(or Science of Earth-worms for Eco-Restoration of Soils and Moderation of Climate)
By Rob Blakemore, VermEcology, Japan (27th May, 2017).
In a tribute to Rachel Carson on her birthday.
Slimeless Spring-I is here – https://vermecology.files.wordpress.com/2015/12/slimeless-spring-and-global-worming.docx .
“Until we have the courage to recognize cruelty for what it is–whether its victim is human or animal–we cannot expect things to be much better in this world. There can be no double standard. We cannot have peace among men whose hearts delight in killing... By every act that glorifies or even tolerates such moronic delight in killing we set back the progress of humanity.”
Rachel Carson (27th May, 1907 – 14th April, 1964). This passionate & compassionate aspect of Rachel Carson reflects in other heroic pioneers such as Soil Association’s founder, Lady Eve Balfour, vegetarian from age eight after watching a pheasant shoot (shocked as any innocent on witnessing needless slaughter).*
Rachel Carson as a child, reading to her pet dog Candy. She died of cruel cancer at 56 barely six months after publication of “Silent Spring” that warned of disastrous synthetic chemical poisons, as opposed to Howard’s natural organic “Law of Return” (Ref). Photo credit: Carson family from the Rachel Carson Council.
“There is no better soil analyst than the lowly earthworm” – Sir Albert Howard (1945).
Life is carbon-based with a need for H2O. The biosphere relies on soils for food, regulation of the water-cycle and soil is the single most important site governing carbon cycle and sequestration. Soils occupy ~81% of “flat” land that is not desert, ice, mountainous nor waterlogged. Approximately 51% of all land is farmed, forested or urbanized (37+11+3%) under direct human management. Despite neither having concern with soils, both NASA & NOAA admit that soil is the greatest active carbon sink (>2,300 Gt or 50%) more so than combined oceans (1,000 Gt, 22%), atmosphere (800 Gt, 17%) and all above-ground vegetation (550 Gt, 12%); moreover they show 120 Gt annual carbon exchange on land compared to 90 Gt in oceans (i.e., 60 : 40 and because photosynthesis gives 6CO2 –> 6O2 this ratio applies to oxygen too). Ocean biomass is at most 0.2% of total and its contribution to net primary productivity (NPP) is as low as 8%. NASA / NOAA have soil as C sink for 3 Gt yr-1 compared to ocean 2 Gt yr-1 (also 60 : 40), plus agricultural land misuse adds 2-3 Gt C yr-1 to the atmosphere.
Soils alone provide 99.4% of human food, plus all our natural fibres and timber. Soils ultimately underpin 88% of global biodiversity and, via nutrient and agrichemical runoff pollution, provision and/or poison the 12% remainder in the ocean. Since marine scientists claim the ocean supports 1 billion people, then soils support the other 6 billion. More than 1 billion people work directly in (toxic) agriculture, about a third of the global work-force but organic husbandry provides greater employment, thus social problems both of health & urbanization are resolvable.
Land-based industrial agriculture has been responsible for up to 30-50% of all green-house gasses (GHG), around 28-40% of excess CO2, and for most species extinctions. A consensus is growing that the Green Revolution was an environmental disaster. Broad adoption of organic or Permaculture principles offers the only practical means to rapidly restore biodiversity, to offset human GHG emission (even if emissions continue!), and to continue to feed a growing human population.
Earthworms are the undisputed mediators & moderators for rebuilding healthy topsoil that is currently eroding at >2,000 tonnes per second (Ref) such that, at present rates, we have only 60 or fewer harvests (UN’s FAO 2015a; Ref). Earthworm populations and species are depleted by intensive, chemical agriculture. Intensive permaculture, however, is much more productive both per unit area and in time (Mollison, 1988). An urgent need is wholly natural vermi-composting at all scales (from kitchen to continent) to replace synthetic fertilizers in order to facilitate transition to broad-acre organics that also has earthworm livestock at its core. Since neither government nor industry-related science not even using funds filtered through “green” NGOs will help, the solution then is on our own plate: to eat less red meat and more organic fruit & veggies (just as the doctor ordered). A new “4 worms per 1000 g soil” initiative is urged for restoration of healthy soils as proponents like Sir Albert Howard and Bill Mollison envisioned.
“All human life ultimately depends on land including the soil and water found there.” – UN’S ELD (2015).
Economy and Society depend entirely upon Ecology which, in essence, is the science of interactions between organisms and their environment, i.e., all things natural. In its broadest sense, it includes all human endeavours both natural and un-natural (e.g. synthetic chemicals). Of nine planetary boundaries within which humanity can safely operate, Rockström et al. (2009) identify these already critically exceeded for: #1 Biodiversity loss; #2 Nitrogen cycle; #3 Climate, and now #4 Chemical Pollution that was tested by Diamond et al. (2015). Regarding species loss, E.O. Wilson says causes (and solutions!), in relative order, are given by HIPPO acronym for: Habitat loss; Invasive species, Pollution, Population & Overharvesting. (We should probably add five more I’s for human Insatiability, Ignorance, Indifference, Inaction and Insolence for our rank arrogance concerning Nature). All factors inter-link ecologically, but habitat is increasingly affected by Climate Change. It is also important to note that all these issues (and solutions!) are strongly linked to agriculture and thus to soils, particularly our fragile topsoils and thus to earthworms that, according to Darwin (1881) and others, are the major builders of fertile topsoils (as are fungi to a lesser extent).
By way of introduction, some relative assessment of biosphere biodiversity is required. We are fortunate in some way that a Census of Marine Life (coml.org) completed their $1 billion, 10 year assessment of the oceans in 2010. Their conclusion was that 250,000 species were known from marine ecosystems and estimated expected total numbers as between 1 to 2 million. As approximately 2 million species are presently recorded on Earth and an estimate of probable totals ranges from 10 to 60 million, then oceans currently support just 12.5% of known species and, at best (2 in 10 million) about 20% or, at worst (2 in 60 million) about 3.33% of estimated totals. Thus between 80-96.67% of all Life on Earth occurs on land:- this is where the biodiversity is and where the focus should be, both scientifically and practically, for both conservation and restoration.
Figures generally exclude microbes. It is yet claimed that a drop (one millilitre or gramme) of seawater has 10 million viruses, one million bacteria and 1,000 protozoa and algae, whereas fertile soil has a billion microbes, most unknown, in each gramme.
The present contribution also reveals that, as with most other organisms, most humans live mainly on land and get 99% of food from soil as well as all timber, other building materials (e.g. clay), and almost all natural fibres (e.g. cotton, wool, bamboo). Basic liveable conditions for humans and most other life forms, in relative order, are: air, water, food, shelter habitat and some form of society (at least for reproduction). NASA / NOAA show that land plants photosynthetically process >60% of atmospheric carbon to produce oxygen (thus, at most, 40% is from oceanic plankton). All rainwater is filtered, mainly via earthworm burrows, and much is stored by soil. As already mentioned, 99% of human food and 100% of our homes and clothing are from soil which ultimately supports almost all of society. This report’s contribution will demonstrate, perhaps surprisingly for some readers, that soils are the major cause, most affected, and the only solution to climate change that is an issue implicated, but subordinate in importance, in both loss of biodiversity and an inconvenient nitrogen (N2) fertilizer imbalance (highlighted by Rockström et al., 2009).
Well over 1 billion people are employed in (toxic) agriculture, representing 1 in 3 of total work-force, with women more active (38 % vs. 33% for men); a large proportion of child labour is also employed, often as unpaid family members (Ref.). Livelihoods of 1.3 billion are said to rely on livestock production alone (Ref.). These families often live in and around sprayed fields and poisoned soils, drawing water contaminated with agrichemicals and farm pharmaceuticals. Organic farms provide safer and greater employment, thus the global problems of social health & uncontrollable urbanization are soon resolved if we look to healthy soils and to the earthworm fauna resident therein.
How important are soils?
