Agricultural run-off sp 09

--Kerstin 08:48, 3 April 2009 (EDT)

Agricultural Runoff

Agricultural Runoff occurs when water from rain or melted snow cannot be held by the soil and therefore runs off into surrounding bodies of water. Runoff moves over the soil collecting pollution from soil erosion, feeding operations, grazing, plowing, animal waste, and application of pesticides, irrigation water, and fertilizer. This pollution then causes runoff into nearby ponds, lakes, coastal waters, and underground sources of drinking water harming both human health and ecosystems.(1)on this site we will be focusing on the agricultural runoff produced by Conventional, Organic, and Amish farming and possible policy changes to prevent it.

Non-Point Discharge

Runoff that occurs on surfaces before reaching a channel is called a non-point source. This differs from point discharge where all pollutants are collected and discarded from one point. When there is an area of land that has multiple point and non-point sources that drain to one common point this area is referred to as a watershed.(3) Pennsylvania alone contains a portion of 57 different watersheds.(Scorecard) Agricultural runoff is a large contributor to non-point discharge.

Leaching versus Runoff and Erosion

There are two main ways that nutrients are washed away from agricultural fields into the watershed system. Leaching occurs when nutrients move downwards into the soil beyond the reach of the plants' use. This usually happens because negatively nutrients, such as nitrates, cannot bind with soil particles and instead move in between them and into the groundwater. Runoff occurs with positively charged nutrients such as phosphorus, which bind with soil particles and are washed over the soil and into waterways (Bellows 2002).

Conventional Agriculture

Conventional Agriculture is an industrialized agricultural system characterized by mechanization, monocultures, and the use of synthetic inputs such as chemical fertilizers and pesticides, with an emphasis on maximizing productivity and profitability.(2)

A History of Conventional Farming

Prior to the twentieth century, the typical American family lived on a small farm. They raised hogs, cattle, sheep, chickens, and planted corn, fruits, garden vegetables, hay, and wheat. Everyone worked long and hard, but the results were often meager. Families barely harvested enough food for themselves. This situation began to change during the last half of the 1800's and it changed remarkably in the next century.

Scientific methods and labor-saving machinery have made farming increasingly productive. The development of improved plant varieties and fertilizers has helped double and even triple the yields of some major crops. Scientific livestock care and breeding have helped increase the amount of meat and products that animals produce. At the same time, the use of tractors and other modern farm equipment has sharply reduced the need for farm labor.

As farming has become less important as a way of life in the United States, it has become more important as a business enterprise. Today's successful farmers are expert not just in agriculture but also proficient in accounting, marketing, and finance. Farms that are not run in a businesslike fashion have great difficulty surviving.

What are pesticides?

Pesticides (or farm chemicals, agro chemicals or agvet chemicals) are those substances which are used to control, destroy, repel or attract pests in order to minimise their detrimental effects. Pests are those organisms like weeds, insects, bacteria, fungi, viruses and animals which adversely affect our way of life. Pests can reduce the quality and quantity of food produced by lowering production and destroying stored produce.

Pesticides therefore are used in many situations such as livestock farming, cropping, horticulture, forestry, home gardening, homes, hospitals, kitchens, roadsides, recreational and industrial areas. They are a vital facet of farming and our everyday life.

Pesticides may be derived from inorganic sources (copper, sulphur), natural organic sources (plants) or be organic compounds synthesised in a laboratory. Many of these synthesised products mimic the activity of natural organic compounds. While the first recorded use of chemicals to control pests dates back to 2500 BC, it is really only in the last 50 years that chemical control has been widely used

There are two major types of pesticides used in Conventional Agriculture.Herbicides and Insecticides.

An herbicide is used to kill unwanted plants. Selective herbicides kill specific targets while leaving the desired crop relatively unharmed. Some of these act by interfering with the growth of the weed and are often synthetic "imitations" of plant hormones.

Herbicides are widely used in agriculture and in landscape turf management. In the U.S., they account for about 70% of all agricultural pesticide use.

An insecticide is a pesticide used against insects in all developmental forms. They include ovicides and larvicides used against the eggs and larvae of insects respectively. Insecticides are used in agriculture, medicine, industry and the household. The use of insecticides is believed to be one of the major factors behind the increase in agricultural productivity in the 20th century. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans; and others are concentrated in the food chain.

