Sustainable Agriculture, Green Energies and the Circular Economy
Sustainable organic agriculture could
cut China’s greenhouse emissions and save fossil fuel use by more than 40 percent;
decentralised, distributed green energies would do the rest for the circular
economy Dr. Mae-Wan Ho
contribution to the International Workshop on Sustainable Food and
Agriculture, Remin University, Beijing 13-15 March 2010
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surveys put food and agriculture under the spotlight
national surveys in China have put food and agriculture under the spotlight.
The results of its first national pollution census revealed that China’s intensive, high input agriculture is a worse polluter than its burgeoning industry.
Wastewater runoff from farms accounted for 13.2 Mt of pollutants, more than
one-third of the total 30.3 Mt discharged into water in 2007. Wang Yanliang of
the ministry of agriculture acknowledged the high contributions from intensive
livestock farming and excessive use of fertilizers and pesticides in the
fields. The Chinese government is likely to more than double its investment to
protect the environment in its next five-year plan  China's Pollution Census
Triggers Green Five-Year Plan (SiS 46).
second study led by Zhang Fu Suo at the China Agricultural University in Beijing
revealed significant acidification of soils in China’s major croplands since
the 1980s as the result of the overuse of nitrogen fertilizers  China’s Soils Ruined by
Overuse of Chemical Fertilizers (SiS 46). Acidification of soils
reduces productivity and can lead to aluminium and manganese toxicities. It is
traditionally treated by liming, which will add considerably to production
costs at a time when the price of chemical fertilizers has surged along with
the price of fuel, and farmers’ income has plummeted despite rising government
subsidies . This is a stern reminder that intensive chemical agriculture
depends heavily on fossil fuels, and leaves a big carbon footprint (see later).
Chinese government announced it would spend more than 818 billion Yuan (US$119.8
billion) towards agriculture during 2010, an increase of over 93 billion Yuan on
the previous year . China’s agriculture still contributes over 11 percent to
the nation’s GDP and employs 40.8 percent of the population [5, 6]
China’s food security is precarious, as it uses
only 7 percent of the world’s land to feed 22 percent of world population .
Wen Tiejun, dean of the school of agriculture and rural development at Renmin University said China does not have to rely on chemical farming, and the government
needs to foster low pollution agriculture.
low pollution agriculture is the heart of the green economy for China as for
the rest of the world, and it is urgently needed if we are to survive the
global multiple crises of food, fuel, and finance as extreme weather associated
with climate change is already exacting its terrible toll in lives and lost
property, and predicted to slash agricultural production  Sustainable Agriculture & Green Energy Economy,
agriculture and green energies go together
ISIS and TWN have
jointly produced a comprehensive report  Food Futures Now: *Organic
*Sustainable *Fossil Fuel Free in 2008, on how organic agriculture and
localized food and energy systems can provide food and fuel security,
mitigating and adapting to climate change, and freeing us from fossil fuel use
altogether. The report is a unique combination of scientific analyses, case
studies on farmer-led research, and especially farmers’ own experiences and
innovations that often confound academic scientists wedded to outmoded and
The companion volume released towards the end of 2009  Green Energies - 100%
Renewable by 2050 (ISIS/TWN publication), documents that the world is
already shifting to renewable energies, and 100 percent green power is realisable
by 2050, making use of available and rapidly improving technologies. The key is
decentralised distributed generation that offers the maximum flexibility to
take advantage of technological improvements, giving people autonomy and
independence from obsolete and wasteful centralised power plants. Germany has demonstrated how to implement decentralised distributed renewable energies
rapidly within the past five years, and is on course to become 100 percent
renewable by 2050, according to its renewable energy industry sector.
