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Calories per acre for various foods

Pullet on pastureThe effects of dietary choices on global warming are hard to disentangle, but all we need is a bit of number crunching to look at the amount of calories we can produce per acre when growing different kinds of food.  The numbers below are drawn from a lot of different sources for U.S. agriculture and include dozens of assumptions, but they should give you a rough idea of comparative acreage required to produce a few staple crops.

Food
Million calories per acre
Assumptions
Wheat
6.4
Irrigated
Corn
12.3
Irrigated
Potatoes
17.8
Irrigated
Soybeans
2.1
Irrigated
Beef
1.1
Cows fed solely on corn, feed to meat conversion ratio of 8, 1000 calories per pound of beef
Pork
3.5
Pigs fed solely on corn, feed to meat conversion ratio of 3.5, 1385 calories per pound of pork
Chicken
1.4
Chickens fed solely on corn and soybeans, feed to meat conversion ratio of 3, 591 calories per pound of meat

Soybean plantI remember when I first started considering my dietary options, I was told that we could feed many more people with the same amount of land if we all became vegetarians.  I was swayed...until I realized that we're talking about feeding people only corn and potatoes.  The truth is that creating protein is expensive in terms of land use whether you're growing soybeans or raising cattle, and if we compare apples to apples you'll notice that pigs actually win over beans.

But the table at the top of this post only considers conventional agriculture (aka CAFOs for meat.)  What about if we instead raise our livestock on pasture and feed them food waste where appropriate?  For cows, you won't see much difference, but pigs and chickens really begin to shine once you return to a more traditional feeding system.  Both of these animals are well adapted to foraging on scraps --- the Vermont Compost Company raises chickens on compost alone while Sugar Mountain Farm cuts their feed bills drastically by raising their pigs on pasture with the addition of waste dairy products.

In societies that don't depend on huge agricultural corporations to feed the masses, a family is likely to have a pig and a flock of chickens that they feed mostly or solely on waste from the farm and kitchen.  Remember that adding some livestock to your diversified homestead also equates to manure to fertilize your veggies, and it's suddenly hard for me to merit the idea of planting a field of soybeans instead.

Our homemade chicken waterer keeps your backyard chickens happy and healthy.


This post is part of our Ethics of Vegetarianism lunchtime series.  Read all of the entries:





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Great post!

Also, Potatoes Win!! (I'm a big fan, lol)

Comment by Bethany James Wed Jun 30 14:30:04 2010

I'm firmly convinced that any sort of polyculture will have increased yield if it incorporates animals into its system. They'll turn scraps into fertiliser (manure) much faster than any composting system, plus they'll give you additional outputs (eggs, meat, milk, wool, etc).

The animals can also be used to do some of the work - e.g. chickens scratch over garden beds, remove weed seeds and pests, spread cow manure, and clean up dropped/spoiled fruit; pigs can gley dams and till up a paddock; sheep can graze down wheat stubble; goats can help control undergrowth and invasive species in forests. Of course they all need management to guide their efforts, but they're tireless workers!

Comment by Darren (Green Change) Wed Jun 30 19:09:18 2010

Bethany --- it is startling how well potatoes do in relation to everything else, isn't it? No wonder they're the staple crop of the small gardener.

Darren --- I couldn't agree with you more. Animals are just one more way of "layering" within your food ecosystem. (And now I know what gleying a dam is! I tried to do a very simplified version of this to make a homemade pond liner when I was in high school, but I didn't know what I was doing and it failed miserably. Now I want to try again!)

Comment by anna Wed Jun 30 20:01:16 2010

Another great post on the subject of the real costs of food. Thanks. I wonder what the "actual" pounds per acre are for grazed meat fed hay & silage in winter. When I lived overseas all the beef, lamb, and pork we ate was local and raised on pasture. (Not really out of an ideology but because no one pinches a penny tighter than a Scottish farmer.) I think the only supplemental feed the animals got that wasn't hay in winter was giant turnips or whatever was left in a crop field.

I want to comment on the last post that those PETA photos are offensive to me too. Not for the nudity but for the conscious objectification of both the model and the viewer. Did you know they also promote the idea that milk is a causal factor in autism? (Yeah, I've got some bones to pick with PETA....)

