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.

 

Food	Pounds/year/ person	Current U.S. average	Oz/day/person (dry)	Oz/day/person (wet)	*Calories per pound	Calories/year/ person	Calories/day/ person
grains	230	200	10.08	30.25	1550	356,500	977
dry beans	50	2	2.19	6.58	1600	80,000	219
oil	40	65	1.75	1.75	4000	160,000	438
sugar	30	150	1.32	1.32	1380	41,400	113
sprouting seeds or nuts	20	17	0.88	2.63	2560	51,200	140
fruit and vegetables	650	570	28.49	28.49	150	97,500	267
potatoes	180	150	7.89	7.89	350	63,000	173
dairy (cheese)	30	37	1.32	1.32	1500	45,000	123
eggs	10	28	0.44	0.44	650	6,500	18
meat	50	180	2.19	2.19	925	46,250	127
Totals	1290		56.55	82.85		947,350	2595
			Wet lbs per day	5.18
*calorie figures from Jeavons, 7th edition and USDA (http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20a208.pdf)

 

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:

 

Food	Pounds/year/ person	Yields/lbs/acre/ year	Acres/crop/ person	As percentage	*Calories per pound	Calories per acre	Class of farmland required
grains	230	2,000	0.12	0.38	1550	3,100,000	I or II
dry beans	50	1,800	0.03	0.09	1600	2,880,000	I or II
oil	40	835	0.05	0.16	4000	3,340,000	I, II or III
sugar	30				1380
sprouting seeds	20	900	0.02	0.07	2560	2,304,000	I or II
fruit and vegetables	650	20,000	0.03	0.11	150	3,000,000	I or II
potatoes	180	20,000	0.01	0.03	350	7,000,000
dairy (cheese)	30	1,249	0.02	0.08	1500	1,873,500	I or II
eggs	10	440	0.02	0.08	650	286,000	I, II or III
meat	50	6	8.33		925	5,550	I, II, III or greater
		Total acres/person	8.63
		Total acres minus meat	0.30

 

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

 

Food	Acres/crop/ person	Acres for County Population	Irrigated?
grains	0.12	10,139	yes
dry beans	0.03	2,449	yes
oil	0.05	4,223	yes
sugar	0.00	0
sprouting seeds	0.02	1,959	yes
fruit and vegetables	0.03	2,865	yes
potatoes	0.01	793	yes
dairy (cheese)	0.02	2,118	yes
eggs	0.02	2,004	yes
meat	8.33	734,675	Acres of Non-prime farmland
Total acres/person	8.63	761,225	Acres Total
Total acres minus meat	0.30	26,550	Acres minus meat = Prime farmland

 

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:

 

Crops needing prime farmland and rotation with green manures (fruit and vegetable area given as 2/3 toward vegetables)
Food	Acres/crop/ person	Acres for County Population	*Green manure factor	Actual Acres	**N lbs/acre/ yr	**P lbs/acre/ yr	**K lbs/acre/ yr
grains	0.12	10,139	1.50	15,208	50	8.8	24.3
sprouting seeds	0.02	1,959	1.80	3,526	80	8.8	48.6
vegetables	0.02	1,920	2.00	3,839	100	13.2	64.8
potatoes	0.01	793	1.70	1,349	70	13.2	97.2
dairy (cheese)	0.02	2,118	1.50	3,176	50	8.8	24.3
eggs	0.02	2,004	1.50	3,005	50	8.8	24.3
		18,932		30,104
*Irrigated clover can fix nitrogen at a rate of about 100 lbs/acre for a year's growth and is appropriate for Mendocino County climate
**Estimates from Appendix II of "Successful Small-Scale Farming: An Organic Approach" by Karl Schwenke, referencing the "Missouri Balanced Farming Handbook
**P and K are often reported in compound forms such as phosphoric acid and potash. I am calculating elemental mass only: P is about 44% of phosphoric acid, K is about 81% of potash.

