It is somewhat amusing to see the Wall Street Journal cover
this topic.  After all, they are the
paper of Wall Street, which I imagine has a “look down the nose” attitude about
the people who grow food for a living, especially small-scale farmers who don’t
use giant machines or buy inputs from Fortune 500 companies.   Perhaps I need to get over a prejudice?

Check out what this reporter did…and on page A1 to boot:

Green Acres II:
When Neighbors
Become Farmers

Suburban
Arugula Is
Organic and Fresh, but
About That Manure...

By KELLY K. SPORS
April 22, 2008; Page A1

http://online.wsj.com/article/SB120882472974233235.html?mod=todays_us_page_one

Not bad!  The people
doing this work are good looking, young, suburbanites.  Probably makes it more palatable to the
readers because they can relate to them. 

The music on the video included at the web site, however, is
kinda hill-billyish.  I enjoy banjos and
blue grass myself, but don’t know any farmers of the generation depicted who
listen to it regularly.  If more young
farmers are needed, it might be better to associate them with rock stars
instead. 

I appreciated the coverage of the SPIN farming method:  http://www.spinfarming.com/

It is great that there is now a marketed entry path to
farming in urban/suburban areas.  I would
like to point out where SPIN differs from what we are advocating in the Energy
Farm Program.  The article explains:

Start-up costs for a
one-eighth-acre farm run about $5,500, says Ms. Christensen of Spin-Farming.
That includes a walk-in cooler to wash and store fresh produce, a rotary tiller
and a farm-stand display. Annual operating expenses, including seeds and
farmers-market stall fees, can add about $2,000. Such a farm can generate
$10,000 to $20,000 in annual sales, she says. That's "an entry point into
farming to see if they have a talent for it," Ms. Christensen says.
"Those that do will eventually be able to expand and increase that income
level quite substantially."

Where we differ is in the use of hand tools instead of
rototillers, and passive cooling techniques instead of walk-in coolers
requiring electricity.  Also, we would
probably be more circumspect about the inputs of manure and other fertilizers
and ask farmers to work on green manure cover cropping and compost making on
site instead.  This is all about the need
to “get off the sauce” of oil, and fossil fuels in general.  Good hand tools are incredibly efficient at
the scale needed for home-scale veggies (http://www.energyfarms.net/node/1509
).

The Wall Street Journal does have some great reporters.  Good going Kelly!  Too bad the editorial pages of the WSJ are
full of garbage about energy and climate issues. 

I saw this today, had a morbid laugh, then got pensive.

(cartoonists web site: http://www.ibdeditorials.com/cartoons.aspx#cararch)

A couple of years ago, biofuels were hot. There were the promoters touting "green" fuels, getting off "foreign oil" and helping "American farmers." A perfect set of environmental, geopolitical and populist allies created a basket of incentives to boost corn-based ethanol production.

A few of us were decrying this as bad policy. The net energy of ethanol was around break even, so it couldn't be climate neutral or help with oil dependency. The rise in food prices would impact the poor around the world, causing much pain and unrest that could destabilize nations. And American farmers would go through another painful boom-bust cycle rather than transition to a sustainable agriculture system that is realistic about energy constraints.

Other issues are exposed by this fiasco. Why is it that so many people ARE dependent on cheap, often imported grains (especially in Africa)? Some have ridiculed the local food movement for potentially depriving farmers in the developing world of their markets in the wealthy nations. But if these developing nations are ones who can't feed themselves, shouldn't we ask if it might be better for them to focus on food self-sufficiency rather than production for export? Especially if our energy and financial policies can cut them off from our food so blithely.

Take a look at not only corn in the fuel tank, but coffee, tea, coconuts, palm oil, cane sugar, papayas, bananas, out of season vegetables, etc. All these tropical products may be produced in places dependent upon trade for money that is used to buy imported staples such as grains. What if they decided to relocalize instead? Would they be better off?

As
crude oil reaches record
highs of $110 a barrel, the connection between the cost of food and the
rise in energy prices can no longer be ignored. In a recent
statement, Josette Sheeran, executive director of the UN's World Food
Program, said the global economy had created "a perfect storm for the
world's hungry, caused by high oil and food prices and low food stocks."
Sheeran continues, “Higher food prices will increase social unrest in a number
of countries which are sensitive to inflationary pressures and are
import-dependent. We will see a repeat of the riots we have already reported on
the streets such as we have seen in Burkina Faso, Cameroon and Senegal."

Sheeran
notes that food prices have been aggressively increasing to historic highs
and cites four major drivers for this:

1.
The rise in oil and energy prices which affect the entire value chain of food
production from fertilizer to harvesting to storage and delivering and access
to water;

2.
The economic boom in nations such as India and China, creating increased demand
for all commodities including food and forcing China, which was a major food
exporter just a little more than one year ago, to now being an importer of
food;

3.
Increasingly harsh and frequent climatic shocks like hurricanes, floods and
drought, have made for some bad harvests in particular regions like Australia
and regions of Africa;

4.
The shift to increased biofuel production that has diverted hundreds of
millions of metric tons of agricultural output out of the food chain, and has
caused food prices to be set at fuel price levels in many places, including,
for example, palm oil in Africa which is now being priced out of household
reach because it is being set at fuel prices as a biofuel addition.

On
the energy front, Sheeran's claim is supported by recent reports coming from farms
across the globe. Although farmers appear to enjoy record commodity prices, the
recent spikes in the cost of fertilizer
and fuel are eroding gains. Not only has the price
of nitrogen fertilizer risen 113% since 2000, but also potash has risen
from $225 a ton to nearly $500 a ton and increasingly scarce phosphate has gone
from $312 to between $800 and $900 a ton this year. The ingredients of these
fertilizers are often imported to the United States from other countries
and these resources are mined and processed using markedly energy-intensive processes
that consume diesel and natural gas.

In
other news, the world’s
largest poultry processor closed a U.S.
processing plant-cutting 1, 100 jobs. The processor blames record feed prices
and U.S.
ethanol policy for the current industry-wide crisis. Even if you are a
vegetarian, the implication of this news is still hard to hear, as it is illustrates
the fact that agribusiness is designed to grow food in a way that creates high
profit. Once the profit margin is challenged the corporate producers of food
may simply quit the job of growing food.

These
trends should be clear indicators to all of us to reduce consumption of
non-renewable resources and begin to support those that are willing and capable
of producing food, fuel, and organic fertilizer close to where we live. Click here to see if there is a CSA or farm in
your area.

Winter is almost over, and with it the time for
introspection also draws to a close. The heavy rains and shorter days have given
us time to create a sign system that illustrates our priorities in the garden. In
the coming year some focuses like crop selection and soil building will stay
the same, and this season they will be enhanced by a winter of planning that we
did not have last year.

Education is also a key priority as we enter the 2008
growing season, and one of the primary tools that we developed this winter is
our garden didactic system. This collection consists of 23 concept signs and 30
profile crop signs. They will be scattered throughout the garden to greatly
enhance its accessibility.

This project was beneficial to the Energy Garden initiative
because in the process compiling the content, we were able to summarize our
work to date. In addition, the signs helped us to identify the focal points of
the garden and the methods that influence its development.

The concept signs consist of:

·
Goals of the Sebastopol Energy Garden

·
Community Compost Collection

·
The Sebastopol Energy Garden Growth Collage

·
Square Foot Gardening Method

·
Natural Farming – The “Do Nothing” Method

· Cover Crops

·
The Water Catchment System

·
Drip Irrigation

·
Culinary Herb Spiral

·
Mandala Garden: The Sheet Mulch Technique

·
Methods of Season Extension: Towards a “Four
Season Harvest”

·
Appropriate Technologies

·
Processing and Harvesting Techniques

·
Tree Guilds: Edible Forest Gardening

·
Garden Cycle Tracking

·
Ethanol Production

·
The Fractional Still

·
Recycling and Compost: Designing “From Cradle to
Cradle”

·
Chickens

·
Biointensive Concepts

·
Permaculture Principles

Each sign corresponds to something that is happening in the
garden or that has influenced its progression. There are also 30 profile crops
that we have chosen because of their ability to help us adapt to Peak Oil.
Instead of a lawn, we are selecting a great range of crops to benefit humans
and the environment. Please see http://www.energyfarms.net/node/1495 for a list
of these crops.

These signs will enable people with a wide range of
understanding of sustainability to experience a transformed suburban lawn. When
people visit this year, during our second growing season, they will be
introduced to a diversity of crops with a large variety of functions. In
addition, they will be exposed to techniques and technologies that are easy to
learn and have the potential to make a big difference in their lives.

The rains will soon stop, and spring will bring a time of
action. We will sow seeds of diversity in the garden and hopefully, inspiration
in the community. The Energy Garden is always open to visitors and we look
forward to helping more people experience the resilience of the Earth.

