Ecological Assessment - Energy
Introduction
All agricultural systems utilize the sun’s energy to convert carbon dioxide into biomass.
However, because agricultural systems differ from natural ecosystems, agroecosystems require
additional energy inputs (Gliessman 2007). Farmers can choose whether or not to obtain that
energy from sources that are sustainable with respect to future agricultural production. These
energy choices can lead to greenhouse gas emissions that cause climate change, which in turn
will decrease agricultural production (IPCC 2007). Greenhouse gas emissions caused by the
combustion of fossil fuels have already caused major global climate change (IPCC 2007).
Worldwide, about one-third of the total anthropogenic climate change due to greenhouse gases
comes from agriculture and land-use change (Paustian et al. 2006). Thus, in order to quantify a
farm’s sustainability it is important to carefully examine its greenhouse gas emissions and,
specifically, energy use.
Farms can consume energy directly or indirectly. Direct energy is mainly used for
operation of machinery, irrigation, and handling of the crop after harvest. Indirect energy is
energy used off-farm to produce inputs used on-farm. Such inputs include pesticides and
fertilizers (Miranowski 2005). We attempt to rate the ecological sustainability of farms based on
farmer choices pertaining to these five energy uses. We quantified the non-renewable energy a
farm uses in the five categories and then combined and standardized those values into an
indicator score between zero and ten. The holon we used for our assessment is the physical farm
boundary and the production and transport of inputs used within that boundary. We evaluated ten
Chinese farms and seven U.S. farms. In both countries, we visited both organic and conventional
farms. Here we report the methodology for calculating the indicator score and a summary and the
results for every farm visited.
Methodology
Fertilizer
Other energy indicators for agricultural sustainability multiply the quantity of fertilizer
applied by some energetic coefficient associated with the type of fertilizer in order to quantify
energy use (Pervanchon et al. 2002). While these estimates may be difficult to obtain, we believe
this is the best framework with which to measure the indirect energy use of fertilizer production.
We will use the formula from Pervanchon et al. (2002) to estimate the energy use from
fertilizers. They used coefficients from Mudahar and Hignett (1987), and then multiplied those
by 0.70 in recognition of the growth of more energy efficient technology since 1987 (Table 1).
That coefficient indicates how many mega-Joules (MJ) of energy are used per kilogram of
fertilizer. We will then multiply that value by the total mass of fertilizer that the farmer applies
per hectare. Finally, we will include the average energy cost of packaging and transporting the
fertilizer, also as estimated by Mudahar and Hignett (1987), again multiplied by the kilograms of
fertilizer applied per hectare. For the transport of non-synthetic fertilizers, we calculate that it
takes 2.89E-3 MJ to transport one kilogram one kilometer by road (Hill 2008). Thus, we will
multiply the mass of fertilizer the farmer applies per hectare by the distance the fertilizer travels
and then by 2.89E-3 MJ/kg/km to find how much energy it takes to transport the fertilizer
necessary to farm one hectare.
Table 1 Energy use for common fertilizers. Values for less common fertilizers are also available.
(Mudahar and Hignett 1987, Pervanchon et al. 2002)
Fertilizer
N
Production
(MJ/kg)
Ammonia
32.1
Packaging and
Transport (MJ/kg)
4.9
Total
(MJ/kg)
37.0
Urea
24.9
4.9
29.8
Ammonium
nitrate
16.8
4.9
21.7
Urea-Ammonium
nitrate
13.8
4.9
18.8
6.0
5.8
11.8
3.5
2.7
5.8
4.4
9.4
7.1
P (single
Granular
superphosphate)
Nongranular
K (Potash)
Pesticides
To find the energy use of pesticides, data was first obtained on the type of pesticide used
and the numbers of acres each pesticide was used on in a given year. From this data, energy
coefficients, in MJ/mt were obtained, mostly from Cecil N. Nagy’s 1999 paper. When energy
coefficients could not be found for the specific pesticide, energy coefficients were taken from
other pesticides within the same chemical class as both pesticides would have similar structures
and thus both would require similar amounts of energy. When energy coefficients could not be
found for pesticides within the same class, the average energy coefficient of all the herbicides or
pesticide energy coefficients provided was used. For organic pesticides for which an energy
coefficient could not be found, the average energy coefficient was divided by two because,
according to Jodi Ziesemer’s 2007 paper, organic farms use about 50% less energy than do
conventional farms.
The MJ/ha energy usage of these pesticides was then calculated by multiplying the
energy coefficients by the application rate, obtained from manufacturer recommendations and
averaged if a range of application rates was given. To get an energy requirement in MJ/ha/yr, this
number was then multiplied by the number of hectares sprayed with the pesticide in a given year.
