by Jeff Gillman
Fertilizers pit two groups against each other: one group that wants to protect the water, and another group that wants to grow crops or have nice lawns.
The Science
The impact of soil fertility on crop production, for everything from grass and beans to corn and oranges, has been well documented. Depending on the crop and the type of soil that is being fertilized, an acre of land (43,560 square feet) may be fertilized with anywhere from 50 to 500 pounds of nitrogen, along with other nutrients such as phosphorus and potassium, usually at slightly lower levels. Particularly with heavily used land, additions of fertilizer may increase crop production by two to three times—or even much more, depending on the crop and the quality of the soil. Land that has been newly cleared of trees or other plant material is typically very rich in nutrients because of the natural cycling of plant and animal materials back into the soil; thus, it needs little fertilization for maximum production. Farmland that has been producing crops for decades—or centuries—will usually need large amounts of fertilizer to produce a decent crop. Here in the United States, we have much more of the latter than the former.
As we’ve placed more and more nutrients into the soil, we have fertilized not only our farms and lawns, but also our lakes, streams, and oceans. Many of the nutrients that we apply never make it to the crops they’re intended for, but rather disappear in a variety of ways, including flowing with the rain into bodies of water. Much of the rest is lost to leaching, or a host of other natural processes, some of which create nitrogen gases that may increase global warming. Cereal crops, such as wheat, corn, rice, and barley, use about 33 percent of the nitrogen that is applied worldwide. Tree crops, such as apples and oranges, are typically even less efficient. Once nutrients leave a farm and reach a watershed, they turn into bad players. They feed algae the same way that they might have fed plants on land, but these algae create big problems. Plants, fish, aquatic insects, and other creatures that live in the water need oxygen to survive. Unfortunately, when water is full of nutrients (which are usually in shorter supply under natural conditions), algae grow and reproduce extremely rapidly and, eventually, they die. Their decomposing bodies use up the oxygen in the water to the point that other creatures can’t get enough oxygen to live.
In addition to the damage in lakes, sea creatures have also been disappearing from the Gulf of Mexico—even before the oil spill of 2010. A dead zone a little bit larger than the state of Connecticut is caused by water coming from the Mississippi River and exiting into the Gulf after having picked up nutrients from some of the largest farming regions in America. Fertilizer runoff from farms and lawns all the way from Minnesota to Mississippi find their way into this river and eventually get expelled into the Gulf. There are dead zones all across the United States, wherever water is overfertilized with the nutrients that feed algae. In 2009 there were about 150 dead zones in the oceans—mostly off the European and North American coasts—which is double the number in 1990.
Nutrients that destroy creatures living in water don’t just come from farms, however. Backyards, schoolyards, parks, and other places contribute nutrients that eventually make their way into a body of water where they can do damage. A common misconception is that applying fertilizers to our lawns creates more runoff of nutrients than leaving lawns unfertilized. Actually, a thick, dense, healthy lawn is better at holding the soil and taking up nutrients from fertilizer than both weaker stands of grass and agricultural land. Hence, while it’s obvious that huge applications of fertilizer might lead to nutrient runoff, the regular, judicious use of fertilizers around homes might actually be needed to encourage the growth of grass and other plants that hold the soil, which might otherwise erode into a body of water or from which nutrients might escape as runoff. As Christoph Gross and his colleagues concluded in a study on runoff from grass-covered soil, or turf, “properly managed and judiciously fertilized turf is not a significant source of nutrients or sediment in surface or groundwater.” This study also showed that more nutrients escape from agricultural land than from the same size piece of land that is covered with turf.