Renewable energy is inexhaustible and does not run out. It is free
once you’ve installed the equipment to capture it, and companies can’t meter it
or cut you off. Most importantly, it is available to all, so no need to fight
To be renewable is not enough, it must be ‘green’.’Green’ energies
are renewable; environmentally friendly, healthy, safe, non-polluting and
sustainable. That rules out nuclear, carbon capture and storage, biofuels, and
its latest incarnation biochar . Biofuels and biochar make clear why we
need to think about food and energy together. Turning food crops into biofuels
has been responsible for the steep food price increases that created hundreds
of millions more hungry people. The push for biofuels in the US and Europe has resulted in accelerated deforestation, land conflicts and “land grab” in poor
countries . Tens of millions of hectares of African ‘spare land’ are being
bought or long-leased by companies from rich countries, not just to grow
bio-energy crops, but to grow food for export to feed people in their own
countries. Bioenergy crops inevitably compete for land that could be growing
food. I shall show later how the potential for energy from waste is more than
enough to satisfy our needs.
This brings me to how ‘sustainable’ should be defined. It is to
endure for hundreds or thousands of years like natural ecosystems, thanks to a
natural circular economy of reciprocity and cooperation that renews and
regenerates the whole (more later). For human beings, it is to use natural
resources responsibly and equitably, to meet the needs of all in
the present without compromising the needs of future generations. The world’s
potential of green energies is truly enormous. Wind power has the potential to
supply the world’s electricity needs 40 times or 5 times all its energy needs.
Solar panels at a modest 10 percent efficiency covering 0.1 percent of the
world’s land surface could provide all our energy needs. Methane from anaerobic
digestion of organic wastes can save over 50 percent of our energy consumption,
in combination with local organic food production. And there are many further
possibilities, according to local resources: microhydroelectric, geothermal,
tidal reef, deep water air-conditioning (but not on large scale), saline
agriculture, and more.
Our enquiry into green energies concludes that the world can be 100
percent renewable by 2050.
·A variety of truly green and affordable options
already exist, and more innovations are on the way.
·Policies that promote innovations and stimulate
internal market for decentralised, distributed generation are key
·Global cooperation is crucial; developed nations
have an international obligation to support developing nations to fight global
warming with renewable energies.
agriculture is the first fuel for the green economy
agriculture produces food, which is fuel for human beings, without which there
can be no economy, green or otherwise. It also satisfies our other basic needs such
as fibres for clothing, wood for construction material, medicinal herbs, biomass
for fuel, paper, etc. In extracting these goods from nature, we need to treat her
as a cherished friend, which is where sustainable agriculture begins and ends. In
return, nature pays us back handsomely
Sustainable agriculture saves energy and carbon emissions, prevents
pollution of the environment, yields more than chemical agriculture, produces
healthier food for the nation, results in more profit for farmers, creates more
jobs, and when integrated with local green energies generation, forms the green
circular economy we need to replace the unsustainable economic model. You can
find the details in our green book . I shall highlight some recent research
and what it could mean for China to adopt sustainable organic agriculture. China is in a good position to set an example for the rest of the world.
It is a common
myth that organic agriculture yields less than conventional chemically
fertilized agriculture. A team of scientists led by Catherine Badgley at the
University of Michigan in the United States refuted this common myth in a study
that analysed 293 examples worldwide in which yields of organic production were
compared with conventional chemical production to give an O/C
(organic/conventional) ratio [10, 11]. The O/C ratios for 10 or the 11 major
food categories of plant and animal products were greater than one, the
exception was ‘meat and offal’, where the ratio was 0.998. The overall average
was 1.321. In other words, organic agriculture is on average 32.1 percent more
productive than conventional agriculture. Furthermore, green manure alone
provides more than enough nitrogen, amounting to 171 percent of synthetic N
fertilizer used currently.
Similarly, a seven year-long field experiment carried out with
farmers in Ethiopia found that crops fed with organic compost out-yielded
chemically-fertilized crops, the O/C ratio averaged over the four most commonly
grown grain crops was 1.34  (see Table 1). Thus, organic production again
increased yields by about 30 percent.