Over 98% of sprayed insecticides and 95% of herbicides reach a destination other than their target species, including nontarget species, air, water, bottom sediments, and food.

Environmental Effects of pesticides

Pesticide impacts on aquatic systems are often studied using a hydrology transport model to study movement and fate of chemicals in rivers and streams. As early as the 1970s quantitative analysis of pesticide runoff was conducted in order to predict amounts of pesticide that would reach surface waters.

Pesticide surface runoff into rivers and streams can be highly lethal to aquatic life, sometimes killing all the fish in a particular stream. For example, in Montague on Prince Edward Island in Canada, nine "fish kills" happened in one year: every fish, snake, and snail was killed in a river called Sutherland's Hole near potato farms from which herbicides, insecticides, and fungicides ran off after heavy rains.

Organic Agriculture

Organic agriculture is the production of food without using genetically modified organisms, sewage sludge, or synthetic pesticides, herbicides, and fertilizers.(Pimental et al. 2005)

A History of Organic Farming

Until World War II, artificial fertilizers and large-scale agriculture were non-existent. Small, family owned farms used crop rotation, cover crops, and natural fertilizers such as manure to keep their crops healthy and productive.

The chemicals used in Vietnam were eventually adopted for agricultural use, resulting in some of our current conventional farming methods.

In 1962, Rachel Carson released Silent Spring, which led Americans to begin to question the artificial products used in agriculture. Since then, and especially in recent years, buying organic produce has become more and more popular [1].

The USDA National Organic Program

While some farmers choose to produce food organically but not to become USDA certified because of the extra costs, most do opt for the certification. This enables their consumers to be sure that certain standards are met.

According to the USDA, "The National Organic Program (NOP) develops, implements, and administers national production, handling, and labeling standards for organic agricultural products. The NOP also accredits the certifying agents (foreign and domestic) who inspect organic production and handling operations to certify that they meet USDA standards."

Overview of Current Regulations

The Organic Food Production Act of 1990 mandates a National List of Allowed and Prohibited Substances that contains which synthetic inputs can be used, as well as which natural inputs cannot be used [2].

Organic certification mandates that farmers:

1. "Select and implement tillage and cultivation practices that maintain or improve the physical, chemical and biological condition of soil and minimize erosion.

2. Manage crop nutrients and soil fertility through rotations, cover crops, and the application of plant materials.

3. Manage plant and animal materials to maintain or improve soil organic matter content in a manner that does not contribute to contamination of crops, soil, or water by plant nutrients, pathogenic organisms, heavy metals, or residues of prohibited substances." (OFPA Section §205.203).

The Results of Current Regulations

Nitrate Leaching: Nitrate leaching occurs up to 50% less in organic than in conventional agriculture. This is mostly because there is no additional nitrogen added to the soils; only clover and grasses, which carry nitrogen, are cropped in the off-seasons (Smilde 1989, Eltun, 1995 Haas et al. 2002. The reduction in N runoff is also attributed to no-till agriculture, when used (Trewavas 2004).

Soil Erosion: According to the EPA, soil erosion is the most common runoff from agricultural practices. When sediments reach waterways, they can block sunlight for aquatic plants, clog fish gills, as well as carry more harmful particles with them.

Organic agriculture has been shown to maintain a soil protection index (i.e. retain soil) up to 80% higher than in conventional farming. This is mainly due to crop rotation, cover crops, and fewer row crops such as corn. Organic farming does involve some practices that can lead to more erosion, such as: more disturbance due to mechanical tillage, wider row distances, slower growth because there is less nitrogen in the soil, and destruction of crops because of diseases.

Phosphorus Runoff: Phosphorus is generally less of a problem for organic farms than it is in conventional agriculture (Stockdale et al. 2002). This is because organic farmers tend to manage their applications of manure, which produces the majority of excess phosphorus, more closely. However, livestock farms may have more difficulty monitoring this and therefore need to monitor their phosphorus runoff more attentively (Bellows 2002).