Remarkably, no-one knows for sure as most basic soil data are wanting. However, FAO (2015) gives a summary of our current knowledge and FAO (2017) states: “99% of the world’s food supply comes ultimately from land-based production with about 50-70% of the land devoted to agriculture.” The vague “50-70%” is likely extracted from FAO (2004) where it says “approximately 50% of the terrestrial areas is devoted to agriculture, while in temperate ecosystems agriculture occupies 70% of the land (Pimentel et al., 1992)”. Whereas Pimentel & Burgess (2013) have soil contribution to human food as 99.7% compared to just 0.3% from oceans & aquaculture combined, Blakemore (2010, 2012) quotes a more generous figure twice this as 0.6% from oceans and 99.4% of food from soils, based on data that can be readily verified from FAO (2004) sources. Moreover, IPCC (2014: 818) states: “Human economies and quality of life are directly dependent on the services and the resources provided by land”, thus they too deliberately dismiss the relatively insignificant ocean contribution. Low fisheries supply is not due to depletion as record yields are reported, yet fish provide at most 7% of all protein consumed by humans (FAO, 2016), so 93% protein is from soil.
Global land area is usually given at about 15 Gha; for example Jobbagy & Jackson (2000: tab. 3) have 12.1 Gha (81%) soil + 2.8 Gha (19% of extreme desert, rock, sand, ice, swamps, marshes, lakes, and streams from Jackson et al., 1997: tab. 2). To give total 14.9 Gha flat land with soil on 81%.
Natural rangelands or grasslands cover 23 % of land area (ca. 3.36 Gha) (ref.), including savannah of Africa, steppe of Central Asia, America’s pampas & prairie and Australia’s outback bush (so it is illogical for meat-eaters not to harvest bison, guanaco or kangaroo). Jobaggy & Jackson (2000: tab. 3 from Whittaker, 1975 & Jackson et al., 1997) have grasslands as 1.5 Gha tropical, 0.9 Gha temperate and 0.85 dry shrubland (total 3.25 Gha). Each of these biomes has its unique, but almost completely unknown or recondite, earthworm fauna (e.g., Blakemore, 2013). Table 1 newly estimates areas.
Table 1. World land use recalculated from FAOSTAT, 2013, 2015; World Bank, 2015 and IAEES, 2015 (proportional figures in braces) after Blakemore (2016a).
Although 2015 was the UN’s designated “International Year of Soil” it was uneventful. But it coincided exactly with one hundred years since Nobel laureate Dr Fritz Haber developed poison gas (killing my great-grandfather, Pte Joe Walton in WW1 trenches) and synthetic nitrogen for munitions that can both be used as simplistic agricultural pesticides and soil fertilizers that are also toxic to earthworms. Ironically, earthworm activity both raises small mounds and fills in hollows in soils, for example burying remains and levelling preserved Western Front trenches from WW1 of 100 years ago.
Yet one gruesomely practical outcome in response to industrial scale slaughter of the Great War of 1914-1918 was development of TRIAGE which is rational prioritizing of casualties in order to treat the most urgent first (Fig. 1). To combat many conflicting and confusing global issues, a similar form of ‘Environmental Triage’ is now required to identify the key problems/solutions we face today.
Historically, the world was at a metaphorical cross-roads in the 1930s with two main paradigms: Sir Albert Howard’s Indore method of vermicomposting (Ref.), or Haber-Bosch urea for synthetic N-P-K and biocide farming (Ref.). Due to the outbreak of the Second World War and the subsequent chemical stockpile, as well as prevailing economic business models rather than ecological considerations, it was an industrial agricultural model that expanded, most notably in a 1940s Green Revolution (Figs. 2, 3).
Figure 2. From Blakemore (2016a). Indexed earthworm (m-2) % decline vs. Green Revolution synthetic Haber-Bosch NH3 fertilizers (Mt N/yr), toxic biocides (Mt/yr) & water (FAO, Tt H2O/yr); a more sustainable ‘Brown Revolution’ is now needed.
Figure 3. Was Green Revolution a Blue Revolution? Indexed area irrigation and artificial fertilizer trends compared to crop yields with Pearson’s coefficient (Gha area irrigated from Freydank & Siebert (2008, http://www.hydrol-earth-syst-sci.net/19/1521/2015/hess-19-1521-2015.pdf and FAO AQUASTAT). Overall, N fertilizer appears rather less limiting than water for Green Revolution plants.
Fig. 2 demonstrates the exponential growth of chemical agriculture with associated food and population increase and, from very limited data, a supposed decrease in earthworms. Note that Rachel Carson’s 1963 “Silent Spring” had little tangible effect on exponential rates of toxic biocide use. Fig. 3 shows a slightly stronger correlation with area irrigated than with synthetic nitrogen application, suggesting that N is not as limiting for “Green Revolution” crops as is generally supposed; these artificial salts just make the plants more “thirsty”. A corollary is that reducing synthetic N fertilizer with natural vermicompost may have no lessening effect on yield but a concomitant reduction in water / biocide use and increased H2O & C storage whilst restoring soil biodiversity.
In this contribution rational Global Triage is attempted and, in a break from “pure” science that by its own definition is pointless, science is applied to solve urgent issues, such as those spotlighted by Rockström et al. (2009) but for which those authors proposed no solutions (Fig. 4).
Figure 4. After Rockström et al. (2009: fig. 1; Nature 461: 472–475) nine planetary boundaries critically exceeded for Biodiversity, N2 cycle and Climate. Chemical pollution was later shown to also transgress the boundary (Diamond et al. 2015) (note however that GMO genetic pollution was not assessed). Green zone is safe.
Of the four major environmental issues (Fig. 4), as well as most of E.O. Wilson’s HIPPO threats, I investigate whether they may yet be resolved by the simple expedient of natural organic farming or the modern, post-industrial, application of what is increasingly called Agroecology that both fit comfortably under the broader umbrella of Permaculture. This single, ethical and practical solution may help fix species/biodiversity loss and, coincidentally, resolve most other lesser, interlinked issues. My considered view is the even more simple: just aiming to “Save the Worm” is perhaps the most expeditious way to achieve the same goal. The foundational reasoning to support this claim is that organic agriculture preserves topsoil and the best way to do this is to encourage earthworms. As Lady Eve Balfour stated in an Introduction to Dr Tomas J. Barrett’s (1947) book “Harnessing the Earthworm” said: “When the question is asked, ‘Can I build top-soil?’ the answer is ‘Yes’, and when the first question is followed by a second question, ‘How?’ the answer is ‘Feed earthworms’”. She also posits that a properly managed task-force of earthworms can restore as much as an inch (2.5 cm) of nutrient-rich topsoil in as little as 5 years.
This is particularly important as recent FAO (2015a) figures show that topsoil erosion due to tillage, wind & water runoff is about 33 Gt per year but Pimental & Burgess (2013: 447) have even more worrying data estimating fertile soil lost from agricultural systems worldwide is 75 Gt / yr. Since a year has 32,000,000 seconds, then ca. 2,300 tonnes of topsoil is lost per second as the most urgent, critical and also most ignored environmental issue (Ref.). A summary from FAO (2015b) is of perhaps only another 60 harvests possible from soils as this vital topsoil resource is depleted. Interestingly, it seems soil will run out well before oil…
Contribution of land use & agriculture/forestry to carbon excess & climate change
In order to apply triage to climate change, estimates for relative proportional factors are required. Conventionally it is due to Greenhouse Gasses (GHG) mostly from burning of fossil fuels (65% in following chart), but surprisingly, despite many years of research (e.g. IPCC – https://www.ipcc.ch), data for land use contribution is difficult to extract.
We may however note as in the charts above causes of Climate Change are primarily as greenhouse gasses, with 76% of these as CO2. In left-hand-side chart above for CO2 alone 11 in 76 or 14.5% is due to agriculture/forestry and other land use (Ref. and see Fig. 5). Note that the 24% other major anthropogenic GHGs are mainly methane (CH4) and nitrous oxide (N2O) that are primarily, over half each or total >12.5%, from ranching and farming, this plus the 11% CO2 from land use gives >22.5% GHG due to agriculture/forestry cf. 24% of total GHGs in right hand side chart (orange slice).
In the right-hand-side chart, GHG emissions are for Power (25%), Agriculture/forestry (24%), Industry (21%) & Transport (14%) and these ratios are approximately the same for CO2 alone, although agriculture/forestry is sometimes quoted as 30% of cause but it also has about 20% of this offset by biological fixation of carbon (FAO AFOLU, 2014).