3MJ was then added to the equation to take into account the average energy required to package
and ship each pesticide. Finally, the energy score was divided by the total hectares of the farm to
get a MJ/ha/yr energy requirement for each pesticide used on the farm. Please reference
appendix one for a complete table of data collected and calculation made.
Machinery
To quantify energy used by farming machinery, we asked farmers to tell us their
aggregate annual fuel consumption. If farmers were able to oblige us and provide this
information, then we simply calculated the total energy (in MJ) contained in the various
fuel types and divided that value by the farm’s size in hectares, thus obtaining a bottom-line
energy total in MJ/ha.
Other farms were not able to provide estimates of overall fuel consumption. This
was especially true for Chinese farms, where agricultural systems have yet to undergo a
similar magnitude of mechanization as conventional western farms. In fact, in many
regions of China, farms still rely almost exclusively on human and animal power to farm.
For us to generate amounts of energy used on those farms, it was necessary for us to
quantify the distinctions in energy use between human powered, animal powered and
machine powered methods of farming, as is done in the table featured below. Farms
relying exclusively on human power were automatically given the most sustainable score
possible for our assessment’s machinery category. If farms used any livestock or
machinery to tend their land, we inquired about the type of machinery used, and also what
tasks those machines performed..
Obviously frequency of tillage and pesticide or fertilizer application is a key
determinant of energy use, since they combine for a substantial percentage of a machine’s
use. It is also critical to recognize that various farming tasks require different amounts of
energy to be performed. For example, using a 50 HP tractor to drag a plow through soil in
the tillage process is nearly ten times as energy intensive than use of the same tractor for
planting or applying herbicides. These differences are reflected in Tables 7.1 and 7.2
included above (Pimentel, 1996). We used the rates of energy expenditure furnished by
these charts as the basis of our calculation for energy used by a farm’s fleet of machinery,
based on the machine type and the tasks performed.
Table 2:
Due to the variability of farms in size, energy inputs were evaluated on a per hectare
basis, rather than as an absolute value. Therefore our final estimate of total energy use by a
farm’s machines was converted into MJ/ha, and this total represented energy expended by
machinery in our assessment’s final scoring index.
Irrigation
To calculate the total energy used by an irrigation system on an individual farm,
questions were first asked to the farmers with regards to what type of irrigation system
was used and how much of the land was irrigated during one season. With the answers to
these questions, the energy total, in MJ/ha/yr, of individual irrigation systems was
calculated. This was done by first finding the number of MJ/yr each individual system used
in a single year. These numbers were found by multiplying the number of hectares
irrigated on the farm each year by the energy requirements of irrigation systems obtained
from J. F. Alfaro and J. Marin V.’s 1994 paper (see table 3). When data was not available for the
irrigation systems used, specifically for flood irrigation and irrigation done manually with a hose,
the number of hectares irrigated each year was multiplied by how much energy the pump used in
these systems would require, given that for both flood and hose irrigation, pumping the water is
the extent of the energy required as distributing the water is either done by gravity or by hand. It
is important to note here that some assumptions had to be made when calculating these numbers,
due to the lack of time to collect data. For example, assumptions had to be made with regards to
how many hours the water pump was used each year, which were calculated based upon how
long it was thought it would take to irrigate the amount of land the each farm irrigated.
Assumptions also had to be made with regards to how high the wattage of the irrigation pump
that they used was, as this data was not attainable within the parameters of our research. To
calculate the MJ used by the pump in hose and flood irrigation, an average wattage of 675 watts
therefore taken and converted into MJ. After the MJ/yr of a specific irrigation on a farm was
found, this number was divided by the total number of hectares on the farm to gain an energy use
of MJ/ha/yr.
Table 3: The energy requirements, in MJ/ha/yr, of certain irrigation systems
Irrigation System
Efficiency Potential
Conventional Sprinkler
6,829
Center Pivot
13,003
Drip
2,754
Micro-Sprayers
3,553
Please reference appendix 2 for a complete table of the data that we collected and calculated for
energy usage.
Post-harvest
Based on 2007 U.S. corn yields, an average liquid petroleum (LP) grain dryer uses 4960
MJ/ha to dry grain from 22% to 15% moisture content (Dougherty and Geuder 2008, Uhrig and
Maier 1992). Thus, if a farmer chooses to use an LP grain dryer, we will add 4960 MJ/ha
multiplied by the proportion of the farm acreage that has its product dried to the farm’s total
energy use. While this is only an average value, it is a crude way of acknowledging that farmers
who use grain dryers use more energy.
