Plant growth, CO2, Soil and Nutrients. (by Diego Fdez-Sevilla, PhD.)

Plant growth, CO2, Soil and Nutrients. (by Diego Fdez-Sevilla, PhD.)

Through my research I have tried to point out in several publications (e.g. link and link) how much relevant are soils in the equation of climatic dynamics. If the weathering and renewal balance of the soils are not in equilibrium with the ecosystem which they are sustaining we keep having to consume resources and produce energy to do it so.

Plants fixing CO2 in our ecosystem act as single big complex organisms when they are structured, like Forests, Mangroves, Wetlands, Grasslands … Single units like trees scattered here and there, do little to sustain an ecosystem. In order for organisms to grow healthy they need more than only CO2, but also space to mature, soils with the proper structure, light, nutrients and the most precious demanded commodity, time.

The world’s forests take up around a third of human-caused CO2 emissions, playing a “gigantic” role in helping to moderate its role in the Greenhouse effect defining our global climate.

Some Research suggests that as human-caused carbon dioxide emissions accumulate in the atmosphere, plants will grow more quickly because the rate of photosynthesis speeds up. This is called ‘carbon dioxide fertilisation’.

This  argument is sometimes used in parts of the media to suggest that additional carbon dioxide is beneficial for the Earth as extra food for plants.

In order to contextualize the implications coming from understanding the feedbacks involved in this issue I have chosen two articles published recently, and I have reviewed their contributions in the subject and the missing links.

Temperature, CO2, Water and Nutrients.

The firsts one looks at the Influence of Temperature and CO2. Published at Nature, 2016. “Boreal and temperate trees show strong acclimation of respiration to warming.” Peter B. Reich et al. (link)

Also discussed at “Carbon Brief” by Robert McSweeney

The second one published in Nature Geoscience (2015) looks at Nutrients availability and limitations.

“Future productivity and carbon storage limited by terrestrial nutrient availability.” William R. Wieder, et al. (link)

Also discussed at

Temperature and CO2 ____________________________

Plants use sunlight, water and CO2 during photosynthesis in order to grow.

Through photosynthesis, plants convert carbon dioxide, water and sunlight into the fuel they need to grow,  locking up carbon in their branches, stems and leaves in the process.

Photosynthesis produces glucose and oxygen. But to release that glucose as energy to fuel growth, plant cells need to respire. Respiration uses oxygen and produces CO2 along with energy and water (evapotranspiration).

So, plants both absorb and produce CO2.

Fortunately, the amount of CO2 that plants produce during respiration is only around half what they absorb during photosynthesis. So overall, plants and trees help soak up CO2 from the atmosphere – helping offset part of what humans are adding by burning fossil fuels.

However, as temperatures rise, scientists are concerned the delicate balance of how trees use CO2 could be upset, potentially reducing their capacity to buffer rising CO2 levels.

Previous research shows that plants respire more in warmer temperatures. Scientists are concerned that if plant respiration rates speed up under climate change, plants and forests might start to kick out more CO2, thus warming the planet even more.

Given the number of plants on Earth, this is potentially a big deal, explained lead author Prof Peter Reich, from the Department of Forest Resources at the University of Minnesota, during a press briefing:

– “Plant respiration returns six times as much CO2 to the atmosphere every year as fossil fuel burning. So even a small increase in this would be big relative to fossil fuel emissions.”

Until now, scientists didn’t really know how well plants and trees would adapt.

To find out, Reich and his colleagues carried out a unique, open-air experiment over five years using 10 common tree species in North America.

The results suggest tree respiration increases by around 5% in a climate that is 3.4C warmer. This is less than half the increase in respiration reported by other studies, and less than the 23% the researchers expected had the trees not adapted to the higher temperatures.

In general, the study’s findings are good news, says Reich:

– “[The results] suggest that the increases in respiration rates for terrestrial plants – and the associated increase in atmospheric CO2 concentration, which results in global warming – may be much less than anticipated.”

In other words, the way plants adapt to rising temperatures means they’ll contribution less to further warming than scientists had expected.

But that’s not to say that tree respiration changes are going to help limit climate change, adds Reich, they’re just not likely to accelerate it as much as previously thought:

– “Unfortunately, the problem we’ve created in the first place with our greenhouse gas emissions still exists.”

A different scientist is wary of drawing conclusions about plant respiration based on just this one study.

Prof Pierre Friedlingstein, chair in mathematical modelling of climate systems at the University of Exeter, says the paper is “not a game changer”.