 

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

 

Prime land required
Area needing rotation	30,104
Area not needing rotation	7,618
Total	37,722

 

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.

 

Fertilizer Requirements per capita
Food	Acres/crop/ person	**N lbs/acre/ yr	N lbs per capita	**P lbs/acre/yr	P lbs per capita	**K lbs/acre/yr	K lbs per capita
grains	0.12	50	5.75	8.8	1.01	24.3	2.79
sprouting seeds	0.02	80	1.78	8.8	0.20	48.6	1.08
vegetables	0.02	100	2.18	13.2	0.29	64.8	1.41
potatoes	0.01	70	0.63	13.2	0.12	97.2	0.87
dairy (cheese)	0.02	50	1.20	8.8	0.21	24.3	0.58
eggs	0.02	50	1.14	8.8	0.20	24.3	0.55
			12.67		2.03		7.30

 

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.

 

Pounds Produced Per Person Per Year
	Nitrogen	Phosphorus	Potassium	Calcium
Urine	7.5	1.6	1.6	2.3
Manure	2.8	1.9	0.8	2
Total	10.3	3.5	2.4	4.3

 

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.

 

Nutrient Content of Straw
Acres in grain	Ton of straw (lbs)	N (lbs)	P (lbs)	K (lbs)
14,260	22,816	342,234	50,194	388,093
	Per capita	3.9	0.6	4.4

 

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.

 

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[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.

 

Summary
Mendocino County Population (2005)	Calories/ person/ day	Weight of daily diet (lbs)	Prime farmland to feed population	Non-prime farmland to feed population	Prime farmland/ person	Non-prime farmland/ person
88,161	2,964	5.19	95,401	706,052	1.08	8.01

 

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.

 

Mendocino County Population (2005)	Prime Farmland Need (Acres)	Per Capita Need	Actual Prime Farmland USDA, 1980s	Implied Per Capita USDA, 1980s	Actual Prime Farmland, Caltrans 2000s	Implied Per Capita Caltrans 2000s
88,161	95,401	1.08	69,105	0.78	35,000	0.40

 

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?

 

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[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_Form/2007_RFG.pdf

[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.

 

Food	Pounds/year/ person	Oz/day/person (dry)	Oz/day/person (wet)	*Calories per pound	Calories/year/ person	Calories/day/ person
grains	275	12.05	36.16	1550	426,250	1168
dry beans	90	3.95	11.84	1600	144,000	395
oil	25	1.10	1.10	4000	100,000	274
sugar	30	1.32	1.32	1380	41,400	113
sprouting seeds	20	0.88	2.63	2560	51,200	140
fruit and vegetables	500	21.92	21.92	200	100,000	274
dairy (cheese)	100	4.38	4.38	1500	150,000	411
eggs	35	1.53	1.53	650	22,750	62
meat	50	2.19	2.19	925	46,250	127
Totals	1125	49.32	83.07		1,081,850	2964
		Wet lbs per day	5.19
*calorie figures from Jeavons, 7th edition and USDA (http://www.nal.usda.gov/fnic/foodcomp/Data/SR20/nutrlist/sr20a208.pdf)

 

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:

 

Food	Pounds/year/ person	Yields/lbs/acre/ year	Acres/crop/ person	*Calories per pound	Calories per acre	Class of farmland required
grains	275	1000	0.28	1550	1,550,000	I or II
dry beans	90	900	0.10	1600	1,440,000	I or II
oil	25	835	0.03	4000	3,340,000	I, II or III
sugar	30			1380
sprouting seeds	20	900	0.02	2560	2,304,000	I or II
fruit and vegetables	500	20000	0.03	200	4,000,000	I or II
dairy (cheese)	100	684	0.15	1500	1,026,000	I or II
eggs	35	220	0.16	650	143,000	I, II or III
meat	50	6	8.33	925	5,550	I, II, III or greater
		Total acres/person	9.09
		Total acres minus meat	0.76

 

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.

 

Food

Acres/crop/ person

Acres for County Population