I wasn't happy with the news in Part 3 of this series, which
basically concluded that Mendocino
County could not be food
self-reliant.[i] To quote the most relevant and discouraging
passage from that essay:

The Caltrans EIR implies that in
about a ca. 20 year span, Mendocino County went from 69,000 to 35,000 acres of
prime farmland, down from and original endowment of 94,000 acres. This does
seem like a remarkably high rate of loss, totaling 34,000 acres or about 1700
acres per year for 20 years. In either case, whether the real figure is closer
to 69,000 or 35,000, both are far from the estimated need of ca. 95,000.

However, I knew that this conclusion rested on certain
assumptions, and that changing these might alter the conclusion. In the end we may be left having to decide
which assumptions are more realistic, or whether what may be theoretically
possible is probable given human nature/folly, or, if you are more inclined,
human spirit/ingenuity.

So I went in search of better news (and the resulting
dopamine reward this could potentially provide) by re-performed some
calculations, starting with the diet. I
will call the diet from part 1 of this series diet 1, and the one presented in
this essay diet 2.[ii] Before creating diet 2, I wanted to be
clearer on what the dietary needs and expectations are in North
America. The USDA has a
fascinating set of web pages. Included
is a survey from the Agricultural Research Service of what several hundred
people eat during a day, which can be extrapolated to the whole population
(standard errors noted) and then broken out by demographic category.[iii] According to this data set, on average, people
eat about 2200 calories per day. As
expected, the very young and old eat the least, and females eat less than males. Another branch of the USDA, the Economic
Research Service concludes that people consume closer to 2700 calories per day
on average.[iv] Changes in American consumption patterns over
time are also discussed in a report by the same sub-agency.[v] In general we are eating more calories than
30 years ago, but we are consistently wasting about 25% of the food produced.[vi]

New Diet Assumptions

For my second go at a model diet, I selected the 2200
calorie per day figure, and I assumed we could get by with half the food waste
of today, which means a production system is required that produces about 2600
calories per person/day. By contrast,
diet 1 used the figure about 3000 calories per day as a guide, which is still
about 700 calories per day lower than what Americans have available to them
from the current system. Diet 2
therefore has less calories available than diet 1, and far less than current U.S.
diets, but is still enough food overall if food waste is half of current
percentages.

Diet 2 is given below, and for comparison I give the current
U.S.
consumption patterns for the modeled foods.
I have made a change in the fruit and vegetable category, where potatoes
are segregated for analysis purposes. Significant
differences between diet 2 and U.S.
averages include much lower meat, sugar and egg consumption, and much higher
dry bean consumption. To compare U.S.
consumption of sprouting seeds (sunflower seeds in my model) I used data on
nuts, which are nutritionally similar. In
the U.S.
this mostly means peanuts, but locally it could be walnuts and
filberts/hazelnuts. I believe diet 2 is
a much healthier diet than current U.S. habits.

Diet 2 also took into account the calories yielded per area
for different food items. This is one
reason why potatoes were given stand-alone status-they efficiently make human
food. When grains are fed to animals,
as in chickens and dairy cows, area efficiency is very low. Diet 2 therefore has fewer animal products
than diet 1, and more veggies and potatoes.
I limited potato consumption to 180 lbs per year because potatoes are
typically edible for only 6-7 months at a time and eating more than one pound
of potatoes per day would get tiresome.
Even with the extra load from vegetables, fruits and potatoes, the total
diet weight is still low, ca. 5.2 lbs, because the total calories are reduced
and grains and dry beans still form the core of the plan.

New Inputs and Yield
Assumptions

In addition to fiddling with the diet, I made a giant change
when modeling the land-area required for the diet-I assumed no limits to
irrigation, which essentially doubles the yields of grains and dry beans.[vii] Remember
also that sugar is modeled as honey and, perhaps optimistically, is given no
direct land area requirement.

So what's in going to be?
Will eating lower on the food chain plus more intensive inputs change
the results? Are we gonna make it? Drum roll.....

First, we look at the acres per person for diet 2:

Not bad! The "acres
minus meat" for diet 1 was 0.76 per person.
Next, multiply by population size:

If you read previous essays you may recall that meat is
assumed to be produced on subprime farmland plus prime farmland in a green
manure rotation. This brings up the need
to account for crop rotations and green manure, thus:

And finally, adding rotation-demanding to non-rotation
demanding areas gives:

So the number here, ca. 38,000 acres, compares favorably to
the amount of prime farmland currently remaining according to the Caltrans
EIR.

Rwanda

Before getting too pleased with the results, I want to put
them into perspective. Let's assume for
the moment that Mendocino
County does have 38,000
acres of prime farmland left, which equates to 0.43 acres per person, or in
metric terms 0.17 hectares. The arable
cropland per capita in Mendocino County is currently slightly less than what Rwanda
had during the genocide period (0.20 hectares).[viii] Scholars have suggested that the tensions
that eventually led to the bloodshed came from the fact that the land base was
barely able to provide enough for the population, and that few subsistence
farmers had the cash to buy imported food.

I am not predicting that the same kind of events would unfold
in Mendocino County under similar circumstances. The point is that when populations are up
against their resource capacity it is normal for stress to build, which
increases the probability of violence.

Fertilizer Impact

Because irrigation is now assumed, the yields of the grains
and dry beans, and by extension the dairy and eggs, increase
substantially. Crops remove nutrients from
the land in proportion to their yield; therefore quantities of fertilizer are
increased per unit area. Three factors
offset increased fertilizer demand per area:
(1) green manure crops are also irrigated and increase in yields at the
same proportion as the crops they support, (2) increased yields means a
decrease in total area required to support the population, and (3) diet 2 is
smaller than diet 1, with fewer animal products.

My estimations are very crude right now, but the overall
impact is that much less fertilizer is required for the diet 2 plus irrigation
model than with diet 1 and no irrigation.

The proportion of fertilizer needs that can be recovered
from humanure is also higher with the diet 2 model. Here's another look at the only reference I
can find for the average nutrient content of human waste.

Adding the straw and other non-edible residue from farming to
the humanure could potentially provide sufficient closure of the nutrient cycle
loop and make the local agricultural not dependent upon large quantities of imports.

The Water Assumption

If about 38,000 acres of prime farmland need to be irrigated
to provide high enough yields, the obvious question to ask is whether the water
resources exist?

The Mendocino County Crop Report shows that about 19,000
acres are in production for apples, pears, and wine grapes.[ix] Another 6000 acres of pasture are irrigated. Perhaps another 1000 acres can be added for
vegetable cultivation, tree farms and nurseries. Therefore, currently around 26,000 acres are
irrigated.

The United States Geological Survey assessed ground water
resources in Mendocino
County in the mid-1980s.[x] In general, valley bottoms with prime
farmland have shallow water tables that are recharged annually given the
usually abundant rainfall regime of the county.

Because much of the area requiring irrigation is sown in
small grain crops, the period of irrigation is limited to late spring, i.e.,
May and June. By mid-late June these
crops will finish maturing and watering should be ceased. I don't currently see water being a limiting
factor for productivity on prime farmland in Mendocino County
as long as the infrastructure exists to access it.

Ground water pumping using shallow wells (usually less than
50 ft) is not extremely energy demanding and should be backed by renewable
energy resources. Encouraging existing
farms (mostly vineyards) to take advantage of any state or federal programs for
renewable energy could help prepare for a more diverse local food system.[xi] Since Mendocino County
likes to promote its wine industry as "organic," and one major winery is the
first to go "carbon neutral" this may not be a difficult sell in the southern
half of the county.[xii]

Alternative Food Sources

A quick mention of what I didn't evaluate: acorns, wild game, fish, seaweed, etc. I suspect acorns could provide for some
serious calories, and the others occasional protein and mineral
supplements. My main worry about wild
game is that it would be extirpated if our current population tried to rely on
it for long. The local ocean-going
fishing industry is probably fuel intensive, but it would be interesting to evaluate
the potential for low-energy input, sustainable fishing off the Mendocino
coast.

Conclusion

Population growth and land-use changes in Mendocino County
have created the surprising situation, in this largely rural area, of a very
low availability of high quality, prime farmland per person. While it is theoretically possible to feed
the current population of the county on likely available farmland, it would
require full-scale irrigation and a restricted diet-and no margin for
failure. Maintaining soil fertility over
the long-term would also mean cycling human body waste and agricultural residue
back to the land.

In this series I did not develop any scenarios about when Mendocino County might need to be more food
self-reliant, nor make a strong case for the benefits of a local food system,
but these arguments can be found elsewhere.[xiii] I found the exercise useful in that it
highlighted the resources on which our population depends-good soil, adequate
water, sufficient mineral nutrients, reliable climate-and quantified about how
much of that exists within our locale.
By following the references provided, similar analyses could be done
just about anywhere.

[i] http://www.energyfarms.net/node/1491

[ii] http://www.energyfarms.net/node/1489

[iii] http://www.ars.usda.gov/Services/docs.htm?docid=14958

[iv] See the
Calories spreadsheet here: http://www.ers.usda.gov/Data/FoodConsumption/FoodGuideIndex.htm

[v] http://www.ers.usda.gov/publications/foodreview/jan2000/frjan2000b.pdf

[vi] http://www.ers.usda.gov/publications/FoodReview/Jan1997/jan97a.pdf

[vii] http://www.energyfarms.net/node/1490;
diet 1 assumed about 18 bushels of wheat per acre, diet 2 about 37 bushels per
acre.

