rainfall in March and April provided adequate moisture for germination. The weather turned increasingly warm and dry in May and early June, stressing the vegetative crop in the southern part of the region, but recent rainfall and cooler temperature have improved the growing conditions. Given normal weather during the summer, spring wheat production in 2002/03 is expected to increase by 10 percent over last year's drought-stressed crop. Spring wheat reached the heading/flowering stage in July and the crop is harvested in August and September.
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