A Farm for the Future BBC2

[Keela]

Whoa - stop the DominicJ bashing!

There are other elements than NPK that plants need. They will get depleted over time if the food crop is continually removed and the nutrients not returned. As DJ rightly suggested returning seaweeds to the soil will help to close the nutrient cycle.

Of course as emordilap it's probably better to skip the sea altogether and compost your own manure (and everybody else's! ).

And why bash spelling mistakes... we can all make them....

[2 As and a B]

No. You're wrong on so many levels it's scary.

Thats quite a strong opening line when we're using terms as specific as "degraded"

The major reason soil dies is because all the microorganisms/worms/etc living in it are killed

See I could just as easily point out that soil is not alive, and therefore you're so wrong its scary.

usually by chemicals.

So you dont believe in mineral depletion?
If you have a portion of soil grow onions, remove the onions, add NPK, grow some more onions, remove the onions, add NPK again ect
The plants grown in the soil wont degrade nutritionaly?

and will lack the other necessary minerals on which plants depend.

"Soil is "degraded" when certain, I'm trying to think of the right word, elements or elemental compounds are taken from the soil by plants, and the plants are then taken away and not brought back."

NPK and round up dont destroy magnesium, they allow farmers to remove it and still grow what appear to be healthy, but nutritionaly limited, crops.

Or so the organic farming website I read told me, it seemed to make sense, at least in its diagnosis of the problem.

DominicJ,

If you don't know what you're talking about then do us a favour and spare us your ignorance.

Take some time to read this: http://en.wikipedia.org/wiki/Humus

[RenewableCandy]

To be fair DJ's post didn't come across as pontificating so much as saying "there's this...so what else is needed?"

Anyway, totally agree about the seaweed: it has all sorts of trace goodies in it (Iodine for starters). But the soil has "structure" as well as just ingredients, I suppose you'd count it as "alive" in the same way that a beehive or a city is "alive". Getting that structure up-and-running, I presume, is what takes the time. Herbicides (or any other "-cides") will detract from the structure-building by killing off some of the builders! Putting too many elements on, no matter how beneficial, without this structure, will mean they just get washed away.

[Prono 007]

The poo produced by livestock and people is fundamental for maintaining soil. This is where the whole "save agriculture by becoming a vegan" falls down - I keep animals as much for their poo product as for their other products.

Isn't the thing with animals is though that our arable land mass won't be big enough to support our population? In, I think it was 'The Party's over' I think one guy reckoned the world could feed up to 7 million people without fossil fuel inputs but that required bio-intensive farming, a strict vegan diet, no land for fuel crops, and composting everything including human remains.

Human manure is an obvious way to go but requires refitting the entire country with compost loos and organising a transport system to get the stuff to where it's needed. That would be a major undertaking but not impossible. The stumbling block, as usual, would be the existing political institutions who seem to believe every problem has an economic solution. In fact they can't seem recognise problems that are not economic in the first place.

[Blue Peter]

The poo produced by livestock and people is fundamental for maintaining soil. This is where the whole "save agriculture by becoming a vegan" falls down - I keep animals as much for their poo product as for their other products. With no animals it would take many, many years to improve the terrible soil I had when I bought my place.

Essentially, this is passing grass through the stomachs of livestock, and, after they've taken their lot out, putting it back on the land. I don't see what the livestock add (indeed, they take away), such that just composting the grass (or whatever you might prefer to grow) could not provide the same,


Peter.

P.S. Sorry to hear about your ribs.

[contadino]

It speeds the whole process up dramatically, and makes it more efficient.

It takes 6 months minimum (8 months realistically) for a full cubic metre compost heap to rot down completely, even using activators like chicken poop, pee and comfrey. Even vermiculture would take 12 weeks, and whilst it produces rich soil, it lacks humus. An animal's gut will do that work in 12 hours. Rabbit & donkey poo can go directly onto soil and benefit crops that would get burned by fresh cow manure.

Fresh cow or horse muck can get ploughed in to soil and will mellow in 2 months max.

Seaweed is great at stimulating growth, but it is not a good fertiliser. It'll help seedlings get established, and will help trees grow, but it won't help them be productive. There is also the issue of transporting seaweed from the coast to inland agricultural areas.

On a separate note, something else occurred to me last night. The point about growing nuts to replace cereals is good. Chestnut flour is pretty common around here still. However, the effort involved in harvesting significant quantities of nuts is far more than with cereal. I have a couple of hundred almond trees, which are harvested by hand (there aren't machines that can do the job.) The first year we spent two weeks harvesting, and every evening for nearly a month shucking the harvest. We then sold the nuts, which would still need shelling, peeling, and milling to make flour. Compare this to 2 days work by hand to harvest the wheat. The quantities are approximately the same.

Nowadays we still harvest the almonds by hand, but take them up the the local farm where the farmer runs them through his (tractor-powered) shucking machine in an hour. As a benefit, the husks are given to his sheep as fodder.

