Nitrogen feeds billions of people, but relies on cheap fossil, damages soils, pollutes water with runnoff and only about 20% actually gets picked up by plant root hairs
On Sat, Dec 7, 2013 at 12:33 PM, dave andrews wrote:
Bbc r4 on the above pointed out how the haber process generated nitrogen feeds billions of people, but relies on cheap fossil, damages soils, pollutes water with runnoff and only about 20% actually gets picked up by plant root hairs, the rest washing away/off_gassing. So why don’t they provide small fertiliser particles coated with impermeable plastic with a tiny hole to permit a root hair to gain limited access, with a range of accessibility to permit long term slow release of nitrogen?
On Dec 7, 2013 2:46 PM, “Nick Balmer” wrote:
Why don’t we just go back to biomass fertiliser, and rotation?
Why can’t we have thousands more anaerobic digesters churning out highly suitable biomass to replace fossil fertilisers?
Before you say this cannot work consider the following.
Farmers like my 3 & 4 great grandfathers used to incorporate biomass into the soil all the year every year. In the 13 years to 1799 moved and incorporate 800,000 1.5 tonne loads of manure onto 1200 acres and made £30,000 in that time when a colonel earned £400 a year.
The soil, sandy heath north of Bury St Edmunds was turned into land capable of enormous barley crops.
As agriculture was squeezed by the 1870’s depression in farm gate prices nearby families like Fison started to make fossil fertiliser by burning coprolites (literally fossilised dinosaur poo.).
This was seen as a panacea because you could get several cart loads of fertiliser value in a single sack.
When farmers started out this worked well, and didn’t really impact because they were just supplementing naturally obtained fertility.
Up until 1945 almost all farming was mixed animals and arable.
Soil without biomass is essentially ground up minerals or silica. It cannot hold fertilisers because it cation and anion balance is all wrong.
Fertiliser chemical bonds have nothing to latch onto as they percolate into the soil. This is why the quality of river water has been so bad until recently because the vast amount of fertiliser spread on the soil leaches out into groundwater.
After 1945 all over the south of Britain and especially East Anglia farmers went over to arable and animals were forgotten. For many years as the biomass content of soil slowly eroded and blew away nobody really noticed, but slowly the farmers found themselves having to put more and more NPK onto the soil to achieve the same results that they had had before.
However you eventually reach a point of no return. You get desert again.
I have personally been involved in making soil from sand. If you have flown into Riyadh Airport you will have seen trees grown in soil I made from sand. There are other places in Dubai where this is also possible.
Before we changed the Cat ion balance in the sand plants would die really fast of chemical in balances. Fertiliser salesmen happily sold us more and more fertiliser, but disease soon undoes any good the fertiliser had done. Most plant diseases are attacked by pathogens in soil and a hidden arms race goes on in healthly soil. This does not happen in soil with minimal biomass or monocultures.
A South African horticulturalist joined us and soon he had identified the problem. We added crusher dust and silt (which changed the Ion balance) and some limited manure. We could not entirely correct the in-balance at first and still had to add artificial fertiliser but in much small quantities to achieve the same effect. What we also found is that once soil organisms reach a critical mass, the change from what was previously sand, to something that is soil is surprisingly fast.
In much the same way that the Big Six Energy retailers are up to every dirty trick in the book to prevent energy usages reductions, that will impact on the size of their available market and bottom line, fertiliser companies and the agricultural industries try to hid the simple truth that continuing in the present way using ever increasing amounts of fossil fertiliser is simply not sustainable.
Most farmers on the ground, especially farmers who own their own farms have been aware of this for decades, if not over a life time.
My father farmed in the 1940’s and 1950’s. We have the farming books he read at that time. Hosier and authors like A G Street knew this truth.
It is only the extraordinary advances in plant science and things like fertiliser application technology that is fending off the crisis. Each innovation is harder to find than the last.
But our obsession with technology and its ability to solve most problems, seems to blind us from the fact that there are really simple low technology ways of reducing fertiliser use.
Add back muck into soil.