It isn’t just the leaves of plants that respire, Friedlingstein points out, the study doesn’t consider how stems, roots and soils will respond to warming. As a result, the implications of the study have been “largely overvalued,” he says:

– “My cautious recommendation would be not to take this study as a demonstration that global warming will not induce carbon loss from ecosystems.”

Nutrients availability and limitations_____________________

Meanwhile, research published in April 2015 in Nature Geoscience suggests that plants won’t have enough nutrients to make full use of the extra carbon dioxide in the atmosphere.  So any benefits will be limited, say the authors.

Plants need the right mix of nutrients to grow. Two of the most important nutrients are nitrogen and phosphorus. But there isn’t an endless supply in soils for plants to use, lead author Dr Will Wieder, from the National Centre for Atmospheric Research in Colorado, tells Carbon Brief:

– “Many ecosystems appear to be co-limited, meaning that both nitrogen and phosphorus are important for plant growth. There are places where one element or the other may be slightly more limiting, but at the end of the day plants need both to build roots, leaves and wood. This is why many fertilizers used in gardens and farms come with both nitrogen and phosphorus.”

While nitrogen is abundant in the air we breathe, most plants can only take it up from the soil. Nitrogen gets into the soil by being ‘fixed’ from the air by microbes and certain plants, such as soy, Wieder says. Phosphorus primarily originates from rocks, and reaches the soil when they are worn down by the weather.

Most climate models used for the latest Intergovernmental Panel on Climate Change (IPCC) report assume that enough additional nitrogen and phosphorus would be available for extra plant growth. But this might not actually be the case, Weider says:

– “This ‘new’ nitrogen and phosphorus would have to come from somewhere, and we found it is unlikely to be supplied from outside the ecosystem, meaning that the increases in plant growth would have to be met through accelerated recycling of nutrients within ecosystems.”

When Wieder and his colleagues included realistic amounts of nitrogen and phosphorus in their models, they found it limited the boost to plant growth from the extra carbon dioxide.

Without limiting nitrogen and phosphorus, plant growth increases by 63% by 2100.

When the team included future limits to nitrogen, they found extra plant growth dropped to 29%. With limits to both nutrients, the boost to growth dropped even further to 20%.

Limits to the amount of carbon plants can take up is only part of the story. Warmer temperatures mean carbon held in soils and dead plants will decompose more quickly, releasing more carbon back into the atmosphere, the study says.

This could mean that, on balance, more carbon dioxide is released from the soil than is absorbed by the plants, Weider says:

– “We’re going to go from terrestrial ecosystems sponging up carbon dioxide out of the atmosphere to actually having them contribute to the problem.”

The findings suggest we can’t count on plants to offset the impact of our emissions as much as previously thought, Wieder concludes:

– “So far, we have greatly benefited from plants removing carbon dioxide from the atmosphere. But if a lack of nutrients limits their ability to keep soaking up carbon dioxide, then climate change becomes an even bigger problem than we thought.”

The carbon cycle is a critical part of regulating Earth’s climate. With the land’s ability to take up carbon diminishing this century, the study suggests society will need to compensate by finding other ways to cut back on emissions if we’re to keep temperatures in check.

Missing gaps

Complete ecosystems

In the first study the methodology applied lamps and cables hooked into a computer system that maintained the warmer conditions whatever the weather. Those trees were in a natural habitat, exposed to wind, rain, insects and animals as they would be in any normal forest.

However, what I find missing is the interaction from all the components of the system under same conditions of temperature. That means, under warmer conditions the mobility of nutrients in the soil increases as well as the loses due to this mobility.Also the availability of water in the atmosphere is different under such a micro-climatic conditions when compared with a regional warming. Furthermore, the life cycles of other relevant invertebrates speed up their development so the impact from their activity is neglected.  This is not only relevant for the metabolism at the roots but also, for the development of leafs and the potential harmful effect from fungi and insects affecting plant growth.

As warmer and wetter becomes the atmosphere, higher are the probabilities of facing an increase in those harmful interactions from fungi and invertebrates.


In the second study the methodology applied look at the limiting effect from the availability of nutrients for an overstimulated metabolic activity.

However, it does not look into the requirements linked with water as a relevant factor playing a key role in the metabolic system.

Changes in the state and structure of soils as well as those at the atmosphere play a big role in this matter.

An overstimulated metabolic system will require more water proportionally to temperature and the availability of the other nutrients. But water can not be contemplated as an averaged mean resultant from changing between completely dry into pouring rain.

The positive effects of water are found when it is available at regular periodic times and without destroying the properties of the soil by dragging material and nutrients out of the system.

