Friday, 14 June 2019

Do agricultural chemicals damage the soil?



Of course Peter Williams' soil is more fertile and contains more organic matter than the farmers' (other than his pasture) and so does your own
When John Humphries took it as a ‘given’ that chemicals damage the soil when questioning the new chairman of ‘Natural England’ (who failed to disabuse him) my hackles rose.
But could he be right?

Most of us welcome the new surge of concern about global warming and the need to combat the shocking destruction of the environment. I am deeply pessimistic that we will or are politically able to do enough about it. I desperately hope I am wrong.
I do hope that global interventions will be more enlightened than wood burning power stations and manufacturing fuels from food crops. Some governmental initiatives have not  been wise.
I fear politicians acting against ‘low hanging fruits’ to satisfy populist fears and not really doing anything worthwhile. There are however exciting new ideas and technological developments that are huge grounds for hope.

Soil destruction and attendant erosion when clearance takes place
A recent report has highlighted the extreme dangers of destruction of soils. Not a new concern, but of ever increasing importance with forest destruction and attendant soil erosion. New weather extremes and human intrusions accelerate this process. Not only is soil’s organic matter a huge reservoir of captured carbon dioxide, fertile soil is needed for both reforestation and high agricultural yields. (note trees can make a contribution to restoring denuded soils)

Don’t blame the farmers
High agricultural yields are essential if we are to feed expanding populations - even though it may be unfashionable to say so. Far better to use land efficiently than further intrude on natural landscapes to create new farmland from countryside.

This neighbouring field might look pretty but does not feed many people
Supporting high yielding crops with fertilisers and other chemicals does not mean that sensible use of set-aside to enrich rural environment cannot benefit both the landscape and efficient farming. 
Many farmers are the very best stewards of the landscape and it is in their own interest to preserve their soil.

The thrust of my piece today is that the real causes of soil erosion is human intrusion (and advancing climate change) and that the use and misuse of chemicals (in terms of soil) is a side show. To over focus on chemicals as a bogyman is an easy cop out for politicians.

Having doubts
At this point in writing this post I thought ‘Where am I going with this? Defending agricultural chemicals is such a minefield and introduces so many environmental issues.”
For example the use of pesticides is much debated and at least some of the multiple uses of insecticides and fungicides must have subtle effects on the soil. For example fungicides might kill mycorrhiza. There is so much to say about pesticides and the environment and not all is l bad. 
Without them world agriculture would be in a very fine pickle.

It’s just that today I want to make the case that the proper use of agrochemicals is not actually bad for the soil and in many cases such as using fertilisers might actually improve them - as illustrated in my earlier posts. 
Humphries’ populist illusion is so potentially harmful to sensible discussion.
There are many issues how chemicals and in particular pesticides could be better used but to discuss them today would be a distraction.
For example farm fertilisers are part of the problem of water pollution and safeguards in their use are important. This harm however is not exclusive to inorganic chemicals and applies also to organic manures, ploughing up grassland and excessive organic oxidation by cultivation.
Farmyard manure contains a lot of nitrogen too

At this stage I lost the plot and dried up!

New Scientist defends farmers and finds no evidence that chemicals are destroying our soils
My mission has been restored after reading James Wong. Apparently our Secretary of the Environment of all people recently stated that we are thirty years away from “eradication of soil fertility” because “we drench our soil in chemicals”.
How crass, how misleading and plain wrong. Heaven forbid his actions based on such nonsense. (Better make him Prime Minister instead? Oh no!)
James spent eight hours trawling academic literature to find any evidence for such a statement and found none whatsoever. He contacted six renowned soil scientists who roundly refuted such notions. They were keen to point out the world soils are in danger but not for this reason.

The best evidence Wong found for farm soils lacking organic matter was a study comparing garden soils with farm soils in Sheffield. They found our garden soils are more fertile! Surprise, surprise, I could have told them that has been true for hundreds of years!

James Wong also pointed out that some modern farming practices such as ‘ no till’ and sensible use of fertilisers in many cases are improving soils. 

Old farming practices were not as enlightened as you might think
He states that many old farming practices were more detrimental than some would have you believe. Wong was not wrong.

Links
These two posts bring us back to fertiliser in the garden
Are fertilisers a good thing?
This post provides links to most of my advice about fertiliser use





4 comments:

  1. "High agricultural yields are essential if we are to feed expanding populations - even though it may be unfashionable to say so."and "the real causes of soil erosion is human intrusion (and advancing climate change)"
    And yet we don't talk about expanding populations. Politicians are reluctant to even mention it, apart from in the context of migration. Every day there are news stories about environmental issues, but very little airtime for what seems to me to be the obvious problem that we need to address. I highly recommend a visit to this website https://populationmatters.org/ which presents a lot of very interesting data, and potential solutions, far better than I can!
    Back to soil! I have been wondering about the impact of surfactants and their biodegradability. But reading about it gave me a headache.

    ReplyDelete
    Replies
    1. That is the real problem Sarah and agriculture is always catching up
      Surfactants are often some kind of soap and I would not expect biodegradability a problem with most or all of those that are not

      Delete
  2. You wouldn’t believe the number of freight trains that pass of allotment daily to transport imported wood chippings to,s nearby power station that was once supplied by the colliery almost next door.

    ReplyDelete
    Replies
    1. The maths do not add up in my opinion - not that I think coal burning to be a good thing.

      Delete

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