Many vegetable farmers keep their produce a walk-in cooler before selling it. Data from
Cooler Connection (2009) indicate that the energy a cooler uses (measured in MJ/month) can be
approximated by the equation:
2370 * Ln(area) - 6278.
If a farm has a walk-in cooler, we will estimate the cooler’s area in square feet and find
approximately how much energy it uses in a month. Then we will divide that value by the farm’s
total number of hectares and multiply by the number of months per year the cooler operates to
find the energy the cooler uses per hectare in a given season. This value will be added to the
farm’s total energy use. Again, while this method is imperfect, at least it roughly estimates the
energy a farm is using for food storage.
Final indicator score
We will use the following equation to calculate a farm’s energy score for fertilizers,
pesticides, machinery, irrigation and post-harvest management out of ten possible points. It is
based off of pre-defined practices for completely sustainable (receiving a score of 10) and
completely unsustainable (receiving a score of 0) farms.
Score = 10.71– 2.97E-4 * Energy use.
While the thresholds are somewhat arbitrary, we have based the values off of previous research
on what constitutes high and low energy use.
Farm summaries and Results
Duang farm, Beijing, China
Mr. Duang used no synthetic fertilizer and all fertilizer came from on-site. Mr. Duang
used no pesticides on his farm. He applies manure is to the field three times annually by
hand, and once during the growing season a 50 HP tractor is used to till. After harvest, a
roto-tiller is used to till in the greenhouses and fields. Collectively, we estimated the
energy use by these machines to total 1380.9 MJ/ha/yr. Mr. Duang used flood irrigation on
0.19 ha for a total of 0.079 MJ/ha/yr. He does not use a cooler or grain dryer, so receives no
energy additions for post-harvest practices. Therefore, we calculate the total energy usage of the
Duang farm to be 1381MJ/ha/yr. Based upon our function, this gives the farm a maximum
sustainability index score of 10.
Ji Yun Liang, Beijing, China
This farm used no synthetic fertilizers, and all fertilizer came from on-site, thus, for our
purposes, it uses no energy for fertilization. Mr. Liang uses no pesticides. As Liang’s farm used
no machinery (besides a seldom used piece of equipment for bailing hay), his energy use
for machinery is 0 MJ/ha/yr. He uses drip irrigation on 0.52 ha for a total of 2,203 MJ/ha/yr.
The farm did have a large refrigerator that was approximately 12 square feet. However, it was
not actually a walk-in cooler, and the regression equation we estimated for walk-in coolers
estimates a negative annual energy use for a cooler with such a small area. While the cooler
obviously uses some energy, the energy use from the cooler is probably negligible when
compared with that of the rest of the farm. Therefore, we calculate the total energy use of the
Liang farm to be 2,203 Mj/ha/yr, which gives them the maximum sustainable energy index score
of 10.
Ai Farm, Near the Great Wall, China
When Mr. Ai had more land, he applied urea at a rate of around 202 kg/ha. It takes
approximately 28.3 MJ to produce, package, and transport a kilogram of urea. Thus, Mr. Ai used
5,723 MJ/ha/yr for fertilization. Mr. Ai used no pesticides. Mr. Ai’s machinery inventory
consisted only of one donkey, which was used once a year for tilling and also handled
delivery of his produce. The donkey is estimated to demand 544.3 MJ/ha/yr. He did not
irrigate, use a grain dryer or chill his produce in a walk-in cooler. Therefore, we calculate the Ai
farms total energy consumption to be 6,267 MJ.ha/yr, which, based upon our function, gives the
farm an index score of 8.85.
Little Donkey Farm, Beijing, China
Little Donkey used no synthetic fertilizer or pesticides and all fertilizer came from onsite. Once a year, the farm borrows a 50 hp tractor to till their fields. This tilling accounts for
1282.4 MJ/ha/yr in energy use. They use flood irrigation on 3.23 ha for a total of 0.43 MJ/ha/yr.
Little Donkey does not use a cooler or grain dryer, so receives no energy additions for postharvest practices. Their total energy consumption is therefore 1282.83 MJ/ha/yr for a maximum
sustainable energy index score of 10.