Among those factors limiting the positive effect of water and its availability are the compartmentalization of water bodies and water flows by human activity as well as the compaction of the soils, loses of material due to runoff and restrictions of space by an increasing pressure coming from settlements and agricultural exploitation among others.

At the same time, water in the air is found as water vapour. It is relevant in evapotranspiration processes where plants take and release water vapour through their leafs. Increasing temperature in the atmosphere increases the capacity of the atmosphere to suck water vapour so either, it will compete for it with plants or use plants as suction pumps to extract water from the soil.


Ultimately, when we look at the effect that CO2 would have over the development of the plant population over the world we have to keep in mind that such synergy will play bidirectionally, interfering also in the development of climatic conditions.

By increasing photosynthetic metabolic activity from plants at higher latitudes there will be higher quantities of water vapour released in the atmosphere and demanded from the soils. That would incorporate water vapour into the atmosphere helping to keep or increase the Greenhouse effect (thermal conductivity), already played by CO2, closer to the Poles. That is happening already.

Water vapor_Temp and NDVI Anomalies North 60 N

Considering that only CO2 can cover all the requirements to feed the plants on its own, it would just underestimate the needs for those ecosystems to perform. Furthermore, to consider that it is good news to have any specie populating any place in latitude and longitude, as long as it is a plant, it underestimate dangerously what their contribution could add into damaging the resilience capacity of native ecosystems, and their interactions affecting regional climatic conditions. (see also category Biological productivity)

Ultimately, we have to consider the net balance between the negative impact triggered from the activities associated with the release of CO2 and the capacity for the ecosystems to remediate the side-effects derived from increasing its concentration. Furthermore, looking at the influence of continentality in atmospheric circulation, how much impact can we expect in the climate from land use and land cover management?

We might have CO2 enough to grow more plants in our planet but, like any “green-house” built to produce groceries, do we have enough water available reaching the places where we need ecosystems to perform? Do we have enough space for them to mature? Does the soil contain the nutrients and structure required to have a self-sustained ecosystem? Does the maturing process of the ecosystem stays in equilibrium with the renewal cycles of matter and energy?

Otherwise, we might have only CO2, and the rest, will have to come from consuming resources as much as producing energy in the process of man-handling their survival. Which in turn requires more CO2 to be emitted and more land to be transformed.

One example

One article published recently at the website “The Economist” reflects the conflicts which I am presenting here.

The article is entitled:

“Money that grows on trees”. Brazil’s economy is crumbling but its giant pulp firms are booming.

LOOK north from atop the 120-metre (390-foot) bleaching tower at the Horizonte 1 pulp mill, and all you see is plantations of tall, slender eucalyptus trees. They stretch from the factory gate, across the gentle undulations of Mato Grosso do Sul, a state in Brazil’s centre-west, all the way to the horizon. “That’s our competitive advantage,” explains Alexandre Figueiredo, who is in charge of production at the plant. Its owner, Fibria, is the world’s biggest producer of “short-fibre” cellulose pulp, which is used to make such things as newsprint, nappies and banknotes. (“Long-fibre” is used for high-grade paper and packaging.)

As its name suggests, Mato Grosso do Sul (roughly, “southern thick bush” in Portuguese) has vast expanses of cerrado, or tropical savannah, a chunk of which was long ago turned into farmland, some of which has more recently been planted with eucalyptus. Most of Fibria’s 568,000 hectares of plantations lie within 200km of its mills. Eldorado, a rival with a mill on the other side of Três Lagoas (a city of 115,000 that is fast becoming Brazil’s cellulose cluster), needs its lorries to drive only a bit farther. No other firm in the world has such ready access to its raw material. Add the balmy climate and rich soils of Brazil’s south and centre-west—where, as Joe Bormann of Fitch, a credit-rating agency, puts it, eucalyptus “grows like a weed”—and it is easy to see how Brazil has conquered 40% of the global short-fibre market. (more here)

Whilst economic pressure demands productivity, nowadays there is also added pressure in justifying the greenness of investment. But very often all attention goes into looking at the forest and few attention is given to the soil on which they rely on. In this case, Eucalyptus are among those species which are very demanding on soils and require a lot of attention when they are introduced in non native ecosystems.

Some studies on this issue can be found already in the following works:

“Water erosion in soils under eucalyptus forest as affected by development stages and management systems.”


