Excess carbon:nitrogen ratios make existing soil nitrogen much less available.

Grazing animals metabolise a large amount of the carbon while redepositing the nitrogen as urine and dung. Overgrazing is not an inevitable consequence.

An alternative way to reduce the carbon level might be to burn the residue but that destroy the nitrogenous compounds as well, leaving only the minerals. This is needed in regenerating Australian native woodland but is wasteful in most agricultural systems.

You could compost the crop residues but would have to factor in the energy required to harvest the residues, turn the heaps regularly and redistribute the finished compost over the land. Grazing would seem to be far more energetically efficient in most circumstances.

Comparing simple tonnages of meat and potatoes is a little misleading as to their respective nutritive values.

Water data …

1. http://www.abs.gov.au/AUSSTATS/abs@.nsf/DetailsPage/4610.02004-05?OpenDocument

2.. specifically on Murray Darling: http://www.clw.csiro.au/publications/consultancy/2004/MDBC_stage2_report.pdf

N.B. There are huge differences between data in 1 and 2 … why?

Short question, long answer. Short answer is ask a farmer how much
water they use and they’ll tell you how much they are supposed to
have used. Ask them how many hectares are being used for
what and then multiply by appropriate figure and you get another
answer. Then go for a boating trip along the Murray and look
for pipes without meters on them … are you getting the picture?

In answer to your question. The Adelaide desal plant will
produce 50-100 giga litres (I’ve seen both numbers). Dairy on
the Murray Darling Basin at its high point was pulling 4200 giga litres.
When water got short, the first people to stop planting was the
cotton and rice. They just didn’t plant, but cattle act like
a permanent planting … eventually they have downsized the herds
but it took quite some time.

Fruit and veg in the MDB was almost 500 giga litres, so nuclear desal
might be feasible for some things if the price and location is right.

Ideally I’d see cities changing. High density around veggie gardens
and fruit trees. I found a great little house at St Peters in Adelaide
recently … tiny front yard with 14 fruit trees … all planted close and
pruned to fit. Cities can produce plenty of food if attitudes can
be changed. Do the maths … think what you can produce from
a square metre (assuming water) during a year: tomatoes, spinach,
capsicum, etc, etc, Or use that metre to grow grain for chooks to lay
eggs. How many eggs do you get from a square metre over the
course of a year? … 1 (or up to 3 with high yield irrigated wheat).
Normal chook feed isn’t just grain … chooks (but not people) need
more protein than that, so chook feed is fortified with various high
protein meals and vitamins and minerals.

when we talk here about nuclear power providing desalinated water, are we talking about drinking water primarily? in other words, I recall you suggesting that desal could not come close to dealing with the freshwater deficit faced by agriculture.

where can I get some numbers on this?

thanks.

g

http://www.sciencemag.org/cgi/content/full/326/5958/1345-c?rss=1

Here it is in full for those without Science access:

Letters
Biofuels: Beware Crop Residues
In the Policy Forum “Beneficial biofuels—the food, energy, and environment trilemma” (17 July, p. 270), D. Tilman et al. propose using crop residues and harvesting biomass from double crops and mixed cropping systems. We point out the potential risks of doing so.

This weeks Science has a stunningly misleading piece from the Livestock
advocacy and research centre (ILRI) which shows how little many top livestock scientists know about soil science.

http://www.sciencemag.org/cgi/content/abstract/327/5967/822

How it got past peer review is beyond me.

