WASHINGTON — Congress has given its final approval to a sweeping five-year farm bill that provides food for the needy and subsidies for farmers.

Ending years of political battles, the Senate vote Tuesday sends the measure to President Barack Obama, who is expected to sign it.

The bill provides a financial cushion for farmers who face unpredictable weather and market conditions. But the bulk of its nearly $100 billion-a-year cost is for the food stamp program, which aids 1 in 7 Americans.

House Republicans had hoped to trim the bill’s costs, but conservatives were eventually outnumbered as the Democratic Senate, the White House and a bipartisan coalition of farm-state lawmakers supported it.

The legislation cuts the food stamp program about 1 percent; the House had pushed for five times that amount.