Comment by Mrs. Fuzzy Thu Jul 1 08:57:03 2010

The soybean council says that soybeans produce "up to 15 times more protein per acre than land set aside for meat production", which doesn't quite seem to jibe with your stats. It's surprisingly difficult to find stats on this online. Here's some from the 70s: http://en.wikipedia.org/wiki/Edible_protein_per_unit_area_of_land

BTW, I think you should look at sheep and goats if you want the strongest possible livestock argument.

Comment by Fred Thu Jul 1 11:05:21 2010

Mrs. Fuzzy and Fred --- I wish the data was more readily accessible! I honestly haven't looked into grazed beef, lamb, and goats at all, and I do need to find a way to crunch those numbers too. Fred is right that goats are able to graze in areas completely unacceptable for other forms of agriculture and could really be the overall winners.

Mrs. Fuzzy --- I appreciate you telling me why the photos were offensive. I found them vaguely offensive too and am trying to figure out why, so your thoughts help.

Fred --- My data for soybeans is relatively firm. I used the average yield in the U.S. for 2002 per acre for soybeans from the USDA, then used the calorie figure from ?the USDA? (whoever puts labels on food.) For pigs, the data is a bit fuzzier because different cuts of meat have vastly different calorie counts, so I just averaged them all without taking into account that you probably get a lot more of certain cuts of meat from a pig than others. Then I used the feed conversion rate from Wikipedia (which is an industry standard). And then I made another assumption, that pigs can be raised on corn alone --- I'm not sure how big an assumption that is! Chickens need some soybeans throw into their diets for protein in the factory farm model, which is why they came out so far behind pigs, but I'm pretty sure that cows can be raised primarily on corn and hay. So I decided pigs were in the cow boat, not the chicken boat --- this could be wrong, but I couldn't find real data anywhere. I suspect that the soybean council's data comes from feeding soybeans to cows (although I'm not so sure people do that) or some other livestock that has a much worse feed to meat ratio than pigs. I'm a bit disappointed that the wikipedia page you linked to only gives an average meat value and a beef value, when beef is probably the worst animal you can raise if you want the most protein per acre.

Comment by anna Thu Jul 1 21:30:04 2010
Very interesting post. It brought to mind another high protein plant, quinoa. Doing a quick calculation I found that one acre produces roughly 2.2 million calories, about the same as soybeans. The great thing, though, is that those calories include all the essential amino acids and a lot more trace nutrients. Not sure how well it grows in Virginia though :)
Comment by Eerik Wed Sep 8 00:25:45 2010
I had no clue that quinoa was so productive! We actually tried it out this year, but couldn't seem to get it to grow well. It's supposed to like high elevations, and I guess we're just not high enough (although I might give another variety a shot after your comment!) We are also trying out amaranth this year, which is growing very well. Not sure how it shapes up as a protein source, though....
Comment by anna Wed Sep 8 08:22:04 2010

Thanks for the great post and site!

For 13 years I lived on a small farm with my spouse and children. The barn had no power and no running water. It was about 100m from the house and carrying water in winter was a lot of work. I also did all the slaughtering myself.

The first year we kept a Jersey cow and mixed breed calf, a couple of donkeys, a half dozen "tri-purpose" sheep, a dozen geese, fifty meat breed chickens, a dozen laying hens with a rooster, and a couple of barn cats. In summer, all were left to range free with the chickens and geese out in the garden and the sheep, donkeys and cattle in the pasture among fruit trees.

A few notes.....the cow and calf drank more water than the rest of the critters combined. We butchered the calf the following fall and sold the cow which never gave us enough milk to be worthwhile and she killed one of our sheep - Jersey's are not a breed I would consider again.

The milk and wool from the tri-purpose breed of sheep (Navajo-Churro) were both deficient in quantity and quality for the work they took and the amount of meat on the carcasses of even 2 year old rams was disappointing for the time and work it took to butcher them (although making my own haggis was a great experience!).

The amount of meat the geese produced was reasonable but the temperament of the gaggle of geese was unsuitable to young children. Dressing geese is also a lot of work to do yourself.