Mitigating the Damage
A number of factors determine how much fertilizer will contribute to the runoff from a farm or landscape. One of the most important is the weather. Fertilizers tend to wash away more quickly with excessive rainfall, so farmers can help prevent nutrient runoff by not fertilizing right before a heavy rain (but a light rain helps the fertilizer work its way into the soil). Likewise, there are a number of ways to manage land to minimize the amount of fertilizer runoff. A row of plant material, called a buffer strip, placed between the area where fertilizer is to be applied and a body of water, such as a lake or pond, slows the movement of fertilizers from the field to the water. Additionally, farms with better soils will typically hold nutrients better than farms with poor soils, and farmers who till their soil are more likely to suffer soil running off of their land and finding its way into the water system than farmers who don’t.
Buffer strips were first suggested in the 1940s by C. B. Brown, who recommended their use to remove sediment from water runoff by filtering it through a screen of vegetation before it entered a reservoir. For the next thirty years or so, these strips were considered handy ways to filter runoff from roads or streets, but not much thought was given to their other uses. Then, in the 1970s, a number of researchers started looking at how well these strips of greenery could remove nutrients that would otherwise enter an aquifer, and lo and behold, they discovered that that these strips could, in some cases, remove 90 percent or more of the phosphorus in runoff water. Today, the use of buffer strips is a well-established—though underused—method of filtering nutrients out of runoff before it enters a body of water.
Most buffer strips include grasses, shrubs, and trees and provide at least ten feet of vegetation between the body of water and the farm field. Generally, the larger the buffer strip the better, because a larger surface area allows for more plants and plant roots to be collecting nutrients from the water. Buffer strips thirty to one hundred feet wide or wider are best, if and when that is possible. The biggest problem with buffer strips is that they often take up land that could otherwise be used for producing crops and this can cut into a farmer’s bottom line.
Today’s farmland is not as capable of holding the nutrients delivered by fertilizers as it once was because, over the years, our soils have lost organic matter to erosion, without having the opportunity to build levels back up. Organic matter is nothing more than carbon-containing compounds that, in soils, usually come from dead animals and plants that build up over many years. This material is very good at holding nutrients in the soil for plants to use. When we harvest our crops year after year without returning vegetable material to the soil, it loses the ability to hold the nutrients supplied by fertilizers. Additionally, the tried-and-true practice of tilling can itself lead to nutrient runoff. Tilling the soil loosens it, allowing it to erode more easily and to eventually find its way into a stream or lake. New techniques that do not involve tilling the soil and that decrease the chance of nutrient runoff are becoming more popular. Called reduced tilling or no-till practices, these techniques push a seed into the ground and then use herbicides or other weed control techniques, rather than tilling, to make sure that the crop that was planted sprouts from the ground, rather than weeds. The use of genetically-engineered, herbicide-resistant crops makes no-till practices easier to implement.
Government Policy
In the garden or on the farm, pesticides and fertilizers are often used in tandem. Fertilizers help the garden grow; pesticides keep unwanted weeds and critters away from the garden. They are the yin and the yang of modern, industrialized farming. But if farmers and gardeners see them as complementary, the federal government treats them as near-opposites. Pesticides are subject to numerous laws and regulations, as we saw in the previous chapter. They undergo safety tests by the manufacturer and are cleared for public use by the government. Fertilizer
s, on the other hand, face no government clearance and almost no direct regulation by the federal government. (The only direct regulation restricts the amount of ammonium nitrate you can buy. Congress instituted the limit in 2007 to make it more difficult for terrorists to buy enough fertilizer to build bombs.) The different legal treatment of the two products is a consequence of their basic functions. Pesticides purposely kill things (hence, they are potentially dangerous to humans, wildlife, and ecosystems), while fertilizers help things grow. Pesticides are sprayed directly on foods, where their residue could be dangerous to consumers; fertilizers are applied to soils and are rarely present on the foods we eat. It is rare for state or local governments to regulate how much fertilizer a person or farmer can apply to their home or field.