Lu Farm, Sichuan province, China
Mr. Lu applies urea, superphosphate and potassium sulfate. He applies an average of 406
kg/ha of urea (11,503 MJ/ha/yr), 546 kg/ha of superphosphate (7020 MJ/ha/yr), and 367 kg/ha of
K2SO4 (3409 MJ/ha/yr). These application rates are deflated because Mr. Lu has 4 mu of
forested steep land on a hillside. Mr. Lu’s total fertilizer energy use is 21,932 MJ/ha/yr. Mr. Lu
uses the insecticide Lorsban on 1.76 ha/yr (844 MJ/ha/yr) and glyphosphate on 0.78 ha/yr (638
MJ/ha/yr). Therefore, his total pesticide energy use is 1,481 MJ/ha/yr. The Lu farm relied only
on the use of a water buffalo to till each year. The water buffalo was only responsible for
tilling the fraction of the farm designated for corn production, thus contributing a mere
90.7 MJ/ha/yr to the farm’s total energy consumption. He uses flood irrigation on 0.2 ha for
an energy usage of 0.67 MJ/ha/yr. Mr. Lu does not use a cooler or grain dryer, so receives no
energy additions for post-harvest practices. Therefore, the total energy consumed per year on the
Lu farm is 23,504MJ/ha/yr, which gives it an energy score 3.7.
Gao Family Farm, Sichuan province, China
The Gao family uses no synthetic fertilizer or pesticides and all fertilizer comes from on-site.
Their farm used not machinery. They use flood irrigation on 0.195 ha of their land for a total of
0.72 MJ/ha/yr. They also hose irrigate 0.46 ha (3.38 MJ/ha/yr). Thus, their total irrigation energy
consumption is 4.1 MJ/ha/yr. The Gao family does not use a cooler or grain dryer, so receives no
energy additions for post-harvest practices. Therefore, their farm’s total energy use per year was
4.1MJ/ha/yr, giving them the maximum sustainable energy index score of 10.
Wang Farm, Sichuan province, China
This farm used no synthetic fertilizer or pesticides and all fertilizer came from on-site.
The Wangs flood irrigate 0.23 ha (2.7 MJ/ha/yr) and hose irrigate 0.23 ha (5.2 MJ/ha/yr). Their
total irrigation energy use is around 7.9 MJ/ha/yr. They did not use any machinery. They do not
use a cooler or grain dryer, so receives no energy additions for post-harvest practices. Their total
energy consumption was 7.9 MJ/ha/yr for a maximum sustainable energy score of 10.
Emei Tea Company, Sichuan province, China
The tea company applies 27 kg/ha of urea, which is associated with an energy use of 802 MJ/ha.
They also apply 135 kg/ha of superphosphate (1736 MJ/ha/yr), and 34 kg/ha of potassium sulfate
(316 MJ/ha/yr). The tea company’s total energy use for fertilizer is 2854 MJ/ha/yr. They use the
insecticide Bifenthrin on 312 ha/yr. Their total pesticide energy use is 143 MJ/ha/yr. The Emei
Tea Company’s sprawling terraced farm was entirely managed by hand, with the exception
of gas powered pruners used to trim the tea bushes. Assuming that these pruners used a
typical 1.2 HP motor, we determined the company’s energy expenditure to total 50.2 MJ/ha
on machinery. They use an overhead sprinkler irrigation system on 104 ha for an energy total of
6,829 MJ/ha/yr. The company uses machinery to dry off 75% of the tea leaves’ mass before
packaging. Using data on energy use from drying corn and a yield of 40 wet pounds of tea per
mu, this means the farm uses about 247 MJ/ha/yr on drying the tea. Therefore the total energy of
the Emei Tea Company farm is 10,123, for an energy index score of 7.7.
Lei tea farm, Emei Shan, Sichuan province, China
Mr. Lei does not use synthetic fertilizer because he believes it makes inferior tea. He uses
Round-up on 0.65 MJ/ha/yr for a total energy use of 638 MJ/ha/yr. Mr. Lei uses no machinery on
his farm. He does not irrigate. He dries his tea over a wood-fired stove. Because the energy for
the stove comes from biomass, a renewable resource, the energy use is sustainable, so we do not
include it. Therefore, the total energy consumed by the Lei farm is .65 MJ/ha/yr, giving it a
maximum sustainable energy score of 10.
Lao Yu farm, Sichuan province, China
He uses no synthetic fertilizer or pesticides and all fertilizer come from on-site. No machinery is
used on this farm. The farm hose irrigates 1.3 ha for a total energy use of 0.62 MJ/ha/yr. He does
not use a cooler or grain dryer, so receives no energy additions for post-harvest practices.
Therefore the farm uses a total of .62 MJ/ha/yr, for a maximum sustainable energy score of 10.
