This blog will be dealing mainly with humus, the dark top-soil of natural earth --- it is the soul of our soil. Because it is a blog on science there will, naturally, be some science in the blog. Since the concern here will be on the response of the soil to chemical fertilizers, the blog will have a considerably large section of chemistry in it. The idea here is to get the basic direction right although there are many micro details which have been condensed into a macro direction-finding theme.
At the end of this blog i drw attention to Peter Brooks' discussion on "Nothing coming from nothing" whic is really on turning from negative direction to positive direction at an instant of realization. This blog is an attempt (perhaps unnecessary) to influence towards that instant.
I do not make any apologies for the chemistry. It is the last frontier of science to be understood properly by otherwise intelligent people. It is also the most important environment-damaging frontier when left in wild, profit-making hands. The handling of chemistry now requires to be tamed the way nature has tamed it to derive benefits from it. Man must realize that he is made in the image of nature and not in that of a warsome, wrathful and vindictive god.
On the whole, I am taking responsibility, as a seventy-year-old chemist, to propose a direction of research which could be cheap and do-able by the young with time to spare ... and ambitions to keep as well. I think I am serving some purpose. The blog is not intended to be read in one sitting.
What's wrong?
Somewhere towards the beginning of this article I come to the surprising conclusion from published data (www.tradingeconomics.com) that the effect of fertilizer on increase in rate of grain production seems to parallel the increase in organic fertilizer production and is far less than the actual rate of increase of fertilizer production! Humus, as I had been taught in my school days, is nature’s fertilizer accumulated over years in the top soil. The topic of the usefulness of humus is pretty much dead now, thanks to contributions from the financial profits from science of big things.
As we are almost certain of the axiom that the profits from big things are almost alwways detrimental to a life of good quality, the science of small things should aim to restore the effects of this humus in a short time.
We take this earth so much for granted! Just like insensitive children take their parentage and their heritage.
At present times, these children say they live in a democracy and are free to do whatever they want as long as they have not done anything illegal as judged by a court of law. It so happens that some of these children seem to be the court of law themselves. In the process they ignore all wrongdoings and pander instead to the needs of a spoilt gadget-philic society that requires to conquer the discomforts of nature. Narure herself should now be acutely uncomfortable with these conquests.
We usually excuse these children because they are immature kids, after all. It does not matter if these kids range from Anna Hazare to people who dance at weddings and NGOs who use Bollywood sponsors for lighting up village nights with solar lights. After all, there is so much bollywood revenue lost when villagers prefer to have real (not virtual) fun in their nights.
When you have farmed and tilled your soil and sown your seeds and nurtured your crops that feed your family’s needs and after you have enjoyed your harvest festival, do you really require other conspicuously consumed merriments of the idle rich?
More importantly, will you succumb to the pressures of your multifarious agencies that tells you how to barter your self-contained satisfaction for a more global commercialisation? This commerce really benefits people who have no empathy with the soil, who cannot hold the soil in the palm of their hands and mourn when the soil is ill or rejoice in efforts you have made to maintain its health.
It now seems that any help for our soil can only come from those who are disinterested in pure commerce and hence effectively disenfranchised. If the society of farmers requires turning the tide of globally insensitive commerce that is ruining their soil, it will probably come from the younger people. (at heart and in mind and in stamina) who can make this choice, before they age and make a private commitment to something else.
Big Science vs Small Science
It is important to realize that the science of big things depend on reproducibility (which is important if one has to make profit) of results which, no matter how restrictive the conditions for reproducibility is, show prospects for commercial profit because of a deemed benefit to society. There is also a patented protection of their profits. Here it depends heavily on recognised scientists of recognised scientific institutes, who, in turn, prefer to depend on the larger funding from commercial agencies. This is most so in critical life-supporting businesses such as GMO food and fertilizers and drugs and pharmaceuticals. The price these scientists pay is that they may have to be sometimes extra careful in justifying claims (murmuring, dharmaraj-like, the real identity of Ashwathma, in the battle of Kurukshetra).
The science of big things would like to fund and be funded about grander, Monsanto-philic, schemes such as genetically modified Bt crops. Nothing of scientific value comes from nothing these “giants” would say. The giants move on to do what motivates them most: add value to their science so that something (more) should come from something (less)..
On the other hand, the science of small things cannot, for its own good, deviate from the path of making unbiased observations. Making commercial profit is not their immediate motive. It could be environment-friendly sustainability, for instance. A good candidate is the science of seemingly small things such as the very fundamental aspects of the life of the soil or humus and the way it influences her progenies. The benefits of humus cannot be reproduced in a court of law because the exact nature of humus that is patentable for commercial benefits is not known and is not likely to be known. Yet, there is a considerable amount of unknown that can be put to systematic scrutiny to quantify, if nothing else, the extent of our ignorance.
What can come from the science that seems to be about the science of small things, --- the science of nothing?
Humus of our past
As Maria in “Sound of Music” (and my nephews’ various Indian English moments) would sing:
“Nothing comes from nothing
Nothing ever could
But somehere in my youth or child hood
I must have done something good”
Without knowing it perhaps, lyricist Hammerstein II, was acknowledging the very prehistory that has so far shaped our immediate present. The way we act in the present will continue to shape the future generation even if the future generation may not realize what in their past shaped their present..
So let us say soil there was and soil shall it remain. It is what we have done with the soil and could do to it in the zwitschenzeit that is important for our cascade of presents that will ultimately shape our future. One, of course, should not think of soil as inanimate and inorganic and dead when one justifies the use of inorganic fertilizers. Its like fighting death with death.