Other sources of excess CO2 from burnt fossil fuels and industry (65 of 76 = 85.5% in left-hand side graph) with cement contributing about 5% (half in its energy use and half in its CO2 calcination loss from limestone – Ref1. Ref2.; and figure below www.WBCSD.org).
My summary of FAO AFOLU (2014: tab. 3-1, fig. 3-2 shown below) data is total gross GHG addition in 2011 was of 10,199 Mt CO2eq as shown in their figure 3.1 after which (page 19) they summarize: “For the period 2001-2010, the largest emission source was agriculture (50%), followed by net forest conversion (38%), peat degradation (i.e., cultivation of organic soils and peat fires) (11%) and biomass fires (1%). Forest (forest management and afforestation) contributed 100% of FOLU removals by sink, and represented a 20% offset of total AFOLU emissions by source ( Tab. 3 -1).”
Surprisingly, (FAO AFOLU, 2014: 43, 47, fig. 3-5 also shown below) burning of crop residues and savannah only gave 197 and 287 Mt CO2eq or nearly 4 and 5%, respectively, (total 9%) of total emissions from agriculture, which itself is just 50% of total AFOLU. In general, actual CO2 released by burning vegetation (about 1.9 kg per kg burnt due to O2 oxidation) is not included because, I believe, it is considered balanced by carbon taken up during plant growth, so the emissions are carbon-neutral. If so, this I think is mistaken as all plants can be mulched or composted and carbon returned to the soil rather than go up as smoke into the atmosphere.
It is important to note that whereas the FAO AFOLU report mentions “organic soils” these are peats, and it totally ignores topsoil humus, both as a source and as GHG sink! Seemingly they overlook or ignore almost all below-ground processes (by earthworms, microbes, roots), thus possibly omit approximately half of all biological activity!!
The following chart from IPCC (2014) also shows “AFOLU” Agriculture/Forestry and other Land Use is 24% of the GHG total problem plus 0.87% from electricity (possibly for fertilizers although other figures quoted below are 1.2%) which if counted as an agricultural process, gives 24.87-25.2% then matches or exceeds the electricity contribution of 25%. How much pumping irrigation, heating greenhouses, freezing produce or the proportion of Transport that is directly related to agriculture is undetermined, but may be substantial proportion, both on farm and off, further increasing its GHG budget. [An estimate from FAO (2014: 66 and Ref.) is extra 785 million tonnes of CO2eq. in 2010 for some of these agriculture related processes, excluding freezing and Transportation; with about 47% for diesel fuel (including just 3% of this diesel used in fisheries)]. IPCC (2014) say: “AFOLU plays a central role for food security and sustainable development. The most cost-effective mitigation options in forestry are afforestation, sustainable forest management and reducing deforestation, with large differences in their relative importance across regions. In agriculture, the most cost-effective mitigation options are cropland management, grazing land management, and restoration of organic soils.” Rather than organically farmed soils, “organic soils” means mainly peatlands, a large store (about 30%) but a very minor AFOLU contribution (just about 10%).
A report by the United Nations Food and Agriculture Organization (FAO 2006), Livestock’s Long Shadow, estimated that 18 percent of annual worldwide GHG emissions are attributable to (intensive) livestock farming. FAO (2006) summarized: “Livestock now use 30 percent of the earth’s entire land surface, mostly permanent pasture but also including 33 percent of the global arable land used to producing feed for livestock, the report notes. As forests are cleared to create new pastures, it is a major driver of deforestation, especially in Latin America where, for example, some 70 percent of former forests in the Amazon have been turned over to grazing.”
A subsequent FAO (2013) report, lowered the intensive livestock production contribution to 14.5% of all GHG emissions which is about half of the total AFOLU contribution, here newly estimated at about 30% of all GHG emissions.
However, a Worldwatch study by Goodland & Anhang (2006) reported that livestock and their by-products actually account for at least 32,564 million tons of CO2e per year, or 51% of their recalculated annual worldwide GHG emissions. These authors later defended their argument in a “peer-reviewed” journal (Goodland & Anhang 2012).
Other summary data is provided by FAO (2014) that contributed to Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) data as given above. This latest report from IPCC (2014: 6) has total global GHG at 49 Gt and AFOLU as 24% (“12 GtCO2eq, net emissions”), possibly “net” because FAO (2014) has some two billion tonnes CO2eq/yr sequestered in forest sinks. Does this imply 12+2 = 14 Gt gross AFOLU emission or 14 in 51 Gt new values giving total of 27.5% GHG from land use?
Therefore, overall, a possibly reasonable estimate is of up to ~30-50% of total GHG attributable directly or indirectly to land use, or rather to land mis-use.
Fertilizer production possibly accounts for 1.2% of the world’s energy use, of which about 93% is for nitrogen-based Haber-Bosch synthetic NH3 (Ref), and this is also responsible for approximately 1.2% of the total GHG emissions (Wood & Cowie, 2004). FAO AFOLU (2014: tab. 4-4) has 725 Mt CO2eq in 2011 or about 14% of total emissions from agriculture and predicts: “synthetic fertilizers may become the second largest emission source after enteric fermentation over the next decade, if increases continue at present rates. This report also has emissions from manure left on pasture at 824 Mt CO2eq, more than 15% of total emissions from agriculture, in the same year.
The carbon C content of the CO2 molecule is about a third (0.27) and CO2e or CO2eq. are for all green-house gasses, or GHGs, evaluated against CO2 indexed as “1”. Regarding just CO2, an authoritative if not definitive summary of 2016 data says “For the last decade available (2006–2015), EFF was 9.3 ± 0.5 GtC yr−1, ELUC 1.0 ± 0.5 GtC yr−1, GATM 4.5 ± 0.1 GtC yr−1, SOCEAN 2.6 ± 0.5 GtC yr−1, and SLAND 3.1 ± 0.9 GtC yr−1” (from Global Carbon Budget; Le Quéré et al., 2016, Earth Systems Science Data. 8: 605-649, http://dx.doi.org/10.3334/CDIAC/GCP_2016). Cement production contributes 5% of totals which they included it in EFF. Translated, this indicates 10.3 Gt anthropogenic carbon emissions, mainly from fossil fuels (FF) and 1.0 in 10.3 or just 9.7% of this from land use change (LUC). Carbon sinks are 4.5 Gt (44.1%) atmosphere, 2.6 Gt ocean (25.5%) and 3.1 Gt (30.4%) land. Interestingly, their land sink (SLAND) is calculated from the “Budget residual” sometimes called a “Residual land sink”.
Le Quéré et al. (2016: 625) also quote from Regnier et al. (2013) that anthropogenic perturbation has increased organic carbon export from terrestrial ecosystems to the hydrosphere (erosion by water) at 1.0±0.5 GtC yr−1 (above natural background rate?).
Haughton (2010: 338, 348) [Houghton, R. A.. “How well do we know the flux of CO2 from land-use change?.” Tellus B 62, no. 5 (2010): 337-351] states: “Globally, the conversion of lands to crop-lands has been responsible for the largest emissions of carbon from land-use change” and “From 1850 to 2000, land use and land-use change released an estimated 108–188 PgC to the atmosphere (Table 1), or about 28–40% of total anthropogenic emissions of carbon (274 PgC from fossil fuels) (Strassmann et al., 2008).” Thus 28-40% excess carbon emission are or have been from land use.
Following FAO (2013) that found intensive livestock farming (rather than organic husbandry) contributed 14.5 % of human-induced GHG emissions [this is not the same as the 14.5% I calculated above for just CO2], a newspaper report (Bryce, 2013) comments: “The FAO’s last livestock report, a 2006 assessment titled Livestock’s Long Shadow, found that farms breeding chickens, pigs, and cows for meat and dairy products, produced a disconcerting 18% of global greenhouse gas emissions” and “Around 30% of global biodiversity loss can be attributed to livestock production, such as the spread of pasture land or turning over forests and savannahs”.
Although these figures vary due to different formulas for budgeting, it is however shown that agriculture in all its forms, which includes much forest clearance, is the major single contributor to GHG emissions. As for water appropriation, about 80% of total use is for watering crops and livestock (a cow needs up to 100 litres of water per day and there are now 1.5 billion cows plus its grin crops are irrigated). Therefore industrial/agrichemical farming is the single largest contributor to climate change with most GHG (25%) and currently about 10-14.5% but historically up to 40% of CO2 as well as being the main cause of Rockström et al.’s biodiversity loss, N2 cycle excess, chemical pollution plus it uses most water and is responsible for most other HIPPO extinction factors.