[viii] http://ideas.repec.org/p/wpa/wuwpdc/0409061.html; See Table 1, divide farmland per household by
adult equivalent household size.

[ix] http://www.co.mendocino.ca.us/agriculture/pdf/2006%20Crop%20Report.pdf

[x] http://www.willitseconomiclocalization.org/files/well/GroundWaterResourcesMendoCounty.pdf

[xi] http://attra.ncat.org/farm_energy/funding.html

[xii] http://www.mendowine.com/MendocinoCountyOrganicWineGuide2006rev.pdf;
http://www.winebusiness.com/news/dailynewsarticle.cfm?dataId=47813

[xiii] http://www.energyfarms.net/node/1488;
http://globalpublicmedia.com/relocalization_a_strategic_response_to_peak_oil_and_climate_change

For this essay I think it would help to step outside of
ourselves as humans, and consider us as another species of animal that depends
upon a daily supply of resources in the forms of food, water, and air for
survival. Strip the emotions from the
implications as best we can. Calling us
by our scientific name, Homo sapiens
Linneaus may adjust the frame of mind accordingly. Linneaus was the man who, in 1758, described
and named humans in a taxonomic system.
In official scientific protocol, the author of a species name must be
given with that name to avoid confusion because sometimes the same name is accidentally
given for different species. But from
now on I will abbreviate and just use H.
sapiens.

Now that we are examining the population of H. sapiens, let us bring the insights of
an ecologist to bear on the question of what resources must flow from the
environment to support this species? Food
derives from soil mediated ecological processes. Good soil by itself doesn't
guarantee biological productivity. The
other chief factor on land is fresh water available in proper quantities and
frequencies. The potential for soil to
produce food is not evenly distributed on Earth. Some places are more richly endowed than
others, and historically I suppose population density would correspond to
biological productivity. With cheap
fossil fuels the limits of local ecology can be temporarily overcome and
millions of H. sapiens now casually
occupy mega-cities in deserts.[i]

The United States Department of Agriculture has codified and
mapped environmental heterogeneity in the form of soil maps.[ii] These will be used to help answer the
question of whether Mendocino
County's current
population of nearly 90,000 H. sapiens
could theoretically be fed with the local land-base available. Previous essays established a hypothetical
diet and calculated the land area needed to grow that diet for the current
population.[iii] A summary table from the diet and area
calculations is given below.

I should remind readers that I modeled the food output per
area according to practices that I considered sustainable, or nearly so. I also assumed a low availability of energy
compared to today, which would impact irrigation capacity. I believe the United States produces so much food
today that half could be lost and there would still be enough to feed the
resident population of H. sapiens. Of course livestock population and nations
dependent upon our exports would be drastically impacted. Among the chief reasons for high crop
productivity in the U.S.
include irrigation and artificial fertilization of wheat and corn. Absent the necessary preparations to
transition to a renewable energy-based agricultural system, and considering
what climate change might do, I would not be surprised if the United States
produced half as much food in 50 years.

Is There Enough Land?

For Mendocino
County no single
reference resource exists regarding soils, but two published soil surveys roughly
dividing the county in half were conducted in the mid-80's.[iv] The text from the Western Survey is on-line
and reports: "About 14,105 acres, or
nearly 1.4 percent of the survey area, would meet the requirements for prime
farmland if an adequate and dependable supply of irrigation water were
available." I have a text copy of "Soil
Survey of Mendocino County, Eastern Part, and Trinity County, Southwestern
Part, California," while the soil data are online for both surveys. Page 127 of the Eastern survey reports: "About
55,000 acres, or nearly 5 percent, of the survey area would meet the
requirements for prime farmland if an adequate and dependable supply of
irrigation water were available."

Only a very small portion of Trinity County
is actually surveyed in the Eastern Part publication and can therefore be
safely ignored. Therefore, Mendocino County as of the mid-1980s had (14,105
plus 55,000) 69,105 acres of potentially
prime farmland.

Regarding non-prime land, the 2006 Mendocino County
crop report estimates that 720,000
acres of range and pasture land were in use.[v]

Compared to what is required to feed the current population
of H. sapiens in Mendocino County
given the modeled diet, adequate non-prime land exists, but prime farmland
falls short.

It May Be Even Worse

The main concern I had with the USDA figures is that they
represent field work from the mid-1980s. Unfortunately, as far as I can tell
local land-use decisions since then have not made protection of farmland a high
priority. So I decided to take a look at
what might have happened to prime farmland over the approximately 20 years
since the soil surveys were completed.

The most recently available, area-wide environmental review
documents relate to plans for local freeway construction, much of which would
go right through farmland. A draft
Environmental Impact Report from the California Department of Transportation
(Caltrans) had this to say about farmland conversion and extent remaining.[vi]

Out of 2,246,400 acres of land in Mendocino County,
94,039 acres or 4.19 percent is considered prime agricultural soils (NRCS-USDA
figures). Of that amount, much is unavailable and covered by roads, highways,
cities, parks, and other land uses. While growth is very slow in Mendocino County, settlement patterns have tended
to occur in areas dominated by prime soils. Only one third, or approximately
35,000 acres, of prime farmland remain available for agricultural use. Besides
the unavailability of prime farmland, changes in hydrology as a result of
agricultural and other human uses have affected the quality and use of prime
farmland.

The Caltrans EIR implies that in about a ca. 20 year span,
Mendocino County went from 69,000 to 35,000 acres of prime farmland, down from
and original endowment of 94,000 acres.
This does seem like a remarkably high rate of loss, totaling 34,000
acres or about 1700 acres per year for 20 years. In either case, whether the real figure is
closer to 69,000 or 35,000, both are far from the estimated need of ca. 95,000.

Can We Just Import
Our Food?

Subpopulations of H.
sapiens are unusual in their extensive exchange of non-food items for food
items and the transport of food over vast distances. When food is viewed as the embodiment of
land, water and nutrients, the importation of food into a subpopulation
requires the export of environmental carrying capacity from other places
occupied by other subpopulations.
Therefore, a subpopulation dependent upon imported carrying capacity
should be aware of consumption patterns in the subpopulations of exporters it
relies upon.

An importing population should ask whether the following
statements are true or false:

1. We can
   feed ourselves without these food imports.
2. Consumption
   of the food we are importing is decreasing among those exporting it to us.
3. Production
   of the food exported to us is not being undermined by unsustainable
   activities that degrade productivity over time, such as loss of top soil,
   pollution, and conversion of farmlands to other uses.
4. Production
   of the food exported to us does not require that the exporting populations
   import supporting resources, such as fuels, fertilizers and water.

To my knowledge, in the case of the population of H. sapiens occupying Mendocino County,
the answer to all these statements is false, which means this population faces
food insecurity.[vii] The nearest source of importation into Mendocino County
would be from within the great agricultural state of California.
Yet the California
population is so large that the tillable cropland (usually equal to prime
farmland) available per person is only 0.30 acres.[viii] Where might California turn? Of the three neighboring states, Nevada and Arizona
are mostly deserts and mountains. The
cropland available per capita in the U.S. overall is 1.45 acres per
person, suggesting sufficient land continent-wide but highlighting a misalignment
of population distribution with carrying capacity.[ix] Furthermore, how can land fertility be
maintained in the Midwest if the nutrients extracted
from the soils are shipped in the form of food to coastal populations who then
flush them down the toilet?

What Would an
Ecologist Think?

H. sapiens are
omnivorous with highly flexible diets.
This enables them to exploit different food resources, and to find
alternatives to a preferred diet when it becomes scarce--a practice called
"resource switching" in foraging theory.[x] The diet modeled in part 1 was based loosely
on cultural norms for consumption of grains and animal products. It might be possible that the Mendocino County population will be able to feed
itself on a diet with greater conversion rates of land area into edible
food. Methods for doing this might
include more extensive irrigation and a diet richer in foods with high caloric
yields per area.

If food imports decline and the Mendocino County
population is unable to feed itself, the population will decline. Population decline occurs through emigration,
lower rates of birth and/or higher rates of death.

In part 4 of this series I will revise the diet model to be
more area efficient. Can sufficient
calories per day be grown using 0.4-0.8 acres per person?

