Preface. Below are excerpts from a devastating critique of current farming practices by the National research council who show the myriad ways that industrial farming is harming the land and future food production.

Farmers are also paid to not farm fragile or biodiverse land, but there’s so much profit to be made on high corn prices and subsidies for ethanol that farmers are increasingly taking their land out of the Conservation Reserve Program (established in 1985) to make money. CRP land reduces soil erosion, improves water quality, reduces fertilizer use, and increases wildlife habitat. Enrollment in this plan has declined 31% (11.2 million acres) from 36.8 million acres in 2007 to 25.6 million acres in 2013.  Since 1986, CRP has reduced soil erosion by 325 million tons per year, 8 billon tons cumulatively.  Making matters worse, the 113^th Congress reduced the amount of acreage that can be enrolled in CRP to save money.

This paper discusses the ways that modern agriculture pollutes cropland and erodes soil profoundly over the natural rate (as much as 87 times more). For example, Iowa has some of the best topsoil in the world, but is losing 3.42 inches on average per century. This has been hidden by the increased production from natural gas based fertilizer (natural gas is both the feedstock and the energy to create it).  But natural gas, like oil and coal, is a finite fossil fuel.

To feed people in the future, “soil quality must be maintained or improved, especially soil’s capacity to supply increasing amounts of water and nutrients… [by improving] tillage and cropping practices to retard erosion…, greater use of cover crops and …perennial, sod-forming crops”.

“Though irrigation is used on only 15 to 20% of total U.S. cropland, it is used on about 70% of land used for vegetable production, about 80% of land used for orchard crops, and essentially 100% of land used for rice production. [Yet] relatively inefficient irrigation systems are still used for much of the U.S. irrigated cropland.”

The ecology of surrounding land is profoundly affected by the chemicals, fertilizer, water consumption and other unnatural and destructive disruptions of growing food, because land use is huge – with over half of all land in the U.S. devoted to agriculture:  “Of the 3,536,700 square miles (9.16 million km2) of total land in the United States, 18% is used for cropland and 27% is used for pasture and rangeland; within the continental United States, agriculture occupies 54% of total land area. Food and agriculture, principally irrigation, account for about 80% of the nation’s total consumption of freshwater stocks”.

The outflows of nutrients, pesticides, and other materials from agroecosystems into nonagricultural ecosystems can be substantial. Consequences include:

1. Nearly 1 million metric tons of nitrogen are delivered annually into the Gulf of Mexico from agricultural lands lying upstream in the Mississippi River Basin, leading to formation of a coastal hypoxic zone.
2. Of the 34,000 metric tons of the herbicide atrazine that are applied each year to U.S. cropland, about 1% moves into associated streams, creating conditions that can exceed thresholds for safeguarding aquatic organisms and human health.
3. Agricultural intensification over the past 50 years had led to accelerating increases in soil sediment deposition in the lakes due to erosion, despite soil conservation efforts.
4. Agricultural practices, principally fertilizer use and manure management, are responsible for about 74% of U.S. emissions of the greenhouse gas nitrous oxide and 84% of the nation’s emissions of ammonia and other NHx-nitrogen compounds.
5. The effects of agricultural toxins can remain invisible and unrecognized for months or years, as DDT and dieldrin did. Administered in the 1940s and 1950s, it took decades to realize these were the causes of bird populations, because their effect was to reduce reproductive efficiency, not outright mortality. Also it took years for concentrations to reach critical levels, making cause-and-effect relationships hard to discern

Alice Friedemann  www.energyskeptic.com  Author of Life After Fossil Fuels: A Reality Check on Alternative Energy; When Trucks Stop Running: Energy and the Future of Transportation”, Barriers to Making Algal Biofuels, & “Crunch! Whole Grain Artisan Chips and Crackers”.  Women in ecology  Podcasts: WGBH, Jore, Planet: Critical, Crazy Town, Collapse Chronicles, Derrick Jensen, Practical Prepping, Kunstler 253 &278, Peak Prosperity,  Index of best energyskeptic posts

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NRC. 2015. Framework for Assessing Effects of the Food System. National Resource council.  Chapter 4. Environmental effects of the U.S. Food system. National Academies Press.

Agricultural activities in the United States contribute significantly to the release of numerous air quality and climate change-related emissions, especially those of ammonia (agriculture contributes to ~90% of total U.S. emissions), reduced sulfur (unquantified), PM2.55 (~16%), PM10 (~18%), methane (~29%), and nitrous oxide (72%).

Soil Resources

Disruption of the balance between soil erosion and soil formation illustrates how agriculture can have a profound effect on the environment through net resource depletion. Erosion is a natural process that occurs on nearly all soils, though rates depend on multiple site-specific factors that include climate conditions and topography. The process occurs in two stages: detachment of soil particles from the soil surface and their subsequent transport and deposition. Erosion by water can occur in sheets, rills, and gullies when rainfall rates exceed a soil’s infiltration capacity; erosion by wind can occur when soil is dry and loose, the surface is bare and smooth, and the landscape has few physical barriers to block the movement of air.

