SOILS. The Skeleton Holding The Muscle On Our Ecosystems (by Diego Fdez-Sevilla, PhD.)
December 5th has been declared World Soil Day by the UN General Assembly, and this year it will mark the conclusion of the International Year of Soils, which is intended to increase awareness and understanding of the importance of soil for food security and essential ecosystem functions.
For over 40 years as an international soil scientist, I have been hearing more and more what I call “The Soil Scientists’ Lament” – the cry that “soils are neglected”, “soils are under-valued”, “inaction on soil degradation is costing hundreds of billions of dollars per year”, “but those who make public policy are not listening to us”.
SOIL. The skeleton holding the meat of our ecosystems.
There is one major issue on soil. Nutrients in soils are managed and replaced naturally through biophysical and biochemical feedbacks. That is part of soil weathering.
When soil weathering is not a natural process in equilibrium with the ecosystem which they support, then you have to “actively” apply measures, chemical and physical measures (from incorporating nutrients to making physical changes in the structure of the soil). As farther apart are your intentional uses for specific soils from their natural capacity outside equilibrium the more you have to invest in form of displacing resources and energy, plus generating subsidiary emissions of waste in liquid, solid, volatile and energetic waste.
That should be enough for policy makers to consider, despite the other none less relevant impact from soil degradation over plant cover, weather linkages, and thus climatic interactions.
Domesticating nature is more expensive and less efficient than what natural processes are able to make on their own. Our planet has the more efficient technology we have seen in our near Universe, our biological systems, performing in the most hostile environment, space.
Replacing such resource by man made “gadgets” does not seem to be the wisest approach. Could it be replaced the functionality of a soil or a forest by man made technology?
Building the house from the roof down
Humans have had the option to decide the usage of different floors in a building. So, where should human locate its office? The highest floor has a lot of light but it is not the one to be accessed quicker. Considering that we can get wild with our imagination and budget, we place it in the first floor with plenty of lighting configurations for our comfort.
By means of albedo, soil humidity, soil water retention, carbon sink, evapotranspiration, temperature regulator, pH, … our soils are living structures like bones are in our bodies. A dead soil is like a dead bone.
Healthy bones are a good simile to healthy soils. Both are physical structures which support tissues. Both are in constant motion trying to repair themselves from physical perturbations, material lost (elements like Calcium, Potassium, …) and the exposition and deposition of hazardous elements (in our bodies due to our diet and in soils due to the chemicals added).
Since there are political barriers restricting access to natural resources, soil is, and will be, as any other source of supplies being generated by environmental systems, a source of dispute. This dispute is being avoided through man made technology aimed to force transformations in our environment in order to replace shortages due to precarious environmental performances result of overexploitation and bad practices. More chemicals are required to increase production in already decimated soils, genetic manipulation on plants is addressed to overcome “environmental restrictions” in otherwise natural cycles of production meanwhile tones of wheat and corn are wasted to control prices, urbanization transforms soils into pavements, minery and man made infrastructures washout and displace tones of soil wasting material in pursue of more relevant “assets”.
We can adapt our environment to our needs or adapt our needs to our environment. One option is less expensive and more sustainable than the other.
Soils in “more depth”
Time ago I was involved in a discussion about soils. One person made a comment which made me realise that once more, differences between points of view are very often originated from considering different pieces of information. So I want to integrate here some bits from such conversation in order to unify criteria. The comment was the following:
“All but two nutrients come from the soil. Even if the underlying rock is low in nutrients, it still has potentially enough of all the required nutrients. It is the organisms that make the nutrients plant-available; they also build soil structure and suppress diseases and pests.”
The parameters which define the soil capacity to support diverse types of plant growth are directly linked with the mineralogy of the soil by its Cation Exchange Capacity CEC, Anion Exchange Capacity AEC, PH, Percent Nutrient Saturation and Percent Base Saturation, physical structure, porosity, …
There are 17 essential elements required for plant growth. The lack of any one of these essential nutrients can result in a severe limitation of crop yield and plant growth — an example of the principle of limiting factors. Of the mineral elements, the primary macronutrients (N, P, and K) are needed in the greatest quantities from the soil and are the plant nutrients most likely to be in short supply in agricultural soils. Secondary macronutrients are needed in smaller quantities, are typically in sufficient quantities in soil, and therefore are not often limiting for crop growth.
The micronutrients, or sometimes called trace nutrients, are needed in very small amounts and, if in excess, can be toxic to plants. Silicon (Si) and sodium (Na) are sometimes considered to be essential plant nutrients, but due to their ubiquitous presence in soils they are never in short supply.
Ultimately, without aid from external influence, the type and characteristics of the soil define the type of plants that can grow but not the other way around.