Because of their effects on clean water and aquatic ecosystems, fertilizers are governed as “nonpoint source pollution” under the Water Quality Act of 1987. Nonpoint source pollution comes from many different places as opposed to a single point. The pollutants are picked up by rainwater and transported to a common collection point where they do their environmental damage. Focusing on nonpoint sources was the result of an evolution of water policy. The Clean Water Act of 1972 (CWA) had focused on point sources of pollution—discharge pipes from factories or municipal sewer or water treatment systems. The law required point sources to obtain permits for discharges into waterways, and regulated the development and dredging of wetlands. The 1985 Farm Bill created the “Swampbuster” program, which barred farmers from federal subsidy programs if they converted wetlands into croplands. Both laws created exceptions for projects that included actions to compensate for the loss of wetlands. These laws addressed the most visible sources of pollution and helped to clean up U.S. waterways, but 40 percent of the waterways did not meet the CWA’s goal of being “fishable and swimmable” thirty years after the law had passed.
The Water Quality Act addressed nonpoint source pollution by requiring states to identify “impaired waters” that fail to meet the state’s own water quality standards and to develop priority rankings of the impaired waters. States are required to update their lists every two years. The states are also required to calculate a total maximum daily load (TMDL) for each of the impaired waters. The TMDL is the water’s “pollution budget,” or the maximum amount of pollutant the body of water could receive in a day and still meet water quality standards. States then develop management plans to improve water quality and the EPA must approve the plans.
The EPA has calculated TMDLs for certain states that did not have the appropriate expertise or resources. The law did not contain a deadline for the states to calculate TMDLs, so when a number of states failed to do so, environmental groups sued the EPA, asking the courts to order the EPA to calculate TMDLs rather than waiting for the states. Suits filed on behalf of thirty-nine waterways succeeded, as of 2009, with the EPA reaching an agreement to do the calculation or receiving an order from the court to do it.
Who Cleans Up?
The EPA has no authority to issue regulations or to undertake any enforcement activity to address nonpoint source pollution directly (we’ll explain why in the next section). The regulations’ teeth are therefore based on the state’s willingness to execute its management plan. If the “fertilizer police” are in your yard, it’s state or local police, not the feds. The management plans imposed by the states may do a wide variety of things, from regulating farmers’ use of fertilizers to encouraging farmers to use new techniques to reduce their runoff. Two of the states that have been most active in regulating fertilizer—Florida and Minnesota—are states with extensive wetlands and waterways, and with tourist industries that thrive on water recreation. Minnesota, in addition to banning the use of phosphorus fertilizers on home lawns unless they are newly planted or a soil test shows the need for one, has also mandated the use of buffer strips between cropland and waterways to reduce the amount of fertilizers and other pollutants that enter the water. Florida hasn’t been terribly aggressive on the state level, but municipalities have produced their own regulations that restrict such things as when fertilizer can be applied, what concentration of nutrients can be in the fertilizer, and how much of the fertilizer can be used during a given time. As an example, Pinellas County passed an ordinance in 2010 that banned homeowners from applying nitrogen or phosphorus fertilizers to their lawns from June 1 through September 30, and prevented stores from selling these fertilizers during that time. This ordinance goes on to restrict the amount of fertilizer that can be applied, and prevents the use of fertilizers within ten feet of a waterway. Professional applicators need to take training courses and become certified in fertilizer application. Golf courses and vegetable gardens are exempt.
Some states, including Nebraska and Illinois, use monetary incentives to reward those who plant grass buffer strips to separate farmland from adjacent bodies of water. This is a great way for farmers to have their cake and eat it too. They get to use normal levels of fertilizer, and by sacrificing some growing land for use as a buffer strip (for which they’re compensated), they capture both nutrients and pesticides before they reach the water.
Other states have taken different routes to protecting critical waterways. Maryland, Virginia, and Pennsylvania, as well as the District of Columbia, signed the Chesapeake 2000 regional compact to protect the Chesapeake Bay. The states and the District agreed to buy and protect wetlands that serve as a filtering system for the bay, and to reduce the amount of farmlands and woodlands lost to development. Other states that have extensive wetlands, but whose economies are dominated by resource extraction, such as Louisiana, have taken much less assertive approaches to dealing with nonpoint source pollution.
