HOLGARAH VALLEY, Afghanistan — The fighting in this fertile bowl flared as the harvest neared, and that was not a coincidence. From bountiful crops of cotton, corn and wheat would come a cut for local commanders. The more land the commanders controlled, the more crop they could claim. So in a place ostensibly at peace 20 months after the fall of the Taliban, they went to war.

Throughout early summer, men toting weapons roamed in pickup trucks. Gunshots echoed. Farmers watched powerlessly, wanting nothing more than to be free of the men who had once fought for their freedom.

Armed by two decades of war, unimpeded by a weak government, the warriors Afghans mustered to fight first the Soviets and then the Taliban are fighting one another for coarser causes these days — land, money, power.

Filling the vacuum left by skeletal state institutions, they outman and outgun the police, while collecting for themselves taxes that Afghan officials say the government could use to build a stronger police force.

As the United States prepares to increase its investment in Afghanistan in the hope of extending the central government's reach, the northern region where this valley sits shows how limited that reach is. The most tangible evidence of a state in many places is a picture of President Hamid Karzai.

"We are the representatives of the government, but we have nothing, and they have everything," the Sholgarah district police chief, Ridar Akbari, said of the militias. He estimated that 500 or more well-equipped commanders and soldiers have taken roost in the valley. To police its 118 villages, he has 48 police officers — earning between $15 and $30 a month — 10 Kalashnikovs, and a jeep.

"I cannot do anything when they fight," he said. It is the same across much of the country.

For Afghans, the power of these local chieftains means living with the constant threat of extortion, of forcible recruitment, fighting and the displacement of families, and the possibility of being denied access to land or water.

It also means living without a neutral state, since loyalties in the local and regional governments are divided. The governor is from one faction, the mayor from another, the police chief from a third.

Tense as the situation is, however, no one thinks it will erupt into civil war, if only because it is in no one's interest. "It is a fragile balance of power, but it is a balance of power," said Michele Lipner, the head of the Mazar-i-Sharif office of the United Nations Assistance Mission to Afghanistan.

While the national army has no presence here yet, the two main factions, Jamiat-e-Islami, led by Gen. Ostad Atta Muhammad, and Jumbesh, led by Gen. Abdul Rashid Dostum, both maintain their own military corps, partly paid for by the Ministry of Defense.

By the thousands, lower-level commanders — sometimes answerable only to whomever has most recently bought their loyalty — also are spread out across remote districts, where they compete for control.

"It's pretty ugly," said Mr. Karzai's chief of staff, Said Tayab Jawad. "How can you have a free election in a big city like Mazar, let alone a small village?"

That concern has prompted an influx of new resources. The Americans are building a new police training center in Mazar. Earlier this summer, a British team of about 70 soldiers and a few civilians arrived with plans to deploy in small groups across the five provinces.

That civilian-military team is one of four currently spread around the nation. The Bush administration is adding, with the participation of other countries, at least four more, in the hope that they can substitute for a large peacekeeping force. Mazar will be a key test case.

The team leader, Col. Dickie Davis, said he has tried to promote peace by verifying security agreements between the factions and shooting down rumors. "We provide ground truth," he said.

Working with Ms. Lipner's office, the team removed 25 top commanders from this valley in early August, bringing an instant, if tentative, calm. When the commanders sneaked , Colonel Davis led a patrol to escort them out again. This month, his team oversaw a local disarmament and arranged for the permanent removal of the eight most troublesome commanders.

Residents were pleased but skeptical that the peace would last.

Colonel Davis concedes his limits working in five provinces that are home to 5.5 million people. "All the soldiers of the Russian Army couldn't subdue this place, and here I am with 70 soldiers," he said. "They have to agree to stop fighting. We can't make them."

He believes, he said, that Generals Muhammad and Dostum truly see the political process as the way forward. But others see a dual reality: warlords wearing the suits of statesmen while dispatching soldiers to sully what were peaceful places. Always, there is a prize to be had.

In Kod Barq, a pretty, if run-down residential complex built by the Soviets on the edge of Mazar, the prize is the adjacent fertilizer factory. Residents say that commanders believe whoever loses control of the residential compound will cede their cut of the factory revenues as well, so soldiers barely out of their teens roam the shady streets.

Once controlled entirely by General Dostum, the compound is now divided between him and General Muhammad. Not long ago, the two sides almost had a shootout, residents say, when they both converged on the meeting hall where the nation's constitutional commission was holding a public meeting.

"These people living here, they are tired of fighting, tired of seeing these armed people," said Kamran, 49, an ice-cream vendor who uses one name. As he spoke, a soldier with a Kalashnikov approached to eavesdrop and buy a scoop. "We want peace," Mr. Kamran said.

In the Sholgarah Valley, the prize is osher — an Islamic tax given as a portion of a crop. This valley is rich enough that its crops are legal. Elsewhere, the prize is a piece of this year's bumper poppy crop and the opium trade, which in some cases is so empowering mid-level commanders that they are no longer accountable to their own factional leaders.

Before the Soviets invaded, people paid taxes to the government, farmers say. When the Islamic fighters battled the Soviets, people willingly gave the tax to commanders. That war is over. But commanders still take osher anyway.

"It should be for the government," said Abdul Sami, a farmer who reluctantly gives 10 percent of his yield to the local Jamiat commander, although admittedly the government does not have tax collectors.

Local young people no longer support the militias, Mr. Sami, 23, said, so the commanders and soldiers now come from outside. Sometimes commanders beat and harass villagers under the control of a rival. Sometimes a rival faction buys a commander, and the village he controls along with him.

The commanders and their soldiers are above the law, said Mr. Akbari, the police chief. When he tries to investigate soldiers for beating a villager who resists their extortion, their superiors tell him to stay out of military matters.

"I am ashamed in front of the people of the district that I couldn't bring peace and stability," Mr. Akbari said. He sometimes tells those with guns, "In the future, people will come to the police chief and complain you did something and I will imprison you."

In the present, they laugh at him.