Table 1 Average yields of four
major crops over seven years and O/C ratios
Delate of Iowa State University and Cynthia Cambardella of the US Department of
Agriculture assessed the performance of farms switching from conventional to
certified organic grain production [13, 14]. The experiment lasted four years: three
years of transition to organic and first year of certified organic growth. They
found that over the four years, corn yield in the organic system averaged 91.8
percent of conventional corn yield, and soybean in the organic system averaged
99.6 percent of conventional soybean yield. The small reductions in yields were
due to bigger reductions during the first and second years of transition. By
the third year, there were no significant differences in yields, but by the
fourth year, both organic corn and soybean yields exceeded conventional yields.
In the initial year of transition, an economic advantage could be gained by
planting legume hay crops or crops with a low nitrogen demand in fields with
low productivity, in order to increase fertility for the following corn crop.
In the second year, yield differences were mitigated by rotation and compost
application, providing sufficient nutrients for the organic grain crop. The
importance of a soil-building cover crop, or legume grass mixture such as the
oat-alfalfa mixture was apparent in the fourth year, when organic corn and
soybean out-yielded the conventional crops.
has been maintaining the 17 acre Long Term Agroecological Research site in Greenfield, Iowa, for the past 12 years, experimenting on four different rotation systems
and comparing organic and conventional yields . In the fourth year of the
latest experiment, organic corn yields averaged across all rotations was 130
bushels per acre compared with the conventional corn yield of 112 bushels per
acre. Organic soybean yields averaged 45 bushels/acre, exceeding the
conventional yield of 40 bushels/acre. Over the 12 years of the experiment, the
average corn yields are 171 bu/ac and 163 bu/ac for organic and conventional
respectively. The 12 year average yields for organic and conventional soybeans
are identical at 47 bu/ac.
As demonstrated by
Delate , the average production costs during the first two years of organic
transition were lower than in the conventional production by $50/ac, chiefly
due to the saving on chemical fertilizers and pesticides. On average, the
organic crops return two times as much earnings over the four years. There is
plenty of evidence that organic farmers earn more than conventional farmers all
over the world .
resistance and resilience
advantage of organic cropping systems is that they are more resistant to
physical stresses such as floods and droughts, and biotic stresses such as
pests and diseases. Moreover, they are more resilient, in that they recover
faster from stresses. These qualities make them perfect for adapting to climate
change thereby improving food security.
study carried out in Nicaragua after Hurricane Mitch found that organic,
agro-ecologically managed farms were more resistant to damage. They had more
topsoil and vegetation, less erosion and economic losses compared to plots on
conventional farms .
A long-term field trial at Rodale Institute in Kutztown, Pennsylvania involving 6.1 ha compared three different cropping systems: conventional,
animal manure and legume-based organic, and legume-based organic. The results
over 13 years showed that organic yields were not different from conventional,
except in drought years, when organic yields were 28 to 34 percent higher than
conventional [17, 18]. Organic soils holds more water, and water percolating
through into the soil was 15 to 20 percent greater in organic soils.
It is estimated
that a third or more of all energy used in US agriculture goes to commercial
fertilizer and pesticide production, the most energy intensive of all farm
inputs . When conventional and organic cropping systems were compared for
energy use, it becomes clear that the major energy saving comes from chemical fertilizers.
For example, the Glenlea long-term study of rotation cropping at the University of Manitoba found that organic agriculture without chemical fertilizer and
herbicide required 35.4 and 45 percent of the energy inputs of the conventional
counterparts , with fertilizer inputs accounting for 51 and 43.4 percent of
the energy savings. Similar results have been obtained in other studies .
It takes approximately 80 MJ of fossil fuel energy to make and
transport 1 kg of fertilizer N to the farm . China used 32.6 Mt fertilizer
N in 2007 , which amounted to 2.61 EJ of energy (3.6 percent of national
energy consumption of 72.2 EJ in 2006), or 57.9 Mt of oil (14.6 percent of national
oil consumption) . China imports both oil and coal. I have not included the
energetic costs of pesticides, which could be 10 to 20 percent more.
nitrogen fertilizers saves an equivalent of 57.9 Mt of oil, emitting 179.5 Mt
CO2 (2.38 percent national emissions). Moreover, using organic as
opposed to chemical fertilizers reduced N2O emissions 22 percent in
a rice-duck system in south China . N2O has a global warming
potential of about 300 compared with CO2. China’s N2O
constituted 8 percent of its 7.527 Gt national greenhouse gas emissions in
2005, of which 70 percent is attributable to agriculture . A 22 percent
reduction in N2O on switching from chemical to organic fertilizer
would reduce 1.23 percent of national greenhouse emissions, i.e., 92.7 Mt CO2e.
