bicides, pesticides and fungicides used
in nonorganic farming also enter
drinking water supplies, posing a variety of threats to human health.
Unlike nonorganic farmers, who
contribute to this disturbing issue, organic farmers, under federal law, must
utilize production practices that “
maintain or improve the natural resources
of the operation, including soil and
water quality.” No other farmers in the
U.S. are held to this standard.
Less Nitrogen Leaching. One of the
most widely known impacts of agriculture on water quality occurs when fertilizer leaches into groundwater and
runoff, polluting water supplies and
causing the well-known “dead zone”
that forms each year in the Gulf of
Mexico. Runoff causes algae to grow
uncontrollably, which depletes oxygen
from the water and literally suffocates
marine life. Excess nitrogen fertilizer
also causes weeds to take over ponds,
reservoirs and lakes as well.
In organic systems, biological fertilizer sources release nutrients slowly
over time, providing more opportunity
for nutrients to be digested by soil organisms and held in the soil instead of
leaching below the root zone. Because
of this, a growing coalition of hydrologists, water quality experts and conservation leaders is advocating for organic
and sustainable farming.
In a 12-year study published in 2010
in Agriculture, Ecosystems and the Envi-
fortunately, history is marked by human failure to properly manage soil. Organic
farming has heralded a new renaissance of soil stewardship that offers numerous
benefits to the planet and humanity.
Crucial soil functions such as water-holding capacity, soil microbial activity and
nutrient cycling are strongly influenced by the structure of the soil, particularly
the degree to which it forms soil aggregates. Without soil aggregate formation,
soil erodes easily via wind or rain, as happened in the Great Plains during the
Dust Bowl of the 1930s.
Soil microorganisms, found in abundance in organically managed soils, secrete glue-like substances that help hold
soil particles together. Organic methods—such as crop rotation, cover crops,
green manures and use of composted
and raw animal manures—help enhance
microbial activity and improve soil quality. Conversely, inputs used in nonorganic farming—including synthetic
fertilizers, pesticides and fumigants—
destroy many of these microorganisms, resulting in lower concentrations of soil
aggregates.
Organic Methods Build Better Soil.
Many scientific studies have confirmed that organic farming methods result in
higher quality soil. A large body of soil quality data comes from long-term systems
comparison trials across the United States, including studies in Pennsylvania,
Michigan, California, Iowa, North Carolina, Maryland, Wisconsin, Washington
and Minnesota. These trials found that, in comparison to nonorganic management, organic farming increases soil organic matter, enhancing the soil’s ability
to sequester carbon, cycle nutrients and absorb water. Futhermore, the study
found increased levels of soil organic matter and microbial activity even when the
organic plots were subjected to routine tillage. 22
Healthy Soils Resist Disease. A small but telling body of research suggests that
improved soil quality can increase crop resistance to disease. In a study from
North Carolina State University, published in Applied Soil Ecology in 2007, researchers found that Southern blight disease, a common soil-borne fungus that
affects hundreds of plants, was three to five times less prevalent on farms where
synthetic pesticides were not used than on conventional farms. 23 While the mechanisms for this are still unknown, scientist speculate that it may involve signaling
between plants and soil, perhaps mediated by soil organic matter. This is an area
where soil scientists and plant pathologists could collaborate on research and
generate extremely useful information for all farmers.
Organic farming builds soil that holds more water,
sequesters more greenhouse gas and prevents nitrogen
from leaching into our water.
Depleted, chemically-farmed soil Nutrient-rich organic-farmed soil
Organic Farming Is Good for Water Quality and Aquatic Life
Water may well become the largest problem facing global agricultural production in the very near future. Not surprisingly, food production practices can have
a strong impact on water quality.
Fewer Toxins in Water Supply. Ground and surface water can be contaminated
by the pesticides, fertilizers and animal wastes that are not absorbed by plants or
soil. In the United States, 64 percent of measured lake acres and 44 percent of
stream miles are impaired; they no longer support one or more of their designated uses such as swimming or fishing, according to the EPA. The synthetic her-
