Officers said the crackdown reflected an awareness by top Army and Defense Department officials that desertions, which occurred among more than 1 percent of the active-duty force in 2000 for the first time since the post-Vietnam era, were in a sustained upswing again after ebbing in 2003, the first year of the Iraq war.

At the same time, the increase highlights a cycle long known to Army researchers: as the demand for soldiers increases during a war, desertions rise and the Army tends to lower enlistment standards, recruiting more people with questionable backgrounds who are far more likely to become deserters.

In the 2006 fiscal year, 3,196 soldiers deserted, the Army said, a figure that has been climbing since the 2004 fiscal year, when 2,357 soldiers absconded. In the first quarter of the current fiscal year, which began Oct. 1, 871 soldiers deserted, a rate that, if it stays on pace, would produce 3,484 desertions for the fiscal year, an 8 percent increase over 2006.

The Army said the desertion rate was within historical norms, and that the surge in prosecutions, which are at the discretion of unit commanders, was not a surprise given the impact that absent soldiers can have during wartime.

“The nation is at war, and the Army treats the offense of desertion more seriously,” Maj. Anne D. Edgecomb, an Army spokeswoman, said. “The Army’s leadership will take whatever measures they believe are appropriate if they see a continued upward trend in desertion, in order to maintain the health of the force.”

Army studies and interviews also suggest a link between the rising rate of desertions and the expanding use of moral waivers to recruit people with poor academic records and low-level criminal convictions. At least 1 in 10 deserters surveyed after returning to the Army from 2002 to mid-2004 required a waiver to enter the service, a report by the Army Research Institute found.

“We’re enlisting more dropouts, people with more law violations, lower test scores, more moral issues,” said a senior noncommissioned officer involved in Army personnel and recruiting. “We’re really scraping the bottom of the barrel trying to get people to join.” (Army officials agreed to discuss the issue on the condition that they not be quoted by name.)