Urban Renewal Think Tank

Suppose that half of the land on every one-acre-or-smaller urban/suburban home lot in the entire nation were devoted to food-growing. That would amount to a little over 5 million acres (pdf) sown to food plants, covering most of the space on each lot that’s not already covered by the house, a deck, a patio, or a driveway. (And in many places it couldn’t be done without cutting down shade trees and planting on unsuitably steep slopes).

That theoretical 5 million acres of potential home cropland compares with about 7 million acres of America’s commercial cropland currently in vegetables, fruits, and nuts, and 350 to 400 million acres of total farmland. The urban and suburban area to be brought into production would not approach the number of healthy acres of native grasses and other plants that are slated to be plowed up to make way for yet more corn, wheat, soybeans, and other grains under the newly passed federal Farm Bill.

A nationwide grow-your-own wave would send good vibes through society, ripples that could be greatly amplified by community and apartment-block gardening. But front- and backyard food, even if everyone grew it, would not cover the country’s produce needs, much less displace our huge volume of fresh-food imports.

From our food production estimate based on the 10 food categories and 160 cases in developed countries, we found that organic production could theoretically generate an amount of food equal to 92% of the current caloric availability (or a yield ratio of 0.92). This ratio is close to that found in a 1990 study by Gerald Stanhill of Israel's Agricultural Research Organization. However, looking at the 133 examples from the developing world, our team estimated food production equivalent to an overall yield ratio of 1.80—that is, 180% of current production in the developing world on a caloric basis.

From these regional results, researchers at the University of Michigan then constructed two models, a "conservative case" and a "realistic case." The "conservative case" applied the yield ratios of organic production to conventional production from the developed countries to worldwide agricultural production (production in both the developed and developing countries). As the yield ratios in the ten food categories were generally lower in the developed countries, applying them worldwide means that slightly fewer calories would be produced under a fully organic global system: 2,641 kcal/person/day instead of 2,786 kcal. However, this number is still above the suggested intake for healthy adults of 2200 to 2500 kcal/person/day, so even under this conservative estimate there would be sufficient food production for the current population. However, under more realistic assumptions—that a switch to organic agriculture would mean the relatively lower developed world yield ratios would apply to production in the developed world and the relatively higher developing world yield ratios would apply to production in the developing world—the result was an astounding 4,381 kcal/person/day, a caloric availability more than sufficient for today's population. Indeed, it would be more than enough to support an estimated population peak of around 10-11 billion people by the year 2100.

jstorvick wrote:You can raise a shitload of tilapia in pretty small tanks

Xtal wrote:Farm-raised tilapia may not be very good for you, unfortunately. The article concludes by saying it makes a difference what the fish are fed on, but doesn't specifiy what feed would produce healthy or unhealthy fish.

http://news.health.com/2008/07/11/popul ... pia-heart/

As for suppliers, “the industry needs to improve ways of farming fish,” said Katherine Tallmadge, a national spokeswoman for the American Dietetic Association. “The whole idea of farming is a great one, but they’re feeding the fish food that’s inexpensive, so they can keep the price down, and it’s having an adverse effect on the nutritional quality of the fish.”

Farmed trout and Atlantic salmon had relatively good concentrations of “good” omega-3 fatty acids compared with “bad” omega-6 fatty acids.

Farm-raised tilapia and catfish, on the other hand, had troubling ratios.

“In the 1970s, we lost the ability to feed the planet with fish we catch,” Chilton said. “Farm-raised fish has to be part of our future, but we must do it correctly. We must feed animals the correct foods. Animals become what we feed them, and we become what we eat as well. The food chain is fairly consistent.”

Justin Boland wrote:...and I'm still trying to find that magical master list of THE BEST CROPS for high-speed high yields.

"Victory gardens" are smart way to hedge against short term system failure and as a cost cutting measure. However, a longer term solution for decentralized agriculture needs to be much, much more productive than traditional gardening. Subscription plots/farming, low cost sensor networks (water, light, PH, etc.), high intensity plot plans, accelerated local composting systems, lawn garden entrepreneurs, tinkering networks, etc. will be needed to flesh out an innovative ecosystem that will drive the productivity curve. Given these innovations, its possible to see a situation were 80-90% of food consumption is locally derived and sold at a small fraction of current costs and at a much higher level of quality/freshness. Resilience needs to be productive/affordable to become dominant.

We've been building an alternative agricultural infrastructure and economic system since the 1970s in this state. It could very easily by maximized using many of the lessons that New Alchemy Institute pioneered during that time.

Gandhi said the heart of satyagraha was swadeshi, local production. Both the spinning of thread and, more famously, the salt march were economic as well as political acts and example of that local production, swadeshi principle. Gandhi's economics was based upon the revitalization of village (neighborhood) production and markets and its goal was full employment not larger GDP or more consumption.