The constant increasing of eucalyptus forest areas in Brazil requires an accurate monitoring of water erosion. The present study aimed to evaluate soil, nutrients and organic carbon losses occasioned by water erosion in eucalyptus planted forests (EPF) at different development stages (2, 3 and 7 years old). Soil erosion sediments were measured and sampled from standard erosion plots installed on Red Argisol-RA (Ultisol) and Haplic Cambisol-HC (Inceptisol). Soil loss decreased as the age of plants increased; at the beginning of plant development, the canopy barely covered the soil surface, exposing the soil to higher erosion at young EPF plantations. Furrow planting system was used in the Red Argisol area and caused higher soil losses (1.1 to 6.2 Mg ha-1 year-1) as compared to pit planting system that was used in the Cambisol area (1.1 Mg ha-1 year-1). It is known that Cambisol is less resistant to erosion than Argisol. However, using pit system in this EPF, resulted in lower erosion and, therefore, nutrients and carbon losses than the traditional furrow system used in Argisol. Concerning the soil loss, this work points to the need of improving soil conservation practices to prevent soil erosion at the earlier stages of eucalyptus plantation. The amount of calcium and potassium were higher than magnesium in the soil sediment.The relatively high amount of carbon found in the erosion sediments raises additional concerns about the environmental sustainability and deserves future research.

Uruguay: Eucalyptus plantations degrade soils and release carbon

In spite of all the scientific evidence existing on the negative impacts of large scale monoculture tree plantations, the Climate Change Convention insists on promoting them under the false argument that plantations can alleviate the effects of climate change, acting as “carbon sinks.”

The negative impacts of monoculture tree plantations in forest areas have been thoroughly studied and documented in nearly all the countries where they are located. However, there is a tendency to minimize the negative impacts these plantations cause on grasslands, the main ecosystem of countries such as South Africa, Swaziland, Uruguay, the south of Brazil and vast areas in Argentina, where such monoculture plantations continue to expand.

This situation, explains Carlos Cespedes, a researcher at the Uruguayan Faculty of Science, is what encouraged him to undertake a study for his doctoral thesis, aimed at assessing the effects of the conversion of grasslands to tree plantations.

In a previous paper, this researcher had demonstrated that eucalyptus plantations have negative effects on grassland soils. In this study, Cespedes had verified that monoculture eucalyptus plantations cause a considerable loss of organic matter and increased acidity, associated to the alteration of the normal values of other physicochemical properties.

The soils of Uruguayan grasslands have an acidity level (pH) of approximately 6.5 – 6.8 (that is to say they are classed as “slightly acid”) although in the case of sandy soil grasslands, these values may be around 5.5. In the analysis of eucalyptus plantations on these same types of soil the results showed much lower values, situated at about 4.5 (values that are defined as “strongly acid”). To understand the importance of this figure it must be stated that pH is expressed on a logarithmic scale, where one point of difference in the pH (5.5 versus 4.5) is considerable. However, it is important to know that a pH of 5 represents a threshold, that is to say, above or below this value significant changes take place in the soil (which would not happen if the change were from 7 to 8 or from 3 to 4), such as changes in its Cationic Exchange Capacity (CEC), a property that is strongly linked to soil fertility as explained further on.

Last thoughts

The health state of our ecosystems is as important as their location and extension.

I believe that there are some questions which are relevant in today’s discussion over climatic variations in a global scale:

Should we consider our planetary climatic dynamics to be driven sorely by thermodynamics, independently from the interaction from biological processes?

“Are thermodynamics defining the state which allow life to evolve in a changing climate? or, Are biotic systems which develop and perform against thermodynamic fluctuations taming the weather?”

I have addressed my take on those questions in previous posts, so in order to not increase the length of this entrance I will leave some links for anybody curious enough:

If biological systems were involved in reducing the impact from climatic variations in the past (Holocene), based on the state of our actual ecosystems, under the pressure of a potential climate drift, we might face a bigger challenge than any prediction based on past records.

Follow-up from previous research

I have been for 13 years looking into the synergies driving atmospheric dynamics and the particles contained within. In my research it has become relevant the heterogeneous distribution, composition and behaviour of; monoatomic and polyatomic molecules in the atmosphere; variations in pressure; location of events driven by the strength of winds and thermal contrasts; the enhanced atmospheric mixing ratio due to convective forcing and/or rain events increasing turbulence; the release transport and deposition of aerosols and their behaviour as rain drop nuclei due to their properties over clouds and rain drop formation, energy flows interacting from processes of evaporation and condensation as well as biological evapotranspiration and respiration, and biochemical processes affecting atmospheric composition (photosynthesis). Furthermore in my research it has become relevant the concentration and time of permanency for different molecular compounds and their different properties interacting in energy flows such as condensable (water) and not condensable gases (GHGs). All those factors (at least) are relevant since they either define or indicate the state of heat transfer efficiency in the atmosphere.