Duofu farm, Nanchong, Sichuan province, China
Duofu buys 20 to 40 one-kilogram bottles of fish emulsion each year from Shanghai,
which is approximately 2000 kilometers away from Nanchong. Since it takes about 2.89E-3 MJ
to transport one kilogram one kilometer, transport of the fish emulsion uses only about 2.1
MJ/ha/yr. They use a pyrethrum on 312 ha/yr (538 MJ/ha/yr) and they apply Bt to 78 ha/yr (35.4
MJ/ha/yr). Their total energy consumption for pesticides is estimated at 574 MJ/ha/yr. Duofu
farm uses a combination of manual labor and a hand-pushed roto-tiller to till their plots of
bamboo, lotus, fruit, and vegetables three to four times a year. We therefore estimate this
extensive tilling to consume 2745.1 MJ/ha/yr of energy. They use sprinklers on 0.13 ha (11.4
MJ/ha/yr), flood irrigation on 13.0 ha (0.1 MJ/ha/yr), and hose irrigation on 16.2 ha (0.4
MJ/ha/yr). Therefore their total energy use for irrigation is 11.9 MJ/ha/yr. Duofu has a 100 m2
cooler. According to the regression equation calculated in the proposal, this means their cooler
uses approximately 1,827 MJ/ha/yr, assuming the cooler is running year-round. Therefore the
farm uses a total of 5,160MJ/ha/yr of energy, for a total energy index score of 9.2.
Lutteke Organic, Minnesota, USA
Lutteke applies 560 kg/ha of Gypsum (424 MJ/ha), 62 kg/ha of a Copper/Manganese
trace mineral package, and 62 kg/ha of lime (45 MJ/ha). Micronutrients like copper and
manganese are generally used in small enough quantities that they do not add significantly to
fertilizer energy use. Thus, we do not quantify their energy additions. Total fertilization energy is
469 MJ/ha/yr. He does not use any pesticides or irrigate his crops. Dennis Lutteke’s expansive
farm requires yearly fuel inputs of 1000 gallons of gasoline, 7000 gallons of diesel, and about
7100 gallons of LP gas used for flaming. Combining these figures, we estimate Lutteke’s
machinery to use 4385.2 MJ/ha/yr. Mr. Lutteke uses a grain dryer on 6.6% of his acreage, which
uses about 327MJ/ha/yr. Therefore, the total energy consumption is 5,181 MJ/ha/yr for an energy
index score of 9.2.
Schrader farms, Nerstrand, Minnesota, USA
The Schraders only apply nitrogen to their corn, not their soybeans. This leads to an
average ammonium nitrate application rate of 122 kg/ha (2649 MJ/ha) over their entire cropped
acreage. They also apply 106 kg/ha of potash (756 MJ/ha) and 50 kg/ha of superphosphate (643
MJ/ha). The Schraders’ total energy use for fertilizer is 4048 MJ/ha. They apply Round-up on
929 ha/yr (633 MJ/ha/yr), Force on 122 ha/yr (6.3 MJ/ha/yr), Dual on 608 ha/yr (1,568
MJ/ha/yr), and Select on 219 ha/yr (10.5 MJ/ha/yr). Their total pesticide energy use is 2,219
MJ/ha/yr. The machinery on the Schrader farm is responsible for consuming 500 gallons of
gasoline and 14000 gallons of diesel in a year. Adjusting this energy use on a per hectare basis,
we find the Schraders to use 2,163.2 MJ/ha/yr of energy for machinery. They do not irrigate.
They dry nearly their entire corn crop. Approximately two-thirds of their land has corn in any
given year. Thus, their grain dryer adds about 3,274 MJ/ha/yr to their energy use. Thus their total
energy consumption is 11,704 for an energy index score of 7.2.
Big Woods Farm, Nerstrand, Minnesota, USA
Big Woods farm applies 4483 kg/ha of lime every three or four years. This averages to
about 1281 kg/ha/year (942 MJ/ha/yr). They use Bt on 9.6 ha/yr (29.1 MJ/ha/yr), Pyganic on 4.8
ha/yr (55.3 MJ/ha/yr), and Entrust on 1.6 ha/yr (1.7 MJ/ha/yr). Their total pesticide energy
consumption is 86 MJ/ha/yr. Big Woods Farm uses approximately 150 gallons of gasoline per
year on 29 acres, for an average energy usage of 1686.6 MJ/ha by the farm’s fleet of machinery.
They use a drip irrigation system on 6 ha for a total energy consumption of 1,377 MJ/ha/yr. They
are transitioning into using a 150 ft2 walk-in cooler, but they have not used it before, so are not
sure how often it will be on. Therefore, it is not counted. Therefore, the total energy consumed
on this farm per year is 4, 091,which gives it a energy index score of 9.5.