You can treat and recover soils using specific plants to fix nitrogen, and to reduce contamination, but only, if the soil allows those plants to grow within the rest of the other parameters (CEC, PH, …).
By knowing what kind of soil you have, you can tell the plants it will grow. By knowing the plants growing in an area, you can tell the type of soil underneath.
Different types of soils are distributed around in our planet. Heavy weathering can be result of natural processes or anthropogenic physical and chemical manipulation giving what are called anthrosols. In both cases, it is decimated the capacity for the soils to regenerate and recover from losses in nutrients, microbiota, microfauna and structure, becoming dependant from human add-ons and care to produce.
Tropical soils are the ones with lowest reservoirs of nutrients due to heavy weathering.
In the rainforest, most of the carbon and essential nutrients are locked up in the living vegetation, dead wood, and decaying leaves. As organic material decays, it is recycled so quickly that few nutrients ever reach the soil, leaving it nearly sterile.
Since many tropical soils are already heavily weathered, they are highly vulnerable to nutrient loss and this is why many tropical soils are difficult arenas for the establishment of agriculture.
Understanding the basic composition of soils helps explain the concept of nutrient cycling and why there are problems with clearing rainforest lands for agriculture, why agriculture fails so quickly and how soils are an important factor influencing forest complexity. (For anybody interested in more info follow these links: rainforestconservation.org and www.mikehorn.com
Soil and Climate
Soil is a part of the natural world that is both affected by and contributing to global warming. Soil is the one of the largest sources of carbon in the world. It is primarily accumulated through plants which ‘fix’ the carbon from carbon dioxide in the air; the soil then directly absorbs the carbon as the plants decay. Additionally, dead leaves and animals are broken down by microbes in the soil and carbon is accumulated.
Around the developed world, soils have been exploited to such extent that they can not produce what it is demanded from them without investing energy and resources. In turn, covering the requirements of those demands raise the consumption of energy and other resources generating all kind of waste from chemical and mineral extraction and production as well as from transportation and soil manipulation by machinery. Furthermore, this forcing over the soil to produce out of equilibrium releases Lixiviates usually polluted with organic or inorganic compounds such as NH3, CO2 or VOC’s which need to be treated (thus more energy and infrastructure demanded).
In the tropics weathering is more rapid than in temperate climates because of heavy rainfall and high temperatures. Since the bedrock is very old and weathered it is also depleted in minerals and nutrients. Mineral release is also inhibited by the acidic nature of many tropical soils. There are few nutrients more than 5cm (2 inches) below the surface of the soil in tropical rainforests. Therefore, the species have adapted by being shallow rooted. Species with strong, long root systems would not find any nutrients to survive.
In other hand, Sayer and colleagues published in 2011 the results from a study looking at the carbon sequestration capability on soils in Tropical Forests under the influence of increasing concentrations of atmospheric CO2. They found that considering an increase in primary productivity in tropical forests attributed to CO2 fertilization, increasing litterfall in a lowland tropical forest enhanced carbon release from the soil, decreasing the carbon sequestration capacity of tropical forest soils.
Using a large-scale litter manipulation experiment combined with carbon isotope measurements, they found that the efflux of CO2 derived from soil organic carbon was significantly increased by litter addition. Furthermore, this effect was sustained over several years. Based on their results, they predict that a future increase in litterfall of 30% with an increase in atmospheric CO2 concentrations of 150 ppm could release about 0.6 t C ha−1 yr−1 from the soil, partially offsetting predicted net gains in carbon storage.
Thus, it is essential that plant–soil feedbacks are taken into account in predictions of the carbon sequestration potential of tropical forests.
Another misconception has been adopted from observed increasing measurements of atmospheric CO2 and its potential boost on photosynthetic activity. Ecosystem effects of increasing levels of atmospheric CO2 will depend on the nutrient status of specific forests. Increased forest production will occur where soils contain adequate nitrogen. In areas where nitrogen is limiting, elevated CO2 levels will not increase the growth of trees — even though photosynthesis may increase. Without sufficient nitrogen, the trees cannot use the additional CO2 for growth. The additional carbon is used by soil organisms and respired to the atmosphere. In addition to contributing to CO2 buildup in the atmosphere such changes in the soil foodweb, which controls nutrient availability for plants, could have long-term effects on ecosystem functioning.
Understanding how much it is being affected the capacity of natural systems to not only stabilize Carbon in structures, but also, to keep them inactive, changes completely the assumption of what we consider to behave as carbon sinks.
And the last, but not least, of all uncertainties under study are the synergies between the impact of land surface variability on the predictability of climate, interactions between the terrestrial and atmospheric branches of the hydrologic cycle, and the impacts of land use change on regional and global climate.
The following pieces of information share some more inside knowledge in this issue:
“Used planet: A global history” (Ellis et al) 2013, PNAS.
