SA Forum is an invited essay from experts on topical issues in science and technology.

Every five years Congress passes a comprehensive bill that sets food and agriculture policy for the nation. When the current bill expires on September 30, Congress may not be able to get another one passed. Power struggles between the U.S. Senate and House of Representatives have put the bill in jeopardy. A big loser could be the environment.

Although the lion’s share of the farm bill goes to farm subsidies and food stamps that are politically popular in the heartland, these bills are also the single, largest source of funding for conservation on private U.S. land. The 2008 bill, which expired in 2012, allocated $24 billion to conservation measures. Last year Congress passed a stopgap bill that did not include any new conservation spending. Unless the conservation provisions are restored, the environmental impact will be dramatic: Little will be grown in the Midwest besides grain crops. Hayfields, grasslands, wetlands and forests will continue to disappear. Air and surface water quality will continue to decline and biodiversity will be lost. Soil degradation will continue at an even faster pace, and dust bowl conditions are likely to return. Farm bill conservation measures mitigate the unintended effects of industrial farming, which in the long term helps farmers themselves and all Americans in general.

Two conservation provisions are especially important to restore: The first is funding for programs such as the U.S. Department of Agriculture's Environmental Quality Incentives Program and Conservation Reserve Program that encourage landowners to plant perennial vegetation on farmland, which can reduce the environmental impact of farming on surrounding land and its residents as well as on the farms themselves. A portfolio of perennials is available, including native grasses, wildflowers, nonnative grasses, shrubs and trees, all of which perform important ecological functions that crops cannot, such as holding soil in place, removing carbon from the atmosphere, cleaning water, slowing runoff, providing natural pest control and creating habitat for pollinators and wildlife.

A growing body of evidence indicates that just a small amount of perennials can provide substantial benefits. The STRIPS study at Neal Smith National Wildlife Refuge, for example, has shown that planting only 10 percent of farm fields with strips of perennial prairie vegetation results in 95 percent less sediment runoff and 90 percent less nitrogen and phosphorus runoff, as well as a 380 percent increase in native plant diversity and a 130 percent increase in native bird abundance. Farm bill conservation dollars can reduce the cost of this practice by 85 percent, making it affordable for farmers and a good public benefit for the taxpayer buck. Without a bill that has conservation provisions, these practices will quickly wither.

The second important provision is conservation compliance. Beginning in 1985 the farm bill required farmers to follow a conservation plan in order to remain eligible for assistance through federal agricultural programs. For example, farmers had to employ approved soil conservation practices on farmland prone to erosion and had to refrain from draining wetlands to plant crops. Most farmers agree that conservation compliance is a reasonable trade for federal assistance. Yet the mandate has never been fully enforced and some factions in the House prefer to eliminate it, which would degrade the land, water and biodiversity we—farmers included—all depend on. The House should follow the Senate’s lead in requiring conservation compliance to receive federal assistance, including crop insurance.

The House seems to be the sticking point. The Senate had passed a farm bill in late 2012 and again on June 10, but in both cases the gridlocked House defeated similar legislation. Failure to pass a new comprehensive bill will most likely kill conservation funding altogether. A new bill for just the conservation measures could be readily defeated. Conservation funds are only about 5 percent of the overall farm bill (the 2008 bill allocated $300 billion but actual expenditures were about $401 billion). They should be reinstated because they play a critical role in safeguarding soil, protecting air and drinking water, and providing habitat for wildlife—including native pollinators—as well as space for outdoor recreation. They also prevent farmers from planting every last acre of the Midwest with crops, at the expense of the environment.