[i] http://www.satellite-sightseer.com/id/1008/United_States/Nevada/Las_Vegas/Las_Vegas_Strip

[ii] http://websoilsurvey.nrcs.usda.gov/app/

[iii] http://www.energyfarms.net/node/1489;
http://www.energyfarms.net/node/1490

[iv] Soil
Survey of Mendocino County,
California, Western Part. http://www.ca.nrcs.usda.gov/mlra02/wmendo/ and http://soildatamart.nrcs.usda.gov/Manuscripts/CA694/0/MendocinoWP_CA.pdf;
search for Mendocino
County at http://soildatamart.nrcs.usda.gov/

[v] http://www.co.mendocino.ca.us/agriculture/pdf/2006%20Crop%20Report.pdf

[vi] http://www.dot.ca.gov/dist1/d1projects/willits/chapter6_10.pdf

[vii] http://www.energyfarms.net/node/1488

[viii] http://www.ers.usda.gov/StateFacts/CA.HTM

[ix] http://www.ers.usda.gov/StateFacts/US.HTM; Note that two soil data sets are used in the U.S. The main data set used for my analyses is
from surveys by soil scientists (NRCS-USDA) to reflect agriculture
potential.In many other cases,
including references viii and ix in this paper, the USDA agricultural census data
are used. These data reflect what land
owners or farm operators report. From my
reading of the reporting guidelines for the 2007 census, what farmers are asked
to report as “cropland” would come close to what is judged by soil scientists
to be prime agricultural farmland. See
section 2 of the census instructions for details: http://www.agcensus.usda.gov/Help/Report_Form_&_Instructions/2007_Report...

[x] http://en.wikipedia.org/wiki/Optimal_foraging_theory;
http://en.wikipedia.org/wiki/Foraging;
http://links.jstor.org/sici?sici=0011-3204%28198312%2924%3A5%3C625%3AAAOOFT%3E2.0.CO%3B2-L&size=LARGE&origin=JSTOR-enlargePage

In the first part of this series I established a
hypothetical diet appropriate to the area I live (Mendocino County)
and the culture (i.e., non-hunter-gatherers, based on familiar domestic foods).[i] Growing food requires land, water, fertilizer
and energy resources and I want to know for a given diet + population do the
resources exist? I am leading myself
through the following series of steps to address that question:

(1) Establishing
a diet, (2) Translate this diet into land area requirements, (3) Scale the land
area from an individual level to the population of Mendocino County,
and (4) Compare to the actual land-base.

As a review, the diet being considered for now is given
below. Perhaps it will have to be
reconsidered following the initial results, which is not difficult to do the
way spreadsheets work.

Farmland
Classification

Classification of farmland merits a discussion. Soil nomenclature and taxonomy is complex,
but by most accounts USDA's Natural Resource Conservation Service's Land
Capability Classes I and II are considered "prime agricultural farmland,"
meaning the soils are deep and fine enough to be tilled, not highly subject to
erosion when disturbed, and not severely hampered by potential seasonal
inundation.[ii] These soils tend to form where alluvial
deposits build up layers of sand, silt and clay in more or less even
proportions. Most of the crops in the
diet designed here require such prime land.
Land suited for grazing may include non-prime land, that is class III
and above, but the productivity of this land class is lower. Tree crops, including fruits, olives and
nuts, may also be sown on non-prime land but with lower yields. Yields on non-prime land can be improved by
seeding with desired species, managing livestock smartly, and fertilizing.

Area Required per
Person

I will begin by taking columns 1 and 2 from the table above
and calculating how much area is required for this diet for one year, i.e., a
per capita land requirement given the above diet. To do this, I must apply estimated yields per
area for Mendocino
County of the specific
crops considered. The results are as
follows:

The tricky part of this step is finding decent, contemporary
information about crop and livestock productivity for Mendocino County.
One issue is that the local ag business is currently dominated by a single,
ethanol crop, rather than a diversity of products as in the past.[iii] Previously, I explored this issue with
respect to grains, and was forced to use data several decades old.[iv]

Because projected grains yields dominate the area
requirements, understanding the yields per acre figure used is most
important. Grains being modeled are the
small grains, chiefly wheat, oats, barley and rye. They all give similar yields per acre. California
is a major producer of wheat, and the yields from most growers in the Central Valley are fantastically high-6000 lbs per acre
is considered normal. Why then the 1000
lbs per acre for this worksheet? The
resources required to achieve 6000 lbs per acre are substantial and
include: pre-planting application of
herbicide, precision seed drilling at high density but even spacing,
application of fertilizer at time of planting, irrigation, and additional
fertilizer application.[v] From my conversations with grain farmers and
UC extension agents I expect the following changes in yield absent the given
input: remove irrigation and yields fall by half (3000 lbs/acre), remove
artificial fertilizer application and yields fall by nearly half again (1800
lbs/acre), remove pre-planting herbicide and precision planting and yields fall
once more (1100 lbs/acre). Because 100
lbs are needed to sow an acre of grains, a 1100 lb harvest nets an edible yield
of 1000 lbs. So my number assumes dry-land
farming methods, lack of sophisticated planting equipment, and no herbicides or
artificial fertilizers. 1000 lbs per
acre is also the yield from historic data when Mendocino County
did grow grains, and it could be argued that soils were less depleted
then. This may be considered a
worst-case scenario, but given current conditions in the County it may be
reasonable. The capital stock of
equipment to grow high yield grains is lacking and energy constraints may limit
use of agro-chemicals and fertilizers as well as irrigation pumps. To avoid yield problems with staple foods
requires planning ahead, considering what inputs may still work in an
energy-constrained County, and investing today in infrastructure that could
last in such an environment.

For olive oil I could find state-level information only and
I assumed 3 tons of olives per acre with 40 gallons per ton oil extraction.[vi] Olive trees are becoming more common within
vineyard operations and small-scale commercial production has increased lately,
including local processing equipment.

As explained in part 1, I use honey as the sugar source so
it doesn't have a direct land area requirement.
It would be good the check with local bee keepers about how many hives
they believe the county can support without seasonal transportation to almond
orchards. My estimate is that one hive
per person would cover the honey/sugar quota.
Another option would be to grow sweet sorghum, which requires summer
irrigation and prime farmland.

Meat and dairy yields are especially difficult to estimate
because they rely on lands of variable quality and encompass a diversity of
production models. As far as I can
gather, livestock here are rotated between winter pasture in the hills and
summer pasture in the valleys. Valley
pastures include both prime and non-prime farmland. Stockman operations sell half-grown cattle
out of the county once rangeland dries in the summer. Conceivably these exported animals could be
eaten when not fully grown, as is done with male dairy cows. Cow-calf operators bring animals into summer
pastures in the valleys. A single
cutting of hay is typically given to valley pasture before animals are placed
on it, which is an important supplement during late summer and fall. In addition to cattle, sheep and goats are
raised, but cattle are preferred here-perhaps based on cultural norms or
because sheep are more susceptible to predation. Animals are usually culled in the fall, reducing
food requirements while the herds are re-established on new grass that emerges
during the rainy season (Oct-May). The
Mendocino County Department of Agriculture gives estimates of the productivity
of different forms of pasture land in the unit of measure called AUM, or Annual
Unit Month, which is the food required to feed a 1000 lb steer for one month
(or ca. 5 sheep), which works out to about 1000 lbs of forage. [vii] The county crop report doesn't give hay
yields, but discussion with local ranchers suggests 5 tons per acre is probably
a good yield. County soil surveys also
give estimates for the rangeland productivity in terms of above ground dry
weight in lbs per acre.[viii] Values
are typically about 2000 lbs per acre, which would provide 1000 lbs of forage,
or enough for 33, 1000 lb cows for 1 day. [ix] But
this is a standing biomass figure at a particular stage of growth and doesn't
indicate how a pasture responds to grazing and then re-growth. Will an acre of rangeland with 2000 lbs of
above ground biomass grazed by 33 cows down to 1000 lbs biomass re-grow to 2000
lbs in 2 weeks or 5 weeks? The answer
likely depends upon the quality of the land, the weather, and the season.

I simply don't have the expertise to sort out all these
variables from first principles. Another
way to go about this is to use total weight of animals produced and divide this
by rangeland and pasture land acreage. The
average live weight for cattles+calves and sheep+lambs for Mendocino County
in 2005 and 2006 was 10.7 million pounds.[x] The actual weight of meat consumed is about
40% of the live weight.[xi] This gives about 4.3 million lbs of meat
produced in the county. There are no
feedlots here and the county does produce a lot of hay, but I am not sure this
represents the meat production of county land only. If we assume it does, however, the following
calculation can be made: Take the 4.3
million pounds of meat and divide by the acres of range and pasture land in use
(720,000 acres) according the county crop report, to yield 6 lbs of meat per
acre.

Humans may consume milk in its liquid form or as
cheese. The table computes in cheese
units equal to about 1.6 cups (12.8 oz) of milk per day. Dairy cows need to be fed in close proximity
to the milking barns, so they are kept on highly productive irrigated or
naturally sub-irrigated pasture, on fog-swept coastal plains, fed grains,
silage and hay or some combination. The
1400 milking cows in Mendocino
County yielded, on a per
cow basis, 6.4 gallons of milk per day in 2006, or 18,800 lbs of milk per
year. From the table below, the land
required to produce these yields can be estimated.[xii] If we assume irrigated pasture for the
forage, Mendocino County irrigated pasture produces about 9200 lbs per
year. Then the other area would come
from grain yields of about 1000 lbs per acre.
So, one milking cow requires (8096/9200) 0.88 acres for forage and
(8275/1000) 8.28 acres of dry-farmed grain, for a total of 9.16 acres per cow. (The grain area could be cut about in half if
irrigated). Since each cow produces
18,800 lbs of milk, this is 2052 lbs of milk per acre. Since cheese is 1/3 the weight of milk, this
yields 684 lbs of cheese per acre. The
grain area could be reduced by more extensive grazing on highly productive
pasture, but this would generally be prime farmland anyway and may not reduce
total area required.