The meat breed of chickens were very efficient but we had them dressed professionally. The laying hens out among the garden were the absolute best source of high quality and easy care food available - NOTHING beats farm fresh eggs but foxes were a problem.

Donkeys were kept for security of the sheep from coyotes and dogs - we never lost any and it was amusing to see how the dogs reacted when confronted by a donkey protecting "its" sheep! But, we never put them to work so I have a hard time recommending donkeys for a small homestead.

The most prolific product on the farm, judging by success of breeding, were the cats! But in truth, the chickens were better "mousers" in the barn than the cats were. Chickens are absolutely nasty when it comes to mice and voles. That being said, we never had a reason to add high protein feed to their diet when they were able to forage in the garden for bugs and worms!

Today, I'd keep a garden, fruit trees and shrubs, a small grain field, chickens and bees. Maybe a fish pond if I could manage it.

Best Regards

James

Comment by James Sat Jul 23 18:51:37 2011
Yep, those are the livestock that give the best return on your time and money investment in my opinion too. (Unless you have a lot of fenced pastures, in which case sheep and cows of designated meat breeds can make a lot of sense.) Thanks for sharing your experience!
Comment by anna Sat Jul 23 21:00:01 2011
One problem here: no single plant is a source of all essential amino acids. To achieve complete protein from plant sources, one must combine, say, corn, rice & beans. To achieve 60 gm protein per day from these (enough to survive but not thrive) one must ingest 6000 calories divided equally among those three- obesity here we come! One could get 60 gm complete protein from about 500 cal of beef. Raising beef can easily be done with minimal input of petroleum and they supply their own fertilizer for a sustainable pasture. Pastures more closley mimic Nature than cropland.
Comment by t brandt Mon Aug 1 20:51:51 2011
That's another excellent point in favor of having animals be part of a diversified homestead. I should have added that to the post!
Comment by anna Tue Aug 2 07:01:19 2011

As it turns out, the body can store amino acids.

And while cattle could be grown in a sustainable manner on pasture, they currently aren't. Not to mention that the treatment of those animals in the most common intensive husbandry is rather cruel. And it over uses antibiotics.

Roland (not logged in; traveling :-) )

Comment by Roland_Smith Tue Aug 2 11:49:00 2011

This is a clear example of a Roland impersonator! First he doesn't log in, then he cites a source other than Wikipedia. Nice try!

More seriously.... :-) I'm very glad you commented because I was raised on the "complementary protein at a single meal" myth. If I'd taken a minute to think about it, I would have realized that of course we store amino acids for days just like we do vitamins and minerals. (Now there's a cooking challenge --- include a third of your recommended daily allowance of all of the vitamins and minerals in a single meal!) The image below (from the website you cited) is very good data to have on hand:

Complementary proteins

About your other point --- I don't think anyone reading this blog would disagree that CAFOs are all around bad. But saying that just because that's the way industrial farmers raise animals, people shouldn't eat meat is throwing out the baby with the bath water. In my opinion, everyone should grow as much of their own food as they can then buy the rest from people they know who live nearby. That's a tough ideal --- we certainly don't get all the way there --- but in that world, you can choose to raise your animals in a humane manner and/or buy from people who do similarly, so your argument loses steam.

Comment by anna Tue Aug 2 15:12:40 2011

a)Don't believe anything about nutrition coming from the govt: they're the reason we have an epidemic of obesity (insulin makes you fat). 60 gm of protein per day will just get you by, if you're sedentary. Active people need more.

(B) We don't store protein in the same sense that we store fat or glycogen (carbs). Our muscles are mainly protein, but we don't mobilize aa's from there except during starvation conditions. OTOH- one needn't get complete protein at every meal. We're not quite that fragile.

(c) Our "industrial" food supply is very nutritious and quite safe- both in terms of infectious factors and in terms of "chemical risks." Antibiotics in livestock are used to improve performance and are completely washed out by the time the animal goes to slaughter. "Growth hormones" (ie- estrogen) is barely perceptible in store-bought meat, and the amount present in a serving of beef is about 12x LESS than the measurable "natural" estrogren in a serving of potatoes! The problem is over-stated by the animal-rights & vegetarian types.