All these calculations above are for “flat earth” 2-D models of the Earth that conveniently overlook topography that may, however, be highly relevant and may double or even quadruple on-the-ground assessments (Blakemore 2012; 2016a; 2016b). Thus flat-land area of 15 Gha may be doubled to 30 Gha and possibly doubled again to more than 60 Gha to something like as shown in the following geoid representation.
The geoid figure above gives the nearest approximation I can find for my different concept of true topographical land surface area versus the flat ocean surface that is important due to solar insolation: i.e., the average amount of solar energy received per square centimetre per minute. Geoid is obviously not the same concept as topography.
It should be noted, however, that Houghton (2010: 348) also says: “New satellites are being designed for measurement of above-ground biomass from space. For example, the United States (NASA) is working to launch the DESDynI mission in ∼2017 and Europe (ESA), the BIOMASS mission in a comparable time frame. Both missions have a goal of determining aboveground forest biomass at high spatial resolution (Bergen, 2006; Zebker et al., 2007; www.cesbio.ups-tlse.fr/us/indexbiomass.html).” And, secondly, as terrestrial calculations are all based on the “Budget residual” this aspect may not be relevant for some calculations as it surely is for others.
Land use is the problem and also the solution for the carbon and GHG issue: The only practical means proven to remove excess atmospheric CO2 is via plant photosynthesis, this is also called carbon capture and storage, or CCS that is often applied to spurious technological “geo-engineering” schemes. And NASA / NOAA show annual carbon exchanges of 120 Gt on land vs. 90 Gt in oceans (ratio 60 : 40) and because in photosynthesis 6 CO2 –> 6 O2, this ration applies to oxygen too. The oceans, much less important to carbon cycle, are also in CO2 equilibrium so extra causes carbonic acidity. Moreover, NASA / NOAA show soil (>2,300 Gt) is already a greater store than all oceans (1,000 Gt), air (800 Gt) and vegetation, e.g. forests and mangroves (550 Gt), combined. Figure 5 shows summary data in which it may be noted that agricultural land-use adds up to 30% of the 9 Gt carbon or ~3 Gt per annum.
Figure 5. Annual fast carbon cycle: yellow numbers are natural fluxes; red human-induced; white is total stored C (Gt). Note land C storage & exchange (120+3) is much more important than ocean (90+2) with ratio 60:40. Global soil carbon estimate in current study is >10,000 Gt. An extra 65,000,000 Gt C is locked in fossil bedrocks as sedimentary limestone or chalk (Srivastava & McIlvried, 2010: tab. 1). Ocean organic C is just 1,000 Gt, its deep reactive sediment cycle is >10,000 yrs and the ocean’s dissolved inorganic carbon (36,300 Gt) is largely irrelevant. Another corrections is that “Fossil pool” should read “Fossil fuel reserves” from Houghton (2003: fig. 1, tab. 1). Image credit: after U.S. DoE (2008) & NASA (2011) as per Blakemore (2016a: fig. 4). Rather than considering topography and relief, NASA’s figures are entirely based on a “flat” Earth! Blakemore (2012, 2016a) argues that topography consideration could easily double this total area, and, at a finer scale, probably double this again above the flat-Earth area. Overlaying this quadrupled soil surface area is the one-sided green leaf-area-index LAI, itself estimated at 4.5 (Ref1 , Ref2.). Moreover, land plants assimilate 31% incident sunlight while in flat oceans only 7% of the incident radiation is available for phytoplankton photosynthesis, the remainder is absorbed/dissipated by water (Ref).
Thus the issue of “not seeing forest for the trees” is rather “not seeing soil for the trees”. An embarrassingly obvious solution is under our feet: we simply need to restore eroded topsoil and the most expeditious way to do this is to conserve earthworms that rebuild topsoil and restore humus.
Biomes that store most carbon
Newly extrapolated data from Jobbagy & Jackson (2000: tab. 3) upon which much IPCC / UN and US DoE data as in NASA / NOAA Fig. 5 is based, is in Table 2. For comparison, Table 3 (IPCC, 2000: tab. 1) includes all land plus above-ground plants.
Table 2. Biomes and soil organic carbon (SOC) budgets at 0-3 m (sorted by area). Note just ice-free and non-desert soil-occupied land area NOT total land area.
|Biome||Area Gha||SOC kg/m2||Index (Area x SOC)||Total SOC 0-3 m Gt||% area||%SOC|
Table 3.Total carbon in (above-ground!) vegetation and soils 0-1 m depth only.
|Total C to 1 m depth Gt||Area %||C %|
|Desert and arid||4.55||8||191||199||30.1||8.0|
Note that extreme desert, rock, sand, ice, swamps, marshes, lakes, and streams (ca. 2.8 Gha or 19% from Jackson et al., 1997: tab. 2) was omitted from Table 2; also the proportions of forests and grasslands that are managed or natural are intermingled. However, clearly tropics have most carbon (>50% excluding about half of non-tropical deserts). This is unsurprising as the temperate and boreal areas although nearly same area are only fully productive for part of the year due to less insolation (sunlight) in winter. From Table 2, forests hold about 47.5% total SOC and savannah/grassland/shrublands 27.3%.
How much of these forests and grasslands are managed currently or historically on these data is indeterminate. However the third-largest, single biome store after forests and grass/scrub in Table 2 is under croplands with 248 Gt C in 0-3 m or 10.6% of global total, all of which is entirely accessible and managed. Immediately obvious priorities are to reduce tropical forest clearance (often for agriculture and recently for palm-oil), to regenerate anthropogenic deserts (due to loss of humus and overgrazing), and to restore arable topsoil by better management. Against conventional beliefs that tropical rainforest have no topsoil, they appear particularly carbon rich.
In the Table 3’s newly compiled model, forests and grasslands are still important but arid desert and croplands have greater potential to store depleted carbon in their topsoils.
Calculation of global topsoil humus resource
From Tables 1 & 2 above, soils seem to occupy ca. 12.5 Gha on ca. 15 Gh land, (5.4 + 4.1 + 3.3 = 12.8 cf. 12.1 in Jobaggy & Jackson, 2000: tab. 3; median value 12.5 Gha) or between 81-85% “flat” land that is not desert, frozen or montane, with about (5.4 + 1.64 + 0.4 =) 7.44 Gha managed on farms, in forests and towns. Thus (37 + 11 + 3 =) 51% of all land and about 60% of all soils are managed in some way (excluding 22-25% grassland areas on 26% soil, storing about 27% total SOC carbon from Tables 1 & 2).
How much organic topsoil on Earth supporting all primary production is unknown.
NASA gives total soil carbon as 2,300 Gt whereas 4p1000.org has total soil carbon 1,500 Gt. The discrepancy is due to the former figure 0-3 m the latter 0-1m depth soil (see Blakemore, 2016a: 8). Blakemore (2016a: 11) also noted that: “Soil carbon values require allowance for intractable glomalin adding a further 5-27% to almost all SOC tallies (Comis, 2002). Plus data from deep soils may increase budgets: e.g., Harper & Tibbett (2013) found C up to five times greater in Australian soils at depth >1 m and down to 35 m in some cases. The Walkely-Black method itself underestimates total C with a correction factor of ca. 1.3 often required, whereas latest techniques using mid-infrared (MIR) spectroscopy may give more accurate readings. These three factors combined would surely increase soil SOC totals. Relating to above ground LAI are underground root-area-indices (RAIs) with fine roots a prominent sink for carbon, often much greater than that of vegetation above ground.”
Based upon NASA / NOAA figure of 2,300 Gt soil carbon multiplied by van Bemmelen (1890) constant (itself recently revised upwards from x 1.724 to x 2.0 – Ref.), Soil Organic Matter SOM ≈ 1.724 x Soil Organic Carbon (SOC) to give a global minimum total of non-mineral, dry, topsoil humus SOM as (1.724 x 2,300) ≈ 4,000 Gt. Or about the same as human appropriation of rain (4,000 Gt) and annual cement use (also 4,000 Gt). Due however to consideration of topography, deep soil carbon and glomalin, this value of soil carbon can be probably quadrupled to >10,000 Gt (see Blakemore, 2016a).