Farm margins are so low at present that the cost of even this is beyond many farms.
This is why farm prices must rise.
Just like the mad situation where generators are only getting 3.5 to 5pkW, and yet retailers get 12 to 15pkW, wheat farmers only get about 16% of the price of the bread sold in shops.
Even fruit growers who retain the highest percentage only get about 40% of the retail price.
If farmers can sell biogas to energy users, they can increasingly undercut other forms of generation like new nuclear and offshore wind. They could also resist the power of the supermarket buyers because they had an alternative.
It is only some of the C and H that is digested in an AD plant. All the N, P & K goes back in digest. Digestate is a really good soil improver. I am really pleased to drive every Saturday morning past Hallwick and Scott and Scott’s farm based plant near Buntingford, where this has been done successfully for two years, and to see Biogen’s new AD plant nearing completion at Bygrave just north of Baldock.
There it will take food waste from London and will produce biomass fertiliser for use on the chalk soils (seriously impoverished by 60 years of abuse by chemical fertiliser overdosing.
Ironically this will appear to be a thoroughly modern idea.
Yet oddly enough if you read Arthur Young’s 1805 Survey of Agriculture in Hertfordshire you will find hat Mr Doo, the farmer was back loading huge amounts of animal and food waste from London for exactly the same purpose.
We thought we were terribly clever in the 20th Century, but we were far too over confident and ignored simple realities.
Phil Harris wrote:
Dave & Nick Thanks for forwarding me Nick’s piece. I am impressed that he and associates did some soil making in KSA! I am also impressed he has farm accounts back to 18thC for 1200 acres! Like Nick I do not think there is a ‘next move’ for British farming along the lines of the last 70 years. I live in the middle of some big farming (still a little bit ‘mixed’) in Northumberland / Eastern Borders and this last 2 years witnessed what I think will be the last move in that direction. The man is going even faster, but he is trying at the same time what he can to get some carbon back into sandy ground, but the farms are still living off Victorian infrastructure like drainage, which will also need ‘input’.
There could be a bit of proof-reading needed Nick, which I would be willing to help with. The account of WWII misses out some key stuff. And Britain, in particular England, has not fed itself since about 1840 when about a fifth of the population (with horses) could only just feed the rest of the rapidly increasing urban 18 million. The 18thC Agricultural Revolution had raised the ‘carrying capacity’ about 3 times in a 100 years, but that was about it.
I have two text books which frame modern agriculture’s recent transition both here and in America and give us both the soil nutrition and mechanisation story. One is Mark Overton’s Agricultural Revolution in England (1500 – 1850
and the other is Geof Cunfer’s terrific account On the Great Plains (Agriculture & Environment).
BTW As a matter of interest, N fertiliser manufacture takes about 5% of world usage of natural gas even though China uses mostly urea made from coal.
very best wishes
PS Cunfer is great at quantifying manuring inputs and losses, among a lot else. But I quote the main framing argument as I see it:
… the 1000 year accumulation of soil nutrients was quickly spent:
“They applied manure as it was available, rotated legumes when it was convenient. But they had no strategy for the very long term. By the 1930s, Rooks County fields had been planted, cultivated, and harvested sixty times without rest. Soil nitrogen was about half what it had been at sod-breaking and crop yields declined steadily. And now no western frontier remained. From the vantage of 1930s, crop agriculture in Kansas does not appear very sustainable. All the arable land in Rooks County – and in the nation for that matter – had been identified and plowed. Soil nitrogen and organic carbon drifted steadily downward, and with them yields and profits. Faced with this dilemma, farmers implemented a dramatic innovation in soil nutrient management. Rather than adopt one or more of the ancient strategies, farmers (and the industrial nation behind them) created a new option. They appropriated abundant cheap fossil-fuel energy to import enormous amounts of synthetically manufactured nitrogen onto their fields. …” page 219, ‘On the Great Plains: Agriculture and Environment’, Cunfer 2005;
— <*> Claverton website: http://tx1.fcomet.com/~claverto/cms/