China has stood by its view that 2009 was a bumper year for crops, despite concerns raised by Washington staff that harvest data has been inflated by misreporting by provincial authorities.
Ye Zhengqin, head of the planting administration department at China's Ministry of Agriculture, said that food supplies reached a new high this year despite weather setbacks, including drought and frost, noted by many analysts.
"Only part of China's crop suffered from the drought and most of the unaffected crop was very good and achieved bumper harvests," Mr Ye told a press conference.
Apart from in the north eastern provinces of Inner Mongolia, Jilin, Liaoning and Shanxi, where crops declined "slightly", provinces "all saw an increase".
A 2.3m-hectare increase in sowings, and a "scientific" approach to tackling rain shortfalls, had also underpinned yields, he added.
China, the world's biggest wheat-producing country and rice grower, is making huge investments in canals, pipelines and aqueducts to transfer water from wetter southern regions to drier areas in the north.
It also employs cloud-seeding, firing rockets containing silver iodide into the sky to encourage the formation of rain droplets.
Mr Ye's comments follow a warning from US Department of Agriculture attaches in Beijing last week that a subsidy system, which pays out according to rates of crop production, may be encouraging regional officials to exaggerate harvest data.
"To gain more allocation of financial aid from the central government... provincial government authorities are occasionally tempted to overstate their grain output in a given year even if the crop was impacted by adverse weather," a report from the attaches said.
While Chinese government agencies had reported "a bumper corn harvest for the sixth consecutive year", the attaches said corn output had come in at 150m tonnes, 9% down on the 2008 crop and well below Beijing estimates.
Mr Ye added that China's plantings of winter wheat for the 2010 harvest stood at 22.5m, about 187,000 hectares higher than a year before.