Here (in full) is a highlighted box highlighting the lack of soil
science knowledge by the authors:

” Box 1. Enhancing livestock productivity through improved dual-purpose crops.
In developing countries, some crops like maize, wheat, sorghum, and millet are dual purpose:
Their grain provides food for humans and their residues are used as feed for livestock. Traditionally
these crops have been bred to improve grain yield and drought and pest resistance.
However, in the past decade it has been recognized that farmers in mixed crop-livestock systems
value the crop residues sometimes as much as the grain owing to their importance as a feed for
livestock, particularly in the dry season (29). Breeding programs for these crops are increasingly
being adapted to include breeding for residue quality without compromising the original objectives
associated with increasing grain yield.
In India, where the demand for crop residues as feed is very high, improved dual-purpose
varieties of sorghum and millet have had significant impacts on the productivity and efficiency of
crop-dairy systems. Small-holders have been able to increase the milk production of buffalos and
cows by up to 50% while at the same time obtaining the same grain output from their crops. This
has increased the demand for dual-purpose crops with relatively high-quality crop residues, and
burgeoning fodder markets have developed around cities like Hyderabad (29).

It should also be noted that the very first statement in the article is either
plain false or highly misleading.

Farmers in mixed crop-livestock systems produce about half of the world’s food. The implication that the livestock in these systems
is a sizeable part of “half the world’s food” is false. With livestock globally
providing 17% of calories and with many of these calories coming from
factory farms, so the implication is false. Much of the potential food output
of mixed crop-livestock systems will be being lost precisely because of
the deleterious impacts of the livestock on soil due to the consumption
of not only crop residues but other biomass and crops themselves. Most
crop residues are so low in nitrogen that they can’t contribute much,
if anything, to actual liveweight growth in the livestock. The cost of
residue grazing is high and any benefits small. The animals will require
additional good quality feed.

The article used by Herrero et al to support their claims of the
value of residues for livestock deals with only one kind
of residue (sorghum) and states clearly:
The crude protein
contents of all [sorghum] stover types were well below 7.5% (Table 2),
the level widely considered as the minimum requirement
for rumen microbes to efficiently digest the feed.

The measured the sorghum stover (residue) crude protein content
was between 2.9 and 4.9 %. Fascinatingly the 2.9% stuff was
fetching the highest price!

I have now had time to read the full Nature article which you very kindly e-mailed to me.

You asked me to report on whether I think you have misrepresented the findings. By and large, I don’t think you have. However, the authors’ conclusions that fire return intervals of less than 10.5 years appeared to be much more important than herbivory in their study areas should be qualified (and the authors do, indeed qualify it). I don’t think you did but you might find this nitpicking. Only 21% of studied sites provided data on biomass of herbivores. These ranged from 0-80kg/ha. No information was given as to whether this was average seasonal stocking density, a maximum at a favourable time of year or a snapshot at a single time. Further, no information was given as to how the biomass was proportioned between wild and domesticated or between browsers and grazers.

A maximum density of 80kg/ha is, of course, low for managed livestock agriculture in areas that have good soil and adequate rain. In more arid areas with poorish soil, the carrying capacity could be much lower than the 80kg/ha. This would best be measured in areas where there were no domesticated stock, no hunting and undisturbed wild herbivores (possibly, national park areas). Ideally, of course, predator elimination might be needed. To this extent, it might be better to look at large ranches with mixed wild and domesticated herbivores but few large predators and, on which, supplementary feeding was not practised unless accounted for by adjusting natural carrying capacity downwards.

In other words, I don’t think the paper, of itself. provided answers to the questions I posed. If I knew what the natural herbivore carrying capacities were relative to those recorded in the study sites, it might have helped – but I don’t. Also, I don’t know how often lightning would strike and start fires. However, I accept that much African savanna might be converted to woodland if one wiped out the wild herbivores, didn’t stock it with domesticated stock and didn’t choose to start fires on it (hoping for the best on the subject of lightning). Anyway, I am not sure that increasing woodland would necessarily be desirable and am not convinced that it would feed more people, help the normally present wildlife or, except in the short term, reduce global CO2 emissions. You could, of course, counter by extolling the potential virtues of biochar sequestration and bio-oil combustion to replace charcoal burning.