SOM values range from <1% in new or eroded soils (as in hot deserts) to 90% in peats, with average topsoil range from 1-6% The average bulk density of “mull, mor and moder” humic topsoils is in the order of 0.3 gcm-3 (Blakemore, unpublished).
Humus or soil organic matter (SOM) has rapid labile forms that are rapidly recycled to plants, and recalcitrant SOM that may endure, unless eroded with topsoil, locking up carbon for centuries or millennia (Ref.). Moreover, vermicomposting is a natural and proven enhancing process that uses specific earthworms to process all organic wastes more rapidly. Returning this to soil replaces synthetic fertilizers and conserves or enhances resident earthworms. Thus compost offers many natural advantages with none of the drawbacks of unproven charcoal applications now heavily marketed (sometimes by “biocharlatans”) e.g., as agrichar or biochar.
For example, “Agrichar” applied at rates of 10-20 t/ha was said incredibly to double or triple initial yields (Ref1, Ref2) and “carbon in agrichar remains locked up in the soil for many years longer than, for example, carbon applied as compost, mulch or crop residue”. However, as the trial started only a few years earlier, this seems speculative. Importantly, my calculation is that 10-20 t/ha is 1-2 kg per m2 and as 1 kg charcoal has volume of about 5,000 cubic centimeters on each 1,000 cm2 (if bulk density is 0.2 g/cm3 or 200 kg/m3); thus a field would be covered 5-10 cm (2-4 inches) deep. Even if rotary-hoed in, this seems wholly unnatural and undoubtedly deleterious to any endemic earthworms (Ref.). Direct comparison is needed with natural and proven vermicompost for which much efficacy data exists including ancillary suppression of pests and pathogens. Following these 2007 reports a decade ago I can find no more recent work, positive or negative, suggesting that program failed despite the initial hyperbole.
Potential of organically farmed soils to store excess carbon
Lal & Bruce (1999) reviewed the potential of the World’s cropland soils to sequester C and mitigate the greenhouse effect: Carbon storage potential of soil organic matter (SOM), as both volatile and resilient (or recalcitrant) humus, in US alone was calculated by them to account for an average of 288 Mt yr-1 (= 0.11 Gt yr-1 CO2e) for at least 30 yrs, or perhaps ~1.7 ppm yr-1 reduction x 30 yrs = ~50 ppm off Mauna Loa’s 400 ppm bringing it to the desired 1990 level of 350 ppm by 2030.
How much soil is actually managed? Some 38% land area is agricultural (FAO), with about 26% as permanent pasture, 10% as arable, and 2% woody crops e.g. vineyards and orchards, just 3% is urban (Tabs. 1-2). Thus, of the 2,300 Gt carbon in soil globally, about 10% or 230 Gt is on arable farms of which only 1% are now organic. However, if all farms converted to organic storing a modest +0.4% carbon for 10 yrs (230 x 0.004 x 10 = 9.2 Gt) equals total annual human emissions of 9 Gt carbon as CO2 and meets 4in1000 Initiative aims. Moreover, from this author’s meta-analyses and independent studies (Blakemore, 2016a, 2016b) crop yields would be the same or higher with lower cost, no pollution and more jobs. Only living earthworms are able to entirely and thoroughly work such an extensive and variable landscape throughout the depth of its topsoil. Conventional farms that harm worms also receive excesses of both fertilizers and biocides (Figs. 2-3) exacerbating both GHG release and HIPPO extinction factors.
According to ACIAR (2014), the world’s four most important crops – maize, wheat, rice and soybean – directly or indirectly (as feed grain) provide around two-thirds of the calories and protein consumed by humans. Cereals account for 58% of annual harvested crop area globally, and directly provide ~50% of world food calories. The next biggest sources for direct consumption are vegetable oils (12%) and sugar (8%). Increasingly, grain – comprising mostly maize – is used as biofuel; current grain total is 130 Mt/yr or roughly 12% of maize production.
Cost of soil fertility mining due to land degradation on maize, wheat and rice alone is estimated at $15 billion per year (ELD, 2015) but projected returns are five dollars per each dollar invested in proper soil management practices (such as those advocated here). [Total land degradation costs are up to $10.6 trillion each year but, with sustainable management, benefits have a potential of $75.6 trillion added to global economy per year through jobs and increased agricultural output (according to UN’s ELD, 2015)].
World production is of the order of Maize, 1,051 Mt; wheat 740 Mt; Rice 504 Mt and Soybean ca. 346 Mt (Ref.), totalling 2,641 Mt. Approximately 1,000 Mt is used for stockfeeds, often for CAFO or intensive battery production (Ref.). Thus, roughly 40% of the main agricultural crops are used for animal feed. This proportion will increase as more people indulge in meat more regularly, or it will decline if agricultural subsidies are removed and the true cost of meat in terms of crops, water use and manure & hormone pollution, plus antibiotic diminution, are included in the market price. Cotton yield is about 25 Mt/yr, (Ref.) but its water and chemical use is disproportionately high.
Due to a need to urgently reduce such excess environmental strain imposed by agrichemical farming, and the considerable contribution it has to atmospheric carbon (28-40%), there is a strong argument to advocate a return to lower-meat based diets and to ensure that cereals, vegetables, fruits and nuts that we do eat are organically sourced. This is where the importance of earthworms comes into play for their many roles on organic farms, including as a prime natural foodstock for aquaponics, pigs and poultry.
Drinkwater et al. (1998; Ref.), in a 15-year study at Rodale Institute found that organic maize-soybean rotation yields were comparable with conventional yields for maize – 7,140, 7,100 and 7,170 kg/ha in manure-based, legumes and conventional systems, respectively – plus the organic fields stored significantly more carbon. This study concluded broad-scale adoption of these practices in USA would sequester up to 30 Mt C yr-1 equal to 2% of its atmospheric carbon release from fossil fuel combustion. And Golabi et al. (2004), in a small pilot study of tropical maize grown in Guam showed compost more than doubled maize yields, soil water (+24%) and SOM (+77%).
From studies by Blakemore (2016a, 2016b), extrapolation of extra carbon in organically farmed soils on areas given over to each of three crops if all organically converted gives total CO2 equivalents (CO2e) of 49.2, 2.8 and 1.1 Gt (total 53.1 Gt) C storage for wheat, rice and sugarcane, respectively. Wheat alone, albeit projected, exceeds global emission (~40 Gt CO2); rice matches Eurozone’s (2.5 Gt); and sugarcane either Japan (1.2 Gt) or UK + Australia combined (0.5 + 0.4 Gt). Extra carbon stored (53.1 Gt CO2e) would equal ~7.3 ppm atmospheric CO2 reduction.
Pasture management offers yet greater potential remedy, recalculated (from Blakemore, 2000) as optimal 222 t ha-1 x 3.6 Gha total grass = 800 Gt C (x 3.667 CO2 conversion factor = 2,934 Gt CO2e) or about equal to present atmospheric values of 3,000 Gt CO2 and 400 ppm.
Even at same human emission/consumption rates, this data shows extra humus has potential to solve carbon sequestration whilst also providing food staples. A meta-study by Rodale Institute in 2014 also concluded that if all cropland were converted to their regenerative model it would sequester 40% of annual CO2 emissions; adding pastures to that model would add another 71%, effectively overcompensating for the world’s yearly carbon dioxide emissions (Rodale, 2015). Moreover, their side-by-side trial after 30+ years (slightly less than the Haughley trial that was 42 years when reported by Blakemore, 1981; 2000) showed organic : conventional yields to be equivalent over a range of crops (but organics higher in drought years), with energy input lower by “1,300 MJ/acre/yr” (= 526 MJha-1yr-1), greenhouse gases lower by “500 lbs CO2/acre/yr” (0.56 tha-1yr-1) and profits higher by “US$368/acre/yr” ($908 ha-1yr-1) (Rodale 2015).