Human use of land has transformed ecosystem pattern and process across most of the terrestrial biosphere, a global change often described as historically recent and potentially catastrophic for both humanity and the biosphere. Interdisciplinary paleoecological, archaeological, and historical studies challenge this view, indicating that land use has been extensive and sustained for millennia in some regions and that recent trends may represent as much a recovery as an acceleration. Here we synthesize recent scientific evidence and theory on the emergence, history, and future of land use as a process transforming the Earth System and use this to explain why relatively small human populations likely caused widespread and profound ecological changes more than 3,000 y ago, whereas the largest and wealthiest human populations in history are using less arable land per person every decade. Contrasting two spatially explicit global reconstructions of land-use history shows that reconstructions incorporating adaptive changes in land-use systems over time, including land-use intensification, offer a more spatially detailed and plausible assessment of our planet’s history, with a biosphere and perhaps even climate long ago affected by humans. Although land-use processes are now shifting rapidly from historical patterns in both type and scale, integrative global land-use models that incorporate dynamic adaptations in human–environment relationships help to advance our understanding of both past and future land-use changes, including their sustainability and potential global effects.
Vegetation cover changes caused by land use can alter regional and global climate through both biogeochemical (emissions of greenhouse gases and aerosols) and biogeophysical (albedo, evapotranspiration, and surface roughness) feedbacks with the atmosphere, with reverse effects following land abandonment, reforestation, and other vegetation recoveries. As a result, the very different land-use histories produced by different models of Holocene land-use change (Figs. 1 and 2) have major implications in understanding the emergence of humans as a global-scale force transforming climate—a key indicator of Earth system transformation and the emergence of the Anthropocene.
The Early Anthropogenic Hypothesis (108) posits that mid-Holocene increases in CO2 and CH4 resulted from early land clearing and other agricultural practices and that these unprecedented interglacial trends in atmospheric composition set global climate on a trajectory toward warmer conditions long before human use of fossil fuels. Furthermore, deforestation in the middle–high latitudes might have amplified Little Ice Age cooling by exposing more snow and increasing surface albedo. Modeled regional and global climate responses to simulated and reconstructed historical land cover changes over the past century and millennium generally agree that anthropogenic deforestation drives biogeophysical cooling at higher latitudes and warming in low latitudes and suggest that biogeochemical impacts tend to exceed biogeophysical effects. However, most simulation studies are based on a narrow set of land cover reconstructions over at most one millennium and do not incorporate the effects of land use and its intensification across the Holocene. As a result, hypotheses relating human activity to historical climate change have yet to be tested rigorously under the full range of plausible historical conditions.
FAO 2015. “Status of the World’s Soil Resources.”
Main report Prepared by Intergovernmental Technical Panel on Soils (ITPS)
The SWSR will constitute the reference document on the status of global soil resources with a strong regional assessment on soil change. The information is based on peer-reviewed scientific literature, complemented with expert knowledge and reliable project outputs (mainly FAO ones). It provides a description and a ranking of ten major soil threats that endanger ecosystem functions, goods and services globally and in each region separately. Additionally, it describes direct and indirect pressure son soils and ways and means to combat soil degradation at all levels. The report contains a Synthesis report for policy makers that summarizes its findings, conclusions and recommendations.
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(This post is part of a more complex piece of independent research. I don´t have founding, political agenda or publishing revenues from visits. Any scientist working in disciplines related with the topics that I treat in my blog knows how to judge the contribution that my work could potentially add to the state of knowledge. Since I am in transition looking for a position in research, if you are one of those scientists, by just acknowledging any value you might see from my contribution, would not only make justice to my effort as independent researcher, but ultimately, it will help me to enhance my chances to find a position with resources to further develop my work.
I believe that the hypothesis that I have presented in previous posts in this blog (here,here and here) could help to understand present and possible future scenarios in atmospheric circulation. However, this is an assessment based on observation which needs to be validated throughout open discussion and data gathering. So please feel free to incorporate your thoughts and comments in a constructive manner.