One could perhaps write in the context of nothing come from nothing, the almost equivalent and certainly (if you are sensitive to profound things) more profound phrase “life comes from life” or “organs from organs” or the mundane but, if you think of it, more prototypical phrase “organic comes from organic”. This could be surprising if you think of soil as something inorganic, like clay, or mica (which usually has some common lighter metallic elements in it like aluminium or .magnesium; I will have some future blog reasons for mentioning this part).
One of the most important examples of good science coming from seeming nothing is that which came from Darwin’s work after he had completed his Beagle journey that led to his Origin of Species. One has to remember that when one enters new field one is almost at the same level as a young student working with an experienced research guide. The last major work of Charles Darwin is on The formation of Vegetable Moulds through the action of Worms (I have used information about this mainly from a recent review by U. Kutschera and J.M. Elliott, Appl. Environm. Soil Sci. 2: 1-11 (2010)).
Darwin himself thought that it was a subject of small importance and that he worked on it because it interested him. This work had its impact with the concept of bioturbation which dealt with biological reworking of soils by “ ... ingestionof the topsoil, and its mixing, grinding, and digestion in the gut, continually exposed rock particles to chemical alteration, increasing the amount of soil ...” It started the area of earthworm research, finding intelligence in the earthworm, which was till then thought to be useful only as bait for fish. This conclusion led to ridiculing of Darwin culminating in a famous cartoon entitled “man is a worm” by Linley Sambourne in Punch around 1881 (http://www.ucl.ac.uk/news/ucl-views/0809/punch). The evolution from chaos through worm, spermatozoid creatures, apes etc and finally to a human (Darwin) . This cartoon is perhaps anticipated in Psalm 119:141: “Though I am lowly and despised, I do not forget your precepts” (rules or principles teaching correct behaviour). Strangely enough, this cartoon which was meant to ridicule Darwin turns out to be quite in line with recent research by Telford, on “A single origin of the central nervous system?” Cell, vol. 129, no. 2, pp. 237–239, 2007.
Although Darwin’s publication on earthworms was a year before his death, his actual observations on earthworms started in 1837 when he was as young as 28. At this age, the best age for starting the science of small things, he is said to have spent his time in the farm of his more famous uncle, Josiah Wedgwood (his mother was Susannah Wedgwood). There Darwin sketched a vertical section of the soil and was the first scientist to have pointed out that the top-soil layer of vegetable earth, now called humus, of every humid country was due to bioturbation caused by earthworms. Darwin would attribute the dark colour of the topsoil (section (a) in the figure above) to a mixture of partially digested leaves and mineral soil in the faecal casts.
Darwin noticed that the layer (c), about six inches from the top, was due to a covering fifteen years earlier with fertilizers from burnt limestone that contains shell fragments, ashes and other minerals.. This gave Darwin an estimate of the amount of top soil produced per year by bioturbation from earthworms as around 25 tons per hectare per year. This is roughly 10 to 20 time the weight of fertilizers used per year in India or China. It turns out that the use of chemical fertilizer has increased nearly fifteen times during the pasc 50 years in India and China.
In an article on the Overuse of Chemical Fertilizers in China, Williams of Macalester University, concluded that “ ... farmers in China are applying more chemical fertilizer than is economically optimal” Williams noted that “ .. in the early 1960’s, as the limitations of organic fertilizer were realized, the emphasis was shifted to chemical fertilizers. “ It is important perhaps to note that in Fig 1 of her article the rate of use of organic fertilizers roughly parallels the rate of growth in grain yield, which, in turn, is roughly fifty times less than the rate of growth of use of chemical fertilizers. This is a major surprise even to me since I tend to be cynical --- and thereby non-objective --- about the benefits of fertilizer.
It not only serves to confirm what is now well known --- that one requires more and more fertilizers to maintain a crop level, but it also serves to highlight the view point that organic fertilizers can do the job as well. I cannot think of a better reason for debunking the myth that chemical fertilizers are necessary to feed a growing population. It only serves to feed a growing ammonia industry for making fertilizers.
There are more surprising statistics for me. Sugar cane production constitutes ~ 90% of Indian agricultural production (if Renuka Mahadevan’s article on Productivity Growth in Indian Agriculture from Queensland Australia is to be believed).
The ratio of the hugely water-intensive sugarcane production to food grain production in India is nearly 11:1 while in China it is nearly 3:1. USA and Europe do not seem to grow sugarcane! "Why waste water?" they must be saying, when poorer countries are dying to waste their water for the yankee dollar? Is it any wonder India has the largest number of diabetics?
The ratio of food grain production to tobacco production is 10.3 in USA and it is 5.4 in India. USA produces foodgrain nearly three times that of India. This is so even though USA has less than 25% of India’s population!
The sugar-cane industry also serves the vice-building (revenue earning) alcohol and tobacco industry.
I am not at all certain now that a ruler of the soil had any connection with the tiller of the soils. It seems we may have taken them for granted. In our country we always have had harvest festivals which is a festival of farmers, who formed the majority of the population.I was surprised, therefore, to read the following. “Paul Louis Courier quotes from La Bruyere the following striking picture of the condition of the French peasantry in his time (late eighteenth century) "One sees certain dark, livid, naked, sunburnt, wild animals, male and female, scattered over the country and attached to the soil, which they root and turn over with indomitable perseverance. They have, as it were, an articulate voice, and when they rise to their feet, they show a human face. They are, in fact, men; they creep at night into dens, where they live on black bread, water, and roots. They spare other men the labor of ploughing, Bowing, and harvesting, and therefore deserve some small share of the bread they have grown." For such rulers, as the present rulers are likely to be, farming is taken for granted. It is only the profit from farming that they are interested in.
