Soil - should we be worried?

[spanners]

Do you think it's fair that they should sort your "shyte" out too though?

I have comic visions of a father's bequests to his children. Upon death the children receive each a brown box containing a large turd with a simple note contained within which reads, "My shyte is now your shyte. May you be truly thankful."

I Like to present problems, It saves people having to look for them

 

[Cowabunga]

Obviously peatland will deplete. That is entirely natural and an inevitable consequence of pure organic matter breaking down in air and through drying. It basically rots away.
Answer? Don't cultivate peat land. If you do, expect it to shrink.

 

[blackbob]

I think we have totally ruined many of our soils over the last 25 years....We have accelerated the decomposition of the SOM through the use of Ammoniun Nitrate ferilisers and excessive cultivation...we havn't replaced much of the P & K that we have removed as it hasn't been economically viable..now we are left with soils that probably will not grow anything..that will make a positve return...time to get back to basics...but basics do not pay the rent or other overhead costs..

Where? In Europe? Sub-Saharan Africa?

 

[grumpy]

Actually I do. I spent a while in Tanzania last year. One particularly memorable rain storm saw me sheltering in a Tanzanian family's mud hut for three hours. Turns out they spoke quite good English and the above picture was painted with some considerable vividity. No joke.

you cant beat the good old days of the British empire,

 

[Robigus]

I think we have totally ruined many of our soils over the last 25 years....We have accelerated the decomposition of the SOM through the use of Ammoniun Nitrate ferilisers and excessive cultivation...we havn't replaced much of the P & K that we have removed as it hasn't been economically viable..now we are left with soils that probably will not grow anything..that will make a positve return...time to get back to basics...but basics do not pay the rent or other overhead costs..

I think this is an overly pessimistic view of the situation, all the farms I know have soils that will grow stuff, with or without added fertiliser.

I don't doubt that there is a lot that we can still both learn and unlearn about soil management, and that farming practices will change, but to say that there will be no topsoil in sixty years is just alarmist nonsense put out to win some one some government funding.

 

[grumpy]

what about the green hell of the bocage?

 

[roscoe erf]

I think this is an overly pessimistic view of the situation, all the farms I know have soils that will grow stuff, with or without added fertiliser.

I don't doubt that there is a lot that we can still both learn and unlearn about soil management, and that farming practices will change, but to say that there will be no topsoil in sixty years is just alarmist nonsense put out to win some one some government funding.

you wont have to worry you will be under water due to melting ice caps

 

[Cowabunga]

I think we have totally ruined many of our soils over the last 25 years....We have accelerated the decomposition of the SOM through the use of Ammoniun Nitrate ferilisers and excessive cultivation...we havn't replaced much of the P & K that we have removed as it hasn't been economically viable..now we are left with soils that probably will not grow anything..that will make a positve return...time to get back to basics...but basics do not pay the rent or other overhead costs..

In other words, even with the decreased inputs and costs, it grows insufficient food to sell.
You can easily stop using AN fertiliser and a simple soil analysis will put you on the right track to get your P and K levels spot on. Want organic matter? Keep cattle and sheep on at least half your land and chop that straw that is not turned into muck by the animals. Simple.

Unless the vegans have their way on animals. In which case every square inch of land would need to be arable of course.

There's even an answer to all-arable depletion. Recycle all human waste. Remove the heavy metals and other contaminants first, obviously. And even remove the N content if you are really fussy about N inputs to crop growing.

 

[Cowabunga]

In answer to the OP 'the ruminant', I've fed 8 acres of re-seeding ground with 130 tons of solid well-rotted yard-bedding muck today. Is that enough feeding for this week? It's also had two tons of ground limestone per acre. Really surprised that the soil level hasn't risen more than it has really.

 

[grumpy]

View attachment 3791 In answer to the OP 'the ruminant', I've fed 8 acres of re-seeding ground with 130 tons of solid well-rotted yard-bedding muck today. Is that enough feeding for this week? It's also had two tons of ground limestone per acre. Really surprised that the soil level hasn't risen more than it has really.

that an ece marston?

 

[exmoor dave]

I'm very very....very worried!... because my landlord is about to start a experiment flood prevention project in my hay fields. They are basically going to peel back the turf, scrape off 3-4" of top soil to build a huge bank (of pure top soil!!!) Put the turf back down and expect it to be all hunky dory!
How many 100's of years did it take for that 4" of top soil to develop?
To make matters worse its all ancient permanent pasture. Which dad likes to say "not even Hitler could get it ploughed up"- because the war ag didn't order it ploughed.

Complete madness!!!!!

 

[Cowabunga]

Yep. On hire for the day. Not sure how much weight it holds but suspect a good ten tons of that well rotted muck. 13 loads were put on 8 acres anyhow and will be harrowed in and seeded by Monday night.
Also sprayed docks off some 80 acres today personally. That's my brother driving the spreader.

 

[Feldspar]

Just a quick point. This issue is not that the soil will disappear, rather that it will become degraded with an associated decline in productivity. It's a question of quality not quantity.

