Chinese in many parts of the country have found their grain rations cut in the wake of reported miscalculations of last year's harvest and a still widening threat from this year's drought.

Travelers from China and reports in a Hong Kong Chinese-language newspaper with links to Peking say some areas exaggerated their grain production reports and have been left with insufficient reserves, a problem that particularly plagued China after disastrous Great Leap forward campaign of the late 1950s.

In some areas, travelers said, individual grain rations of as low as 15 pounds a month have been reduced by another 1.3 pounds, at a time when millions have been aksed to work strenuously to fight the drought.

Official reports of water shortages, previously noted in seven provinces of both northern and southern China, have now spread to the provinces of Szechwan, perhaps the country's leading grain producer, and Anhwei. A front-page commentary in the official People's Daily yesterday said factories, offices schools and army units should release their personnel immediately to join bucket bridges in the fields.

Economists, grain leaders and other analysts remain uncertain about the actual severity of the drought and its possible longterm impact, despite the official Chinese statement that it is the worst in at least 27 years. Some agricultural experts say rainfall statistics for some announced drought areas are not too far below usual levels up to February. They add that the amount of water reaching the northern wheat crop in the next few weeks will be crucial as the seeds that were dormat over the winter enter the period of most rapid growth.

Travelers say that in some rice-growing areas stocks are so low that newly harvested grain is being eaten rather than being stored as usual.

They report shortages of some meats, and a 20 per cent reduction in pork rations for Kwangtung Province, which surrounds this British territory.

Some analysts - and Peking-linked newspapers here - say that with the worst of last year's political troubles over and with the substantial improvements in irrigation, the Chinese should be able to pull off a good harvest through the labors of the millions enlisted in the drought work.

Western analysts have been engaged in a vigorous debate over the actual size of recent Chinese earlier Chinese reports of healthy Shaded provinces are reported to be having problems with their food supply, suggested the crop could not have been significantly above the approximately 280 million tons reported in 1975.

After Mao Tse-Tung's widow and other Peking dogmatists were purged last October, the new administration of Hua Kuo-feng began to take a more pessimistic view.

It blamed Chiang and her "gang of four" for trying to unseat local party administrators and for crippling decision-making so much that production dropped severely in at least six provinces.

The New Evening Post, a Communist-backed daily here, has reported a "tense situation" with regard to food supply in the provinces of Chekiang, Kiangsi, Fukien, Szechwan, Yunnan and Kweichow, nearly all areas that reported severe factional strife last year.

One factor leading to the food shortage, the newspaper said, was the possibility that "some exaggerated the actual statistics. Production was creased their figures . . . Thus the state took its share of the grain according to that exaggerated figure. It looked like there was enough left for the people to eat, but in reality there was not."

Some of the economic difficulties may arise from problems with the once faction-ridden railroads.

Hong Kong recently experienced a sudden drop in the supply of eggs coming from China, but then received several boxcars of eggs at once, suggesting that produce is experiencing transportation bottlenecks.

The New Evening Post said the present situation was much better than the aftermath of the Great Leap Forward, more than 15 years ago. This year, it said, the Chinese do not have to contend with the sudden withdrawal of Sovietaide that helped cripple them in the early 1960s.