For eggs I have a book called "Living with Chickens" that
advises a quarter pound of grain per layer per day. My logic then went as follows: assume 200 eggs per hen/year, fed 90 lbs of
grain/year/bird, so 90 lbs of grain yields 200 eggs, or 0.091 acres of grain
per 200 eggs, with each egg weighing about 0.1 lbs. 200 eggs/0.091acres = 2192 eggs/acre at 0.1
lbs per egg = 220 lbs of eggs/acre. Even
when chickens are pastured (which I prefer) they still require these grain
inputs to get high egg yields. Note that
old laying hens can go in stew pots but this contribution to the meat diet
isn't included.

Fruit and vegetable production yields are in line with county
records for tree crops and my own experience with intensive vegetable
cultivation. These yields assume summer
irrigation water.

Discussion of Initial
Results

I am concerned by the total of 9 acres. From my previous readings, the number "about 1
acre per person" stuck in my head (about 0.4 hectares) as to what is required
for a diet familiar to people in North America and Europe.[xiii] Of course, many countries are already well
below 0.4 hectares per person for cropland.
They have diets with fewer animal products, less area demanding crops
like grains, and more root crops with high yields and decent caloric density, such
as potatoes. Will a "local diet" run up
against land (and water) limits, forcing a change in the kinds of foods we can
hope to eat?

The reason for the 9 acre per capita value is the inclusion
of meat that depends upon low productivity rangeland and pasture. The previously cited value of 1 acre per
person refers to the area of high quality land, or prime farmland. For Mendocino County,
I am going to assume that meat is produced on non-prime farmland, whereas the
other foods are more reliant on good tillable acreage. When the meat area is excluded, a more
comfortable figure of ¾ of an acre per person is calculated for the remainder. From part 1 of this series we see that the
food produced on this ¾ acre represents 96% of daily calories-basically an
ovo-lacto-vegetarian diet.[xiv] Notice also how fruit and vegetables, which
are the darlings of farmers markets, only use 3% of the ¾ acres (Fig. 1). True food security requires growing the high
calorie crops. In this diet grains and
dry beans are estimated to require 50% of prime farmland area directly, and
since eggs and dairy rely on grains 90% of the ¾ acres is actually grain plus
dry bean area.

Fig. 1. The acreage
required to produce each class of food per person, absent meat. Note that because sugar is based on honey it
is given no area.

Area Required for the
Population

In 2005, the human population of Mendocino County
was estimated at 88,161.[xv] I will divide land requirements into two
categories: prime farmland and non-prime
land. On a per capita basis for this
diet the prime farmland need is 0.76 acres and the non-prime 8.33. Multiplying each per capita allocation times
the population yields 66,778 prime and 734,675 non-prime acres (these are
spreadsheet derived numbers that include more than 2 decimal places in the per
capita figures). For the prime farmland
portion, the assumed irrigated area in this diet-land model is 6803 acres (10%)
and the non-irrigated 59,975 acres (90%).
Land area could potentially be reduced significantly if much more area
can be irrigated.

There is an additional factor that needs to be considered
however. Lands that are not tilled and
are subject to low intensity grazing do not have any crop rotation patterns to
consider. Rangelands and pasture may be
rested, animals of different species may be placed on them to balance the plant
species being consumed, and desired plant species may be over-sown, but their
fertility does not rely on incorporating "green manure." Fertilizers may be frequently needed for
pasture if it is used for hay that is exported from the land, and less often if
used to feed a resident grazing herd.
The removal of animal flesh from a land-base does eventually require
nutrient replacement.

If organic agricultural methods are used (part of my
assumption) then the area devoted to food classes grains, sprouting seeds,
vegetables and food reliant on grains will need to be rotated with nitrogen
fixing legume crops. For example, if a
field is sown in wheat for two years, the following year it may be a field of
clover. Clover can be under-sown with
grains to improve cover crop establishment time and reduce erosion. To ensure that the nitrogen being fixed by
the clover doesn't all go into the clover seed, mowing or grazing is done. This creates some overlap, therefore, between
the land-base devoted to animal and non-animal production. By grazing and spreading manure, animals can
improve the land needed to produce crops.

What this means is that some proportion of the prime
farmland is not directly involved in food production each year, thereby
increasing the prime farmland area required.
At the same time, the area being set aside for green manure can be used
for grazing or making hay, thereby decreasing the non-prime land required. It is also possible to lightly graze animals
on fields of annual winter grain crops, though opportunities for this may be
limited in non-irrigated production systems since early and vigorous fall seedling
establishment is not reliable. Pasture
hens may be ideal for this practice since they cause less soil compaction in
recently tilled land.

To sort out how many acres of cover crop are needed to fix
nitrogen for a given acre of food crop, I started with the pounds of nitrogen
fixed per year by clover, which is about 100 for irrigated conditions and I
estimate about 60 lbs for non-irrigated land.[xvi] The nutrients removed by a crop is
proportional to the yields. Using the
pounds of nitrogen removed by a crop per year given the estimated yields, I was
able to compute a "Green manure factor" that became a multiplier for the actual
area required for that crop.[xvii] For example, if wheat removes 30 lbs of nitrogen
per year from the soil when dryland farmed, then growing 1 acre of wheat will
require a half acre of green manure. A
farm could theoretically have 3 acres, with a rotation pattern of clover,
wheat, wheat, and be balanced for nitrogen.
In this situation if you multiplied the 2 acres in wheat by the "Green
manure factor" of 1.5, you would get the 3 acres required to support the
nutrient cycle. This is the same basic approach
used by Bagdley et al. in their review paper of the yields of organic
agriculture.[xviii]

The total prime farmland needed is therefore the area for
crops requiring green manure rotation plus the area of those that do not, which
sums to 95,401 acres.

Because about a portion of the prime land can be lightly
grazed, subtracting this area from the non-prime land allocated to meat
production reduces the non-prime land needed to 706,052 acres.

The adjusted per capita prime land requirements are
therefore 1.08 acres of prime farmland and 8.01
acres of non-prime farmland. I am
somewhat astonished that after all these complex computations we arrive at the
number "about 1 acre" per person.

Beyond Nitrogen

Green manures fix nitrogen and add organic matter to the
soil, but most commercial fertilizers add nitrogen, phosphorus and potassium
(NPK). It may also be necessary to apply
other, more minor nutrients, as well as lime to adjust pH and add calcium, less
regularly. So even if the nitrogen issue
is covered by green manures, what about the rest? Imports to the land may come in the form of
rock phosphate, wood ash, oyster shells, green sand, and kelp meal-some of
which are produced in energy intensive mining operation, and most of which
currently require long-distance transport.

The amount of nutrients needed to grow the food for one
person per year can be estimated by the sum of the multiplication of the area
per crop by the nutrient demand per area.
Local sources of nitrogen would be legume cover crops. Potassium is extracted from the soil by trees
and can be used agriculturally by adding wood ashes to compost. Phosphorus may be the most difficult to
gather as a field supplement.[xix] In the natural nutrient cycling of this
bioregion, salmonoids would bring the richness of their flesh back to the land,
essentially countering the process of water removing minerals from continental
lands over time. A strong salmon run
could therefore be important for future agriculture.

Another plentiful but usually overlooked local source exists
for nitrogen, phosphorus, potassium and other vital minerals. The Chinese figured out thousands of years
ago that human excrement (feces and urine to be precise) is a valuable source
of fertilizer. Here in the U.S.
we spent gobs of money trying to get rid of it, but that may have to change.

Data on the fertilizer value of a year's supply of human
excrement is hard to come by. Two
references I have cite a 1956 report from the World Health Organization.[xx] Table 1 from "Future Fertility" is reproduced
here:

Nitrogen can become a gas and be lost during decomposition
unless care is taken to balance the carbon:nitrogen (C:N) ratio of the
composting process.[xxi] Human wastes have a 5:1 C:N ratio, but
starting a compost pile with 35:1 is best for retaining nitrogen. Assuming most of the nitrogen and other
nutrients can be efficiently retained; human waste can be recycled to yield
about 50% of nitrogen needs, all phosphorus needs, and 40% of potassium
needs. This topic warrants a detailed
discussion on its own, but that will have to wait for another paper.

