Afghanistan has banned the use of ammonium nitrate fertilizer. The reason is that this fertilizer, mixed with the right amount of fuel oil, can be detonated as an explosive. Some 90 percent of the roadside bombs use ammonium nitrate. Farmers have 30 days to sell their ammonium nitrate to the government, or have it seized without compensation. The government has, for years, been urging farmers to stop, for environmental reasons, using ammonium nitrate. But farmers don't like urea based fertilizers, which are now the only kind they can legally use.
The terrorists can still smuggle ammonium nitrate in from Pakistan, but the government can probably make it difficult to sneak ammonium nitrate in via truck. Bringing the fertilizer in over the mountain trails, on mules is more expensive. But the Taliban can afford to pay, because of their links to the drug gangs. Both groups want foreign troops out of the country, so heroin can be produced and smuggled without interference.
In Afghanistan, IEDs (Improvised Explosive Device, a roadside, or suicide car bomb) now cause over 70 percent of NATO casualties. It has also been discovered that there was one big difference between the IEDs in Iraq and Afghanistan; the explosives used. In Iraq, there were thousands of tons of munitions and explosives scattered around the country after the 2003 invasion was over. This was the legacy of Saddam Hussein, and the billions he spent on weapons during his three decades in power. The Iraqi terrorists grabbed a lot of these munitions, and used them for a five year bombing campaign.
With no such abundance of leftover munitions, the Taliban had to fall back on a common local explosive; ammonium nitrate. This is a powdered fertilizer that, when mixed with diesel or fuel oil, can be exploded with a detonator. While only about 40 percent the power of the same weight of TNT, these fertilizer bombs are effective as roadside bombs. But they are bulkier and a slurry. Moreover, the fuel oil must be mixed thoroughly and in exactly the right proportion, otherwise the explosive effect is much less than expected. But the biggest problem is that if you can't get the ammonium nitrate, you have no explosives.
For the past year, U.S. and NATO forces have been searching for ammonium nitrate. Even the supplies held by farmers were being taken. But the troops were paying twice what the farmers paid for it. Thus many farmers are voluntarily turning their ammonium nitrate (usually in 50 kg/110 pound bags) in for the instant profit. Other, non-explosive, fertilizers were made available to the farmers, at equivalent cost to ammonium nitrate. Imports of ammonium nitrate into Afghanistan were being monitored, but the Taliban either paid high prices for the stuff, or just stole it. All this didn't make it impossible for the terrorists to get the fertilizer, but just more difficult. This effort resulted in fewer, and less powerful, bombs. The ban on ammonium nitrate will make it even more difficult to build the bombs.