The Senate Agriculture Committee, more used to dealing with farm subsidies than Wall Street, has drawn enormous interest from lobbyists and donors.

Timothy Geithner, center, Treasury secretary, with Senators Blanche Lincoln and Saxby Chambliss of the Agriculture Committee.

From The New York Times:

Assessing the battle to overhaul the nation’s financial regulations recently, Jamie Dimon, the chief executive of JPMorgan Chase, left no doubt about the consequences if Congress cracked down on his bank’s immense business in derivatives.

The forum for all this attention is not the usual banking and financial services committees, but rather the Senate Agriculture Committee, a group more accustomed to dealing with farm subsidies and national forest boundaries than with the more obscure corners of Wall Street.

A main weapon being wielded to fight the battle, of course, is money. Agriculture Committee members have received $22.8 million in this election cycle from people and organizations affiliated with financial, insurance and real estate companies — two and a half times what they received from agricultural donors, according to the Center for Responsive Politics.

Much of that lobbying has centered on Senator Blanche Lincoln, the Arkansas Democrat who is the committee’s chairwoman and who last week introduced the bill that would prevent banks from trading derivatives directly.

The daughter of a sixth-generation rice farmer, she has found herself navigating a dangerous channel between Wall Street firms, which raised $60,000 at two fund-raisers for her re-election campaign so far this year, and her constituents, many of whom want a crackdown on the speculation that led to the financial crisis.

Other committee members, on both sides of the aisle, also have reaped donations from people and companies in the derivatives business, including Senator Saxby Chambliss of Georgia, who is the committee’s ranking Republican member; Kent Conrad, the North Dakota Democrat; and Charles E. Grassley, the Iowa Republican.

The committee will be the main arena for the derivatives fight for reasons dating to an era when farming was more important to the nation’s economy than finance. In their simplest form, derivatives can provide financial protection on the value of an investment or commodity. For example, by putting up a relatively small amount of money, a farmer could buy a derivative known as a forward or futures contract that would guarantee a set price for crops and thereby guard against ruinous price swings between planting and harvest.

But the most esoteric derivatives — which also are the most profitable for banks to create and trade — have little economic purpose other than to let investors place financial bets, critics say.

A more complex type of derivative helped to inflate the housing bubble in recent years, as Wall Street repackaged high-risk mortgages into securities that speculators could use to bet on the direction of the housing market. Financial institutions earned millions of dollars in fees for creating the securities. But many of the derivatives became worthless when foreclosures skyrocketed, leading to billions of dollars of losses — and taxpayer bailouts — at the banks and insurance companies that owned them.

Now, these obscure and largely unregulated securities — more than $600 trillion of which are tucked into investors’ portfolios, according to the Treasury Department — are at the center of the fight over financial reform led by the Obama administration.