Improving Non-prime Land

Some may feel tempted to "improve" non-prime farmland and
thereby increase the area available for intensive cultivation. I don't find it credible to rely on non-prime
agricultural land for significant productivity of major staple foods. The required inputs per area to make a naturally non-fertile soil and poorly textured
soil able to be cultivated are immense.
This can be done in someone's backyard, no doubt, but on a scale to
significantly contribute to grain production is not viable. However, non-prime land can be an important resource
for grazing animals, some perennial crops, and through intensive modification small-scale
cultivation of specialty crops or vegetables.

Research done for New York
State, for example, found that the
most area efficient diet was vegetarian and required 0.6 acres per person-very
close to the ovo-lacto-vegetarian diet plan for Mendocino County. By adding 0.1 acre per person in the form of
permanent pasture, the total number of people that could be fed in NY State was
increased.[xxii] (Note:
this was the thesis work of a Cornell
University graduate
student and so is far more thorough than my own!) While this addition of permanent pasture in
NY was 17% above the tillable cropland, in this exercise for Mendocino County
the non-prime acreage is 6.3 times greater.
Reasons I can think of for this huge difference are much more productive
pasture in upstate New York due to summer rains, and methodological flaws on my
part in estimation of Mendocino County range and pastureland productivity (the
amount of meat in the NY and Mendocino diets is similar).

The next essay will examine the actual land-base of Mendocino County.

Acknowledgement

Christoffer Hansen deserves thanks for reading drafts of
this work. He questioned my assumptions,
forcing me to explain them more clearly, and double checked the math in many
places. Any remaining errors are my
own.

[i] http://www.energyfarms.net/node/1489

[ii] http://soils.usda.gov/technical/handbook/contents/part622.html
and http://www.dot.ca.gov/ser/vol1/sec3/community/ch23farm/chap23farm.htm#Ch24Definitions

[iii] http://www.mendowine.com/

[iv] http://www.willitseconomiclocalization.org/files/well/FoodSecurityReport.pdf

[v] http://anrcatalog.ucdavis.edu/pdf/8208.pdf

[vi] http://ucce.ucdavis.edu/files/filelibrary/2161/29131.pdf

[vii] http://www.co.mendocino.ca.us/agriculture/pdf/2006%20Crop%20Report.pdf

[viii] Soil
Survey of Mendocino County,
California, Western Part. http://www.ca.nrcs.usda.gov/mlra02/wmendo/ and http://soildatamart.nrcs.usda.gov/Manuscripts/CA694/0/MendocinoWP_CA.pdf;
search for Mendocino
County at http://soildatamart.nrcs.usda.gov/

[ix] http://www.bakewellrepro.com/sarahflackarticle.html

[x] http://www.co.mendocino.ca.us/agriculture/pdf/2006%20Crop%20Report.pdf

[xi] http://www.shutersunsetfarms.com/index_files/Page949.htm

[xii] http://www.oznet.ksu.edu/library/lvstk2/mf754.pdf

[xiii] http://dieoff.org/page40.htm

[xiv] http://www.energyfarms.net/node/1489

[xv] http://www.city-data.com/county/Mendocino_County-CA.html

[xvi] http://attra.ncat.org/attra-pub/covercrop.html

[xvii] I
can't find a web-available reference for the table I used, but a similar table
using non-organic agricultural demands and so generally with higher values is
here: http://benson.byu.edu/Publication/Lessons/EN/Agronomy/SoilFertility.asp

[xviii] http://www.journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1091304&fulltextType=RA&fileId=S1742170507001640
and related press release: http://www.ns.umich.edu/htdocs/releases/story.php?id=5936

[xix] http://www.energybulletin.net/28720.html

[xx] http://www.jenkinspublishing.com/humanure.html;
with quantities in terms of pounds produced per person per year given in John
Beeby "Future Fertility: Transforming
Human Waste in Human Wealth" Table 1.
Ecology Action.

[xxi] http://en.wikipedia.org/wiki/Denitrification

[xxii] http://www.news.cornell.edu/stories/Oct07/diets.ag.footprint.sl.html

I live in a rural part of northern California in a county named Mendocino. There are about 90,000 people here, in an
area of about 3500 square miles, for a population density of 25 people per
square mile.[i] This is considered, and it feels like, a low
population density. So naturally I think
most people assume that if we had to grow our own food here we absolutely
could.

But as a data-driven empiricist, I wanted to do the math on
this. I posed the question: Could the land-base of Mendocino County
support its current population of people if it needed to? This initial question leads to many others,
including: What is the theoretical diet
being consumed? What are the yields per
area of the parts of the diet? What
kinds of soil, water and energy systems are needed to produce those yields? And, do the requisite land-water-energy
resources exist at the levels implied by the diet demands?

If you don’t live here why should you care about an analysis
done for Mendocino
County? Well, the point is that this exercise can be
done any place and is generally instructive on how our diets are dependent upon
a whole suite of resources. How do you
feel about the future of those resources globally, nationally or closer to
home? Does thinking about these topics,
running the numbers and considering scenarios influence your thoughts about
where to live, who to talk to, and what to invest in?

Before I get into those questions, it is important to
explain some of my basic operating assumptions.
First, I am interested in this question for a number of reasons that
revolve around energy and security. I
believe that global energy availability will decline this century as fossil
fuel reserves are depleted. I also
believe that burning those fossil fuels is a bad habit anyway since they muck
up the climate system upon which food production depends. Now, amazingly, our current food production,
distribution, storage and preparation systems are highly dependent upon the
very fuels that are going into depletion and spewing pollution into the
environment.[ii] When envisioning what it means to produce food
in the future for Mendocino County I therefore assume a low energy input
agriculture, meaning organic fertilizers, limited irrigation, and local
distribution systems. As it turns out,
this is also the system that would produce the fewest greenhouse gas
emissions. I don't want to argue about
the merits of conventional vs organic methods, or localism vs globalism in
trade, but simply state my position that whether out of necessity or moral
choices, the only option for sustainable production of food over the long-term is
through relatively local and organic systems.

Quite astonishingly to me, the potentially important goal of
local or bioregional food self-sufficiency is rarely considered. For example, my chin almost hit the floor at
a climate change conference in Sacramento
a few years back when the following actually happened. A senior professor of hydrology from UC Davis
gave a presentation of what looked to me like severe water shortages in California due to climate change melting winter snow
packs, not to mention the potential for severe flooding of the Central Valley, one of the most important agricultural
regions on the planet, from sea level rise.
The maps he showed of the havoc-ridden area included a complete build
out of the Central Valley into suburban
housing, which was presented as sort of a pre-ordained eventuality. When someone pointed out to him that it looks
like there's almost no more food production in California in this scenario, and
that the state would, under the conditions of less water, higher seas, longer
and more severe heat waves, etc. still have 60-90 million people to be fed,
which begs the question where might their food come from he replied, "We'll
import it." As far as I could tell, this
position was the standard one not only of the academics in the room, but of the
state bureaucrats organizing the event.

In any case, soon afterwards I began exploring some
alternative scenarios, one of them a few years ago being a rough estimate for what
food self-reliance would entail around here.[iii] Recently others have done similar work, such
as analyses for the state of New York[iv]
and Britain.[v] Not having a degree in agriculture I don't
feel highly qualified to do this, but I do have a doctorate in biology and am
comfortable with basic math and spreadsheets.
I have also become a vegetable farmer recently, so do have some personal
expertise in a limited aspect of food production. If readers find glaring errors, poor
assumptions or better data I am keen to hear about it. As a scientist, my main goal is to get as
close as possible to the truth, wherever that leads.

The Diet

Every locale has a combination of climate, soils and culture
that when combined with other assumptions related to future energy and food
system methodologies will limit the reasonable range of food species available. It is difficult to be purely scientific in
this situation because what people prefer to eat is governed by personal taste
and physiology. So I made some judgment
calls when proposing the basic mix of foods given a local, sustainable system
in place. Keep in mind I am also
considering this from a population level.
So while some may see "beef" and say that they are vegans, or see
"dairy" and fuss about their food allergy, that is beside the point.

Human nutrition is highly complex and controversial. In this case I envisioned a culturally
appropriate healthy diet based on a mixture of factors and guiding principles,
including: (1) maximizing food diversity,
(2) emphasizing fresh produce for vitamins and minerals, (3) considering the
relationship between soil health and rotation among production types (e.g.,
pasture and field crops), (4) the importance of food storage, and (4) the
weight of food ingested per day. I also
set a goal to produce close to 3000 calories per person on average. The population can get by with less, perhaps
2400 calories per person, but food waste can't be totally avoided and good
years may be followed by bad ones. Food
is so important that we should plan for excess just in case. This is common sense and used in engineering
all the time, such as building the bridge a bit stronger than the maximum load
it is supposed to carry.

With that lengthy explanation, I offer the following table
of foods, their proportions, and how they form a complete diet at an individual
level. Each row deserves some further
discussion.

Because of our winter rains and dry summers, grains will be
dominated by plants with C3 metabolic pathways, chiefly wheat, rye, oats and
barley, also known in the trade as "small grains." By contrast, corn, sorghum and rice would
require summer irrigation for high yields.