Erosion is perhaps the most important land degradation process associated with agriculture. Direct comparisons of soil erosion rates under different forms of land management have shown 1.3- to 1,000-fold differences, with mean erosion rates of 0.05 mm per year for sites under native vegetation and 3.94 mm per year (78 times higher) for agricultural sites managed conventionally.

The mean rate of sheet and rill erosion on U.S. cropland in 2010 was estimated by the USDA (NRCS, 2013) at 6.1 megagrams (Mg) per hectare/year; the mean rate of wind erosion that year was estimated at 4.6 Mg per hectare/year. Erosion due to water in ephemeral gullies can also be an important form of soil loss, but it is not assessed in widely used soil erosion assessment tools such as the Revised Universal Soil Loss Equation and the Water Erosion Prediction Project model. Nonetheless, by combining values for sheet, rill, and wind erosion, the minimum mean value for erosion on U.S. cropland is 10.7 Mg per hectare/year. Assuming a soil bulk density of 1.3 Mg m–3, that rate is equivalent to the loss of 0.82 mm of soil per year.

Though erosion of soil from cropland at a rate of 0.82 mm year–1 may seem insignificant, it is at least an order of magnitude greater than the rates of soil formation cited earlier. Consequences of this imbalance can be seen in an evaluation of soil dynamics in Iowa, which contains some of the most productive rain-fed croplands in the United States. Based on the mean rate of soil formation reported by Cruse et al. (2013) for four Iowa soil series (0.11 mm year–1) and the mean rate of erosion due to sheet, rill, and wind losses on Iowa cropland (0.98 mm year–1) reported by the USDA (NRCS, 2013), net loss of soil would be 0.87 mm year–1. Viewed in a more historical context, net loss of soil would be 87 mm per century (3.42 inches)

Despite the loss of considerable amounts of topsoil from U.S. croplands due to erosion, crop yields have generally increased over the past century, largely because technological advances, including more intensive use of fertilizers, have been able to mask the potential effects of soil degradation.

However, as noted by Cruse et al. (2013), to make use of technological advances in the next century, especially those related to plant genetics, soil quality must be maintained or improved, especially soil’s capacity to supply increasing amounts of water and nutrients. In this regard, changes in tillage and cropping practices that retard erosion will be critical, especially increased adoption of minimum tillage and zero tillage techniques, greater use of cover crops, and more widespread use of perennial, sod-forming crops.

Though irrigation is used on only 15 to 20 percent of total U.S. cropland, it is used on about 70% of land used for vegetable production, about 80% of land used for orchard crops, and essentially 100% of land used for rice production. [Yet} relatively inefficient irrigation systems are still used for much of the U.S. irrigated cropland.

Rates of groundwater withdrawal are increasing throughout the United States relative to rates of replenishment (In some cases, such as for croplands drawing on the Ogallala (High Plains) Aquifer, the imbalance between water withdrawal and recharge may prove too costly or impractical to maintain current levels of crop production.

Interactions among food, agriculture, and the environment are of major importance in the United States for three reasons: the large land area the system occupies, the large quantities of resources it consumes, and the strong connections that can exist between agricultural and nonagricultural ecosystems. Of the 3,536,700 square miles (9.16 million km2) of total land in the United States, 18% is used for cropland and 27% is used for pasture and rangeland; within the continental United States, agriculture occupies 54% of total land area.

Water use exemplifies the disproportionate impact of the U.S. food and agriculture system on natural resources. Food and agriculture, principally irrigation, account for about 80% of the nation’s total consumption of freshwater stocks.

Exports (i.e., outflows) of nutrients, pesticides, and other materials from agroecosystems into nonagricultural ecosystems (i.e., inflows) can be substantial. For example, Alexander et al. (2008) estimated that nearly 1 million metric tons of nitrogen are delivered annually into the Gulf of Mexico from agricultural lands lying upstream in the Mississippi River Basin, leading to formation of a coastal hypoxic zone. Of the 34,000 metric tons of the herbicide atrazine that are applied each year to U.S. cropland, about 1% moves into associated streams, creating conditions that can exceed thresholds for safeguarding aquatic organisms and human health. Heathcote et al. (2013) studied trends in sedimentation for 32 lakes in Iowa and found that agricultural intensification over the past 50 years had led to accelerating increases in soil sediment deposition in the lakes due to erosion, despite soil conservation efforts. Fluxes between farms and the atmosphere also are important. Agricultural practices, principally fertilizer use and manure management, are responsible for about 74% of U.S. emissions of the greenhouse gas nitrous oxide and 84% of the nation’s emissions of ammonia and other NHx-nitrogen compounds.