Such an attitude, one would think, cannot be allowed to continue, of course. A knowledge of the soul of the soil would seem to be more important for human survival than what could as well be the useless jingle-less stacks of money.
What is Humus?
The soil is as animate as any of us can ever hope to be once we acknowledge the humus of the soil.
So, being an analytical scientist, we have to ask the (vocationally stupid) question that no real farmer will ask.
It turns out that even those who have written on the subject do not really know what humus is. The one most certain thing about humus is that it exists ,,, in the sense that one knows what one was referring to. Apart from that its “… most conspicuous feature is the lack of specific knowledge concerning the organic matter of the soil.” (Schreiner and Shorey 1909).
We need to ask the “What is humus?” question first of all to learn what humus is not (sometimes referred to as vegetable earth) before one convinces other vocations about things they should or should not do to preserve life in the soil. Most of the uncertainties in the definition of humus comes from some definitions of humus that I have picked up at random from the literatture on the net (quoted in italics).
Humus is a kind of amorphous, brown or brownish black,hydrophilic, acidic, polydispersed organic matter and moredispersed widely in soil, sediment, and water (such as lakes,rivers, oceans and groundwater, etc.). It is not only a major source of soil nutrients but also has a significant impact to physical, chemical and biological properties of soil, it is one of the indicators of soil fertility.
Decomposition of dead roots, green manures, grass clippings, leaves and so forth does not necessarily yield the correct biochemical properties to result in the formation of humus as the only precursors of humic acids are amino acids, which must come from a source of protein … compost alone (made out of carbohydratres) are a poor source of the humic acids
Humic acids are flexible aliphatic aromatic highly functionalized molecules that can act as photosensitizers, retain water, bind to clays, at as plant growth stimulants and scavenge toxic pollutants.
The important feature of humus has been outlined by Waksman (Proceedings of the National Academy of Sciences, 1925) who would write “When organic matter, in the form of green manure, plant stubble, straw, leaves, roots, etc., is added to the soil, decomposition sets in immediately, as can be conveniently demonstrated by an increase in the evolution of carbon dioxide. The rate and nature of decomposition depend upon the organisms concerned and soil environmental conditions. Sooner or later the rate of decomposition becomes. more or less uniform, after the easily available ingredients of the organic matter are decomposed; the residual organic matter then becomes a part of the soil, is converted into "humus" or is said to be "humified." This "humus" decomposes only very slowly and will persist in normal Foils for considerable time.”
What are the benefits of Humus?
It is not a myth that forest cover prevents floods because the humus retains water. Once in 1980, when .Lalitha and I were encouraged by Sunderlal Bahuguna’s daughter to get away from an international environmental team that was visiting Bahuguna’s ashram in Silyara in the Himalayas, we visited Gangi, trekking along the Bhilangana. There were virgin Rhododenfron forests. Walking on the soil of that forest was such an experience. The soil was so soft and springy that is seemed like a huge sponge. It did seem that this sponge couls soak up a large amount of water.
In an article of 1868 Geoff Marsh had written: “The surface of a forest, in its natural condition, can never pour forth such deluges of water as flow from cultivated soil. Humus, or vegetable mould, is capable of absorbing almost twice its own weight of water. The soil in a forest of deciduous foliage is composed of humus, more or less unmixed, to the depth of several inches, sometimes even of feet, and this stratum is usually able to imbibe all the water possibly resulting from the snow which at any one time covers, or the rain which in any one shower falls upon it. But the vegetable mould does not cease to absorb water when it becomes saturated, for it then gives off a portion of its moisture to the mineral earth below, and thus is ready to receive a new supply; and, besides, the bed of leaves not yet converted to mould takes up and retains a very considerable proportion of snow-water, as well as of rain.”
Marsh would add “The hygroscopicity of humus or vegetable earth is much greater than that of any mineral soil, and consequently forest ground, where humus abounds, absorbs the moisture of the atmosphere more rapidly and in larger proportion than common earth”.. He would add “... unhappily, the primitive forests are disappearing so rapidly before the axe of the woodman, that we shall never be able to estimate with accuracy the climatological action of the natural wood, though all the physical functions of artificial plantations will, doubtless, one day be approximately known.”
The science of small things can ask how one can artificially restore the top soil and save the world from the tyranny of excessive or useless advertisement-driven application of chemical fertilizer? A stressed soil gives a stressed life with the corollary that a life in a mutually beneficial relationship with the soil will have less stress (even if it means tremendous loss to corporate revenues and yuppie life-styles of the conspicuous consumer).
The important feature of humus has been outlined by Waksman (Proceedings of the National Academy of Sciences, 1925) who would write “When organic matter, in the form of green manure, plant stubble, straw, leaves, roots, etc., is added to the soil, decomposition sets in immediately, as can be conveniently demonstrated by an increase in the evolution of carbon dioxide. The rate and nature of decomposition depend upon the organisms concerned and soil environmental conditions. Sooner or later the rate of decomposition becomes. more or less uniform, after the easily available ingredients of the organic matter are decomposed; the residual organic matter then becomes a part of the soil, is converted into "humus" or is said to be "humified." This "humus" decomposes only very slowly and will persist in normal Foils for considerable time.”
