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New Science
New to 'Western' science! (N2S!)
New to 'Western' science! (N2S!)
Much of this soil story is 'new to science'. Soil Science dates back nearly 200 years, but here we have a new way of seeing soil. Imagine being IN the soil, perhaps a small creature a millimetre long, that somehow can see into the blackness and determine the structures in which strange new communities live.
It is 'new to science' in that, while many of the stories come from peer-reviewed sources, they have not been seen in relation to each other in the overall context of soil evolution- that has been going on for hundreds of millions of years - unseen.
The idea of soil evolution itself is new, although I do know of a Japanese scientist also promoting soil evolution. If soil is a ' natural body' or 'living entity' it must have evolved - by means of natural selection - in many different environments.
Each 'N2S' suggestion will take time to debate and decide whether it is 'true'. Here are some of the main ones..
Soil evolution. We talk about evolution over a period of several hundred million years. It sounds a long time, bit only 1/10th the life of this planet. but not below ground. It is has to fit with the evolution we know above ground, but it is more complicated as it is harder to see.
Soil Decomposition developed over a period of 500my in three waves. First, around 400mya, bacteria , and both mycorrhizal and saprophytic using aerobic processes called mineralisation, by soil scientists (geologists say 'mineralisation' that is making minerals). This releases nitrates & phosphates from organic matter, and so providing key plant nutrients. The second wave about 100 my later involved the de-lignification by newly evolved fungi tha could break down dead wood, while the 3rd major wave was of humification, when bacteria in animal guts of worms and small arthropods broke organic compounds down to humus and humic substances.
Soil aggregation is related to decomposition and also did not arrive all at once. The 'primary' aggregation occurred 400mya when there were glomalin related sticky substances (see below) and secondary 200 my later when the humic substances became widespread.
The first land plants to change the nature of the land surface were mosses not lichens, as many believe, like BBC's Earth series
The role of small soil animals in relation to rest of the soil web has been largely ignored by many soil scientists and even the new ones who talk a lot about microbes. Yet their numbers and diversity must mean they play vital roles in several important soil functions, particularly glomalisation and humification
400mya there came perhaps the greatest leap forward made when we see the significance of how springtails sprang from water film to land in mosses.
7. These springtails go on to play a vital role in establishing transferring energy from above ground, by eating bacteria and then mycorrhizal fungi, a process I am designating as 'glomalisation'. This provides energy to below ground systems, and in so doing set up basis for building basis for soil, by turning glomalin into GRSPs. Recent research in China and India providing help as to what could have gone on then in relation to glomalin/GRSPs. The GRSPs act like glues and play a vital role in Primary Aggregation which produce mainly microaggregates that starts widespread soil structures 300-200mya.
8 Four distinct early soils evolved in Carboniferous period in relation to the vegetation growing on the levees, ponds, mudflats and swamps, indicating that soil is probably not monophyletic, to use a cladist term. Four forms of early soils appeared each based on the way clay and organic matter intertwined, mainly without humic substances.
9 This 100-200m year gap between the two forms of aggregation may help explain similar gaps in evolution of several animal groups, like lower to higher oribatids, hemi to holo-metabolous insects, and why it took so long for enchytraeids to become earthworms.
10. As the soil grew, it provided a new environment for the evolution of creatures, in particular insects. Early insects evolved in soils, through hemimetabolic egg/nymphal stages/adult processes, to emerge and take over the skies, but then come back to earth as holometabolous egg/larva/pupa/adult in order to exploit new soil and explained by great Russian scientist, Ghilarov, barely known in the west.
11. Post 200mya - more herbaceous stuff. now being decomposed by anearobic humification which could occur in animal guts, and thereby distribute throughout the soil, across the globe. The end result - humic substances, are another form of adhesive to make more aggregates. This is when 'higher' oribatid mites, termites, and earthworms entered the picture - a question Darwin did not offer an opinion on.
12. Proper terrestrialisation - when all sorts of decomposition work together, with several sorts of glues making more complex aggregates from the poo of various animals to provide a complete soil so that others can inhabit. It started with insect larvae, which transformed the world ecology.
13. The answer to Darwin's dilemma of how flowering plants spread so rapidly, 'lies in the soil'. Newly evolving adult insects can pollinate plants, while their larvae can colonise this more expansive soil.
14. Not till after the grasses take over around 50mya do the in-plant-nitrifiers - a mixture of old soil fungi and bacteria - produce the holy grail of agricultural scientists, plants with their own fertiliser.
15. All this represents a paradigm shift in soil science, from considering the physical and chemical elements mixed in a microbe mush to considering what goes on in a richly populated city of various architectural structures.
If this gives you the impression that soil evolution followed some sort of linear line, then I apologise for givnig that - I had it myself. Then I realised (thanks to Colin!) that its evolution, like all life, ebbs and flows, comes and goes.
When looking globally, ice caps, deserts and the sea, plus tectonic shifts, cover and kill soils. Much of soil evolution is dealing with the recovery from that. Some processes emerge, or are more involved, while at other times, other processes and properties come into play.
Imagine when looking at soil through the ages, it is like an enormous amoeba, ever-changing and moving around the world.
A new term is being proposed called ‘metaphenome. “Innovative approaches are required to reveal the details underlying the myriad of interactions carried out by naturally complex soil microbiomes, and the interplay between and within different kingdoms that result in the soil metaphenome." (Janssan & Hofmockel 2018)
Peds and Pores
Peds and Pores
We are seeing a switch from looking at peds - by breaking up soil, to looking more at pores, where the life goes on, by leaving soil intact
The events here are all verifiable from reputable, peer-reviewed sources - indicated by quoting authors and the date of publication and linking directly to the online version. This is the first time they have been put together like this. It is a new way of seeing soil from previous soil science. There are many competing versions of several of these soil-related events and how they fit together. The explanation here is that the soil has been evolving for nearly half a billion years, but has gone through a number of distinct phases.
When deciding on whether these events are true, we need to ask whether it is possible, and plausible and then how is it provable. If you choose to dismiss, then you have to ask: 'how, when and where did that particular part of earth emerge, and does it fit with what we already know? Let's look at the challenge that faces us
We hear about 'blue-sky' research, where unanticipated scientific breakthroughs are claimed to be more valuable than the outcomes of 'agenda-driven' research, but we should hear more about 'brown-soil' research - down to earth practical work that may save the planet and all who live in it.
Can I propose a new area of science-based study of soil, called ‘soilology’. The existing study of soil is called ‘pedology’, based on the importance of the soil structures - peds. But it is a bit ped-estrian! There is increasing emphasis being put on the spaces between the peds - the pores. ‘Soilology’ extends this to cover all life in and around those peds while also nodding to ‘sociology’. Nowadays we cannot separate science from society; they co-exist. Our society lives works and plays on our soils. What happenes to our soils depends on our society. I suspect many people would already think the science of soil should be aclled ‘soilology’.
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