As these examples illustrate, environmental effects of the U.S. food and agriculture system reveal traits of a complex system. In particular, they can involve spatial displacement, with large distances possible between sites of pollutant discharge and sites of their ultimate impacts. The system’s environmental effects also may be characterized by temporal lags, with effects remaining largely invisible or unrecognized for months or years. For example, following the introduction of chlorinated hydrocarbon insecticides, such as DDT and dieldrin, in the 1940s and 1950s, declines in bird populations were not recognized as being related to use of these chemicals for a number of years. Because their toxic effects included reduced reproductive efficiency, rather than just direct mortality, and because concentrations did not reach critical levels until “biomagnifications” had occurred with movement of the pesticides through the food web, cause-and-effect relationships were initially difficult to discern. By the 1970s, when understanding of the large effects of this class of pesticides on non-target organisms increased, most of the chemicals were banned or severely restricted in many developed countries. Currently, there is concern over the ecological impacts of neonicotinoid insecticides, which were introduced in the 1990s due to their lower mammalian toxicity relative to organophosphate and carbamate compounds and are now widely used throughout U.S. agriculture. Emerging data indicate these compounds may be primary factors in the decline of honeybee populations through chronic effects on behavior, health, and immunity, and increased susceptibility to pathogens and parasites

Biofuel production from crop materials has been championed as a means of reducing fossil fuel use and limiting GHG emissions, but some analysts have concluded that it can be responsible for environmentally undesirable indirect land-use change effects, whereby shifts from food and feed production to biofuel production in one region may lead to the conversion of grasslands and forest lands to croplands in others, with concomitant increases in net carbon dioxide (CO2) emissions, soil erosion, and nutrient emissions to water

The evolution of pesticide resistance in target pests also exemplifies how agricultural management practices can elicit unwanted effects that might be avoided by analysis of alternative management systems. Since the mid-1990s introduction of transgenic crops resistant to the herbicide glyphosate, glyphosate use in the United States has increased 10-fold, making it the most heavily used pesticide in U.S. agriculture and a strong selection force acting on weed population genetics. Concomitantly, glyphosate-resistant weeds have become increasingly prevalent and problematic. In an analysis of ways to address this problem, Mortensen and colleagues (2012) concluded that simply stacking new genes for resistance to additional herbicides in crop genomes was unlikely to prevent further cases of herbicide resistance in weeds, and that a more efficacious approach would be to develop and implement integrated weed management systems that employ a diverse set of tactics, such as crop rotation, cover cropping, planting of competitive crop cultivars, and appropriate use of tillage and herbicides application.

Private Producer Perspective

Most food is produced by farmers who rely on agriculture for their livelihood. Although evidence abounds that farmers care about environmental stewardship, surveys repeatedly show that profitability is an overriding concern. Farmers in the United States hold property rights that give broad latitude over how to manage their land so long as they do not cause harm in direct and measurable ways. However, their actions may cause economic externalities through air, water, or biotic changes that are indirect and often hard to measure. The profit-maximizing approach to nitrogen fertilizer application on corn illustrates a rational process where an economic externality can lead to environmental degradation. To begin, note that fertilizer, land, and corn are private goods that belong to the farmer. But the aquifer under the farm, the streams nearby, and the atmosphere have no owners—they are common property resources. Corn yield typically increases with increasing applications of nitrogen, but yield increases at a decreasing rate and ultimately reaches a plateau due to genetic yield potential or shortages of other inputs. For a corn producer who is deciding how much nitrogen fertilizer to apply to a corn crop, the standard rule for profit maximization is to apply more fertilizer up to the point where the pay-off from adding more fertilizer just equals the cost of acquiring and spreading that fertilizer. Up to that point, each added unit of fertilizer will fetch greater value of marketable corn. As fertilizer application rises and corn yield tails off, a rising share of fertilizer applied is not taken up by the corn plant. Instead, it converts to nitrate and is carried by water into streams that may contribute to marine hypoxia; it may also convert into nitrous oxide and move into the atmosphere as a GHG.

Because no one owns the waterways or the air, the costs to other people of using those environmental media as waste recipients are external to the farmer’s decision. Similar external costs can accrue from other privately rational decisions by farmers. Examples include specializing in highly profitable crops at the expense of biodiverse natural areas that provide habitat for beneficial species, such as songbirds, pollinators, and the natural enemies of certain agricultural pests.

The common property dynamic contributes importantly to depletion of shared resources like the Ogallala (High Plains) Aquifer. In the century since farmers learned that the semiarid High Plains region was underlain by this vast aquifer, irrigation has dramatically expanded crop production. However, due to low rainfall in the current era, the aquifer’s recharge rate is dwarfed by water withdrawals, resulting in a 30 percent depletion of the groundwater supply today in western Kansas, with continuing depletion expected despite rising private costs of withdrawing water from greater depths. Because no one owns the groundwater, there is no assurance that if one person conserves, that person will have more of the resource available later.

Because U.S. farmers have broad property rights to manage their land as they see fit, U.S. agricultural environmental protection policy focuses on paying farmers for environmental services. A variety of federal programs under the historic series of farm bills since 1985 (most recently the Agricultural Act of 2014) pay farmers for environmental services through sharing the cost of environmental stewardship practices (e.g., under the Environmental Quality Incentives Program), renting farmland that offers conservation benefits (e.g., Conservation Reserve Program), or paying for environmental services from working lands (e.g., Conservation Stewardship Program).

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