For thousands of years, China's farmers have used human manure, or
"nightsoil", as fertilizer (King, 1911). In this example from the Tai Lake Region, nightsoil
is collected and stored in large ceramic
tanks or water-tight slate-lined or
concrete pits. Manure and urine are collected in buckets within the household,
or deposited directly in the storage tanks, which are usually located in the
animal stall and toilet area of the household. Occasionally urine is collected
and applied separately. It is common to
mix pig manure with nightsoil in
storage, as pig stalls are connected to storage tanks via a sluice, to
facilitate collection of pig manure and urine. Prior to intensive use of
synthetic fertilizers, nightsoil
was an important fertilizer for nearly all
crops, including rice and wheat. Now, nightsoil is applied
mostly to small-scale
vegetable plots and other rainfed household crops. The primary reason for this
change is that nightsoil is applied in liquid form, so that it is much heavier
than chemical fertilizers.
As vegetables and rainfed crop fields are usually
nearer to the household than paddy fields,
nightsoil use is now concentrated in
these areas. Another reason for preferential use of nightsoil on horticultural
crops is that it is believed to enhance the productivity and flavor of these
crops, especially Bok Choy.
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Nightsoil is a nutrient-rich fertilizer that sustains soil fertility and crop
yields. By applying
nightsoil over large areas of cropland, nutrients are
recycled within the farm, without risking
pollution of surface waters with
nitrogen and phosphorus-rich wastes. The recycling of phosphorus
in human wastes
is especially important- humans are the top consumer in agroecosystems. Modern
sewage management technologies cause the eventual loss of soil P to oceans and
landfills. Now that populations have grown and nightsoil use has become more
concentrated in rainfed crop areas,
nightsoil applications may be increasing the
flux of surplus nitrogen and phosphorus to surface waters, leading to
eutrophication. There have always been health risks associated with nightsoil
use
(Richardson, 1950). One traditional adaptation to this risk is the near
total avoidance of raw foods in China. Health risks have been further reduced by
contemporary awareness of the spread of germs in human wastes, with farmers
avoiding contact with nightsoil more now than in the past. Nightsoil
is also
allowed to ferment longer in the tank before application. As chemical
fertilizers provide an inexpensive and convenient nutrient source, nightsoil use
is on the wane, and flush toilets are
becoming more common. If the trend toward
nightsoil overapplication in small areas and sewage dumping continues, serious
environmental damage is unavoidable, and dependence on.
Human Waste Used by 200 Million Farmers, Study Says
August 21, 2008
Facing water shortages and escalating
fertilizer costs, farmers in developing countries are using raw sewage to
irrigate and fertilize nearly 49 million acres (20 million hectares) of
cropland, according to a new report—and it may not be a bad thing.
While the practice carries serious health risks for many, those dangers are
eclipsed by the social and economic gains for poor urban farmers and consumers
who need affordable food, the study authors say.
Nearly 200 million farmers in China,
India,
Vietnam,
sub-Saharan Africa, and Latin America harvest grains and vegetables from fields
that use untreated human waste.
Ten percent of the world's population relies on such foods, according to the
World Health Organization (WHO).
"There is a large potential for wastewater agriculture to both help and hurt
great numbers of urban consumers," said Liqa Raschid-Sally, who led the study
published by the Sri Lanka-based International Water Management Institute (IWMI)
and released this week at the World Water Week conference in Stockholm, Sweden.
Health Risks
The report focused on poor urban areas, where farms in or near cities supply
relatively inexpensive food. Most of these operations draw irrigation water from
local rivers or lakes. Unlike developed cities, however, these areas lack
advanced water-treatment facilities, and rivers effectively become sewers.
When this water is used for agricultural irrigation, farmers risk absorbing
disease-causing bacteria, as do consumers who eat the produce raw and unwashed.
Nearly 2.2 million people die each year because of diarrhea-related diseases,
including cholera, according to WHO statistics. More than 80 percent of those
cases can be attributed to contact with contaminated water and a lack of proper
sanitation. But Pay Drechsel, an IWMI environmental scientist, argues that the
social and economic benefits of using untreated human waste to grow food
outweigh the health risks.
Those dangers can be addressed with farmer and consumer education, he said,
while the free water and nutrients from human wastewater and feces can help
urban farmers in developing countries to escape poverty.
Waste Into Water
Agriculture is a water-intensive business, accounting for nearly 70 percent
of global fresh water consumption.
In poor, parched regions, untreated wastewater is the only viable irrigation
source to keep farmers in business, according to Drechsel. Mark Redwood, a
senior program officer with the Canadian International Development Research
Centre, said that in some cases, water is so scarce that farmers break open
sewage pipes transporting waste to local rivers.
Artificial Meat Made From Human Poop
Japanese researcher Mitsyuki Ikeda
has accomplished what we’ve all dreamed of doing: He has extracted protein from
human fecal matter and turned it into edible, artificial meat. Yep, that burger
pictured above is a human poopburger. A noble intention, Ikeda went down this
road in order to be resourceful by recycling poop, which in theory, would
actually help create food for the less fortunate — although one may say anyone
who has to eat a poopburger is pretty unfortunate.
Currently, the poopburgers are quite expensive,
costing around ten to twenty times the price of regular meat, because each
burger has to factor in the price of Ikeda’s research. As delectable as
“poopburger” sounds, Ikeda calls the poop extract “sewage mud,” which only
sounds slightly better. Head on past the break to see a short video segment
featuring Ikeda and his poopburger
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