So phasing out N fertilizers would result in a total saving of 272.2 Mt CO2e,
or 3.62 percent of national emissions.
biggest savings are due to organic soils, which sequester a lot of carbon. A
long term study at the Rodale Institute in Kutztown, Pennsylvania, USA, found that organic soils sequester on average 4.114 tonnes of CO2/ha/y , while
soils in conventionally managed crops did not increase in carbon content. China has 166 million ha of crop lands in 2007 . If all the croplands were converted to
organic, the amount of carbon sequestered would be 682.9 Mt of CO2,
or 9.07 percent of national emissions. Thus, a total of 917.9 Mt CO2 would
be mitigated each year, representing 12.19 percent of national emissions.
has a further 66 million ha of average- and low-yielding farmlands, 4.4 million
ha of wasteland, and 400 million ha of plains and grass-covered hillsides, 5.44
million ha of usable fresh water areas and 2 million ha of coastal tidal flat
areas that are not yet fully explored for agriculture, as pointed out in an
Asian Development Bank report . Sue Edwards of the Institute of Sustainable
Development based in Addis Ababa describes how she and her colleagues have
successfully rehabilitating degraded land into fertile croplands , which may
be relevant to how China’s additional land could be explored for agriculture.
Permanent pastures, properly managed, are ideal for raising livestock
sustainably, while sequestering huge amounts of carbon in the deep roots of the
perennial grasses  Organic
Agriculture and Localized Food & Energy Systems for Mitigating Climate
Change, SiS 40).
China has been supporting anaerobic digestion for industry and rural
households since 2003. However, its use on farms is still quite limited. Dong
Renjie and colleagues at the China Agricultural University of Beijing have
drawn attention to the increasing quantities of livestock wastes from
agriculture, which emit lots of greenhouse gases, especially CH4,
amounting to 800 Mt a year. Half of that could be mitigated, however, if the
livestock wastes were subjected to anaerobic digestion . At the same time,
it would yield 13.9 Mt of methane containing 0.774EJ of energy to use as fuel
and mitigate an additional 53.5 Mt CO2e emissions in substituting
for fossil fuels.
Anaerobic digestion could include human manure (traditionally used
as crop fertilizer in China). Agriculture is estimated to employ 40.8 percent
of the population [5, 6]. A study by NASA to prepare humans for space-travel
indicates that the average human produces about 100 g of solid manure containing
25 g of volatile solids (VS), plus about 2 litres of urine containing another 25
g VS and 6 g of toilet paper, making 56 g VS . Anaerobic digestion of the
wastes from 40.8 percent of 1.4 billion (571 million) would yield 11.671 Mt VS
a year, resulting in 2.0168 Mt of methane or 0.112 EJ energy.
In addition, China has unused primary agricultural and forestry
residues estimated at 263.285 Mt/y in dry mass, and secondary agricultural and
forestry residues of 47.889 Mt/y . Plant biomass has a higher yield of
methane, up to 0.266 kg per kg total solid . Thus, the total biomass from
unused primary and secondary agricultural and forestry residues could generate 82.756
Mt of methane or 4.6 EJ of energy. Incidentally, anaerobic digestion of potato
wastes achieved a 95 percent recovery of theoretical energy content, much
higher than fermentation into ethanol . The proposal to convert biomass
wastes into second generation biofuels such as cellulosic ethanol  should
be carefully reviewed and compared with anaerobic digestion, a much cheaper and
mature technology that can benefit farmers the most, especially those in
developing countries .