Waksman then asks the important question: “Why does this take place, why does a part of the organic matter decompose rapidly and a part only very slowly? … most of the nitrogen and minerals introduced into the soil with the natural organic materials remain bound up in this soil "humus." How does that take place?”
The other question for the science of small things is do we need to know, at least roughly, the essential ingredients that are required of the top-soil, to give it all the benefits that humus gives?
Some Chemistry in the Science of Small Things
Since we have to understand the need (or not) of chemical fertilizers, this blog will contain some chemistry. There will be no apologies. The language and the symbols of chemistry is something that one has to understand if one has to counter the claimed miracles of chemistry without countering some empirically established (the only kind of establishment one should care to bow to) chemical philosophy that need not require a QED.
Typically, one thinks of the role of carbon dioxide and water to produce the world’s energy requirement in the shape of carbohydrates, which we write as a string of n CHOH groups or n(CHOH). Usually the process is written as
6CO2 + 6H2O ---> 6CHOH + 6O2 (1)
For aerobic as well as illuminated life equation 1 is part of a cleansing photosynthetic reaction on going from the left-hand-side to the right-hand-side.
Eqn 1 is a spin non-conserving reaction since oxygen as evolved is a paramagnetic molecule and the others are not. Because of this this is not a spontaneous reaction and requires the agency of excited states (accessed by light), spin-conserving intermediates,(accessed by transition metals as in chlorophyll) and energy producing ligands (such as adenine triphosphates, ATP, as in the dark carbon-inserting reaction of the Calvin cycle) which drive the endothermic reaction to the right in eqn 1,
Eqn 1 is CO2-scavenging on going from left to right and CO2 polluting in the reverse direction (from right to left), even if it is useful in producing energy by burning wood. It should be the energetically favoured spontaneous step when a plant dies once the spin conservation is taken care of. When spin conservation is not guaranteed the reverse rate will be slow.
The actual chemical work on molecular structural aspects of Humus is difficult, because by its very nature it cannot be definitive, The chemistry of the humus depends on the nature of the soil, the forst canopy, the rainfall, water sources and so on. The closest one may get to is the structure of a naturally occurring highly oxidised version of humic acid obtained from leonardite (see http://www.phelpstek.com/portfolio/samples/humic_acid.html) which is shown below. It is the oxidised form that is thought to be useful in in breaking up compacted soil or clay and helps in providing micronutrients to the plant. In the context of earthworm and top soil, this activation of the soil must be similar to bioturbation. As one can see humic acid has a section (to the left viewing the structure) which has a large density of oxygen while the right is less so and has probably some features of cholesterol, (which, I thought, in my B. Sc (chem.) days, to be a very complex structure).
This begs the question of whether the synthetic pathway for carbohydrates stems from the chemistry of carbon and water alone. For anerobic and dark conditions,, which must be dominant in buried layers, we may, eliminating 6O2 from 6CO2 in the LHS and 6O2 from the right hand side of eqn1, we obtain carbohydrates as
C + H2O CHOH (2)
A more familiar form of this reaction (catalyzed by acids is the hydration of ethylene to ethanol or the dehydration of ethanol to ethylene.
CH2=CH2 + H2O < --- > C2H5OH
Eqn (2) is the most simple way of getting carbohydrates --- by hydrating carbon. It eliminates the need for using carbon dioxide or oxygen as such and requires only the presence of carbon and water under anerobic conditions. Of course, you cannot place diamond or graphite in water and get carbohydrates. But you may do so when you start with what one may now call nascent carbon or an active form of carbon such as what we now know as carbon nanotubes, C60-like buckyballs, grapheme sheets.
Both the reverse and forward directon in eqn 2 is not environment unfriendly. The reverse direction in eqn 2 could suggest a route for the formation of humus while the forward direction would suggest a step for the generation of carbohydrates and other biofuels for bio-species without requiring the agency of sunlight.
As far as I am aware, eqn 2 has not been seriously considered as an alternative pathway. So overwhelming has been the evidence for the photosynthesis pathways and so high the level of funding for it, that it has not been thought necessary to look for an alternative,
At the same time, when the photosynthetic pathways were being established, elemental carbon chemistry was confined to the reactions of the stable allotropes of carbon --- the layered graphite with an hexagonal network of carbon, and diamond with a tetrahedral network. These compounds are characterized by their long-range ordered structure in solids. They are also rather inert to reactions with water, oxygen carbon dioxide at room temperature.
We now know that there are other allotropes of carbon which have at least one dimension that is very small or of nano-scale (0.001 micron to .01 micron). The three-dimensional (3D) nano-carbon is a foot-ball shaped sphere now known as bucky ball or fullerene, after the xtraordinary Buckminster Fuller, the motivator for geodesic domes. The 2D nano-version are the carbon nanotubes the smallest of which are the single-walled carbon nanotubes (SWNT). The 1D version is graphene, which is a single sheet of graphite.