Pahl’s Farm, Minnesota, USA
Averaged over all the land, Pahl’s farms applies 32.3 kg/ha of ammonium nitrate (542
MJ.ha/yr), 74.6 kg/ha of superphosphate (960MJ/ha/yr) and 37.3 kg/ha of potash (111MJ/ha/yr).
This leads to a total fertilizer use of 1,613MJ/ha/yr. For pesticides, Pahl’s used Round-up on 41
ha/yr (53 MJ/ha/yr), Callisto on 194 ha/yr (46 MJ/ha/yr), Outlook on 194 ha/yr (91 MJ/ha/yr),
Eradicane on 194 ha/yr (1268 MJ/ha/yr), Treflan on 77 ha/yr (739 MJ/ha/yr), Strategy on 146
ha/yr (2587 MJ/ha/yr), Atrazine on 194 ha/yr (500 MJ/ha/yr), Dual on 194 ha/yr (500 MJ/ha/yr),
Liberty on 41 ha/yr (10 MJ/ha/yr), Admire on 146 ha/yr (94 MJ/ha/yr), Force on 235 ha/yr (23
MJ/ha/yr), Actara on 1 ha/yr (.03 MJ/ha/yr), Pounce on 461 ha/yr (46 MJ/ha/yr), Warrior II on
461 ha/yr (46 MJ/ha/yr), and Capture on 461 ha/yr (46 MJ/ha/yr). Pahl’s total energy
consumption from pesticide use is therefore 6,050 MJ/ha/yr. Pahl’s farm uses 4000 gallons of
gasoline, 15000 gallons of diesel, and 10000 gallons of LP gas annually. Dividing that
cumulative energy over their sprawling 1200 acre farm, we determined that Pahl’s machinery
accounts for 7,306.1 MJ/ha/yr. They use a center pivot irrigation system on 389 ha for a total
energy use of 10,408 MJ/ha/yr. Pahl’s has a 5000 square-foot walk-in cooler that uses about 174
MJ/ha/yr. Therefore, their total energy consumption is 25,551 for an energy score of 3.1.
Earthen Path, Minnesota, USA
Earthen Path applies lime fertilizer. He did not report an actual application rate, so we use
that of Big Woods, another organic farm. Thus, fertilizer energy is approximately 942 MJ/ha.
They use a pyrethrin on 34 ha/yr (81.2 MJ/ha/yr) and Bt on 31 ha/yr (193.7 MJ/ha/yr) for a total
energy use of 275 MJ/ha/yr. Earthen Path goes through 250 gallons of gasoline every year to
power his farm’s machinery. This lends 5436.6 MJ/ha of energy use to his land. Earthen Path
uses a drip irrigation system on 6 ha for a total energy consumption of 2,754 MJ/ha/yr. Earthen
Path has a 144 square-foot walk-in cooler that uses about 3884 MJ/ha/yr. Therefore, their total
energy usage is 13,292 MJ/ha/yr for a energy score of 6.8.
Gardens of Eagan, Minnesota, USA
Gardens of Eagan applies lime fertilizer. She did not report an actual application rate, so we use
that of Big Woods, another organic farm. Thus, fertilizer energy is approximately 942 MJ/ha.
They use Bt on 10 ha/yr (396.8 MJ/ha/yr) and Alldown on 0.2 ha/yr (1 MJ/ha/yr). Their total
energy use for pesticides is 398 MJ/ha/yr. Gardens of Eagan uses 50 HP tractors to perform three
major tills and three minor tills each year. We estimate these instances of tilling to account for
5770.8 MJ/ha of energy per year. They use a drip irrigation system on 1.1 ha for a total of 75
MJ/ha/yr. Gardens of Eagan has a 300 square-foot walk-in cooler that uses around 716 MJ/ha/yr.
Therefore, their total energy use is 7,901MJ/ha/yr. Therefore, their total energy index score is
8.4.
Discussions
Examining our ecological assessment’s final energy scores, several interesting trends are
apparent. The most glaringly obvious generality is that the Chinese farms that we visited were
found to be vastly more sustainable in terms of energy use than their American
counterparts. This is attributed primarily to the absence of heavy duty machinery on many of the
farms we saw, which still rely almost exclusively on manual or animal labor. If machines were
used on Chinese farms encompassed by our assessment, they were typically small 6 or 50 HP
tractors.
One unexpected finding of our study is that small farms occasionally garnered worse
overall scores than larger farms, bucking the conventional wisdom that suggests that smaller
farms are inherently more geared towards sustainability. This phenomenon is due largely to the
fact that the larger farm’s energy use is distributed over a much larger area.
