WASHINGTON — Congress is poised to send a massive, five-year farm bill that provides food for the needy and subsidies for the nation’s farmers to the White House for President Barack Obama’s signature.

The Senate was expected to pass the almost $100 billion-a-year compromise bill Tuesday; the House passed it last week. The bill provides a financial cushion for farmers who face unpredictable weather and market conditions, while also continuing to subsidize services for rural residents and communities who have hit hard times in recent years. The majority of the bill’s cost is food stamps, which supplement meal costs for 1 in 7 Americans.

House Republicans had hoped to trim the bill’s costs, pointing to a booming agriculture sector in recent years and saying the now $80 billion-a-year food stamp program has spiraled out of control. Partisan disagreements stalled the bill for more than two years, but conservatives were eventually outnumbered as the Democratic Senate, the White House and a still-powerful bipartisan coalition of farm-state lawmakers pushed to get the bill done.

The final compromise bill would get rid of controversial subsidies known as direct payments, which are paid to farmers whether they farm or not. But most of that program’s $4.5 billion annual cost was redirected into new, more politically defensible subsidies that would kick in when a farmer has losses. The food stamp program was cut about 1 percent; the House had pushed for five times that much.

Senate Agriculture Chairwoman Debbie Stabenow, D-Mich., said Monday that she and her House counterpart, Rep. Frank Lucas, R-Okla., tried to craft a bill that would work for all regions of the country, “from traditional row crops, to specialty crops like fruits and vegetables, to livestock, to organics, to local food systems.”