These nano-carbons are prone to oxidation near room temperature more easily than the macro-sized carbons, graphite and diamond. Graphite itself is known to be oxidized by strong oxidizing agents to form what is known as graphite oxide with C:O ratio varyin between 2:1 to 3:1. Atomically thin monolayers of grapheme oxide (see picture above) may be obtained from graphite oxide using alkaline solutions. The structure of this grapheme oxide is similar to that of oxidized humic acid or another constituent of humus, fulvic acids (see picture above) in terms of the density of oxxygens relative to the carbons. Lignin, which is the most studied component of wood also has aspects of its structure which are similar to that of humic and fulvic acids. Graphene oxides and lignin differ from humic and fulvic acids by not having nitrogen atoms as part of their structure,
It is perhaps pertinent to emphasize that the oxygens are deliberately coloured the red colour of blood in the above diagrams, because of the critical role oxygen plays in the dynamics of carbohydrates in life just as it is in our blood.
What is not clear is whether these nano-carbons are inert to oxygen, carbon dioxide, water at room temperature. If one is not prejudiced, the signal that one gets from all the published noise on nano-carbons is that it is very difficult to get a condensed (non-gaseous) phase of these nanocarbons without oxygen contamination.
I have doodled below some possible schemes for the relation between carbon and carbohydrates. I think that they can happen with the multi-functional (enzymatic) soil with its nano carbon and nano cabon-oxygen systems given the large number of organic or inorganic chemicals, pH conditions, minerals, whatever (click to expand).
Evidence for the above reactions at a small molecular scale is not difficult to come by. These reactions usually occur in the laboratory at temperatures considerably higher than room temperature. The contention is that these are larger molecules which have considerable double bond character or are substituted considerably by heteroatomic and more electronegative atoms. They are in a soil which consists of various minerals and enzymes and biospecies that have their own room-temperature chemistry. There are also nano-space such as micropores, an lamellar clay spaces that increase solvation effects and electric fields that are known to catalyze reactions. For instance inorganic zeolites with pores of molecular dimensions are known to mimic tertiary protein structure of an enzyme leading to the development of what is known as "ship-in-a-bottle" metal complexes which has, for instance, oxygen chemistry similar to that of haemoglobin. The critical aspects of these catalysts is that the geometry of the activation site closely mimic that of the transition state geometry of the reaction thereby reducing the barrier to reaction and increasing the reaction rate at lower temperatures. The advantage of an enzyme is that their geometry is flexible and adaptable as compared to zeolites. This aspect is likely to be reproduced in bioactive humus.
Quite early in the era of C60 science my friend Carlo Taliani of Bologna drew my attention to a publication from his group (Synthetic Metals, 1993) in which they found that oxygen molecules are trapped on the surface of C60. These molecules desorb as diamagnetic singlet oxygen on illumination with light. There would be no problem of spin conservation in eqn 1 when diamagnetic oxygen molecules react with diamagnetic carbon. The formation of oxygenated carbon products, including carbohydrates, would be favoured in this case
I had once ventured in the early 1990s to make nano particles of metal oxides and sulphides by decomposing appropriate organic polymers and inorganic salts in nitrogen. I had thought that the nanoparticles would be in a graphitic medium.
I did not publish any of the results from the considerable volume of experiments we had done because of patenting possibilities, and also because, quite frankly, as experimentalists we Indians are reluctant to worry about reproducibility in India. My colleagues did not have the inclination to repeat and tidy up the experiments to the extent I would have liked.. There was no real patenting expertise available in the CSIR in those days and we ended up with one (US Patent No. 5,643,508) as a statistical information of use to the DG-CSIR after a delay of many years.
I always found photoelectron and infra-red spectroscopy evidence for considerable amount of oxygen in the nano-composite we had made even if I did not have any oxygen in the starting samples. It was Carlo’s information that made me rethink on the nature of nano-carbon I had in my composites. The nano-carbon has a spontaneous tendency to take up oxygen from carbon dioxide, water or air.
It would now seem that the nano-carbons with their double bonds have highly reactive carbon sites which may take up paramagnetic oxygen which are converted to –C-O- linkages quickly (in crop cycle time scales certainly) either through the agency of water, acids, singlet oxygen states and so on.
A coincidence of circumstances can make the soil with its various functional groups in reactive nano-scale laboratories behave like a swarm of enzyme-like functionalities. Given a desired direction (say, from a potential difference caused by a perturbation such as rainfall, tilling, sowing) the fertile, many-functional, soil seems to come up with a combinatorial solution to sustain its function of providing endlessly like Annapurna, the goddess who provides perpetual nourishment without seeming to require material inputs.
Role of clay-rich soil
Clays are metastable layered materials which are formed at low temperatures by the erosion of silica-containing rocks by slightly acidic aqueous solutions containg dissolved gases such as carbon dioxide, nitroegen oxides and so on. The clays are aluminosilicates which have corner-shared tetrahedrally coordinated (Al,Si)O4 groups. Since Al cation is trivalent and Si cation is tetravalent charge-neutrality requires the replacement of divalent oxide (O2-) ions by monovalent hydroxide ion (-OH). The –OH groups are critical to stabilising the layered structures. The hydrogen in the –OH groups can be exchanged with potassium or sodium cations which become more easily solvated in the presence of water. Removal of aluminium by leaching with strong acids such as nitric acid or sulphuric acid removes-OH groups from the clay and subsequent mineralization to silica-rich oxides.
Since these clays are metastable they are rhermodynamically prone to transformation to the more stable three-dimensional oxides.In such a case the beneficial-water-storing properties of clay is lost. This, in turn, would affect the quality of the humus.
I have outlined below a scheme of “cartoons” which could seem to be obvious truths but which does not seem to have been put forth as a reason for the surprising lack of increase in productivity of food grains per unit of chemical fertilizer used.