[Catweazle]

All this talk of putting NPK into the soil is a red-herring. Sure, everything is made from elements and these particular elements are required but you have to consider that the elements are useless to humans unless plants assemble them into useful molecules that our bodies can work with. Plants need specific conditions in order to perform this work and it's those conditions that we need to preserve for future generations, killing all life in the soil and pumping it full of chemicals could backfire spectacularly.

We know what plants need, they've been growing in it for millions of years, it's only relatively recently that we've decided to pump all our waste into the sea instead of burying it in little holes on our land.

[Blue Peter]

It speeds the whole process up dramatically, and makes it more efficient.

There might be an initial speed up, but once you have a steady-state system, is there that much gain? E.g. in a livestock system, you might harvest your hay in June to be used the following winter, but composting can begin immediately.


Peter.

[contadino]

There might be an initial speed up, but once you have a steady-state system, is there that much gain? E.g. in a livestock system, you might harvest your hay in June to be used the following winter, but composting can begin immediately.

That's not something I've considered from a UK perspective, probably because the annual cycle is different here. Hay is used twice a year - high summer and deep winter, and the haymaking calendar is consequently different. It doesn't sit around as much waiting to be used.

[happychicken]

The poo produced by livestock and people is fundamental for maintaining soil. This is where the whole "save agriculture by becoming a vegan" falls down - I keep animals as much for their poo product as for their other products.

Isn't the thing with animals is though that our arable land mass won't be big enough to support our population? In, I think it was 'The Party's over' I think one guy reckoned the world could feed up to 7 million people without fossil fuel inputs but that required bio-intensive farming, a strict vegan diet, no land for fuel crops, and composting everything including human remains.

Human manure is an obvious way to go but requires refitting the entire country with compost loos and organising a transport system to get the stuff to where it's needed. That would be a major undertaking but not impossible. The stumbling block, as usual, would be the existing political institutions who seem to believe every problem has an economic solution. In fact they can't seem recognise problems that are not economic in the first place.

We'd just have to revert to doing what the Tudors did and have Gong farmers

http://en.wikipedia.org/wiki/Gong_farmer

[Billhook]

Peter -
while I'd be the first to agree the potential benefits of well rotted compost,
it has limitations bpth in scale and in content.

Re scale, supposing I wanted to displace agribiz fertilizers in just one country over say just one million ha.s -
at best I'll fence the crops being grown to make the compost to exclude deer & rabbits (high and small mesh)
or risk losing a lot and need to plant a far greater area.
I'll also have the massive workloads of mechanized plowing, cultivating, harvesting, loading, carting, stacking, and turning the yield
and then turning again, loading, carting and spreading the many million tonnes of product.

By comparison, traditional mixed farming (on which sundry popular modern approaches are based)
firstly uses low large mesh fences only to enclose stock while hedges are re-established (hedges don't exclude deer or rabbits)
and then relies on the livestock to collect most of the herbage.
Then, while sheep are mostly wintered out in the UK, many cattle and ponies are wintered in (barns & stables)
(and are fed on hay and fodder crops harvested and carted to storage)
both for their shelter and to save the pastures getting poached to hell and to have the dung fall where it can be readily stacked to mature.

All of which saves a vast amount of extra work that compost demands, that no farmer I know of has yet seen fit to undertake.
The nearest approach is the occasional growing of a green manure crop for plowing in as part of a normal crop rotation.

Secondly, re. content, it would be a mistake to assume that dung is either standard or no better than compost, (which also varies greatly).

AFAIUI, dung holds far more developed compounds that are both better retained by the soil
and far more easily assimilated by the growing plants, but I am not expert in this matter.

The largest sustainable compost operation I've heard of is in the New Forest,
where around 5,000 tonnes of bracken compost is made annually, rotating the harvest between a number of plots,
but this is for retailing to the public for its gardens.

The advances on normal dung-piles we look to here is to put all barn manure through a fermenter (with its minor CH4 output)
for the sake of the output slurry which, after aerobic maturing, is of exceptional value as a fertilizer -
and which could be readily mixed with our charcoal product for the Terra Preta trials.

Perhaps the neatest most integrated approach to soil improvement is to include Jerusalem Artichokes as part of a multi-year rotation,
since they offer several benefits.

First, they come up late, after most weeds have germinated and put out their leaves - which are killed by the Jerus' dense shade,
thus helping clean the soil of weeds.

Second, once the crop is well set underground, digger pigs (e.g. Tamworths) can be folded on (strip at a time)
to smash down the huge Jeru foliage while digging up the tubers (which they love) -

which means that a very large green manure crop is dug into the soil along with the pigs' dung as the best of starters for its rotting down,
and the pigs clear more deep weed roots from the soil (thistle, dock, nettle etc)
and their digging means that subsequent soil-preparation for a grain crop is much reduced,
and many pigs can grow large and very well flavoured on the normally huge yield of Jerus per acre.

Personally, it seems to me that anything that can be composted is usually better fed to the pigs,
whose dung is far more valuable as a fertilizer.