OTOH- there's something so self-satisfying about raising your own natural food and that alone is worth it. We have the dilemma that we can't supply the masses with enough food without using the hi tech industrial ag techniques, yet those will be unsustainable once the petroleum runs out. Anybody know a "cubit" is? ;-)

Comment by t brandt Tue Aug 2 17:25:41 2011

I completely agree with you on points A and B. In fact, the amount of protein you need is one of the myths I just learned about last year.

However, I think that hormones are the least of the worries from industrial meat. What I find much more troublesome is the omega 3/omega 6 ratio due to the animals not having access to pasture, and the resultant ill health of people depending on these meats. And, of course, the sustainability issue (for the same lack of pasture reason.)

Comment by anna Tue Aug 2 18:35:58 2011

Don't get me wrong, Anna, I'm not arguing that industrial ag is best, only that it's good enough and that it's required to feed our huge population. Loss of habitat due to over-population is the biggest problem facing the environment, but I'm not (quite ;-) ready to start killing off excess people. Few of us are lucky enough to have the land and resources to grow our own food. The others are stuck.

I'm a physician practicing almost 40 yrs. This cholesterol thing is a fraud unsupported by the statistics. You're right that pasture finished beef has a better omega-3 to omega-6 FA ratio than feedlot beef, but the impact of that on health is rather shakey: the difference is statistically significant, but probably not clinically significant (kinda like a 400 ft home run sounds better than a 350 ft HR, but it doesn't make any difference to the score of the game.)People not lucky enough to have ready access to pasture finished beef shouldn't worry about it. Mainly, they're missing out on the better texture and taste. BTW- there was a recent study from Scandinavia that showed beef given feed but finished for the last 6 weeks on grass showed the same good 3-/6-FA ratio as pure grass fed beef.

Comment by t brandt Tue Aug 2 19:34:05 2011

I'm not sure I agree that industrial agriculture is required to feed our huge population. I read an intriguing blog by the author Sharon Astyk and she often mentions the huge amount of growing area available to us that we don't use --- I'm not talking cutting down wild ecosystems, but instead growing broccoli in your front yard, using fruit trees instead of ornamentals around public buildings, etc. I haven't done the research to know whether Sharon has data to back this assertion up, but the other things she writes seem on track, so I suspect her thesis is correct that we could grow our own food using the land available to us even without depending on industrial agriculture.

What's stopping us from each growing our own food is need. We have the time to do it --- the average American spends as many hours watching TV per week as Mark and I spend growing all of our own vegetables along with significant amounts of our starches and meat. And growing space is available even in the city if you're willing to hunt it down. (I highly recommend Rachel Kaplan's Urban Homesteading for tips on finding growing areas even if you live in an apartment.) However, when the industrial agriculture system combined with government subsidies make it so crazy cheap to buy your food, what's the point of putting the effort into growing it? I read somewhere that Americans spend about 10% of our income on food, which is lower than it's ever been and much lower than anywhere else in the world. No wonder the backyard vegetable garden is no longer the norm.

(As for the population issue --- you don't have to kill off people to lower the population. Choosing not to have kids, making access to birth control more readily available, and improving peoples' standard of living tend to naturally create declining populations. But that's a whole 'nother kettle of fish!)

I'd be intrigued to hear more about "This cholesterol thing is a fraud unsupported by the statistics." I've been reading recently that eating cholesterol isn't usually bad for you --- is that what you mean?

I'm not sure how important the omega 3/omega 6 ratio is for the entire population, but for me personally it seems to be key. I've got a lot of mental illness in my family, and starting to eat more pastured meat (and increasing my meat levels in general) worked wonders on my tendency toward depression. 10% of Americans are on antidepressants and it seems like pastured meat would be a better solution.

The Scandinavian study makes perfect sense. That's pretty much how large scale pastured poultry operations are run too, and it does make sense that what the animals ate at the end of their lives would make the most impact on the nutritional content of the meat.

Comment by anna Tue Aug 2 20:22:55 2011

re population: due to the phenomenon of "population momentum", even a One-Child-Policy strictly enforced (not likely as long as any of us libertarians are around) it would still take 3 generations of growth to occur before a fall was seen. Thats's 60-90 yrs, and with oil only predicted to last about 40 yrs and food production so dependent on oil, we got problems.

