I just spent three days talking about biofuels with other scientists who work at historically black land grant universities. These institutions exist in most southern states because of an 1890 law requiring states to either set up a land grant institution for people of color or demonstrate that race was not an admission factor at their existing institution. Kentucky State University, where I work, is one of these '1890 land grants.'

The 1890 land grants are interesting because of their mission to serve under-served constituencies, including minorities and people with limited resources. The 'get big or get out' prescription sometimes associated with land grant universities ought to be an anathema to 1890 land grant universities.

This week's meeting was called to explore ways for 1890 land grants to contribute to USDA goals, including "the development of biofuels and processes to efficiently convert renewable plant products to fuel." It came at a time when food prices are skyrocketing and people are going hungry, in part because a growing proportion of America's corn is being turned into fuel.

At one point I expressed to a USDA economist my opinion that the large scale corn to ethanol program has been a complete failure, neither reducing carbon emissions, nor contributed to energy independence. The economist surprised me with his defence that neither of these were program objectives. The real goal, he said, was to raise corn prices. By that measure the program has been a resounding success(!).

After three days of intense discussion we hammered out a list of research objectives for 1890 land grants working on biofuels. They are:

1. Identify, produce, characterize and improve alternative feedstock crops.
2. Develop and optimize small scale technologies for biofuel production.
3. Evaluate and improve biofuel and byproduct quality.
4. Educate and train students, farmers, and other professionals regarding biofuels.
5. Analyze economic, environmental and social impacts of biofuel production and use.

So those are my guiding principles as I continue to participate in the Energy Farms Network and collaborate with the Post Carbon Institute. Over the summer I'll work with researchers from Virginia State University and North Carolina A&T University to pull together a full proposal, based on these objectives, for a collaborative project involving all eighteen 1890 land grant universities.

Some of my current research is funded by Southern SARE, so I took note when the organization released a position paper on the type of biofuel research it will fund in the future. SARE identifies eight themes for future projects to "expand the focus in bioenergy beyond corn- and soybean-based ethanol and biodiesel:"

1. Energy conservation and efficiency;
2. Energy efficient production practices;
3. Non-biomass renewable energy sources;
4. Alternative biomass feedstock production systems;
5. Environmental impact of bioenergy production;
6. Community and rural development impacts of bioenergy production;
7. Local and regional economic impact of biofuel production; and
8. Whole farm integrated energy systems.

It looks like the Energy Farms Network is on the cutting edge.

-----

• The goal is to feed more people, not fewer people. There is an old adage that has already been quoted about putting all your eggs in one basket. If I were one of those fifty people who was being fed by only one farmer, I'd be more worried than if there were four or five-or ten. Suppose the one farmer dies?
• Two and a half percent of the population is feeding all the rest. That is very small. And as far as I can see, nobody is worrying about where the cutoff point is. There is always a bottom half. We are always concerned about eliminating the bottom half because we say they're inefficient. I think that our doctrine of efficiency is suspect anyway because it only applies to major quantities. We waste stuff at our place all the time because we can't sell it. It's too little to sell. You can't give it away unless you cook it for somebody.
• How small do you let the percentage of farmers get before you are in danger? We have no alternative energy source on the farm now. When one farmer's feeding fifty people he is absolutely dependent on petroleum. When the economy shifts to reflect the realities of energy, it may be too expensive to produce some of this food; certainly at current prices.
• --Wendell Berry, 1974 http://www.tilthproducers.org/berry1974.htm

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.

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.