WASHINGTON — Almost afraid to say it out loud, lest they jinx their record, U.S. troops in Afghanistan achieved one small but important victory over the past year: They found and avoided more homemade bombs meant to kill and maim them than a year ago, thanks to a surge in training, equipment and intelligence.

Bomb-planters have picked up the pace during the summer months, planting improvised explosive devices, or IEDs, along roads or footpaths. But the explosives are no longer the leading cause of death and injury in Afghanistan.

In the first three months of this year, only 5 percent of the bombs planted across Afghanistan hit their mark, according to Lt. Gen. Michael Barbero, director of the Pentagon’s Joint IED Defeat Organization. That’s down from 10 to 12 percent over the same three-month period a year ago.

The new figures released to The Associated Press show a slow but steady decline, from a high of 368 deaths caused by IEDs in 2010 to 252 in 2011, according to the privately run Icasualties.org, which tracks war casualties. That decrease has happened even as the military has begun to withdraw its surge of 30,000 troops, scheduled to be complete by September this year. Troops are often more vulnerable as they withdraw from an area.

Officials concede that the rate of bombs that cause casualties has risen slightly from April through June, as NATO troops attacked Taliban-held areas in a return to heavy fighting with the summer months. But the year is on track to be lower still than each of the previous three years, with 77 deaths from IEDs so far out of 162 total troops killed, halfway through 2012, according to Icasualties.org.

Barbero credits the slow turnaround to three years of an increase in intelligence-gathering equipment such as towers and aircraft outfitted with an array of cameras and other detection technology that have given U.S. commanders an edge, enabling them to spot the bombers as they approach often-traveled routes or revealing the signs of freshly dug earth where the explosives have been buried.

They installed “towers and balloons that give you persistent stare” to spot the Taliban trying to bury a bomb or approach a base in a bomb-laden car at fast speed, Barbero said. “Every commander told us (they) love those, because they can see (the threat) and take action.”

Training is the second key factor — teaching the troops how to use devices such as a hand-held remote robot with a camera that they can throw over a wall, then wheel around, checking if the coast is clear and trying to see whether the area shows telltale signs of being mined with explosives. The IED organization focused last year especially on equipment to help foot patrols, because so many troops were losing limbs, Barbero said. They rushed hundreds of devices into the field that are like a window washer’s telescoping pole, repurposed with a hook on the end, to probe for hidden bombs on footpaths.

That welcome trend is tempered by the looming drawdown of troops from Afghanistan by 2014, which will spell tough choices for commanders trying to balance keeping enough combat troops on the ground to challenge the Taliban with keeping enough intelligence support teams on the ground to keep combat troops safe. Then once the troops draw down, the small numbers of special operations forces and intelligence teams left behind will have to rely on smaller numbers still manning the sensors in the sky.

That reality is already being discussed by lawmakers on the congressional committees that oversee intelligence matters and the armed services.

“We may seek to offset the drawdown by boosting intelligence assets,” said Rep. Adam Schiff, D-Calif., a member of the House Intelligence Committee.

Even with those assets, the troops face another headache Barbero has not been able to solve: Explosives manufactured in the tribal areas of neighboring Pakistan still pour across the border. Pakistani officials say only a fraction of 1 percent of Pakistan-made fertilizer gets turned into bombs used in Afghanistan. Barbero counters that 86 percent of IEDs in Afghanistan are made from ammonium nitrate from fertilizer made in Pakistan. In frequents trips to visit Pakistani officials, he requests that they find a way to change the fertilizer’s composition to make it hard to turn into explosives.

He’s made the same plea to the international fertilizer industry, telling a conference in Qatar this year to join in a global campaign to dye the ammonium nitrate to help track it, and to develop “a non-detonable formula.” In two years of pleading with the industry for a solution, no one has come up with one yet.