OTOH- as reported recently on "AgPhD" on RFD-TV, we can expect a
doubling of US ag yield over the next 2 decades. Only 40% of that will be due to improved genetics, the rest simply by universal adoption of relatively simple things like improved irrigation, better use of drain tiles and simply improved settings on the seed planting machinery.(!)

Amazingly, in Africa, most farmers still don't plant crops in rows, but use the ancient method of broadcasting seeds. This eliminates the use of irriagation or even of weeding to advantage. They could double yield just by that simple change.

But that's the dillemma I mentioned earlier: by increasing yield, we're just increasing carrying capacity so that when resources (oil) finally give out,the population must crash from an even higher level-- even more suffering.

This is why I asked facetiously about a cubit in an earlier comment- referring to the story of Noah. We each ought to be planning on how to take care of ourselves and those close to us. The day for some universal solution that will make everyone happy is past. We missed our chance for that.

To keep "growing your own" in perspective- a family of 4 working hard would require on the order of 3 million calories per year. As you pointed out in the original article here, that's do-able on an acre- the biggest problems being diversity and seasonality of harvest.

Comment by doc Tue Aug 2 22:31:01 2011

I don't think One-Child-Policies work except in totalitarian situations, but it's very possible to make the world more conducive to fewer children. You've got a good point about the population decline taking too long, but I think it's still a step you have to make in the right direction since it will help in the long run. As you said:

By increasing yield, we're just increasing carrying capacity so that when resources (oil) finally give out,the population must crash from an even higher level-- even more suffering.

If you cut down the population at least some first, there's less suffering.

Which is the same reason I'd recommend against bringing modern farming tactics to Africa. Broadcast seeding actually makes a lot of sense when you're working by hand and don't have tractors to till up the ground between the rows or pumps to move lots of water. In fact, I use that method extensively in my high yield, no-till garden.

Comment by anna Wed Aug 3 17:00:14 2011
I'd be interested to know if anyone has the data for the yield from hemp? I've heard that it's a highly efficient crop for producing protein, and apparently uses no pesticides or herbicides, wondered if anyone can shed any light on this?
Comment by Max Wed Sep 14 15:58:19 2011
I don't have any firsthand information, but a search of the internet suggests that hemp seeds contain 22% protein (which is pretty good for a plant) and that hemp plants can produce around 876 pounds of seed per acre. At 45 calories per tablespoon (=15.5 grams), that would be 1.2 million calories per acre, or roughly equivalent to non-pastured beef. Unfortunately, that's really not that great considering that beef has a much higher percent protein.
Comment by anna Wed Sep 14 20:03:13 2011

Oh brother... You just showed us an industry chart, and then made vague -verbal- claims that the numbers on protein produced per acre are better on pasturage and 'waste', and -then- you even -more- vaguely claimed (in fact only insinuated) that this makes the protein per acre superior for chickens and pigs than for plant food crops.

I pronounce your -claims- to be -total- nonsense until you actually show your -own- chart clearly comparing protein output per acre of pastoral meat animals vs plant food crops.

And your inclusion of 'waste' fed to the animals is equally bogus. It took massive acreage of land and inputs to create that 'waste', a factor that you are totally leaving out of your vague non-numerical 'equations'.

So. Show the actual numbers and -include- relative acreage used to produce the supposed 'waste' to prove your flimsy case.

I predict you won't, because you already know full well that the yield per acre for plant food crops will dwarf the yield from meat animals under such an analysis.

Comment by Eric Brooks Sun Jan 15 17:23:32 2012

Eric --- I think where we're on different wavelengths is our frame of reference. My conclusion is that a diversified farm on the scale of an acre or less will give you more protein if you include animals. I suspect you're thinking about mainstream factory farming, where you simply can't create the kind of vibrant ecosystems we can here --- where chickens can't live on table scraps and worms because there are ten thousand chickens and only two people.