I'm doing a directed reading on Gandhian economics and my raw notes are at
http://www.globalswadeshi.net/forum/top ... dations-of
http://www.globalswadeshi.net/forum/top ... j-swadeshi
http://www.globalswadeshi.net/forum/top ... ic-thought

The need is:

15 litres water / day / person
2200 calories / day / person
2 million people (Lucas lives in the Canary Islands).

A Seawater Greenhouse setup for vegetable production produces 1.2 litres / m2 / day. Which is consumed by the vegetable production in the greenhouse. You should easily be able to get a yield of 30 kg / m2 / year from the greenhouse. (Some greenhouse growers, under less ideal conditions are able to double this yield, but lets use that for now.)

Eggplant, 0.25 calorie / g < http://caloriecount.about.com/calories-eggplant-i11209 >
Tomato, 0.18 calorie / g < http://caloriecount.about.com/calories- ... 529?size=4 >
Lettuce, 0.2 calorie / g < http://caloriecount.about.com/calories- ... ine-i11251 >
Green, snap beans, 0.3 calorie / g < http://caloriecount.about.com/calories- ... een-i11052 >

So for simplicity sake, lets assume 0.25 calorie / g vegetables. For 2200 calories then you need 8800 grams of vegetables / day to meet your calorie requirement. The so called Gorilla Diet.
http://www.beyondveg.com/billings-t/cal ... 1c.shtml...

Lets supplement it with a little bit of fish, we are talking about an island nation. Lets say one fillet of white fish (154g) / person / day, that is 265 calories. < http://caloriecount.about.com/calories- ... ies-i15223 >

Add two potatoes 2x 136 g / person / day, which is 236 calories. (Not sure of growing potatoes on the island, but I think we can use the cool air stream in the shade tent behind the greenhouse for colder climate to do that.)
< http://caloriecount.about.com/calories- ... ed-skin-... >

2200 - 265 - 236 = 1699 calories. If the remainder is vegetables then you need 6796 g vegatables. Lets say 6.8 kg / person / day.

Which shows that you probably will need to supplement with some avocados and nuts, maybe sundried tomatoes etc. but this is a “back of the envelope” calculation, so lets leave that for now.

For simplicity sake we will assume that all the vegetable yields are the same in the greenhouse for all vegetables. So one person needs 6.8 kg / person / day. 6.8 x 365 days = 2482 kg. Yield / m2 is 30 kg. Which gives 2482 kg / 30 kg/m2 = 82.7 m2 / person / year to grow the vegetables, lets say 83 m2 to make it easier.

1 hectare is 10 000 m2, so that feeds 120 people for one year with vegetables. So you need 2 million / 120 = 16 667 hectares of greenhouses, plus the space to grow the potatoes.

Lets do a sanity check on that. How much is that? Almeria in southern Spain has in the range of 25,000-30,000 hectares of greenhouses. According to one source (below) they only get about 9kg / m3 from their greenhouses (in 2000), but that is fairly typical for Almeria yield according to my sources.
http://www.schundler.com/spain.htm

Almeria is a huge exporter of vegetables. Think of it as about 1000 Euro / ton of vegetables. Do the math. It is a lot. Great income.

Ok, so the Canary Islands can become self sufficient in food if they want to, building a powerhouse of vegetable exports using only sustainable energy. The islands are pretty windy, so running window power stations for the power needed to drive the process in the greenhouse is possible. How much energy would be needed? Lets be conservative and assume 20 kW peak load per hectare for pumping power. 20 kW x 16700 = 334 000 kW = 334 MW. Which is 100 modern windpower stations at peak load. Not bad.

(The greenhouses perform a cooling function in the process of evaporative cooling which is about 250-400 kW / 1 kW of pumping power. That is a nice output, getting cooling power worth 250-400 times what you put in.)

Ok the water then?

A Seawater Greenhouse can output significantly more water than what the standard greenhouse will output, if we have access to cold water. The Las Palmas solution used deep water from nearby the island. < http://www.seawatergreenhouse.com/gran_canaria.htm >

Lets assume you have access to 1000 meter deep water within three, four km of the coast. Then you can build a pipeline there and go get the nice 6-8 C water. This type of cold water will improve the water output from the condensers in the greenhouse significantly. Lets assume we get 10x more water out this way. So you get 12 litres / m2 greenhouse / day. That is 10 litres extra, that the greenhouse won't need for the food crops you are growing.

10 litres x 10000 m2 (one hectare) = 100 000 litres or 100 m3 water per hectare. 16 700 hectares will then produce 1 670 000 m3 water. Or 1,7 million m3 water.

2 million people use according to our assumption above 15 litres /day / person = 2 million x 15 = 30 million litres or 30 000 m3.

So our setup would produce more water than we need. In fact this is probably quite a good idea, as the pipeline and pumping to bring up that water would cost quite a bit.

How much? A pipeline being build in Curacau where I have been looking at the business case a bit.
http://www.otecnews.org/articles/curacao-swac.html

That pipeline would cost about Euro 15 million to build. It is supposed to bring in water at about 500 litres / second. In one day that would be 43,200 m3. I am not sure, without having to take out the big calculator, how much that heat transfer that will give us the ability to condense. I would have to check that. But we are in the right ball park, I bet it is the right order of magnitude.