Another observation we have gleaned from our assessment is that the smallest differences
in energy use by organic and conventional farms exist in the arenas of machinery and irrigation.
Lastly, it is worthwhile to note our observation that crop farmers typically used less
energy than vegetable farmers. This may be attributed to the fact that they do not irrigate as
much.
Works cited
Cooler Connection. 2009. Operating cost for walk-in coolers and freezers. [online] accessed 12
Nov 2009. http://blog.uscooler.com/index.php/2009/ operating-cost-walkin-coolerfreezer/
Dougherty, E. and J. Geuder. 2008. 2007 corn crop a record breaker, USDA reports. USDA
Newsroom. [online] accessed 11 Nov. 2009.
http://www.nass.usda.gov/Newsroom/2008/01_11_2008.asp
Gliessman, S.R. 2007. Agroecology: the ecology of sustainable food systems. CRC Press: Boca
Raton, FL.
Hill, H. 2008. Food miles: background and marketing. ATTRA: National Sustainable
Agriculture Information Service. [online] accessed 30 Oct 2009.
www.attra.ncat.org/attra-pub/foodmiles.html.
Intergovernmental Panel on Climate Change (IPCC). 2007. Fourth Assessment Report of the
Intergovernmental Panel on Climate Change. Cambridge University Press: Cambridge,
United Kingdom and New York, NY.
Miranowski, J.A. 2005. Energy consumption in US agriculture. Outlaw J.L., Collins K.J. and
Duffield J.A. (eds.) Agriculture as a producer and consumer of energy. CAB
International.
Mudahar, M.S. and T.P. Hignett. 1987. Energy requirements, technology, and resources in the
fertilizer sector. Helsel Z.R. (ed.), Energy in World Agriculture. 2: 26-61. Elsevier:
Amsterdam and New York, NY.
Nagy, C.N. 1999. Energy Coefficients for Agriculture Inputs in Western Canada. Canadian
Agriculture End-Use Data Analysis Centre. [online] accessed 24 Jan 2010.
http://www.csale.usask.ca/PDFDocuments/energyCoefficientsAg.pdf.
Paustian, K., J.M. Antle, J. Sheehan and E.A. Paul. 2006. Agriculture’s role in greenhouse gas
mitigation. Solutions: Pew Center for Global Climate Change.
Pervanchon, F., C. Bockstaller and P. Girardin. 2002. Assessment of energy use in arable
farming systems by means of an agro-ecological indicator: the energy indicator.
Agricultural Systems. 72: 149-172.
Pimentel, D. and M. Pimentel. 1996. Food, energy, and society. University of
Colorado Press: Niwot, CO
Uhrig, J.W. and Maier D.E. 1992. Costs of drying high-moisture corn. Purdue University
Cooperative Extension Service. [online] accessed 11 Nov. 2009.
http://www.ces.purdue.edu/extmedia/GQ/GQ-3.html
Ziesemer, J. 2007. Energy Use in Organic Food Systems. Natural Resources Management and
Environment Department Food and Agriculture Organization of the United Nations.
[online] accessed 26 Jan 2010. http://www.fao.org/docs/eims/upload/233069/energy-useoa.pdf
Appendix 1: The Energy Consumption of Pesticide Usage on Farms
Farm
total
ha
Duang
Ji Yun Liang
Ai
Little Donkey
5.2
0.65
0.26
14.95
Lu
0.78
Gao
0.72
Wang
0.23
Emei Tea Co.
Lei
Lao Yu
pesticide
act. ingredient
MJ/mt
none
none
none
total ha/yr
app.rate/ha
0
0
0
0
0
0
0
0
0
372.3
843.9076923
0
633.64
total:
0
637.4861538
1481.393846
0
0
0
0
47.74
143.2488462
633.64
0
638.2553846
0
134.54
35.3304
total:
538.1984615
35.36886154
573.5673231
134.54
35.3304
total:
35.3304
134.54
538.2061538
35.37655385
573.5827077
29.14581261
55.26337308
chlorpyrifos
255000
1.76
glyphosphate
glyphosate
511000
0.78
none
104
Bifenthrin
pyrethroid
217000
312
0.65
3.25
Roundup
none
glyphosate
511000
0.65
0
.00146 mt
a.i.
.00124 mt
a.i.
.00022mt
a.i.
.00124 mt
a.i.
Dofu
78
pyrethrum
BT
108500
126180
312
78
.00124mt
a.i.