I believe that kind of large scale farm is bad for the earth, whether it's growing soybeans or chickens. Instead, we grow all of our own vegetables and an increasing amount of our fruit and meat. Our waste didn't take acres off the farm to create --- it's the seeds from the butternut squash we grew right here.

Unfortunately, on the homestead scale, it's really tough to come up with any numbers at all. Not many little people with a backyard flock even measure the amount of feed they give their chickens and the eggs and meat they get as a result. It's even tougher to factor in how the manure output increases the amount of food you actually got from the grain you fed those chickens. It's a complex thought problem, but any ecologist will tell you that as you diversify an ecosystem, more individuals can coexist in the same space. That's what I'm telling you about adding animals to a small homestead.

Comment by anna Sun Jan 15 18:21:46 2012

No, I am simply asking you to show numbers to back up your claims; which it appears from your response, you have no intention of doing.

You are wildly speculating (in a way that defies laws of physics by the way) and you simply need to prove your speculation.

I challenge you to do so with actual numbers.

You won't be able to.

As to thinking of factory farming; you are incorrect there as well. You need to compare apples to apples. For example numbers for a sustainable permaculture farm with pastoral meat production versus numbers for a sustainable permaculture perennial veganic garden of equal acreage with tiered food sources (including food trees) planted on the same land where you will wastefully employ huge swaths of pasturage.

Again. You are making wild claims that have no basis in reality.

Show the numbers.

Comment by Eric Brooks Tue Jan 17 15:41:57 2012

You said many of the same things you said before, to which I would respond the same way I did in the last post:

  • There aren't many studies of small-scale polycultures, so I can't give you numbers.

Your additional point that I'm defying the laws of physics, though, is one that I meant to address in my last comment. You're referring to "energy can be neither created nor destroyed", I assume.

What you need to understand is that energy in food systems ultimately comes from the sun, and most of that energy generally goes to waste (ie, turns into heat.) A polyculture can capture more of the energy than a monoculture. I'm not talking about creating energy, just being more efficient about keeping it in the food system. For some numbers --- this post shows how mainstream agricultural fields capture only about half the energy captured by a temperate forest.

It all comes down to efficiency of capturing and cycling those nutrients. Yes, as you go up the food chain, you lose quite a bit of efficiency if you don't cycle the "waste" from those animals back into other types of food. But on a small homestead, you can cycle nutrients to your heart's content with the goal of capturing as much energy as a forest or wetland, not as a monoculture agricultural field.

Comment by anna Tue Jan 17 16:21:19 2012
Don't forget that legumes such as beans and peas are vital to soil conservation. Grains are heavy feeders, and a small layer of chicken manure on top is not going to compensate for the large ammount of nitrogen they drain out of the soil. ANY sustainable gardening program MUST include legumes. Southern Purple Hull Peas (Called "Cow Peas" up North and out West) are my personal favorite... they tolerate drought, have few pests, produce handsomely, and fix a lot of nitrogen into the soil.
Comment by Liquidsteel Tue Jan 17 19:56:42 2012

I love your subject line. :-)

I agree that cover crops are key, although I tend to focus on the non-legumes since they add a lot more organic matter. On the other hand, chicken manure is strong stuff --- it doesn't take much to equal the nitrogen provided by a cover crop.

For example, cow peas produce between 65 and 315 pounds of nitrogen per acre. The chicken manure compost we recently applied to our garden has an N-P-K of 3-4-4, which means I'd only need to apply about 33 pounds of compost to get a pound of nitrogen, or a bit over 5 tons per acre to get 315 pounds (comparable to the best case scenario of cow peas.) That's approximately 6.5 cubic yards of chicken manure compost per acre, or 0.05 inches of compost spread evenly across the acre.

Or, to look at this another way, if I wanted to get the same amount of nitrogen from cow peas as from the half inch of compost I apply before each crop, I'd have to keep the land out of production long enough to run through 10 plantings of cow peas. Perhaps you can see why I value the chicken manure so highly?