Dry beans can also be grown in the cool season if lentils
and chick peas are chosen. Pinto types
are summer-irrigation dependent. For
both grains and dry beans I will assume yields from dry-land (i.e.,
non-irrigated) methods. Irrigation could
potentially double yields.

My calculations for oil use olives. I prefer olives because, unlike field crops,
they can be established on non-tillable soils and so don't necessarily compete
for prime ag lands. Trees can also find
deep water sources and may not require irrigation once well established. Olive oil is also versatile and prized for
its flavor.

Honey is the sugar source in my diet mix. Other potential sugars include sweet sorghum
and sugar beets. I prefer honey because
of lower processing costs relative to sugar crops, and honey bees are
synergistic with food crops rather than competitive for land area. About one hive provides enough sugar per
person.

Sprouting seeds are included as a storable and portable
source of high calories and nutrition, including vitamin C. The crop modeled in this diet plan is
sunflowers. I like sunflowers because they
are a prolific summer source of nectar for honey bees, they can be used as an
oil crop if necessary, and they produce good biomass in stalks and seed
heads. Tree nuts could also be
included/exchanged in this part of the diet and have the advantage of not always
needing prime ag land.

Fruit and vegetables are a diverse assortment of standard
crops, including lettuce, cabbage, potatoes, carrots, grapes and apples. The caloric density ranges about 10-fold
(zucchini, 64 calories/lb, garlic 676 calories/lb) but averages 200/lb when
calorie staples such as potatoes are included.

Dairy calculations are based on a soft cheese, such as
mozzarella, which has 3 times the caloric density as whole milk. The allotment here is equivalent to 1.6 cups
of fresh milk a day, but cheese is used for ease of comparisons among mostly
sold foods. Cheese also stores and
transports well so should be encouraged.
In reality I'd expect a mixture of consumption patterns, such as a cup
of milk a day and a modest piece of cheese.

I am using chicken eggs, about 1 per day per person.

Meat assumes domestic animals such as fowl and
ruminants. I prefer rotational grazing
systems that mimic multi-species flocks.
Chicken is less calorie dense than beef, so an average is used. The most common livestock here are cattle and
sheep, so I will likely emphasize their needs when calculating land area though
other species warrant consideration. The
amount of meat in the diet, 50 lbs per year, is about 1/3 the current U.S. average
and works out to 2.2 oz per day, or just under a pound per week. I am not expecting people to eat tiny
portions of meat each sitting, but perhaps a pot roast or leg of lamb shared
among a family on Sunday dinner. While
this quantity of meat seems low by current U.S.
standards it is the same as modeled for an area-efficient diet in New York State and would be the envy of many
parts of the world.[vi]

An additional factor when considering a diet is the total
weight of the foods being consumed each day.
Human stomachs get uncomfortable when given too much food, so foods with
high caloric density offset the weight of foods with low density. Some foods are eaten with their natural
content of moisture, whereas others are stored dry and are hydrated during
cooking. The table multiplies the dry
weight of certain foods (grains, dry beans and sprouting seeds) by a factor of
three to estimate their weight when ingested.
Keeping the diet below 6 lbs per day is a goal.[vii]

I like this diet because it feels normal to me, and appears
very healthy. A quarter of the daily
weight of food is in the form of fruits and vegetables (Fig. 1). Eggs, dairy and meat are present but not in
unhealthy proportions. Oils and sugars
are recognized as important but their presence is moderated appropriately. Whole seeds are the main caloric staples,
including cereals, legumes and other seeds (Fig. 2). I would like a nutritionist to look this over
and let me know if I am especially high or low on anything in their view. Overall, I think I struck a nice balance that
will likely provide enough calories, protein, minerals and vitamins without
excessive food weight (5.2 lbs per day), using a mix that stores well and is
culturally familiar.

Fig. 1. The daily wet
weight (ounces) of food is given by food class.

Fig. 2. The daily
calories of food are given by food class.

Okay, so step 1 is complete, establishing a diet. The next steps are: (2) translate this diet
into land area requirements, (3) scale the land area from an individual level
to the population of Mendocino
County, and (4) compare
to the actual land-base.

[i] http://www.city-data.com/county/Mendocino_County-CA.html

[ii] http://www.cias.wisc.edu/pdf/energyuse.pdf

[iii] http://www.willitseconomiclocalization.org/files/well/FoodSecurityReport.pdf

[iv] http://www.news.cornell.edu/stories/Oct07/diets.ag.footprint.sl.html

[v] http://transitionculture.org/wp-content/uploads/2007/CanBritain.pdf

[vi] http://www.news.cornell.edu/stories/Oct07/diets.ag.footprint.sl.html;
and original article here: http://www.journals.cambridge.org/action/displayAbstract?fromPage=online&aid=1091328&fulltextType=RA&fileId=S1742170507001767

[vii] Duhon,
D. 1985.
One Circle: How to Grow a Complete Diet in Less Than 1000
Square Feet. Ecology Action, Willits, CA.

Most institutions, such as the food aid NGOs or the US
Department of Agriculture, express concern about food security in terms of the
ability for poor people to purchase adequate food. The USDA, for example, measures food security
by asking households a series of
questions (http://www.fns.usda.gov/fsec/FILES/FSGuide.pdf), including:

Q1 Which of these statements best describes the food eaten
in your household in the last 12 months: we always have enough to eat and the
kinds of food we want; we have enough to eat but not always the kinds of food
we want; sometimes we don't have enough to eat; or often we don't have enough
to eat?

Q1a (IF SOMETIMES
OR OFTEN NOT ENOUGH TO EAT) Here are some reasons why people don't
always have enough to eat. For each one, please tell me if that is a reason why
you don't always have enough to eat.

Not enough money for food

Too hard to get to the store

On a diet

No working stove available

Not able to cook or eat because of health problems

Income-based Food
Security

This is a valid way to think of food security. If food prices are high relative to income,
or if other compelling expenses such as housing, health care and transportation
also require a large portion of income, then securing adequate food on an individual or family level will be
problematical. I will refer to this kind
of food security as "income-based food security." Personal misfortunes or failings, structural
economic inequality, recessionary business cycles, and monetary crises are
examples of conditions that cause or exacerbate income-based food security. Asking heads of households is a proper way to
understand this class of food security.

In general, households don't actually produce food, nor do
they move food from producers to markets.
Given current environmental and resource trends, the income-based food
security perspective has some gaping blind spots. Instead of just asking food eaters questions,
should we also be querying food producers, distributors, fertilizer
manufacturers, supermarkets, energy experts and climatologists?

Distribution-based
Food Security

Globalization of food commodities has greatly distanced food
consumption from food production. Most
people in industrialized nations, and quite a few in poor but food importing
nations, are therefore highly dependent not only on the ability to pay, but on
the ability to distribute food from places of production, storage, and
processing to retail and home. Absent
either the liquid fuels for shipping vehicles, or sufficient roads, rails and
port infrastructure to carry and receive cargo, food becomes scarce no matter
how much money someone has in their wallet.
Examples include a place after a natural disaster or a war (Gulf coast
post-Katrina), a nation embargoed for political reasons (Cuba in the 1990s), and acute shortages of fuel
or trucks (UK trucker strike
in 2000, Italy
recently). With transportation
disruptions grocery store shelves can go bare within days. I will refer to this kind of food security as
"distribution-based food security." Just-in-time
delivery systems, oil depletion, violence in oil producing regions, and "acts
of god" threaten distribution-based food security.

Production-based Food
Security

Total food output has increased dramatically over the past
50 years, far outpacing even the rise in population. The reasons for this increase in production,
however, and the broader environmental costs incurred, suggest that food
production will flatten and perhaps decline in the coming decades. Productivity gains were driven principally by
increases in non-sustainable inputs, such as irrigation water from depleting
aquifers, nitrogen fertilizer from natural gas, and greater mechanization in
general requiring more fossil fuels. None
of these are sustainable solutions, meaning they are bound to fail in the end
without ample and timely substitutes.
Cultivation, irrigation, fertilization, herbicide and pesticide
practices have also led to massive erosion of topsoil, leading to a steady
decline in the quality of the land base supporting agriculture. Urbanization, severe erosion, and the long
history of forest clearing end up reaching the limit in the total quantity of
arable land as well. And finally, the
stable climate system upon which farmers, seeds, cultures and markets have
adapted to is wobbly. Expectations are
for extreme weather variance and a general decline in crop growth over
time. These related forces I term
"production-based food security."
Overall, the quantity of food is threatened by depletion of resource
stocks (fresh water, oil, natural gas, mineral fertilizers), degradation of
soils, and climate change. Many would
also add genetic diversity and aging farmers to this list.

These three classes of food security threats are not
unrelated, of course. Rising energy
costs impact the costs of production and distribution, which in turn lead to
food inflation. But by framing security
in these different ways, we can more clearly see the stresses in the food
system and their underlying causes. All
three classes of food security threats are occurring simultaneously, but at
different rates and severity among different populations. Social movements have arisen in response, and
their different emphases reflect the classes of threats summarized here. These movements also offer potential
strategies to deal with each situation (See Table 1).