In presenting the advantages of eating more vegetables and less meat/dairy, particularly in savanna-type areas, you could be over-simplifying matters. Suppose that ,maybe, 5% of the savanna could be used for arable but not the rest (due to water restrictions) and suppose that all that arable production went to people. Are you sure it would provide more human food than if 95% of the savanna were used for grazing and 5% used for supplementing the grazing animals. I haven’t attempted this calculation myself so it’s not a trick. In fact, my personal preference might be to leave the 95% for wildlife and exploit tourism (including controlled hunting) but this would depend upon a continuing stream of affluent trippers burning up fossil fuels with their flights. It would also directly replace domesticated ruminants belching out methane with wild ruminants doing the same.

I agree that many Africans are keeping unsustainable numbers of livestock on the areas they have available to them, given water constraints. (Apparently, the same could be happening in the Murray Darling basin). However, it remains the case in Africa that cattle and goats are not, by and large, competitors with arable but, rather, with wildlife.

The only way of turning significant amounts of unstable savanna into productive arable is to import water (from underground or from rivers) and fertilisers made from fossil fuels. Carrying capacity of humans can be greatly increased by use of said fossil fuels and this explains why the global human population is already greatly exceeding natural carrying capacity and will crash unless alternative forms of affordable energy are made available to replace fossil fuels when they run out. An attempt to revert to organic (sustainable?) farming will create the crash even before the fossil fuels run out.

It is quite true that a vegetarian approach to human nutrition requires less inputs than an omnivorous one. However, it is a false step to suppose that, if those who can currently afford meat became vegetarian, there would be more food for the poor. It costs money to produce food and, if the poor had it, they wouldn’t be hungry. The wealthy could (and do) buy food for the poor which tends to beget even more hungry poor. It may be possible to encourage the poor to use their resources more efficiently but efforts to do so are not always successful, hampered as they may be by poor governance, corruption and, possibly, inappropriate advice. In fact, agricultural infrastructure has tended to collapse consequent to the end of colonialism and the granting of independence.

Finally, I would go along with the potential for nuclear batteries but where do I get one and how much do they cost? Where can I go to see one working?

Douglas: 1) you have the Nature paper now. If you think I’ve misrepresented
it, then let us all know, but I’ve tried to represent it accurately.
2) see 1)
3) There are 2 basic ways to think about food.

A) Maximise food production from a given region/country.
B) Minimise land required to feed a given population.

A) calls for maximum appropriation of land to human use. Any land not
used for us is “wasted” unless we dedicate it as a reserve. If it doesn’t
have some iconic species in it to give it that special status, then it is
fair game (an appropriate expression). B) doesn’t accept, for example,
trucking thousands of cattle into the Lake Eyre basin to take advantage
of rare big rain events which would other wise be “wasted” on waterbirds,
reptiles, and dare I say it … plants.

Your comments on non-protein nitrogen are interesting and illustrative.
I’m not sure what you are talking about, but in feedlots this is typically
thinks like cow and chicken shit. Feed this to ruminants and the gut
flora make the N into protein. I say the best use for cow and
chicken shit is as fertiliser for plants to make into protein.

It is definitely my suggestion that Africans get fed and this isn’t
happening now, despite abundant livestock … it isn’t happening
because of the livestock. So yes convert savanna to farmland where
possible, reforest anything you don’t need. The goal is to feed people
without deforesting what’s left of the jungle. The other requirement is
cheap energy to replace charcoal, wood and dung for cooking … nuclear
batteries look the best options. Mass produced 10MW batteries buried
all over Africa to take the pressure off the remaining forests. This is
our payment to them to keep those jungles!

Lenton’s paper is free and has a little more on the issue:

http://www.pnas.org/content/105/6/1786.abstract

It is certainly true that trees change the microclimate in all kinds of
ways which will influence water flows.