How much would the greenhouses cost to build? Well, the nice thing with them is that they are instantly profitable. As soon as you have one built it starts making money (ok so it takes a month or three for the vegetables to start maturing, but it is quick). So you can build something like this in stages and gradually prove the concept and be profitable at every step.

Did I say that it is easy to grow without using pesticides in he Seawater Greenhouse? Another synergistic effect. But that requires another story.

On the subsistence agriculture level, we permies regularly have designed production systems around the world, which feed everyone living in a given house within a 50-foot radius of the house. This rule of thumb holds pretty well because the more folks who live there, the bigger the house, the larger the surface area, so no more than 50 feet is really necessary.

The math is easy. With a polyculture, yields of 3-10 pounds of food per square foot are easy to come up with in most climates. For comparison, commercial agriculture in California , which is way inefficient, routinely runs about 1.5-2.5 pounds per square foot per year across a wide variety of crops. People need to eat about two pounds of mixed food a day if active, or around 750 pounds a year. In a good but somewhat sloppy design, you need about 500 square feet per person MAXIMUM. In a very good design, 200 square feet will do the job. If your diet is heavy on grain you'll need more space but not an astronomical amount. Utilize a greenhouse to extend seasons and exchange air rich in carbon dioxide from chicken houses or human houses, which otherwise would go to waste, and yields ratchet up even more. Take a little more space and include ducks and aquaculture into the mix and the yields become quite diverse and substantial. This sort of system is typical in Vietnam now and there is no longer any measurable hunger there. Wouldn't it be nice if the US could do that with its "superior" first world agricultural system?

Stocks of foodstuff are dangerously low

Low stocks of foodstuff make the world's falling agriculture output particularly worrisome. The combined averaged of the ending stock levels of the major trading countries of Australia, Canada, United States, and the European Union have been declining steadily in the last few years:

2002-2005: 47.4 million tons
2007: 37.6 million tons
2008: 27.4 million tons

These inventory numbers are dangerously low, especially considering the horrifying possibility that China's 60 million tons of grain reserves doesn't actually exists .

California
California is facing its worst drought in recorded history . The drought is predicted to be the most severe in modern times, worse than those in 1977 and 1991. Thousands of acres of row crops already have been fallowed, with more to follow. The snowpack in the Northern Sierra, home to some of the state's most important reservoirs, proved to be just 49 percent of average. Water agencies throughout the state are scrambling to adopt conservation mandates.

The minimum amount of agricultural land necessary for sustainable food security, with a diversified diet similar to those of North America and Western Europe (hence including meat), is 0.5 of a hectare per person. This does not allow for any land degradation such as soil erosion, and it assumes adequate water supplies. Very few populous countries have more than an average of 0.25 of a hectare. It is realistic to suppose that the absolute minimum of arable land to support one person is a mere 0.07 of a hectare–and this assumes a largely vegetarian diet, no land degradation or water shortages, virtually no post-harvest waste, and farmers who know precisely when and how to plant, fertilize, irrigate, etc.

[FAO, 1993]

If you're interested in the maximum yield, you might look into the Biointensive method. This book, by John Jeavons, claims that less than half an acre (~ 0.2 hectares) can support a family of four, or about 0.05 hectares/person

On the basis of these figures, a vegan diet can meet calorie and protein needs from just 300 square metres using mainly potatoes. A more varied diet with plenty of fruit and vegetables, grains and legumes would take about 700 square metres. Replacing a third of the calories in this diet with calories from milk and eggs would double the land requirements and a typical European omnivorous diet would require five times the amount of land required for a varied vegan diet.

...

Quite simply, we do not have enough land to feed everyone on an animal-based diet. So while 840 million people do not have enough food to live normal lives, we continue to waste two-thirds of agricultural land by obtaining only a small fraction of its potential calorific value.

Obviously access to food is an extremely complex issue and there are no easy answers. However, the fact remains that the world's population is increasing and viable agricultural land is diminishing. If we are to avoid future global food scarcity we must find sustainable ways of using our natural resource base. Industrial livestock production is unsustainable and unjustifiable.

"Ninety percent of the world's food is derived from just 15 plant and 8 animal species." 2

"Biodiversity - and especially the maintenance of wild relatives of domesticated species - is essential to sustainable agriculture."1

75% of the genetic diversity of crop plants has been lost in the past century. 1

"Over the past 40 years, approximately 30% of the world's cropland has become unproductive."

"During the past 40 years nearly one-third of the world's cropland (1.5 billion hectares) has been abandoned because of soil erosion and degradation."

"About 2 million hectares of rainfed and irrigated agricultural lands are lost to production every year due to severe land degradation, among other factors."

"It takes approximately 500 years to replace 25 millimeters (1 inch) of topsoil lost to erosion. The minimal soil depth for agricultural production is 150 millimeters. From this perspective, productive fertile soil is a nonrenewable, endangered ecosystem."