Pathogens: Pathogens are disease-causing organisms, which are found in manure. Humans can negatively be affected when consuming organic produce or using water, which has had close exposure to manure. To avoid these problems, the NOP mandates the carbon to nitrate ratio of the compost to begin at between 25:1 and 40:1. The compost must also remain heated for a specified time and temperature. Finally, manure cannot be applied in direct contact with produce up to 120 days before harvest, or indirect contact up to 90 days before harvest.

Inputs for Amish Agriculture

Current Regulation in Pennsylvania

In 1987, Congress amended the Clean Water Act (CWA) establishing Nonpoint Source Management Program, section 319. This amendment was made in order to increase federal assistance for State and local efforts at reducing nonpoint source pollutants. The new legislation provides for grant money to be given to States, Territories, and Indian Tribes for supporting all aspects of nonpoint source implementation projects. [3]

According to the U.S. Environmental Protection Agency (EPA), water quality assessments performed by individual States continue to show that nonpoint source pollution is the leading cause of damage to surface waters of the U.S. The major non point source pollutants from agricultural, as described by the EPA, include nutrients, sediment, animal wastes, salts, and pesticides.

Monitoring NPS pollution is difficult because runoff does not emanate from a single point, but leaves every farm in so many places that accurate monitoring is essentially impossible. [4]

Under the U.S. Environmental Protection Agency[5], the National Management Measures to Control Nonpoint Source Pollution from Agriculture provides officials at the state and local level with guidance for the implementation of nonpoint source pollution management programs. The document contains information on the best available, economically achievable means of reducing pollution of surface and ground water from agriculture. The National Management Measures to Control Nonpoint Source Pollution from Agriculture is over three hundred pages of in-depth of management and measurement practices for NPS pollution. This includes guidelines for nutrient and pesticide management, erosion and sediment control, animal feeding operations and grazing management.

Possible Solutions to Minimize Environmental Impacts

Nonpoint-source pollution (NPS) occurs at inefficiently high levels because farmers have no incentive to consider the externalities of their production. [6] An efficient solution for nonpoint source pollution should maximize expected economic benefits. Thus, a basic cost-benefit analysis of NPS pollution would be the private net benefits of production minus the economic cost of pollution.

Cost-effective environmental policies are considered as such if they achieve some measurable objectives or goals at lowest possible cost. This is why strategies for water quality protection, such as NPS reduction, are heavily dependent on both intended goals and policy for achieving those goals. [7]

PA

In their 2007 annual report on non-point source pollution, the Pennsylvania Department of Environmental Protection (PDEP) laid out the following five goals[8]:

"Goal 1: Improve and protect water resources as a result of nonpoint source program implementation efforts. Show water resource improvements by measuring reductions in sediments, nutrients and metals or increases in aquatic life use, riparian habitat, wetlands, or public health benefits. By 2012, through combined program efforts, remove 500 miles of streams and 1,600 lake acres that are identified on the State’s Integrated List of All Waters as being impaired because of nonpoint sources of pollution.

Goal 2: Coordinate with watershed groups, local governments, and others in the development and implementation of 20 watershed implementation plans meeting EPA’s Section 319 criteria to protect and restore surface and groundwater quality.

Goal 3: Improve and develop monitoring efforts to determine how projects and programs improve water quality and/or meet target pollution reductions including total maximum daily loads.

Goal 4: Encourage development and use of new technologies, tools, and technology transfer practices, to enhance understanding and use of techniques for addressing nonpoint source pollution.

Goal 5: Assure implementation of appropriate best management practices to protect, improve and restore water quality by using or enhancing the existing financial incentives, technical assistance, education and regulatory programs."

How Management Practices Work to Prevent Nonpoint Source Pollution

Minimizing the amount of pollutants available (source reduction);

Retarding the transport and/or delivery of pollutants, either by reducing water transported, and thus the amount of the pollutant transported, or through deposition of the pollutant;

Remediating or intercepting the pollutant before or after it is delivered to the water resource through chemical or biological transformation [9]

When considering policy creation for nonpoint source pollution other important factors include economic incentives, available technology, liability and education.[10]

Notes

Bellows, B. 2002. Protecting water quality on organic farms. National Center for Appropriate Technology.

Trewavas, A. 2004. Fertilizer: no-till farming could reduce run-off. Nature 427, 99 (8 January 2004).