See here: https://dl.sciencesocieties.org/publications/books/abstracts/sssaspecialpubl/replenishingsoi/1

 

[Cowabunga]

Just a quick point. This issue is not that the soil will disappear, rather that it will become degraded with an associated decline in productivity. It's a question of quality not quantity.

See here: https://dl.sciencesocieties.org/publications/books/abstracts/sssaspecialpubl/replenishingsoi/1

That is much simpler to rectify through changes in farming practise over a reasonably short timespan, where it is happening, which isn't around here as you can see from the sh!t being spread and my bag-muck bill for the year.

Basically the article is about Africa and how more nutrients would grow more food. Pretty obvious to most people I'd have thought.
Here is the crux of it quoted below........

"his approach combines basic principles of soil science with environmental economics. Combinations of P fertilizers and organic inputs can replenish soil N and P nutrient stocks in Africa and restore service flows to near original levels. Phosphorus replenishment strategies are mainly mineral-fertilizer based, with biological supplementation. Nitrogen replenishment strategies are mainly biologically based with mineral-fertilizer supplementation. Africa has ample phosphate rock (PR) deposits that can be either used directly or processed to reverse P depletion. Decomposing organic inputs may facilitate the use of PR in P-depleted soils. Leguminous tree fallows and herbaceous cover crops grown in situ play a major role in N capture and internal cycling in ways compatible with farmer constraints. Soil-fertility replenishment was found profitable in three case studies, but smallholder farmers lack the capital and access to credit to make the initial investment. A cost-shared initial capital investment to purchase P fertilizer and germplasm for growth of organic inputs combined with effective microcredit for recurring costs such as fertilizers and hybrid seed is seen as the way forward."

 

[Jackson4]

ooohhhhh... phew

 

[Cowabunga]

ooohhhhh... phew

Yep, looks like we will still have soil after all. I knew we would.

 

[Feldspar]

That is much simpler to rectify through changes in farming practise over a reasonably short timespan, where it is happening, which isn't around here as you can see from the sh!t being spread and my bag-muck bill for the year.

Basically the article is about Africa and how more nutrients would grow more food. Pretty obvious to most people I'd have thought.
Here is the crux of it quoted below........

It is true that changes to farming practices in the short term can affect long term trends - not a ground breaking claim. Also whilst it is obvious that more nutrients will grow more food, that is not the interesting issue. The key question is how to provide those needed nutrients in the light of the present shortfall and decline in soil fertility (as described in the article, for example). Do you get these nutrients out of a bag, out the back of an animal, through changing management practices or a combination of these and other factors?

On the point about the endurance of soil. Rereading a bit of that article it is clear that nutrients are being lost in considerable quantities. Without wishing to get lost in semantics I would say that to me these nutrients form part of what I understand to be "soil"; if they are being lost then de facto the soil is physically disappearing, seemingly without replacement, over large areas of Africa. You may not find this in your little of portion of the green and pleasant land, I accept, but then what interesting point does that prove?

 

[Cowabunga]

It is true that changes to farming practices in the short term can affect long term trends - not a ground breaking claim. Also whilst it is obvious that more nutrients will grow more food, that is not the interesting issue. The key question is how to provide those needed nutrients in the light of the present shortfall and decline in soil fertility (as described in the article, for example). Do you get these nutrients out of a bag, out the back of an animal, through changing management practices or a combination of these and other factors?

On the point about the endurance of soil. Rereading a bit of that article it is clear that nutrients are being lost in considerable quantities. Without wishing to get lost in semantics I would say that to me these nutrients form part of what I understand to be "soil"; if they are being lost then de facto the soil is physically disappearing, seemingly without replacement, over large areas of Africa. You may not find this in your little of portion of the green and pleasant land, I accept, but then what interesting point does that prove?

You are making assumptions about falling fertility which are not relevant to professional educated farmers. It sounds good to say that fertility is falling but the evidence suggests that that is not the case generally and that yields are as high as they have ever been, weather and pestilence permitting.

That article, relevant to areas of Africa where subsistence farming is normal, which isn't all of Africa by any means, illustrates exactly how to replenish those basic nutrients to increase yields. It says that there is plenty of rock phosphate in Africa and that they should grow legumous N fixing crops in a rotation and some N fertiliser. There is no mystery and the main constraint is education and finance. Not an insurmountable or indeed serious problem and easily solved given the financial incentive.

And THAT is the critical point. Africans need to produce non-agricultural and export-agricultural goods in order for the population to be able to buy food. They need a non-agrarian family income so that they can afford to pay those farmers a sustainable price that allows the farmers to buy the inputs in order to feed their population. Without that disposable income, Africa and any other region is doomed to unsustainable agriculture; subsistence farming and general regular hunger.

Oh! The nutrients in the soil do not make up any significant portion of the total soil. The lack of these nutrients makes not more than the tiniest fraction of soil volume. Basically they are soil chemicals whose physical volume is insignificant. Adding P, for instance, even in the form of rock phosphate, needs to be broken down by the soil acidity into a soluble form to be utilised by plants. It doesn't take much to replenish soil P levels in terms of volume, but if you imagine that it adds say half an inch to soil depth, keep on dreaming.