Some things that really stuck out for me include:
1. 90 % of fires are anthropogenic and 2/3 of those are livestock-related. Couple this with the new push to reduce black carbon emissions due to the belief black carbon is a leading (if not the leading) cause of rapid glacial melt, and the estimate that 40 to 50 percent of black carbon comes from forest fires and we can guestimate that livestock are the single largest source of black carbon (with a global warming potential of 4470 times that of CO2) — making livestock a much bigger cause of climate change than previous estimates.

2. I recently read that when many African nations reported their emissions to the IPCC, they didn’t report much, and I did not see them reporting large amounts of methane emissions. This indicates there is a lot more methane out there warming the planet — again making livestock a much bigger cause in climate change than previous estimates.

3. Groups like the Arctic Council is calling for a reduction of methane, tropospheric ozone and black carbon as a rapid way to reduce Arctic ice melt. They state the best way to reduce ozone is to reduce methane, and that any methane reductions will help the Arctic. they also say that regional black carbon reductions (from industry in the northern hemisphere and diesel), while others call for black carbon reductions from people in india burning biomass for fuel to halt Himalayan ice melt. We already know livestock are the single largest source of anthropogenic methane from Livestock’s Long Shadow, and with these links to forest fires and black carbon — and methane’s role in creating ozone — it means the best way to bring about to bring about rapid planetary cooling and halt (or slowed rate) of glacial ice melt. (Brazilian scientists have found that there is black carbon in Antarctica and 30% comes from Africa, 50% from biomass burning in South America, 20% from industrial causes in South America — indicating that most of black carbon in Antarctica is from the livestock industry).

4. All those African leaders so upset in Copenhagen, claiming that setting a goal of keeping emissions reductions to under 2C was tantamount to a death sentence for Africa can now take control of their own destiny — not rely on the worlds largest developing nations — to ensure food security, water security, national and regional security and create planetary cooling by ending livestock production, allowing the forests to come back and farming plant-based foods.

Bravo! Great research. I look forward to more posts expanding my understanding of the role livestock play in climate change!

Susan, California, USA

Great stuff as usual. Having done a lot of aid work in Africa personally, I can vouch for how bad the situation has gotten in places. All kinds of terrible social mores lead to sub-optimal methods of food production, and environmental destruction. The Africans I met LOVED meat! The idea that it was keeping them in poverty never really occurred to them. The vegetable farmers I met in Namibia were white and rich, from using 0.1% of the land that would be used to produce the same food using ranches. What it requires most is skills transfer and capability building (mechanics, agriculture, etc). If the aid agencies focused on that, they would gradually be able to pull themselves up by their bootstraps to better lives for all.

Makes me want to get back over there, clutching your article!

Cheers,

Bruce Poon

Hank: If we manage to adapt to changing water regimes, peak oil and overpopulation driven conflicts … topsoil loss may well be the final horseman of
the apocalypse. But the bottom line is simple. Crops feed the planet, 83% of
global calories. Less livestock means we need less crops (particularly pigs
and chickens). The most effective way to reduce the requirement for cropping is
to reduce the populations that eat the crops … pigs, chickens, cattle, people. I favour prioritising the first 3.

Thanks for your reply. I looked at the Nature link to which you referred. Not being a subscriber, I only had access to the abstract. This stated that savannas were unstable when MAP exceeded of 650mm and depended on fires and herbivory to prevent canopy closure. In other words, the unimportance of herbivory to which you allude was not mentioned in the paper’s summary.

