Rippling in the spring breeze, amber wheat and lush green fields in this central Indian agricultural belt along the Tawa River end abruptly at the edge of a vast and harsh moonscape of barren land.

The black soil suddenly becomes spongy underfoot, devoid of any plant life and useless for cultivation because of waterlogging and salinity. Peasants, whose hardscrabble lives have been bound to the soil, dismiss the phenomenon as just another natural calamity. They move elsewhere or seek another livelihood.

But the barrenness is man-made, the result of costly dam and canal irrigation projects that have unwittingly transformed once productive farmland into vast "wet deserts."

Government environmentalists say that 15 million acres of Indian farmland worth $21 billion have been ruined because of waterlogging and salinity caused by poorly planned irrigation projects.

According to B.B. Vohra, chairman of the government's National Committee on Environmental Planning, another 25 million acres of the total 100 million acres under irrigation are threatened with damage by ill-conceived irrigation projects.

Worldwide, environmentalists say, as much agricultural land is lost each year to poorly designed irrigation as is gained through effective new ones.

"It is one of the greatest unrecognized environmental problems in the world today. We are systematically destroying our most valuable resource, and nobody is paying attention," Vohra said in an interview at his New Delhi office. Vohra is former secretary of the Agriculture Ministry.

The $360 million Tawa River dam and canal scheme, which was designed to irrigate nearly 60,000 acres of farmland, is a microcosm of the waterlogging problem that India faces, environmentalists say.

A "wet desert" estimated to cover nearly 3,000 acres has been created along the Tawa River, a tributary of the Narmada River, prompting the auditor general to warn that the project could cause more harm than good.

Irrigation Department officials in the Madhya Pradesh state capital of Bhopal, 50 miles north of here, said that the estimates of lost land had been exaggerated and that steps are being taken to reclaim damaged soil and prevent further waterlogging.

"Waterlogging is not going to be a problem of the future. We are taking steps to assure that it will not be a problem," said V.M. Chitole, chief engineer of the department.

The current problem, the environmentalists and irrigation officials agreed, stems from inadequate drainage and the construction of poorly designed and unlined canals. They leak, and the seepage waterlogs the fields with three times the water the crops require, while at the same time raising the underground water table to dangerously high levels.

Consequently, crop yields, which the West German-assisted irrigation project was to have increased tenfold, began plummeting when water was first released into the fields in 1975. Compounding the problem are deep trenches that were dug alongside the canals to provide soil for their embankments. The trenches fill with rising groundwater, which stagnates.

"The trouble is, when they decide to irrigate an area and they draw up plans for a dam and reservoirs and canals, they just don't think of proper drainage. If they did, the project would become financially unattractive, and engineers have to sell their projects," Vohra said.

Proper drainage, he said, involves redistributing millions of cubic yards of earth, leveling land, lengthening distribution channels and building dams in such a way that they do not accumulate silt and deteriorate, resulting in seepage.

The problem becomes more acute, Vohra said, in light of the fact that a third of the total available land in India is uncultivable and another third has been "environmentally degraded" in one way or another, leaving only a third to meet the agricultural needs of nearly 700 million people.

He called farmland waterlogging "the major problem for the environment today," and said he doubted that irrigation policies would be fundamentally changed unless a popular movement got under way.

Two years ago, there were riots in the southern Karnataka state as farmers who owned waterlogged land refused to pay taxes. In the Tawa River project, a group of farmers started a protest movement after project officials told them they would have to pay the equivalent of $13 an acre to pay for land-reclamation costs. The farmers refused to repay loans from the state.

State irrigation officials here and in Bhopal said that on the basis of criticism of the Tawa River project, proper drainage has been ordered as essential in all new irrigation plans. The improvements are to include lining canals with either polyurethane or cement.

Officials said they are stepping up reclamation of waterlogged farmland in Madhya Pradesh, including 80,000 acres that were ruined in the Chambal Valley north of here.

Improvement of irrigation planning has received some impetus from international agencies, including the World Bank and U.S. Agency for International Development, irrigation officials said. But environmentalists complain that "vested interests" in India--the bureaucracies of state irrigation departments--are bent on building more irrigation projects as cheaply as possible to provide work for themselves.

"This is why new projects are conceived years before existing schemes are anywhere near completion, and the pipeline of new schemes is always kept full," Vohra said.