In the figure below a rough sketch of the role of humus in enhancing the rle of clay in healthy soil is shown. To the left of the figure a rough sketch os a typical phyllosilicate clay such as montmorillonite a Wikipedia formula of which is (Na,Ca)0.33(Al,Mg)2(Si4O10)(OH)2•nH2O.
The structure of clays may be thought of as thin (~ 1 nanometer) slabs of alumina-silicates with surface hydroxyl groups (top centre of above figure, click to expand). In a medium containing water and metal ions such as that of potassium, the –OH groups are exchanged –to form, for example, -OK groups. These groups become solvated easily by water. Because the solvating water molecule has a different chemical potential from free water outside, space between the layers increase by accommodating more water and equalizing the chemical potential.
The oxidised form of humic acid (HA) is known to contain –OH groups, the hydrogens of which may be exchanged with potassium, for instance. This helps in the HA binding to the –OK groups in the soil, Because of the large size and the multifunctionalIity of HA the swelling between the layers may be stabilized (central blue cartoon in above figure). Such swollen layers are stabilised n the presence of humus. The swollen layers are then amenable to bioturbations through agencies such as earthworms as proposed by Darwin. There are other important factors, of course, but, I think, Darwin’s evidence for the rate of accumulation of top soil because of earthworm activity remains the most impressive aspect.
In the absence of humus-forming leaf litter or forst canopy, the intercalated humus-derived acids are removed. They are likely to be replaced by more acidic compounds groups derived from fertilizer additives which contain MOx compounds such as carbon dioxide, nitrogen oxides, sulphur dioxides. These acids are not only likely to leach out components derived from substances such as humic acids but also the lower valent mrysl ion such as aluminium or magnesium or iron ions which cause the incorporation of –OH groups in the clay layer. Further, the incorporation of interlayer, Si-MOx-Si (M = C, N, S) linkages coul lead to an irreversible conversion to stable S-O-Si layers and the loss of clay-like characteristics and a desertification as schematically illustrated below. Such a process finally leads to conversion silica-rih soil which do not swell and retain water causing a desertification.
The desertification or loss of clay-like character.is similar to that obtained by heating or calcining clay. Wikipedia informs us that calcined montmorillonite is used as a soil conditioner for playing fields or for growing stunting growth ofplants as in, whaI think, is athe perverse bonsai culture, which can be encouraged in hilly terrains where soil run-offs donot allow top soil to form. The desertification process also prevents (see Wikipedia) the intercalation of lipid molecules that are so necessary to form first micelles and then vesicles and membrane walls.
This increases of salinity or soil- acidity has marked effects on rich-soil-feeding (endogaeic) earthworms and less so on top-soil litter-feeding (epigaeic) earthworms. It would seem that the leaching out of the intercalated organic matter has different effects on different earthworms.
It is perhaps amusing to note that despite Darwin’s experience on Origin of Species it seems that he had not worried about the species of the earthworm (there are more than 4000 of them; (see review of book by Munnoli et al on soil-earthworm plant relationship, published by Global Science e-books). It now appears that you require specific earthworms for specific soils. Exotic species in commercial plantations can spoil the fauna of the soil. For example, earthworms and other faunal species have disappeared from Indian tea plantations.
We must preserve the original soil to preserve the original species which takes from the land and gives back to it the same way it took. Exotic species are unlikely to do so. .
The soil becomes stressed due to increase in salinity because of high amounts o carbonic. Sulphurous, nitrous or nitric, hydrochloric acids as well as high amount so sodium and chloride ions. There is what is known as a physiological drought because of which the osmotic potential of water in the soil which have negative effects on plant growth, especially on the uptake of water by the roots. For example, the formation of CHOH in eqn 2 by the hydration of active carbon in nano-carbons could be a source for the uptake of carbohydrate from the soil without the agency of light. All it requires the pre-formation of carbonaceous matter in the soil, which we call humus.
Evidence for eqn 2 is well-known. When ethylene is mixed with steam and passed over a catalyst consisting of solid silicon dioxide coated with phosphoric(V) acid. The temperature used is 300°C and the pressure is about 60 to 70 atmospheres. Such strong conditions may not be necessary when the double-bond C=C linkages are found in nano-carbons. For example, it is known that hydrophobic C60 becomes hydrophilic on contact with surface of water because of the incorporation of –OH groups in the C60 framework. This gives the aqueous solution a orangish colour.with an absotion maximum between 400-500 nm.(chlorophylls , beta-carotene also have an absorption peak in this region).
It remains to be investigated whether the fine primary roots, that are known to have the function of water and nutrient uptake are also grow by the uptake of the fundamental carbohydrate building block –CHOH-groups without necessarily requiring oxygen in the photosynthetic route involving the leaves.
Once in March of 2009 while driving down the Konkan ghats on the way from Hatip (where our very good friensa, the Raos have jad the courage and perseverance to set up an organic friendly farms) we came across what looked like forest fires (left of picture below, click to expand). The popular mythe of city-bred industry-sponsored environmentalists is that these fires are caused by villagers as part of their slash and burn strategies, There isthe lore that controlled burning reduces severe forest fires later. Some say that the forest fires are to clear forests for farming. All this may be so to some extent, but the traditional farmer may have another reason.