Plant nutrient issue
Regarding Rockström et al. (2009) nitrogen (N2) cycle issue; the graph (Fig. 6) from the Haughley Experiment clearly demonstrates, firstly, that organic fields have higher intrinsic nitrogen (ca. 600 vs. 150) due to storage in organic humus SOM. And, secondly, that plant macro-nutrient mineralization and availability fluctuate seasonally due to earthworm and soil microbial activity both in synchrony with the plant needs and also in proximity to the plant roots. Routine spot nutrient checks are rendered irrelevant.
Figure 6. Haughley experimental farm N-P-K data for 1952 showing fluxes and much higher values in organically managed fields (Mixed and Organic) with FYM and compost use rather than synthetic fertilizers as in the Stockless section. This key graph from Balfour shows exactly where promoters from Liebig and Lawes/Gilbert to IFA go wrong: mere spot checks miss huge biostimulatory fluxes.
This supports compost, or vermi-compost, negating need for synthetic N-P-K. Along with the seemingly better correlation of water to yields than with nitrogen (Fig. 3) from the Green Revolution perspective. A return to restore traditional methods seems a valid option and removes problems of poisoning of air & water supplies and eutrophication.
Soil biodiversity issue
Regarding global biodiversity, Blakemore (2012) estimated 210,000 soil invertebrates (now updated to 310,000 species Ref.), with the final total certainly much higher. As noted in the introduction above, >88% of organisms on Earth actually live on or depend upon the soil with probably <12% in oceans. My recent IUCN review of 200 native New Zealand earthworms, redlisted about 20 as extinct or likely soon to be (i.e., ~10%).
Simultaneously with the present work, a de facto biodiversity triage has been formulated by Newbold et al. (2016) that found on average 85.6% of land biodiversity depleted in the last few years (time scale unspecified?). In their figure black areas are most critically damaged, often by intensive agriculture and grazing (shown here as Figure 7). But, yet again, soil biodiversity is mostly taken for granted as the authors say: “The data probably also underrepresent soil and canopy species”.
Figure 7. Approximate abundance decline from 100% of species in primary vegetation biomes(areas above safe limit in blue) (from Newbold et al. 2016).
Thus, even though these authors overlook sub-surface species in the soil, it is seen that land has many threatened habitats. As a final statement on contributions of soil vs. oceans: global net primary productivity (NPP) data shows 115 Gt/yr above-ground on land vs. 55 Gt/yr in oceans (~32%) with total biomass 1,837 Gt on land and a meagre total 3.9 Gt in oceans (~0.2%) which completely sinks arguments about importance of oceans, estuaries, algal beds & coral reefs (just 1.6 Gt/yr productivity & 1.2 Gt total biomass) or tropical mangroves (Ref1 from “R.H. Whittaker, quoted in Peter Stiling (1996), “Ecology: Theories and Applications” (Prentice Hall)”; Ref2). The figure below illustrates the land and ocean deserts.
These findings should be tempered with knowledge that, yet again, “estimates rarely account for below ground productivity” thus greatly underestimating the land budgets, and they certainly exclude topography! If below-ground productivity is taken into account (e.g. roots, mycorrhizae) the land contribution might be doubled, thus the ocean contribution halved to about 16%, with topographical consideration, this may easily be halved again to 8%. The last claim by marine biologists that the ocean is the world’s largest habitat ignores the atmosphere’s support, albeit temporarily, for many spores, seeds, insects, spiders, birds, mammals, etc. For land, surface topography is again ignored with earthworms burrowing as deep as 15 m and also ignored are endoliths, the often microscopic organisms found at depths greater than 3 Km deep in rocks on land.
Soil biology remain particularly poorly studied despite being described both as much more biodiverse than rainforest or coral reefs and as unexplored as the planets; e.g. “Soils – The Final Frontier” by Science (11th June, 2004 Special Issue No. 5677; Fig. 8).
Figure 8. Cover of Science magazine, June, 2004.
Earthworm aspects of soil conservation/restoration
Finally, after setting the scene, we can talk about actual earthworms. Numbering up to 1,000~2,000 m-2 (10-20 million per ha) in fertile soils with biomass as high as 5,000 kg ha-1 (5t ha-1), earthworms often outweigh the above-ground stocks (Fig. 9).
Figure 9. Unseen earthworms outweigh humanity, all other livestock and pets.
Earthworm abundance and diversity increase in a truly sustainable system (or decline in a depletive system) and they relentlessly convert all organic ‘wastes’ into humus-rich compost while processing all atmospheric CO2 in 12 yr cycles (Ref). Their burrows [~9,000 km/ha according to Kretzchmar, 1982 down to 15 m according to Sims & Gerard (1999: 27) and Blakemore, 2016] aerate, improve H2O infiltration and, importantly, provide habitats for many other beneficial organisms & microbes.
Wormless soils need to be ploughed/plowed regularly, require extra irrigation plus subsidized artificial chemical N fertilizers and biocide sprays to fight off plant infections and infestations. This toxic burden has severe impact upon non-target innocents and anyone fed the crops – including humans who choose to eat meat – as well as poisoning the soil, air, waterways & oceans. Another reason for earthworm conservation, is that it is impossible to “geo-engineer” the many benefits that earthworms freely and relentlessly provide.
Earthworms are revitalized as key to agricultural sustainability & planetary stability. Ancient in origin (probably pre-Cambrian but certainly >500 million yrs ago) they are ubiquitous and synonymous with topsoil humus, the basis of terrestrial food-webs and the ultimate detritivor. Yet they are severely depleted by cultivation & agrichemical excesses of industrial farming. In comparison, studies by the author (Blakemore, 2016a, 2016b) show a diverse array of up to 23 earthworm species per organic farm site (mean 13 spp), implicated in 16-80% increased crop or pasture yield (mean +39%) plus an average of 12% extra soil moisture storage (range 8-90%) compared to conventional neighbour farms. Restored carbon sequestration at two to three times higher in pasture and the three crops studied: viz. winter wheat, paddy rice and broadacre organic sugarcane, is sufficient to off-set human emissions of CO2 in a short time frame. Such findings are highly relevant in terms of looming species extinction & climate change with requirement to meet the needs of a growing population. Some of the benefits of earthworms are shown in Figure 10.
Figure 10. Effects of earthworms on soils & plant growth (after 2 weeks) (Blakmore, 2016); note that agrochemical trials use sterilized soil to avoid such variability ‘complications’ rather than embracing soil biological benefits.
The question of earthworms contributing to GHG fluxes is a moot point as only nett carbon sequestration has weight because, rather obviously, fluxes fluctuate. This issue is presented and resolved in Blakemore (2016a) where it says: “Yet even in their most menial roles, earthworms are claimed either to exacerbate GHGs (e.g., in a report authored by doctoral student in Lubbers et al., 2013) or to ameliorate them (e.g., Zhang et al., 2013), as was already debated by Edwards (2009).”
Megadriles (terrestrial earthworms) have approximately 7,000 species currently described plus 3,000 microdriles (lesser semi-aquatic species) that represent just 20-25% of probable earthworm totals (Blakemore, 2016d). Unlike in the oceans where currents distribute species broadly, as for wind-borne species on land, earthworms are particularly restricted and often highly endemic. In fact their ancient origin and long persistence means that at the family level their global distribution complies with plate tectonics, and was used as early supporting evidence for continental drift.
As Howard (1945) noted, observations from my own surveys of farms in Australia and Asia is that earthworms are often entirely absent under some chemical crops but may be abundant under organically managed soils (Blakemore, 1994; Blakemore, 2010: tab. 1; Blakemore, 2016a, 2016b, 2016c; Blakemore & Kupriyanova, 2010; Blakemore & Grygier, 2011) e.g., absent from some sugarcane in Australia and Okinawa, or rice in Japan and Philippines. Reinterpretation of 1980 Haughley data (Blakemore, 2000a) showed that its worms were depleted by 44% in 40 years when organic went to conventional chemical management. In contrast, two organic farms in Philippines established only about ten years earlier had substantial restoration of both earthworm numbers (by 57-122%) and biodiversity compared to their conventional neighbours with the species numbering up to 21 on one farm with an average 13 earthworm species per organic farm from eight studied sites (Blakemore, 2016b).