Regards,

Billhook

[goslow]

don't know about pigs but we have GUINEA pigs and they quite happily munch through our salad leftovers...so I have less "nice" food waste to put on the compost that might attract vermin - their poo goes on instead - thats my suburbanite 2p-worth anyway.....

[Prono 007]

We'd just have to revert to doing what the Tudors did and have Gong farmers

A lovely term for what was obviously a shit job.

[JohnB]

We'd just have to revert to doing what the Tudors did and have Gong farmers

I think Happychicken is talking crap

[mrb]

while I'd be the first to agree the potential benefits of well rotted compost, it has limitations bpth in scale and in content.

Re scale, supposing I wanted to displace agribiz fertilizers in just one country over say just one million ha.s - at best I'll fence the crops being grown to make the compost to exclude deer & rabbits (high and small mesh) or risk losing a lot and need to plant a far greater area.
I'll also have the massive workloads of mechanized plowing, cultivating, harvesting, loading, carting, stacking, and turning the yield and then turning again, loading, carting and spreading the many million tonnes of product.

By comparison, traditional mixed farming (on which sundry popular modern approaches are based) firstly uses low large mesh fences only to enclose stock while hedges are re-established (hedges don't exclude deer or rabbits) and then relies on the livestock to collect most of the herbage.
Then, while sheep are mostly wintered out in the UK, many cattle and ponies are wintered in (barns & stables) (and are fed on hay and fodder crops harvested and carted to storage) both for their shelter and to save the pastures getting poached to hell and to have the dung fall where it can be readily stacked to mature.

I think this is a bit of a straw-man, you give worst case for compost and best case for animal manure?
Surely there will be greater losses for manure, I have tried to give equivalent examples below. (Of course these scenarios will have different outcomes re: nutrients and advantages/disadvantages.)

Animal manure:
growing->harvesting->transport(to storage)->storage->transport(to animals)->fed to animals->manure collected->manure transported->manure composted->manure spread
Compost:
growing->harvesting->transport(to heap)->composted->compost transported->compost spread

Animal manure(in situ)
growing->animals "harvest" crop
Green manure:
growing->"harvest"

Is it not true that many (most?) organic farms use animal manure from non-organic farms? I believe that there are already local shortages of animal manure and this would only get worse with an increase in organic farming. IMO this is the real problem of scale with organic farming! Was this not something mentioned in the program - organic farming being reliant on conventional farming and all that that entails.

All of which saves a vast amount of extra work that compost demands, that no farmer I know of has yet seen fit to undertake.
The nearest approach is the occasional growing of a green manure crop for plowing in as part of a normal crop rotation.

Here I agree a closer approximation is extensive use of green manures instead, a farmer who has seen fit to undertake this approach is Iain Tolhurst (here are some more) (An article on this very subject by Iain Tolhurst.)

Secondly, re. content, it would be a mistake to assume that dung is either standard or no better than compost, (which also varies greatly).

AFAIUI, dung holds far more developed compounds that are both better retained by the soil and far more easily assimilated by the growing plants, but I am not expert in this matter.

Agreed it's a mixed bag, and depends greatly on what type of animal/green manure/compost.
However green manures seem more flexible.
Some grow quickly, some fix nitrogen, some have deep roots that both bring up nutrients from the subsoil and improve soil structure, they can be mulched or composted (in situ or elsewhere) or any combination of the above!

Personally, it seems to me that anything that can be composted is usually better fed to the pigs, whose dung is far more valuable as a fertilizer.

Perhaps by some specific measure it is more valuable (perhaps by weight, or time, or X?) but it can't be in every situation and maybe not in most?

It speeds the whole process up dramatically, and makes it more efficient.

By what measure of efficiency?
I can't see how it is possible to more efficiently produce food calories or useful fertiliser using animal manure than green manure or compost (if both are using best practice)?

"Livestock excrete 70-80 percent of the nitrogen, 60-85 percent of the phosphorus, and 80-90 percent of the potassium fed to them."
Both green and animal manures release about 50% of nitrogen (I imagine it is similar for the other nutrients?) in the first year or so and then slow down.
Using the nutrients via an animal will always result in lower *total* amounts, although it's possible they may be more available or somehow "better".

As for speed, common crops (e.g. red clover, oats) used as fodder or green manures will obviously take the same amount of time (or less fro green manures) to grow.

Pros/cons of each approach...
Animal manure:
Pros:
Some animals may improve soil structure
Some animals may eat weeds root 'n all
Cons:
Ammonia volitization
Some animals may degrade soil structure (compaction)
May contain weed seeds
May contain bacteria - E. Coli/salmonella
May contain parasites
Worse greenhouse gas output (Lots of methane!)

Green Manure/Compost:
Pros:
Likely to improve soil structure
May bring micro/macro nutrients from sub soil
Likely to suppress weeds
Prevents soil erosion (vs. bare ground in winter say)
Less greenhouse gases emitted for same amount of nutrients
Cons:
Possibly requires more human labour (although I would say unlikely)

All this is open to debate of course but I don't think the case for animal manure is as strong as many believe.