According to Li Jingming, Technology Development Centre, Ministry of
Agriculture, who spoke on Sunday 14 March , the Chinese government is
aiming for 40 million household anaerobic digesters and 4 000 large digesters
that will produce a total of 19 billion m3 methane by 2010. By 2020,
there will be 80 million household digesters and 8 000 large digesters
producing 44 billion m3 methane.
advantages of anaerobic digestion are well-known (see Box 1 ). The enormous
energy potential from wastes in the form of methane coupled with its overriding
environmental and agronomic benefits stand in stark contrast to the many
harmful consequences of producing biofuels from energy crops, first or second
Advantages of anaerobic digestion of organic wastes
·Produces an abundant, readily available source
of bioenergy that does not take land away from growing food
·Takes a wide range of feedstock, including
livestock and human manure, crop and food residues, paper, bakery and brewery
wastes, slaughterhouse wastes, garden trimmings, etc, and the yields of methane
generally better in mixed waste streams
·Biogas methane is a clean cooking fuel,
especially compared to firewood (and dung)
·Methane can be used as fuel for mobile vehicles
or for combined heat and power generation
·Methane-driven cars are currently the cleanest
vehicles on the road by far
·Biogas methane is a renewable and carbon
mitigating fuel (more than carbon neutral); it saves on carbon emission twice
over, by preventing the escape of methane and nitrous oxide into the atmosphere
and by substituting for fossil fuel
·Conserves plant nutrients such as nitrogen and
phosphorous for soil productivity
·Produces a superb fertilizer for crops as
·Prevents pollution of ground water, soil, and
·Improves food and farm hygiene, removing 90
percent or more of harmful chemicals and bacteria
·Recycles wastes efficiently into food and energy
resources for the circular economy
A combination of organic agriculture and anaerobic digestion in China has the potential to mitigate at least 23 percent of national greenhouse gas
emissions and save 11.3 percent of energy consumption (see Table 2). In other
words, sustainable agriculture with anaerobic digestion saves more than the
agricultural sectors’ emissions and energy use, and contributes to other
sectors of the green economy. Most importantly, it prevents up to 13.2 Mt
pollutants leaching into the nation’s water supply.
N fertilizers saving
Total for org. agri.
Livestock manure ghg saving
Hum manure methane
Ag.& for. res. methane
Total for AD
circular economy with green energies and sustainable agriculture
China has been
promoting the circular or recycling economy for some time, and enacted the Circular
Economy Promotion Law in 2008 . At the 4th China International
Recycling Economy Summit in October 2009, Chinese experts called on the
government to promote circular economy to boost China’s economic recovery .
Yang Boling, former president of the Chinese Academy of Sciences, urged
government at all levels to make plans to advance the circular economy and
improve controls on energy use and pollution. But he said it would be difficult
during the financial crisis.
it is not difficult at all. When you transform the dominant linear monoculture
model to the circular model, you turn output into input again. Switching to a
circular green economy means more efficient use of energy and resources, hence
providing quick profit in energy savings.
Anaerobic digestion is obviously a key technology in the recycling
economy, as it recycles organic wastes efficiently into food and energy
resources. This is most clearly seen in the eco-farm concept introduced by Dr.
Xue Dayuan, Chief Scientist of Environmental Protection of Biodiversity . I
call it the Dream Farm  - formalized from the scheme of waste-management
engineer George Chan - an abundantly productive farm with diverse crops,
livestock and fish ponds, built around anaerobic digestion of livestock and other
organic wastes; the biogas generated satisfying energy needs.
George Chan, in turn, learned about circular economy from the
Chinese peasants who perfected the dyke-pond system of Pearl River Delta . The
Chinese peasants, like many traditional indigenous farmers, know that nature
runs on the circular economy, which is why it is sustainable. There are many
dyke-pond systems. In one version, pigs, elephant grass, mulberry and silkworms
are raised on the dykes, the wastes and elephant grass go to feed up to 5
species of carp in the ponds. The pond water is used to ‘fertigate’ the crops
on the dykes, and pond mud used as additional fertilizer. The system was so
productive that it supported 17 people per ha in its heyday. This is the kind
of productivity that China needs for its limited land.