However, on approaching closer to the area of smoke, we found (centre of photographs above) that patches which were previously coated had central regions where leaves and branches were pile to be burnt or had been recently burnt. This practice was common in the area and elsewhere it turned out later. They were perhaps returning the nano carbon to the soil in this process and generating carbohydrates from the soil. This speculation gave us a better appreciation of the smoke-enhanced sunset (right of above) of that day.
As a starting point, the intellectually abled younger generation of the sub-twenty kind have the advantage of being scientifically unbiased. They may carry out field work on quantifying aspects of the practice that I just referred to above.
There does not seem to be a unique reason for the practice of burning crop fields, nor what benefits the burning brings. In general, empiricists tend to think that burning fallen leaves is not beneficial to the soil. Searching the net for older references, I found in The Farmer’s Register vol 2 printed in 1835 the following comments for the Tobacco Planter in USA:-
“The tobacco planter’s mode of cleaning new ground by raking up the leaves and trash and half-decayed vegetable matter, and then burning it all is a wasteful operation. These materials if spread on exhausted spots in the fields, and ploughed in, would impart life enough to throw up such a crop of rye, or oast, or clover, as to make it easy afterwards to restore them in their original fertility. ... He that advocates burning will be convinced of its rapidly impoverishing effects .. (and that) ... this process will entirely exhaust the vegetable matterin the soil... “
From the recent report of a Training modeule on the managemenet of soil fertility in Watershed Support Services and Activities Network (WASSAN), Secunderabad, I gleaned the following:
“In summer before ploughing, many farmers collect together the crop residues from their fields and burn them. This is done to tidy up the fields and to prevent damage to the legs of bullocks or buffaloes while ploughing. A lot of crop residues can badly affect land preparation, sowing germination, importantly burning also reduces the risk of pests and deceases hosted by crop residues being carried over to the next crop. Ash from the burning stubble and other crop residues adds some fertility back to the soil. Especially potassium, but most organic matter and nutrients are lost. For this reason, burning of crop residues is generally discouraged.”
The sugar cane industry in India has another massive problem with it producing nearly 15 million tonnes of leaves. It would also seem that there would be a significant amount of water saved considering that for a full season, one requires 15 million liters of water per hectare for producing 100 ton of millable sugar cane. The sugar cane leaves have lignin and silica which do not decompose easily and are not good as fodder for animals. As such they are of little use so that they are treated as ‘sugar-cane trash”. The “trash” is traditionally burnt. When you think that 1 ton of firewood is equivalent 20 million BTU, and 3500 BTU gives 1KWH of electricity, 15 million tonnes of sugar seems to be equivalent o 1 million megawatt of electricity. This “trash” has the capacity of generating several thousand times the power generated by solar and wind energy. This seems to be a staggering number even if there is a mistake in the calculation.
If sugar cane was not grown at all and wood was grown instead, the power obtained by burning the wood would seem to be the most efficient way for using solar energy to generate electricity. Not that I am a great advocate for electricity because it would be wated anyway --- say, for advertisements and lighting up the nights. If the wood is from fruit-beariing trees or bamboo, or sorghum (jowar) crops one would imagine that food scarcity, or shortages in building material, or non-cotton fibres for dress, or sorghum jiggery instead of sugar, sorghum crop for thatched huts would solve most of our shirtage problems. It would only be at the expense of the diabetes industry, the cement industry, and the builders lobby.
Nowadays such thoughts are considered reactionary and harmful to the prosperity of human beings, especially those who are encourages to seek only virtual or exotic realities in pursuit of strengthening a World-Bank or IMF-encouraged economy. Maybe such "dangerous" thoughts would be useful again when reality or and/or realization (even of the Marxist kind) sounds ominous bells. They seem to be doing so now no matter how much counter spin is used in propaganda machines.
It would seem it may be better to be prepared.
How will you use, say, the big amounts of sugar-cane leaves if you are dumped with them? One may imagine that the leaves from sugar-cane could serve to create humus in the soil as well and restore the fertility of the soil that has been now seemingly damaged by the use of fertilizers.
If one knew how?
The more pressing problem is that healthy humus has been created over long times. How can we restore humus-like characteristics to the soil? Does the burning of leaves provide a quick-fix to some extent?
I think one important approach could be an investigation of the way one burns wood so that it adds fertility to the soil.
It should be perhaps a low-temperature burning in the presence of water and in the vicinity of soil. I have found from personal experience that on heating nitrogen and oxygen-containing polymers mixed with metal salts of organic acids under anaerobic conditions a nano-composite of oxygenated and hydrogenated carbon with small amounts of nitrogen (which I will call as CHONx) is obtdained as a nano-scale composite with metal oxide, This nano-composite when heated above 500-600 in anaerobic conditions become graphitic with loss of water and carbon monoxide or dioxide. It is this partially graphitised CHONx (or G-CHONx) metal oxide nano-composite that acts as good lithium-ion conductors showing good potential for lithium ion batteries, super-ionic conductors and under suitable conditions also as supercapcitors.
It is not practical to heat crop residues under anaerobic conditions although there seem to have been some attempts to get charcoal blocks from sugar cane leaves for fuel purposes using this method.
When the “leafy trash” is burnt as a big heap with smokeless high flames the temperature exceeds 500-600 C and one obtains mainly G-CHONx-like carbon which is not beneficial.
On the other hand, burning large amounts of not so dry leaves spread on soil in a thin layer (as in the middle of figure above) such that only a thick water-vapour-laden smoke as in the forest smoke on the left of the figure above) is obtained could provide CHONx material with possibilities of enriching the to- soil with CHONx-clay nano composites that could serve as humus-like precursors. When this happens the smoke could temporarily make the atmosphere filled with “brown cloud”-like or smog-like dust particles at low altitudes. For low-temperature fires one does not expect this cloud to lead to the more dangerous high-altitude pollution.