You refer to a 20 year study in which fire (deliberately set) was important in savanna maintenance but not herbivory. Having worked for brief periods in East Africa both on the detrimental effects of elephants on established forests and on increasing cattle productivity, I have a few comments and observations that may be relevant.
1) Elephants are generally accepted as being important in preventing grassland from being engulfed entirely by trees and, in fact, being capable of clearing open spaces in closed canopy areas. I would imagine that wild browsers (eg black rhino, kudu, gerenuk, giraffe etc etc) might have similar effects on woody vegetation that you describe for goats.
2) Depending upon the sizes of the study areas to which you referred, perhaps 20 years isn’t long enough to enable the dismissal of the importance of lightning. In any event, my point about “anthropogenic forest” was not addressed.
3) Cattle productivity in my study area was very low without “tweaking”, mainly because beasts couldn’t be finished for five or six years. They gained weight towards the end of rainy seasons and at the start of the following dry season only to lose about 80% of it during the rest of the dry season and start of the next rains. (Tropical grass is very rapidly maturing and its digestibility level falls much quicker than that of temperate grass due to lignification. High lignin grass cannot be eaten in the same quantity as younger grass because the ruminant takes longer to process it. It is ironic , in fact, that a ruminant’s appetite drops at the very time it needs to eat more to compensate for the falling energy density of its diet. Zebras, though not digesting fibre as efficiently, compensate by upping their appetites in compensation for falling D values. In extreme droughts, therefore, they tend to survive while ruminants may die).
4) On the ranch I was involved with, dams were constructed to impound surplus rainy season water for irrigation of less than 1% of the area. On this, maize was grown, allowing cattle to finish at a weight and in a condition that would not otherwise have been achieved for several more years. There was also sufficient maize for the farm labourers. The most economic approach appeared to be use the open range for store cattle production and wildlife (with tourist income potential) and the productive, irrigated bit for finishing only. This allowed for much greater meat production than could otherwise have been achieved. The point I am trying to make is that the critical factor is the ready availability of water. One couldn’t have used the majority of the ranch for arable production but it produced cattle and only a small proportion of the diet of these cattle was competing directly with humans for food – that used in the short finishing period.
5) We also found trace mineral deficiencies were quite common (eg selenium) which severely limited grazing livestock productivity but which were relatively easily and cheaply rectified.
6) One further comment on protein. For ruminants, one normally talks of crude protein in relation to dietary requirements and crude protein can include non protein nitrogen (useless for people) but as good as true protein for 50% of the ruminant’s protein needs for maintenance.

Hank Roberts gave a link which touched on the scramble for arable land in Africa by outsiders. There is no doubt huge potential to produce more food there. Not all methods applied are necessarily unsustainable but there are no doubt plenty of examples of aquifer mining and other short term expedients. In terms of greenhouse gas output, I would be interested in the relative effects of ripping up savanna and consequent soil carbon loss with leaving it for cattle and wildlife to graze. I would also be interested in the potential for slow pyrolysis and carbon sequestration in the organic carbon- poor soils in many parts of Africa. The forests that you would like to regenerate might have greater utility if they could, in part, contibute to soil improvement elsewhere.

I agree that supplementation would be far more effective and efficient for developing world populations, since you could throw in zinc and iron as well as possibly your fat-solubles A E D & K.

> http://www.spiegel.de/international/world/0,1518,639224,00.html
> http://globalpolicy.org/social-and-economic-policy/world-hunger/land-ownership-and-hunger.html

The same business model that stripped the topsoil off of Europe and the Americas is now starting to do the same kind of extractive agriculture in Africa.

As for B12. The US Institutute of Medicine recommends supplements
for anybody over 50 … because the supplements are MORE bioavailable
than that in meat. As you age reductions in gastric acid (and
other factors) typically lead
to poor absorption of foodbound b12, but not the crystalline stuff in
supplements.
http://www.nap.edu/catalog.php?record_id=6015

Meat is a very expensive way to get B12 … . And if people in animal-rich
countries like the US and Australia still need supplements (plenty
of foods have B12 added to them, and it’s not for us vegans, we don’t
have that much market power!), then providing animal based sources
in developing countries is grossly inefficient. I’ve been trying to
find the root source of b12 used in Australia, and it
seems to come mainly from Chinese pharmaceutical makers. The stuff
is very cheap. Farmers use it for sheep and cattle grazing cobalt deficient
pastures … so you might as well eat it direct from the factory and
cut out the middleman.