CHICAGO (Reuters) - Agriculture leaders including lawmakers from President Donald Trump’s Republican Party on Thursday criticized his planned 21 percent cut to discretionary spending at the U.S. Department of Agriculture (USDA), saying it could take a toll on the rural communities that helped elect him last November.

Trump has proposed slashing the USDA’s discretionary budget by $4.7 billion to $17.9 billion by halting funding for rural clean water initiatives and rural business services, reducing some USDA statistical services and cutting county-level staff.

The president has already vowed to alter trade deals that have largely boosted farm incomes and targeted health care policies that have particularly benefited the rural poor.

“America’s farmers and ranchers are struggling, and we need to be extremely careful not to exacerbate these conditions,” said House Agriculture Committee Chairman Michael Conaway. Farm incomes are down 50 percent from four years ago, he added.

Opposition is already building in Congress.

“I strongly oppose the Trump administration’s proposed budget cuts to programs that are critical to farmers, ranchers and families in small towns across America,” Debbie Stabenow, ranking member of the Senate Agriculture Committee.

The American Farm Bureau Federation (AFBF), the country’s largest organization representing farmers, said county-level USDA staffing cuts and reduced statistical services could hurt members.

“A lot of farmers and growers rely on USDA’s statistical capabilities to make a lot of marketing and risk management decisions and planting decisions,” said John Newton, AFBF director of market intelligence.

The proposal did not give details of which services could be cut.

Trump’s blueprint aims to save $498 million by eliminating a program that helps fund clean water and sewer systems in small communities.

The budget proposal would also eliminate a food aid program, which had $182 million in funding earmarked for fiscal 2017. Its planned $6.2 billion for the Special Supplemental Nutrition Program for Women, Infants and Children is about $150 million less than fiscal 2016. Under former President Barack Obama, the program was reduced by $273 million between fiscal 2015 and 2016.

The plans for USDA spending were part of Trump’s budget blueprint, a broad outline of spending proposals for the fiscal year ahead.

It does not cover “mandatory” spending established by law, like farm subsidies, only “discretionary” programs where lawmakers can adjust spending.

The White House has said it plans to release a traditional full budget in mid-May.

The USDA oversees agriculture, rural communities and nutritional programs, including funding for school lunches. The agency also publishes closely watched global farming production statistics.