The problems of our food system are so deep and connected to
so many other structures in our societies that only a multi-faceted approach
that recognizes these relationships offers meaningful, long-term change. Fortunately, many are aware of this. Take for example the Community Food Security
Coalition (http://www.foodsecurity.org/),
which describes itself as:

The Community Food Security
Coalition (CFSC) is a non-profit 501(c)(3), North American organization
dedicated to building strong, sustainable, local and regional food systems that
ensure access to affordable, nutritious, and culturally appropriate food for
all people at all times. We seek to develop self-reliance among all communities
in obtaining their food and to create a system of growing, manufacturing,
processing, making available, and selling food that is regionally based and
grounded in the principles of justice, democracy, and sustainability. CFSC has over 200 member organizations - join
us!

The CFSC connects groups from across the spectra of social
organizations throughout North America. I think it would be wise for each community
to find their own set of players, from food banks to farmer's markets to
community farms, and work together.

Imagine, for example, providing stable income to a local,
organic community farm for growing food distributed to a school with many low
income children? There, in one set of
connections economic justice, decreased transportation, and sustainable
agriculture strategies are integrated and reinforced. Who wouldn't be in favor of that?

[Note: A slightly modified version of this is also available on The Oil Drum, with a couple hundred reader comments: http://www.theoildrum.com/node/3415]

Among the cadre of folks
who think about food systems and sustainability in the U.S., there's a
concern about the number of farmers and their age. Only about two percent (5,802,000/29,5410,000
in 2004) of the U.S.
population is part of a farm family, and the average age of principal owners of
farms is about 60 years.[i] Since mechanization and the fuels that power
machines are what enable such a small agricultural labor force, is it reasonable
to assume that a decline in fossil fuels will require more farmers?

Others, such as peak oil
educators Richard Heinberg and Sharon Astyk, have suggested this will indeed be
the case, even going so far as to put a rough number on the future farmers of
America. Their estimates are based on
looking at the proportion of farmers in an early to pre-industrial economic
system in the United States,
when about a third of the population engaged in agriculture. They then adjust for current population size
to arrive at the admittedly tentative figure of 50 to 100 million farmers (or
members of farming families) needed to feed a population of 300 million.[ii]

As these authors point
out, not only is the absolute number very large compared to today, but given
the age of the current crop of farmers it implies that a rapid education of
youth will be required to keep bread on the table. Given the importance of this topic, I feel
that more diverse and sophisticated forms of analyses are needed. Just as we use multiple lines of evidence to
understand the evolution of life, oil depletion, and climate change, we need to
look for confirmation from many angles.
Furthermore, better knowledge potentially gets us closer to grasping the
scale and rate of change required to cope with the problem in the same way that
depletion rates in existing fields and net exports analyses do in the oil
situation, or the timing and consequences of melting ice sheets and release of
methane from warming permafrost do in the climate system.

Perhaps we can validate
or refute this scenario by further use of the comparative method. The comparative method is what Heinberg and
Astyk used in their analyses-comparing a future scenario to a potentially
analogous historic past. In the analysis
presented here, I take as a given that the United States (and other high
energy consuming industrial countries) will have less energy available in the
future. The comparison I use is not
historic, but contemporary. I know that
today some nations have much less energy consumption than others and
anecdotally I am aware that poorer countries tend to be more agrarian. If nations with less energy consumption have
more farmers, it would support the notion that a reduction in energy
consumption in the U.S.
(and other industrialized countries) will lead to an increase in farmers.

So let's take a
look: Is there a discernable inverse
relationship between energy consumption and agricultural populations among
nations?

First, I had to find
total population by nation and agricultural population (which I believe means
farmers and their immediate dependents) by nation. These data can be downloaded from the United
Nations Food and Agriculture Organization (FAO) (http://faostat.fao.org/site/550/default.aspx).

Simply dividing the
agricultural population by the total population gives the percentage that live
an agricultural life. The range of this
figure is huge, from essentially zero for places like Singapore to over 90% for places like Bhutan. I really don't know how accurate censuses
data are from the 204 countries used (not all places are fully independent
nations, e.g., Puerto Rico is separated from the U.S. in these data sets), but
assume figures are in the ballpark.
Certainly citizens of Bhutan
and Singapore
have vastly different livelihoods.
According to 2004 FAO data, overall about 41% of the world's people
still live in families who work in agriculture (2.6 billion out of 6.4
billion).

Most nations (about 70%) have 40% or less of their
population in agriculture. This means
that the fewer countries with high percentages of agricultural workers have
large populations, e.g., China
and India
are 64% and 52% respectively and equal about a third of the total world
population. In all likelihood, large
populations correlate with high population density. As a 1997 paper by Conforti and Giampietro showed, economic forces in poorer nations
with dense populations tend to retain farmers.[iii]

Second, I had to find
energy consumption data. It is difficult
to locate data on use of wood, animal dung, etc., but for commercial energy
such as oil, natural gas, coal, and electricity the Energy Information Administration
(EIA) of the U.S. Department of Energy has available spreadsheets for download
(see table E.1 http://www.eia.doe.gov/iea/wecbtu.html).

While this doesn't include
all forms of energy, it does cover the forms most readily usable in an
industrial agricultural system.

I had to do some work to
harmonize the two data sets, which meant using 2004 data and limiting the
analysis to 204 nations-which I figure is fairly complete. Then I plotted percent agricultural population
as a potential response to per capita energy consumption and got the figure
below.

As expected, nations with
relatively little commercial energy consumption tend to have lots of
farmers. But the relationship doesn't
appear linear (perhaps putting energy on a log scale would change that, the X
axis ranges from 0-1000 and the Y axis from 0-100) and is not very tight. While supportive of the general hypothesis, I
find it impossible to use this method and these data alone to get at the scale
and rate of change questions.

What might it mean, for
example, for the U.S.
to be using 3/4 less energy by 2050?
Many places today are already using that much less energy and have just
as small of an agricultural population as the U.S., but surveying the spreadsheet
it appears that many could be considered special cases, such as small islands
swarming with tourists or tax havens for the wealthy, which can simply afford
to purchase most of their food.

Other questions that
arise include: Whether U.S. farming can
remain as energy intensive as it is today by taking a larger share of resources
from other sectors of the economy? Because
no modern economy can survive without them, I would expect extraction and
production sectors, such as mining, agriculture and manufacturing to decline at
a slower rate than, for example, finance, tourism, and real estate. Are dramatic efficiency gains still to be had
in conventional U.S.
agriculture, or has the farm sector already been through enough energy and
financial dramas to have played out the easy options?

As in any good subject
for research, answering one simple question provokes a series of more difficult
ones.

Though I may have just
done so, I am mistrustful of studying this issue in isolation. Nagging at me is the question of whether the
globalized industrial system is inherently unstable in the face of multiple
challenges, including energy scarcity but also the converging crises spawned by
the surging weight of humanity. Climate
change, financial wobbles, violent conflicts and related spin-offs can
unpredictably disrupt the vast system of trade that moves fertilizers, seeds
and replacement parts that keep industrial agriculture humming. I think we are already seeing hints of this
scenario in the U.S.,
as farmers run short of diesel fuel during harvest season and end up leaving
crops in the ground.[iv]

While I would appreciate
more work towards the questions posed here (and contact me if you have ideas and
skills to help), I also caution against analysis paralysis. There are multiple reasons why agriculture
needs to undergo a profound shift and spending too much time trying to
circumscribe the problem may delay us moving towards appropriate
responses. I believe the broad vision of
what needs to be done already exists-food that is more local, organic,
produced, processed and distributed by renewable energy systems, and using cultivation
methods that put the soil health first. Making
that argument to those who are reluctant or suspicious, however, could use some
better research that connects the dots credibly between energy depletion,
climate change, food security, and demographics.

[i] Hollis, P. 10 May 2005. Demographics study reveals facts about farm
operators in U.S. . Farm Press. http://southeastfarmpress.com/news/051005-Farm-demographics/;
The cited article is based on primary data from the 2002 U.S. Census of
Agriculture (http://www.agcensus.usda.gov/Publications/2002/index.asp). The average age of U.S. farmers being about 60, as
claimed today, is extrapolated from the 2002 data, with an update due from an
ongoing 2007 census.

[ii] Heinberg,
R. 2006.
Fifty Million Farmers.
Twenty-Sixth Annual E. F. Schumacher Lectures. http://www.smallisbeautiful.org/publications/heinberg_06.html; Astyk, S.
2006.
http://casaubonsbook.blogspot.com/2006/12/50-million-100-million-200-bazillion.html

[iii] Conforti, P and M. Giampietro. 1997. Fossil energy use in agriculture: an
international comparison. Agriculture, Ecosystems and Environment 65
(1997) 231-243

[iv] Reuters. 12 September, 2007. "Not so Corny: Fuel Shortages May Hurt Corn
Harvesting."
http://www.foxnews.com/story/0,2933,296551,00.html