Comment by anna Tue Jan 17 20:35:33 2012
my wife was a marketing director of a mid size firm in china before rexcently moving here to marry me. she grew up in northern china. her son is 12 and i watch what i cook now, not too much. everything is finished from the meal, not a spoon full of left over. where she is from (harbin area, as far north as manotoiba canada) they do not grow rice. so they eat very little of it. a lot of potatoes, and wheat. i have 80 acres of mountains outside of fresno calif, only really good for grazing, i did try apples and black walnuts, which i gave up on and they still keep growing. she came and is planting everything! i have always had a 10 foot by 15 garden, but that is "small potatoes" for her. my point is that in china, my whole place would be planted, the local indians had a saying "plant your seed, spit and jump back" it really can grow in my area, and the warm days and cool nights increase sugar and taste.
Comment by ken Sat Feb 18 08:36:50 2012
Ken --- You mention that your acreage is really only good for grazing and apple and walnut trees. That's one of the goals of permaculture --- to use places like that for agriculture without destroying it. It sounds like you've hit on just the right way to do it.
Comment by anna Sat Feb 18 17:31:50 2012
my land is only good for grazing. too do walnuts or apples, you need semi flat land and lots of it. i put in apples only for a roadside fruit stand for my parents to come out and retire on. the walnuts are native to the area, small nuts, they are used around the worlds for roots to regular walnuts, and i planted a few 100, thinking i would topwork them someday. the apples only a 1/2 acre, were great for my parents but it has been many years since they were worked. we live in a country that can support many more people. i did not know that china is very cold, very cold. it is about the size of the US and feeds a billion people every day. their problem is they have a billion 3 hundred thousand people. if they can do it, we could do it with the warmer climate we have.
Comment by ken Sun Feb 19 09:12:26 2012
You might enjoy reading Sepp Holzer's Permaculture. He does some pretty amazing things in terrain that's probably tougher than your farm. He uses a lot of soil building crops and adding rotting wood in early years to get the soil to the point where it can support trees. With a little love, most places can support tree life.
Comment by anna Sun Feb 19 13:35:48 2012

It does not take 6000 calories on a vegan diet to ingest 60 gr of protien, and that amount is sufficient for a very active athlete, much less a sedentary individual. I was vegetarian the year I set the school record for 10,000m at UC Berkeley (yes, Cal). (I'm still on the all time list.) I ate about 4000 calories/day then. Now I'm down to about 2500. My wife is vegan and I eat that way much of the time, with no ill effects.

I'm calculating the relative energy use for different food types.

Comment by Richard Sun Jul 22 22:54:45 2012
Richard --- I appreciate your firsthand input, but am not sure what part of the post you're referring to. I don't mention people's daily calorie needs anywhere, just how much land it takes to raise those calories.
Comment by anna Mon Jul 23 06:57:54 2012
I was responding to t brandt in an earlier post. (This website doesn't see to allow direct replies on comments.)
Comment by Richard Mon Jul 23 16:54:03 2012

Here's the correct output per acre for several food products based on USDA data. Note that the protein per acre is still higher for grains and beans than beef.

Cal/Ac  Protein g/Ac

Corn 3,207,782 121,507 Wheat 3,893,561 150,038 Soy 1,958,588 187,972 Beef 795,047 82,388 15% fat ground cooked

Comment by Richard Mon Jul 23 16:57:33 2012

This page turns up near the top when you search the web for "calories per acre". Unfortunately several of the crop yields listed at the top are definitely wrong. Commenter "Richard" point sthis out to some extent. Corn in the US yields roughly 3.4 million kcal/acre.

  • harvest: 33 million ha
  • yield: 9600 kg/ha
  • 86 kcal/100g = 860 kcal/kg
  • 8.3 million kcal/ha = 3.4 million kcal/acre
  • 2.7*1014 kcal/total crop = 270,000,000,000,000 kcal
  • divide by 730,000 kcal per human-calorie-year
  • 375,205,479 human-calorie-years/crop
  • so, could feed 375 million people
  • not including waste
  • assuming that calories = metabolic energy (not exactly true)

Corn is generally considered to be 86 kcal/100g, which is 860 kcal/kg. Your numbers are probably from heat-value kcal, which is roughly 4x higher than edible kcal. Wood has an average heat of combustion of 3600 kcal/kg. Burning corn kernels (actually common when it's cheap) would be similar.

Comment by A. J. Tarnas Sat Nov 30 22:00:28 2013