If you feel like sharing this post I would appreciate to have a reference about the place or platform, by private or public message, in order for me to have the opportunity to join the debate and be aware of the repercussion which might generate d.fdezsevilla(at)gmail.com)
For anybody interested in the posts related with this discussion here I leave you those more relevant in chronological order (there are comments bellow some of them. Please check them out):
- New theory proposal to assess possible changes in Atmospheric Circulation (by Diego Fdez-Sevilla) Posted on October 21, 2014. http://wp.me/p403AM-k3
- Why there is no need for the Polar Vortex to break in order to have a wobbling Jet Stream and polar weather? (by Diego Fdez-Sevilla) Posted on November 14, 2014. http://wp.me/p403AM-mt
- Gathering data to make visible the invisible (by Diego Fdez-Sevilla) Posted on December 22, 2014. http://wp.me/p403AM-pN
- State of the Polar Vortex. Broken? From 29 Nov 2014 to 5th Jan 2015 (by Diego Fdez-Sevilla). Posted on November 29, 2014. http://wp.me/p403AM-o7
- Probability in the atmospheric circulation dictating the Weather (by Diego Fdez-Sevilla) Posted on January 15, 2015. http://wp.me/p403AM-rm
- Meteorological Outlook Feb 2015 (by Diego Fdez-Sevilla) Posted on February 7, 2015. http://wp.me/p403AM-sU
- Revisiting the theory of “Facing a decrease in the differential gradients of energy in atmospheric circulation” by Diego Fdez-Sevilla. Posted on February 10, 2015. http://wp.me/p403AM-to
- Matching Features Between Land Surface and Atmospheric Circulation (by Diego Fdez-Sevilla)April 23, 2015
- Drops of Weather. (by Diego Fdez-Sevilla)March 7, 2015
- Steering climate´s course (by Diego Fdez-Sevilla)March 27, 2015
- Climate. Looking at the forest for the trees (by Diego Fdez-Sevilla)April 9, 2015
- Matching Features Between Land Surface and Atmospheric Circulation (by Diego Fdez-Sevilla)April 23, 2015
- Domesticating Nature. (by Diego Fdez-Sevilla)May 7, 2015
- A roller-coaster of temperatures in South Europe. Spain (by Diego Fdez-Sevilla)May 14, 2015
- Talking about climate (by Diego Fdez-Sevilla)May 12, 2015
- News from an Ecosystem (by Diego Fdez-Sevilla)May 20, 2015
- In climate it is becoming Less probable to not have a High probability. (by Diego Fdez-Sevilla)May 29, 2015
- Drinking from the source (by Diego Fdez-Sevilla)June 5, 2015
- Communication takes more than just publishing thoughts. (by Diego Fdez-Sevilla)June 9, 2015
- Extreme climatic events, implications for projections of species distributions and ecosystem structure (by Diego Fdez-Sevilla)June 18, 2015
- The scope of Environmental Science and scientific thought. From Thought-driven to Data-driven, from Critical Thinking to Data Management. (by Diego Fdez-Sevilla)June 26, 2015
- Atmospheric Circulation and Climate Drift. Are we there yet? (by Diego Fdez-Sevilla)July 2, 2015
- Lateral thinking. From Micro to Macro (by Diego Fdez-Sevilla)July 4, 2015
- Something for the curious minds. Climate and Streamlines (by Diego Fdez-Sevilla)July 17, 2015
- Solar Activity and Human Activity, Settling Their Environmental Liability. (by Diego Fdez-Sevilla)July 24, 2015
- Atmospheric composition and thermal conductivity? (by Diego Fdez-Sevilla)August 6, 2015
- Latitudinal barriers and typhoons (by Diego Fdez-Sevilla)August 13, 2015
- The Earth is Ticking (by Diego Fdez-Sevilla)August 20, 2015
- What if, the relevant bit lies hidden on identifying the pattern behind similarities instead of trying to match anomalies? (by Diego Fdez-Sevilla)September 3, 2015
- A Climate “Between Waters” (by Diego Fdez-Sevilla).September 8, 2015
- Sensing Atmospheric Dynamics (by Diego Fdez-Sevilla)September 22, 2015
- InFormAtion. The “Act” of “Giving Form” to “Knowledge” (by Diego fdez-Sevilla)September 30, 2015
- Arctic Intake of Water Vapour (by Diego Fdez-Sevilla)October 7, 2015
- SST Anomalies and Heat Waves. Are They Not All Just Heat Displacements? (by Diego Fdez-Sevilla)October 16, 2015
- Discussing Climatic Teleconnections. Follow Up On My Previous Research (by Diego Fdez-Sevilla)October 21, 2015
- Follow-up on Arctic circulation 30 Oct 2015 ( by Diego Fdez-Sevilla) October 30, 2015
- There is Ice or Frost In Antarctica? (by Diego Fdez-Sevilla) November 5, 2015
- Starts Raining Drops of Winter at Mid-Latitudes. The new Autumn? (by Diego Fdez-Sevilla) November 10, 2015
- Press release. Ask NASA (by Diego Fdez-Sevilla) November 12, 2015
- Following the Behaviour of the Jet Stream (by Diego Fdez-Sevilla) November 19, 2015
- What Is Wrong With The Concept “Bio”? (by Diego Fdez-Sevilla) November 26, 2015
- Energy. Looking For Sources of Something We Waste. (by Diego Fdez-Sevilla) December 3, 2015