Early research by Wollny (1890: Forschungen auf der Gebiet der Agrikultur-Physik, 13, s. 381) found addition of earthworms to soil led to a marked increase of cereal grain (by 35-50%) and of straw (by 40%). While not considering organic farming per se, a recent meta-analysis confirmed earthworm presence corresponding to crop yield increases of 25% (van Groenigen et al., 2014), which is comparable to average ~39% extra organic yield in soils with earthworm proliferations determined in accompanying studies by Blakemore (1994, 2000, 2016b). Thus earthworms are both monitors and mediators of healthy soil and thus of higher yields with less environmental and social costs.
Environmental triage has shown a complexity of problems, but a solution as embarrassingly simple as helping earthworms to restore humus. The best way foreward is twofold: firstly to recycle all organic ‘wastes’ & manures via vermi-composting and secondly to enhance populations of field-working worms by appropriate management. The traditional, innovative & scientific methods of organic farming and Permaculture appreciate the importance of earthworm conservation. This is finally being more widely recognized as a solution to the critical environmental and social issues, e.g. COP21’s “4 per 1000 Initiative for Climate and Food Safety” (http://4p1000.org). The essence of their new advocacy is a return to organic farming, and organic farming is earthworms.
My humble proposal, along the lines of “4 per 1000 Initiative” (that refers to extra organic carbon % in topsoil needed to reduce global greenhouse gasses), is to aim for “4 worms per 1,000 g soil” – thus maintaining an entirely reasonable earthworm population of 400 m-2 and 4 million worms per ha (see – Darwin’s birthday article Ref.).
Agroecological or organic farming approaches include agroforestry (planting trees and crops on the same parcel), biological control of pests and diseases through the use of natural predators (IPM), water harvesting methods (e.g. Yeomans’ keyline), intercropping, green manure cover crops, mixed crops, livestock management (including earthworms!), cell-grazing and a range of additional practices.
According to an UN summary study (UN 2010) agroecology led to an average crop yield gain of 79% and potential to store in soil humus 5.5 to 6 Gt of CO2-equivalent per year by 2030. Permaculture is a broader concept including human habitation and social aspects in its designs for natural production and proper living, nevertheless it too depends entirely on earthworms and eschews synthetic chemical biocides (Ref1, Ref2).
As a rapid solution, the broad conversion to organic farming/permaculture as a priority may yet “Feed Us All” says Worldwatch Institute (2006) whilst also, incidentally, preserving biodiversity, sequestering carbon and saving both water & fossil energy.
Closing remarks are taken from an EU summary (EU, 2012):
“The ecological value of soil biodiversity is increasingly appreciated as we understand more about its origins and consequences. The monetary value of ecosystem goods and services provided by soils and their associated terrestrial systems, an entirely human construct which assists putting their significance into an economic context, was estimated in 1997 to be thirteen trillion US dollars ($13,000,000,000,000). The soil biota underwrites much of this value.” [Note: this value is about the same as USA GDP].
“To date [Sept. 2012], no legislation or regulation exists that is specifically targeted at soil biodiversity, whether at international, EU, national or regional level. This reflects the lack of awareness for soil biodiversity and its value, as well as the complexity of the subject. The management of soil communities could form the basis for the conservation of many endangered plants and animals, as soil biota steer plant diversity and many of the regulating ecosystem services. This aspect could be taken into account or highlighted in future biodiversity policies and initiatives.”
Warranting re-ascendency to their former position as premier farm livestock, the last word is from Rachel Carson on soil organisms: “none is more important than the earthworm”.
*It would be remiss of me not to urge readers who have made it thus far to take a step further and delve into Lady Eve Balfour’s “Living Soil”, either the original 1943 book or the easily digested IFOAM summary in Switzerland in 1977. This current year is 100 years since Fritz Haber first unleashed toxic chemicals on us. It is seventy years since Sir Albert Howard, who provided us with more natural, organic options, passed. And, now, forty years since Lady Eve’s cogent presentation. Both latter organic advocates appreciated the great value of earthworms. Much of their instructional information is strikingly familiar and remarkably topical with the self-same issues currently yet unresolved although we have long known the cure. In her IFOAM talk she takes the time to explain the basics. Here is a vital link – http://journeytoforever.org/farm_library/balfour_sustag.html. She eloquently said: “There are two motivations behind an ecological approach — one is based on self interest, however enlightened, i.e. when consideration for other species is taught solely because on that depends the survival of our own. The other motivation springs from a sense that the biota is a whole, of which we are a part, and that the other species which compose it and helped to create it, are entitled to existence in their own right. This is the wholeness approach and it is my hope and belief that this is what we, as a federation, stand for.” Turning this into an 80 character haiku tweet: “Reasons to preserve Nature: it’s ethical, right & virtuous; if we don’t we die”.
Lady Eve Balfour(1898-1990) had a full life (Ref1, Ref):- Vegetarian since age 8, aching to be a farmer from age 12, by 20 was a farmer in 1st World War employing Land Girls; bought her own farm at age 21. Learning to fly, sail and play jazz, in 1930s she pioneered the Haughley Experiment before founding the Soil Association and writing The Living Soil (Faber & Faber 1943). She then embarked on world tours to explain the process, spreading the message as far as to NZ and Tasmania. An essential link – http://organiccollege.com/dl/file.php/1/the-living-soil.pdf.
As a sad annex, Tuvalu with lowest GHG contribution in the World (Ref.) is perhaps suffering the most, destined soon to sink; disappearing from the “Face of the Earth” under the aggressive “Pacific” ocean. How much above sea-level is your home?
[RJB, 27th May, 2017 Email: firstname.lastname@example.org]
After this essay was completed, a new publication was sent out in May, 2017. Here I will briefly review “UNLOCKING THE POTENTIAL OF SOIL ORGANIC CARBON” (FAO, 2017). This 36 page report mentions “microbe” six times, “agro” and “biochar” four times, “compost” twice but there is no mention of: humus, topsoil, fung, myco, verm, worm. Remarkably, I can find no comment on organic farming/husbandry.
I cannot tell how many of the authors of the report are chemists, but the affiliations and citations are from agricultural engineers or agronomists or (conventional) soil scientists (= chemists or sometimes physicists). Soil biology, if acknowledged at all, is diminished to microbes (there is no specific mention of fungi or mycorrhizae). Soil ecology and earthworms seem totally ignored. This is particularly unsettling as in an opening paragraph they claim biological processes: “Soil organic matter (SOM) is a key element of soil health because it regulates many soil functions, including carbon storage as soil organic carbon (SOC); the storage, availability and cycling of plant nutrients; soil biodiversity; soil porosity, aeration, water-holding capacity and hydraulic conductivity; thermal properties; and mechanical strength.” Mechanical strength (unless this is consistence) is perhaps more of an civil engineering/surveying quality, but the other highlighted items are all surely regulated by earthworms!
As far as I know, SOM is the same as humus and worms make humus (as Darwin, told us in 1881: all healthy topsoil routinely passes through their bodies). Also – and I am willing to be corrected if wrong – there in nothing else in soil other than the earthworm with the biomass, guts and muscle to recycle nutrients, increase porosity, aeration and water-holding capacity. I just cannot see how a microbe or mite can have any such power. Possibly it could be argued that microbes co-opt the plant roots to make these pores and cavities, even at a stretch they do this by feeding the earthworms. My observation, and many published studies, show it is earthworms that remove the plant litter from the surface, mix it into the soil and consume the soil matrix throughout its profile. Plant roots often follow earthworm burrows, not vice versa, and root hairs actively seek out worm castings as preferential sources of mineralization or nutrient exchange. Earthworm activity provides habitat and often nutrition, either when alive or dead, for most other soil inhabitants/microbes as well as being the ultimate detritivour.
The FAO report gives total from IPCC of 1,417 Gt C in Soil Organic Carbon (SOC) in 0-1 m soil which is at the low end of one of their sources, Batjes (2014: tab. 6) who has:
|Globally (Gt)||Soil 0-30cm||Soil 0-1 m||Soil 0-2 m|
|Total C (org. + inorg)||906–969||2,157–2,296||–|
|Soil Nitrogen N||63–67||133–140||–|
From later data it seems FAO assume about the same amount in the next two metres of depth as they also provide figures that the great northern Permafrost soils hold 30% of the total SOC stock to a depth of 2 m [they omit to quote this 0-2 m SOC is 827 Gt Ref.], with estimated SOC stocks of 1,035 GtC at 0-3 m depth (thus more than 30%?). This 30% SOC at 0-2 m would give a total carbon mass of about 2,800Gt and the extra 0-3 figure would increase this to about 3,008 Gt and thus 1,035 is just >30%? Peatlands on the other hand, they say has total 447 Gt as an unknown percentage but presumably about this is only about half of the 30% or about 15% (but a large discrepancy is other estimates of 550 Gt C in peat and 30% of total land carbon – Ref.).