I have proposed a Dream Farm 2  (see Fig. 1) which, in addition
to anaerobic digestion, explicitly incorporates green energies at small to micro-scale
(and include permanent pastures and woodlands). This mix of energies not only
ensures a reliable supply, but can reduce energy use by at least 30 percent through
exploiting ‘waste’ heat from power generation, and preventing energy loss in long
distance distribution and transmission.
Figure 1 Dream Farm 2
The diagram is colour-coded. Pink is for energy, green for
agricultural produce, blue is for water conservation and flood control, black
is waste in the ordinary sense of the word, which soon gets converted into food
and energy resources. Purple is for education and research into new science and
technologies. The advantages of Dream Farm 2 are presented in Box 2.
The advantages of Dream Farm 2
for efficient use of resources and productivity
·Energy use at the point of
production improves efficiency by up to 60 percent
·Runs entirely on renewable
energies without fossil fuels, hence saving up to 100 percent of carbon
·Increases sequestration of
carbon in soil and in standing biomass
·Reduces wastes and environmental pollution to a
·Conserves and purifies
water and controls flooding
·Produces a diversity of
crops, livestock and fish in abundance
·Fresh and nutritious food
free from agrochemicals produced and consumed locally for maximum health
opportuni8ties for the local community
zero-entropy economy at work
·Assembles in one showcase
all the relevant technologies that can deliver sustainable food and energy and
a profitable zero-carbon green economy
·Provides an incubator for
new energy and food technologies
education and research opportunities at all levels from infants to university
students and beyond
·Promotes similar farms all
over the world
Approximately 57 percent of China’s carbon emissions come from the
energy sector, according to the energy mix given by the International Energy
Agency . An efficiency saving of 30 percent would mean a reduction of 17.1
percent in carbon emissions. The green potential of Dream Farm 2 is given in
Table 3. As can be seen, Dream Farm 2, if generally adopted in China, would mitigate 40 percent of greenhouse emissions, and save 41 percent of energy
consumption, only counting anaerobic digestion. So, with the addition of solar,
wind or microhydroelectric as appropriate, such farms could compensate, in the
best case scenario, for the carbon emissions and energy consumption of the
entire nation. The key to the success of Dream Farm 2 is local production and
local consumption for both food and energy.
potential of Dream Farm 2
Energy savings local gen.
1 287.1 Mt
2 983.6 Mt
economy of the organism and sustainable systems
When you transform the linear into circular, you turn output into
input again, thus, you end up conserving energy and resources and the system
renews itself (Figure 2).
Figure 2 From linear to circular economy
In the ideal, the organism’s circular economy satisfies the zero-entropy
condition (Fig. 3), entropy being made up of dissipated or waste energy.
Figure 3 The zero-entropy model of organisms and sustainable
The zero-entropy ideal depends on coupled cycles of activities at
every scale, activities that generate energy are directly linked to those
requiring energy; thereby minimising the dissipation of energy and materials,
and even the wastes exported to the environment is minimum, which makes sense,
as the organism depends on the environment for input. Sustainable ecological
and agroecological systems work precisely in the same way (Fig. 4). Lots of
life cycles are coupled together, and the ‘wastes’ of one organism is nutrient
Figure 4 The circular economy of organisms and sustainable systems
The green economy (Figure 5, left) contrasts strongly with the
dominant brown economy.
The brown economy is based on infinite growth fuelled by maximum
dissipation and exploitation of people and planet. It does not close the circle
to build up structure or dynamic cycles. Boom and bust are inherent to the
brown economy, so financial collapse is nothing new. More seriously, it has destroyed
the earth’s habitats and brought us climate change.
The circular green economy is built on reciprocity and cooperation.
It closes circles and builds balanced dynamic structures that sustain the
whole, and enable us to thrive in balance with the earth. As you can see, more
lifecycles can be added into the system to make it bigger, provided these
lifecycles are linked by reciprocity and cooperation. It is intuitive to see
the different lifecycles as biodiversity; the more biodiversity, the more
productive the system. This balanced growth at every stage is the essence of
sustainable development. We should have no hesitation to opt for the green