.00028 mt
Hexi
65
pyrethrum
Bt
108500
126180
260
65
.00124mt
a.i.
.00028 mt
126180
108500
9.6
4.8
.00028 mt
.00124mt
Big Woods
11.74
Bt - dipel
Pyganic
pyrethrin
MJ/ha/yr
0
0
0
0
Lorsban
0
MJ/ha
Entrust
Lutteke
Organics
405
spinosad
126180
none
1.6
a.i.
.000085mt
10.7253
total:
1.717247019
86.12643271
0
0
0
The Energy Concumption of Pesticide usage on farms cont'd:
Farm
Pahl's
total
ha
486
pesticide
MJ/mt
total ha/yr
Roundup
glyphosate
511000
40.5
Callisto
mesotrione
309643
194
Outlook
dimethenamid
309643
194
Eradicane
Treflan
Strategy
atrazine
Dual
EPIC
trifluralin
ethalfluralin/clomazine
180470
167000
308000
313390
313390
194
76.8
145.8
194
194
313390
40.5
Liberty
metolachlor
glufosinateammonium
Admire
imidacloprid
252360
145.8
Force
tefluthrin
217000
234.5
Actara
thiamethoxam
252125
1
Pounce
permethrin
217000
469
Warrior II
lambda-cyhaloturin
217000
469
app.rate/ha
.00124mt
a.i.
.00037mt
a.i.
.00074mt
a.i.
.0176m.t.
a.i.
.028m.t. a.i.
.028m.t. a.i.
.004mt a.i.
.004mt a.i.
.0004mt a.i.
.00124mt
a.i.
.00022mt
a.i.
.00005mt
a.i.
.00022mt
a.i.
.00022mt
a.i.
MJ/ha
MJ/ha/yr
633.64
52.80950617
114.56791
45.73904226
229.13582
91.47191169
3176.272
4676
8624
1253.56
1253.56
1267.900757
738.9296296
2587.206173
500.3984362
500.3984362
125.356
10.45250617
312.9264
93.88409284
47.74
23.04121399
12.60625
0.032111626
47.74
46.07625514
47.74
46.07625514
Capture
Earthen Path
Schrader
Gardens of
Egan
5.67
pyrethrin
Bt
921
Roundup
40.5
bifenthrin
217000
469
108500
126180
34
31
glyphosate
511000
921
Force
Dual
tefluthrin
metolachlor
217000
313390
122
608
Select
clethodim
316300
219
126180
10
154829
0.2
Bt
Alldown
citric acid/garlic
.00022mt
a.i.
.00124mt
a.i.
.00028mt
.00124mt
a.i.
.00022mt
a.i.
.004mt a.i.
.00014mt
a.i.
.00028mt
.00124mt
a.i.
47.74
total:
46.07625514
6050.492582
13.454
35.3304
total:
81.20564374
193.693545
274.8991887
633.64
633.6432573
47.74
1253.56
6.327122693
1568.245844
44.282
total:
10.53285342
2218.749077
35.3304
396.804
191.98796
total:
1.022162765
397.8261628
Appendix 2: The Energy Consumption of Irrigation Usage on Farms
Farm
Duang
Ji
Ai
Little Donkey
Liu
total ha
system type
ha
total MJ/yr
MJ/ha/yr
5.2
0.65
0.26
14.95
0.78
flood
drip
none
flood
flood
0.19
0.52
0.41
1,432
3.23
0.195
6.48
0.52
Gao
0.72
flood
hose
0.195
0.46
0.52
2.43
Won
0.23
flood
hose
0.23
0.23
0.622
1.2
104
total:
710216
Emei Tea Co.
Lei
Lao Yu
Dofu
104
0.65
3.25
78
58.5
total:
306.18
0.722222222
3.375
4.097222222
2.704347826
5.217391304
7.92173913
6829
0
0.624615385
11.38166667
0.096923077
0.415384615
11.89397436
4.710461538
drip
6
16524
1377
none
0
0
0
ha
389
total MJ/yr
5058167
MJ/ha/yr
10407.75103
overhead spri.
hose
sprinkler
flood
hose
Hexi
65
hose
Big Woods
12
Lutteke Organics
405
0.078846154
2203.2
0
0.43
0.666666667
1.3
0.13
12.96
16.25
2.03
7.56
32.4
The Energy consumption of Irrigation usage on farms:
Farm
Pahl's
total ha
486
system type
center pivot
Earthen Path
Schrader
Gardens of Egan
5.67
drip
921
none
40.5
drip
5.67
15615.18
2754
0
1.1
3029.4
74.8