I know from experience that polymers which would otherwise decompose and in nitrogen and evaporate without leaving any non-volatile residue would form a nanocomposite with metal oxides when they are formed simultaneously by co-heating with a metal compounds. . Heating leaves at low temperatures may, therefore, allow such oxide-CHONx nano-composites to be formed. One may therefore, if one is lucky, begin to mimic the bioturbation of earthworms noticed by Darwin and probably noticed through the images without any fanfare or surprise by tillers of the soil.
We may have now managed to convince financially motivated farmers to maintain “modern” agricultural practices of using fertilizers and excessive water. The SOST can experiment on the influence of CHONx fired by various methods using various leaves from various canopies on plant-growth when admixed in the soil. One will not require expensive equipment to start this work.
The most appropriate way to work on the effect of artificial CHNOx would be to working in conjunction with farmers who are already using CHNOx as in the Konkan example above. One can learn from their experiences and record and experiment further.
One does nto expect the top-soil to be as healthy as the naturally formed humus. One learns in any case and one can only benefit in a non-corporate sense from this learning. On the other hand low-temperature firing of spread foliage cannot be doing more environmental harm.
The turning point: when nothing comes from nothing?
We may now interpret the sayig (Genesis) “Dust thou art and unto dust thou shalt return” as an expression of “carbohydrates thou art and unto carbohydrate thou shalt return” or better still “humus thou art and unto humus thou shalt return”. In the in-between life comes and goes in its never ending cycle helped by the brown soul of the soil.
In the process it would seem as if nothing has changed, --- not despite, but because of the life in between. Nothing can only come from nothing, eventually.
Thou hast nor youth nor age
But as it were an after dinner sleep
Dreaming of both
(T. S. Eliot, Gerontion)
Every philosophical system stresses the fact of nothing coming from nothing or ex nihilo nihil fit, which, I suppose, could mean that nothing can be created from or disappear into nothing. But it does not dispute the issue that nothing could be existing forever. It is just the way we grow out of it or into it that we see life.
Maintaining that state close to zero is important in, what my background would assert, a combined annihilation/creation or destruction/creation sense of Siva.
I chanced upon a net-piece (http://direct.vtheatre.net/doc/brook.html) of Peter Brooks on “Does nothing come from nothing?” . This is the title of his Edwards Jones lecture in 1994. I have no personal experience of Peter Brooks but I did see his Mahabharatha and I was very impressed. The scene of Krishna talking to Ptince Arjuna on the battlefield is so different from what we are used to in our own imagery but so much more powerful (http://www.youtube.com/watch?v=_B4Z1PB97KY) than we have imagined . Peter Brooks’ stage-manship shows up when he uses only a chariot wheel to depict the war scene.
What struck me in this article was his insistence on the instant of a scene.
"So I ask you : Does nothing come from nothing ? For instance, if one takes a purely behaviourist view on the living process, if every single action of a human being comes from inner conflicts and pressures whose causes can be traced to recognisable, social, cultural, racial, environmental factors, if this is true, then every single form of behaviour out of which life and theatre are made comes from "Something". … Nothing in the theatre has any meaning "before" or "after". Meaning is "now". An audience comes to the theatre for one reason only, which is to live a certain experience and an experience can only take place at the moment when it is experienced. … What has been up till then individual experiences becomes shared, unified. At the moment when the mass of people becomes one, there is one silence and that silence you can taste on the tongue."
He was reminiscing about the talk after the performance he gave to inmates of French psychiatric hospital. Brooks was struck by the audience and felt “…it was quite an extraordinary experience because of the intensity of the listening. In fact, it compelled the actors to have a quite unusual degree of sensitivity. They felt that the least image that they projected could easily go too far and be dangerous to the patients.“ When they gave the same performance to the psychiatrists of the hospital “ … we could actually feel and hear the movement of four hundred brains, debating with themselves whether they agreed or disagreed with what they were seeing. And this produced a hum that was quite audible.”
"When, through a whole complex series of factors, everyone is stimulated to an unusual intensity of perception, then the actor, the actor's body, one actor's interrelation with another, the whole group's interrelation with one another all create a new form of interrelation with the audience. Out of this comes a genuine participation of all who are present because there is a living flow that is uniting the separate entities into one field of life. When this happens, the shared experience turns from being a negative zero into a zero that is climbing up a scale of quality, until it eventually reaches a level of perception in which the zero is positive. … At this level, Nothing can come from Nothing. The dynamics of performance can bring something out of nothing, until a true nothing that comes from nothing returns to nothing again."
Brooks was talking about the transition from “reducing to zero” to “increasing from zero”. This is the classical turning point in physics where, in one dimension, the particle in motion stops and starts a return motion.
At this instant of the turning point when action becomes we should not be in Eliot’s Gerontion (“civilization gone rotten” Grover Smtih)
What will the spider do,
Suspend its operations, will the weevil
Delay? De Bailhache, Fresca, Mrs. Cammel, whirled
Beyond the circuit of the shuddering Bear
In fractured atoms.
There is a chance to be born again from our roots using the small-science understanding buried in the dark humus soul of our soil.
We should not be in Gerontion.
Even if it takes us some time to get out of it.
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