For Drylands, they claim 47% of the Earth’s land surface containing “about one-quarter of the global organic carbon store” [unstated but given as 27% or 431 of 1,583 Gt total from original source, Ref.; tab. 22-4 which as just noted above should possibly be 431 of 3,008 or just about 14%].
Grasslands, they say, cover approximately 40% of the Earth’s land surface, represent 70 % of the global agricultural area, and contain about 20% of the world’s SOC stock. Grasslands, they state, have high inherent SOM content, averaging 333 Mg/ha which, because they give SOC as about 58% of SOM, I thus calculate as roughly 193 Mg/ha SOC total in grasslands. From my accounting, these four FAO habitats have 30+15+14+20 = 80% of global SOC which is confusing as my Table 2 above has about 46% of global SOC carbon stored in forest soils! FAO figures are obviously at odds.
This report further states that: “Livestock production systems occupy about two-thirds of the world’s agricultural land for the production of animal feed (80 percent for grazed pastures and 20 percent for the production of feed crops). With global demand for livestock products expected to double by 2050.” Here I will quote in full their source, Gaitán et al. (2016 kindly provided as Open Access), for the purpose of critical and scientific review, as these authors’ data seems particularly important and pertinent:
“Livestock production occupies two-thirds (34 Mkm2) of the world´s agricultural land (49 Mkm2) for production of animal feed (grazed pastures, 80%, and feed crop, 20%), while a quarter (3.5 Mkm2) of the crop area (15.2 Mkm2) produces animal feed [1–3]. In the Brazilian Amazon region, which represents 37% of Brazilian herds, cattle ranching is intertwined with deforestation, which globally was the largest region contributing to deforestation during 1990–2010 . Deforestation in Brazil releases 590 t of CO2-equivalent (CO2-eq.) for each hectare cleared . Moreover, in Latin America, an estimated 2 Mkm2 of grazing land is severely degraded  with low forage availability, reduced vegetative cover and lost soil fertility.
Global demand for livestock products, principally milk and meat, is expected to double by 2050, particularly in developing countries [7, 8]. Livestock production is responsible for over 50% of greenhouse gas (GHG) emissions from agriculture [9–11], accounting for 7.1 billion t CO2-eq. yr-1. Globally, emissions from the livestock sector represent 14.5% of anthropogenic emissions , with beef and milk cattle accounting for 41% and 21%, respectively . Recent analysis of beef production showed that some grass-fed beef systems have lower climate impact than feedlot systems .”
I bolded the part of the last paragraph that corresponds to my earlier assessments above.
At the FAO (2017) meeting the International Fertilizer Association (IFA) was represented by a director. IFA produce a complex global trade map (Ref.), and claim (truly?) almost 1 million people are employed in the industry most (66%) in China and that global annual raw material production and trade is worth US$302 billion about half in sales. Total nutrient sales in 2015 they estimated at 245 Mt of which fertilizers accounted for 76% and Nitrogen accounts for more than half of synthetic fertilizers. This association is involved neither in compost nor in dolomite or lime sales, but an International Lime Association (Ref.) has 350 Mt/yr production which includes cement.
Data above should be tempered with knowledge that land degradation due in no small measure to loss of natural soil fertility and excess Nitrogen (see Rockström et al., 2009) costs all of us up to $10.6 trillion each year, but, if sustainable land management was implemented then we could potentially benefit with $75.6 trillion added to global economy per year through jobs and increased agricultural output (UN’s ELD, 2015).
Conversely, global vermi-compost is mostly local and is essentially a free alternative to synthetic fertilizers/biocides, or rather, it is a modern restoration of traditional methods. Thus the use of compost is proffered with some good advice offered from FAO as far back as thirty years ago! This report (FAO 1987) says: “One of the most important and rewarding methods of increasing agricultural output is by raising the level of soil fertility, both by improving the long-term structural stability and moisture retention of the soil and by increasing the supply of plant nutrients. Much can be accomplished within a local community by recycling back to the soil, preferably via a compost heap, all the organic waste materials available, from crop, animal and human origins… If this is done successfully, there should be less need to import mineral fertilizers from outside the community, and especially from outside the country with its effect on the country’s balance of payments and its requirements for an adequate transportation and distribution system.”
In contrast this latest FAO (2017) report in its introduction says “The link between SOM and soil fertility has been known for more than a century.” I find it particularly telling that FAO agronomists here quote Sir J.B. Lawes & Sir J. H. Gilbert (1885) as their prime authorities on humus or SOC fertility. Those guys started the whole N-P-K superphosphate industry, supported by vested interest from Rothamsted by Gilbert who was a direct student of reductionist Baron Liebig! In that paper almost all mention of “manure” means synthetic chemical manure (although I suspect the FAO do not realize that). That paper also only mentions worms once and the authors miss atmospheric nitrogen fixation that was unidentified until 1888 plus they have no mention of Darwin (1881)! And why do FAO ignore Sir Albert Howard (1945, Refs.) – ever critical of Rothamsted (Ref.), Lady Eve Balfour (1943, 1975) or even the Rodales’ “Greener Revolution”? It is a bit disconcerting too that FAO (2017) quote the Global Soil Partnership (GSP, 2016) publication on soil biodiversity (but even here I cannot find a total of soil species?) as this present a “democratic” summary, one page each, for most soil organisms although I argued to emphasize the key animals being rewarded with a mere acknowledgement. Sure, as an ecologist I know that all components all play a part, but sometimes it is 0.0001% against 90% contribution. And, as I often advocate, we need to urgently prioritize based on ENVIRONMENTAL TRIAGE. There is nothing in the living earth as mighty as an earthworms to move soil (ant or termite nests are localized and they are really just soil tourists or interlopers using it as habitation before flying off, never incorporating soil within their bodies). Whereas earthworms have a sucker-like pharyngeal pad, one or more muscular gizzards (some new Tasmanian species I found have multiple gizzards), plus calciferous glands and intestinal caeca to inoculate microbial symbionts. Their hydrostatic skeleton is capable of generating remarkable turgor pressure to force passage and they have such an intimate relationship, both internally & externally, with soil as to be eponymously synonymous. Below is a photo of an exceptional earthworm, but even in comparison to ordinary earthworms some as small as just one cm, most other soil organisms (except hibernating grizzly bears who also eat worms) are puny. Most soil inhabitant are about the same size as this full-stop: .
[Giant Ecuador worm from Sumaco Volcano identified as Martiodrilus crassus (Rosa, 1895); photo courtesy of Steph (Hoppy) Hopkins, from www.projectnoah.org/spottings/426166028].
Actually, now I am more confused. Just as I finished this review, I find they cite another FOA (2017a) 90-page report entitled “SOIL ORGANIC CARBON the hidden potential”, just as with FAO (2017b) “UNLOCKING THE POTENTIAL OF SOIL ORGANIC CARBON”, both titles misconstrue what is known by organic farmers for centuries and by enlightened ecologists: viz. soil organic carbon (= SOC = humus) is not a new “potential”, it is a REALIZED RESOURCE that has been depleted by poor management, chemical pollution, and by wrong, incomplete or conflicting advice from quasi-authoritative organizations. This earlier 2017 report at least mentions “humus” twice, “earthworms” thrice and admits their SOM definition includes “soil organisms” (cf. Fig. 9 above!!), but presumably just dry weights. Then there is the even earlier FAO (2005) THE IMPORTANCE OF SOIL ORGANIC MATTER. I defer review of these newly revealed reports until another day…
Bhudevi, the Hindu goddess of Mother Earth in an Art impression, may well turn her back on inappropriate soil abusers. (Image fair use courtesy of http://www.mfa.org/collections/object/bhudevi-260351).