In 1999, the EPA issued a proposal to revise the TMDL regulations. The revisions would have required states to submit schedules for TMDL calculations and implementation plans for their TMDLs, among other things. States objected to the burdens this would place on them. Point source groups fought with farm groups—each attempting to ensure that they wouldn’t be the ones who had to clean up their act. And environmentalists (who supported making the regulations tougher and more specific) thought states were given too much time before having to make water quality improvements. Without strong support and with many strong opponents, the EPA revised the proposal in 2000, but then withdrew it entirely in 2003 (after the Clinton EPA had become the Bush EPA). The regulations have not been acted on since.
The Supreme Court has recently complicated the EPA’s regulation of point and nonpoint sources of water pollution even further. In two separate cases, Solid Waste Agency of Northern Cook County v. Army Corps of Engineers (2001), and Rapanos v. United States (2006), the Court took the EPA to task for regulating waters beyond those explicitly required by the Clean Water Act’s “navigable waters” language. The EPA had traditionally interpreted this wording broadly, to include large wetlands and any waters that flow into navigable waterways or that cross state lines, because such waterways affect drinking water, fishing, and other public uses that the act was designed to protect. The Court called the breadth of this interpretation into question, specifically arguing that waterways within a state, creeks that sometimes go dry, and lakes unconnected to larger water systems are not navigable waters and thus do not qualify for EPA regulation. The rulings injected tremendous amounts of uncertainty about which waterways the EPA could regulate—and thus who it could punish for polluting them. States were not immediately in a position to regulate or enforce laws on these waters, since they had relied on EPA regulation and enforcement for the prior forty years.
The Political Dynamics
A high priority of the federal government is ensuring an adequate food supply, and crop subsidies are a major policy used to achieve this goal. If protecting our water from fertilizers and pesticides were one of the government’s highest priorities, in contrast, we wouldn’t have crop subsidy programs. Understanding these subsidy programs is vitally important to understanding why we use as many chemicals
as we do.
Crop subsidy programs have been in place since the Great Depression in the 1930s to ensure that the nation has an adequate supply of food, and that farmers have some protection against natural booms and busts of the farm economy caused by things outside of their control, like the weather and the national economy. The government uses a number of techniques to do this, from providing direct payments to farmers if the price of a crop drops too low, to buying surplus food for antipoverty programs, to allowing farmers to set up regional monopolies to prevent lower-priced goods from entering their markets. The government does this because farmers face a basic problem: the better the yield, the less the farmer earns. If all farmers who grow the same crop have a good year, there is a lot of supply on the market. The greater the supply, the more the price of the food drops. Consumers don’t eat more (or not that much more) just because more food is available or because it is cheaper. If some farmers go bankrupt and lose their farms—which would help to decrease the supply of food, increase the price, and keep the remaining farmers profitable—the risk is that there won’t be enough food in the next bad year, when the weather or the pests don’t cooperate. That’s not a risk the government is willing to take, not to mention the major job losses that would occur in small-town America.
LARGE corporate farms receive most of the farm subsidies and have most of the political clout in Washington, but they use the family farmers to make the argument to retain subsidies, since family farms are a potent symbol of America’s pastoral past. It would be extremely hard for public opinion to support a policy that causes regular folks to lose a farm that had been in their family’s hands for generations, in the name of cold-blooded economic efficiency. Small family farms would be affected by the loss of subsidies because they have a smaller margin for error. Moreover, farmers’ spending supports the farm supply and equipment sales people, the banks, the insurance agents, and others throughout the rural economy. For politicians, subsidies are a small price to pay to keep the rural population quiet. Both Democrats and Republicans compete for the votes of rural residents, and neither party wants to alienate them.