 

[Feldspar]

You are making assumptions about falling fertility which are not relevant to professional educated farmers. It sounds good to say that fertility is falling but the evidence suggests that that is not the case generally and that yields are as high as they have ever been, weather and pestilence permitting.

That article, relevant to areas of Africa where subsistence farming is normal, illustrates exactly how to replenish those basic nutrients to increase yields. It says that there is plenty of rock phosphate in Africa and that they should grow legumous N fixing crops in a rotation and some N fertiliser. There is no mystery and the main constraint is education and finance. Not an insurmountable or indeed serious problem and easily solved given the financial incentive.

And THAT is the critical point. Africans need to produce non-agricultural and export-agricultural goods in order for the population to be able to buy food. They need a non-agrarian family income so that they can afford to pay those farmers a sustainable price that allows the farmers to buy the inputs in order to feed their population. Without that disposable income, Africa and any other region is doomed to unsustainable agriculture; subsistence farming and general regular hunger.

Oh! The nutrients in the soil do not make up any significant portion of the total soil. The lack of these nutrients makes not more than the tiniest fraction of soil volume. Basically they are soil chemicals whose physical volume is insignificant. Adding P, for instance, even in the form of rock phosphate, needs to be broken down by the soil acidity into a soluble form to be utilised by plants. It doesn't take much to replenish soil P levels in terms of volume, but if you imagine that it adds say half an inch to soil depth, keep on dreaming.

Ach, quite a bit to go on here.

OK, so firstly I agree that there does seem to be a solution in the form of African phosphates, cover crops et cetera but that only works if these solutions are affordable as indeed you mention. I still think the question of how to provide nutrients is an interesting one because I don't have any evidence that the aforementioned solutions are in fact affordable. Your way out of the poverty cycle seems plausible but is it actually workable? I.e. what evidence do you use to form the claim about the viability of generating disposable income from growing non-agricultural crops?

Agree that nutrients in the soil do not constitute a great proportion of the soil by mass / volume and agree that their loss will not cause great changes in the amount of soil (correcting my previous post). What I still do claim is that some soil is being lost, albeit only a small fraction, and that lost fraction is important and should be of concern. [Perhaps lost organic matter (due to changes in soil structure and % aeration) might give a larger change in soil volume - not sure.]

What source do you refer to in your first paragraph which shows no global decline (that's how I interpret "generally" in your post) in soil fertility levels? Whilst falling fertility levels might not be occurring for many professional educated farmers, the link I provided states that they are happening for many who do not fall into that category. I would guess (only a guess though) that the majority, or at least a large proportion, of the world's agricultural lands are not managed by professional educated farmers which means there is still a big problem even if, as you claim, the solutions are obvious.

 

[Cowabunga]

Ach, quite a bit to go on here.

OK, so firstly I agree that there does seem to be a solution in the form of African phosphates, cover crops et cetera but that only works if these solutions are affordable as indeed you mention. I still think the question of how to provide nutrients is an interesting one because I don't have any evidence that the aforementioned solutions are in fact affordable. Your way out of the poverty cycle seems plausible but is it actually workable? I.e. what evidence do you use to form the claim about the viability of generating disposable income from growing non-agricultural crops?

The rest of the world that does have disposable income is good evidence. Pretty universally they have a population that can afford to purchase food and an agriculture that supplies it in a sustainable way. In other words they at least maintain fertility and output from one year to the next and one decade to the next. Indeed for the most part yields increase in these areas.

Agree that nutrients in the soil do not constitute a great proportion of the soil by mass / volume and agree that their loss will not cause great changes in the amount of soil (I never claimed that it would). What I do claim is that some soil is being lost, albeit only a small fraction, and that lost fraction is important and should be of concern. [Perhaps lost organic matter (due to changes in soil structure and % aeration) might give a larger change in soil volume - not sure.]

What source do you refer to in your first paragraph which shows no global decline (that's how I interpret "generally" in your post) in soil fertility levels? Whilst falling fertility levels might not be occurring for many professional educated farmers, the link I provided states that they are happening for many who do not fall into that category. I would guess (only a guess though) that the majority, or at least a large proportion, of the world's agricultural lands are not managed by professional educated farmers which means there is still a big problem.

A large proportion of subsistence farming is due to poor education and lack of farmer income due to the lack of disposable income by the general population. Hence a high proportion of the population are engaged in agriculture in which they manage only to unreliably produce enough food for their own consumption. Since they have no external income they have nothing to spend on their agriculture.
There are other kinds of farmers that are short term, big scale 'farmers' though. Typical of some types of farmers that, for instance, clear rainforest and crop it by using only the nutrients contained in the cleared land. This works for a while, with P levels high due to burnt vegetation, but at some point that land is either abandoned again to the forest [hence re-forestation] or it begins to be farmed scientifically by professional farmers.