Chinese officials, urged on by alarmed scientists, have called for massive tree-planting efforts throughout the country to halt what they say is the threat of much of the country becoming a desert.

Many scientists here blame what they see as a major ecological crisis on the government's effort in past years to feed the mushrooming population by clearing all possible land for grain. Some suggest the only solution may be to grow less grain, a potentially disastrous action given the population's steady growth toward 1 billion people.

Liu Houpei of the Chinese Academy of Science said in the People's Daily that steep slopes in Kiangsi and Sichuan provinces have been cleared and planted so that all the soil has washed away. He said such action "reflects the total lack of scientific knowledge of many officials. Some directing agriculture know nothing about it."

Over several centuries of farming in the Yellow River basin of northern China, where Chinese civilization began, much of the soil has flowed away. The Yellow River is now heavily laden with silt, making irrigation and power generation difficult, and the northwestern Chinese desert has expanded.

Richer, more fertile lands to the south are watered by the Yangtze River, a much deeper, less muddy river. But Guangming Daily of Peking reported: "Some people are now worried that the Yangtze may turn into a second Yellow River. Such concern is not unwarranted."

According to Liu, a member of the Academy of Science's natural resourses survey committee, "the damage done by loss of soil through destruction of forests and reclamation of land for cultivation is even worse in the south than on the high plateaus of the Yellow River."

In the last several weeks much of the Chinese press had called for tree-planting activities to build a "great green wall" against the encroachment of more desert and infertile, alkaline land. But one foreign analyst here cautioned: "The great difficulty is that in this case, no matter how well they pursue the campaign, no one now will live to see any definite benefits. Such campaigns are often dropped with it is expedient."

A scientist in his thirties wrote in the People's Daily, with an editor's warning that the article was a personal opinion, of the need to specialize the economy and end the 30-year-old attempt to make the country self-sufficient in grain. He said priority should be given to improving transportation, then to reforesting and getting more food through livestock raising and fishing. "For the time being, the production of food grain could be reduced," he said, a suggestion the editors of People's Daily apparently feel uncomfortable with.

The widespread publicity about China's ecological crisis reflects new candor allowed in the official press. Chinese leaders appear to hope it will help underline the gravity of the problems and thus encourage more efforts among peasants to tree planting.

"They will also have to resolve to stop cutting so much," one analyst said. This is difficult in a country where fuel and wood is often scarce. The demand for furniture is skyrocketing among children of the 1950s and 1960s baby boom who are now trying to start families. A survey team from the China Forestry Association reported that forests in the southwest visited in October had been denuded. If the cutting continued at the current rate, they said, there would be no forests at all in the area in 30 years.

Another scientist from the academy, Zhang Tianceng, said severe erosion caused by "deterioration of the soil and the destruction of forests" had affected "more than one-tenth of the whole territory of China." In the upper and middle reaches of the Yangtze, he said, "the amount of soil carried by water has doubled since 1958." Another People's Daily article in December, however, outlined in unusual candor the still overriding need to increase farm production, saying that "in certain regions in the northwest and southwest, the peasants do not have enough to eat."