Derived from addressing synergies and feedbacks between those factors in previous posts, some of my conclusions are:

  • GHGs have the potential of enhancing the thermal conductivity of the atmosphere increasing the capacity of the system to absorb, contain, transport and release energy (in all its forms, kinetic (wind related), thermal (Heat) and potential (mass)) throughout latitudes, longitudes and altitudes.
  • The most important component in the atmosphere carrying such intake of energy is water vapour due to the enhanced thermal conductivity of the atmosphere resultant from GHGs forcing.
  • In a first stage, due to the compartmentalization of atmospheric circulation in the poles thanks to Polar Jet streams, the Equator and Midlatitudes absorb the major change in thermal conductivity (increase in temperature).
  • Due to asymmetric distribution of land surface and GHGs conc between hemispheres, the NH receives the biggest impact than the SH.
  • Once the thermal contrast in the NH Polar Jet Stream is worn out, the polar circulation opens its volume in the atmosphere to accommodate new forms of energy carried by water vapour and GHGs, increasing its thermal conductivity.
  • As a result, the thermal transfer efficiency from mid latitudes would expand into polar latitudes, enhancing heat transfer processes northwards (heat waves) as well as the meltdown of ice caps and precipitation in liquid form out of season (already happened this winter 2015/16).
  • Also, the frequency of masses of air from Polar and Mid Latitudes crossing over the Polar Jet Stream increases the level of exposure to extreme variations jeopardising the development of natural cycles in flora and fauna, when they occur out of season, due to a weak Polar Jet Stream. (see related posts)
  • In other hand, masses of air and pressure systems containing more energy than its surroundings (Thermal/Kinetic/Potential), can create “blocking patterns”, or move higher in altitude instead of dissipating its energy when moving upwards in the atmosphere. Masses of air having the capacity of carrying such thermal energy without dissipating it when moving upwards generate what it is called Sudden Stratospheric Warming events. (also seen through this winter 2016).
  • My only point is that temperature is not only a measure of Energy, it is a measurement of the state for the density of a particular type of matter. Without matter there is no temperature. So, wherever yo measure temperature there is matter. Which type of matter exists at each point where we measure temperature is the main relevant point in environmental assessments. And then, which conditions allow for such matter to be there, in such concentration and physical state, latitude and altitude. If temperature at Earth’s surface is increasingly spread over higher latitudes and altitudes, as they are, it is because there is molecular matter holding it. If water vapour carries heat at the surface might be because at higher levels GHG,s are doing their job retaining heat radiated from above and bellow from escaping to out space. That creates a positive feedback through the whole atmospheric column and in latitude.

Every reasoning pointed out here is linked to observed events and records which have been addressed in previous publications.

For all those reasons, I appreciate any feedback in order to consolidate the validity of what my research points out from a multidisciplinary approach, or to discuss possible weaknesses suggesting the need for reassessing any consideration.


PerspectiveSince October 2013 I have been studying the behaviour of the Polar Jet Stream and the weather events associated as well as the implications derived into atmospheric dynamics and environmental synergies.

Many of the atmospheric configurations and weather and climate events we see these days are very similar with the progression followed since 2013. Please take a look at posts addressing those events from previous publications in this blog or look at the categories in the top menu. Also at research-gate. Feedback is always welcomed either in this blog or at my email (d.fdezsevilla(at) All my work is part of my Intellectual Portfolio, registered under Creative Commons Attribution-NonCommercial 4.0 International License, license and it is being implemented at my profile in researchgate. I will fight for its recognition in case of misuse.


About Diego Fdez-Sevilla, PhD.

Citing This Site "Title", published online "Month"+"Year", retrieved on "Month""Day", "Year" from By Diego Fdez-Sevilla, PhD. More guidance on citing this web as a source can be found at NASA webpage:! Bachelor in General Biology, Masters degree "Licenciado" in Environmental Sciences (2001, Spain). PhD in Aerobiology (2007, UK). Lived, acquired training and worked in Spain, UK, Germany and Poland. I have shared the outcome from my previous work as scientific speaker in events held in those countries as well as in Switzerland and Finland. After couple of years performing research and working in institutions linked with environmental research and management, I find myself in a period of transition searching for a new position or funding to support my research. In the present competitive scenario, instead of just moving my cv and wait for my next opportunity to arrive, I have decided to invest also my energy and time in opening my own line of research showing what I am capable of. The value of the data and the original nature of the research presented in this blog has proved to be worthy of consideration by the scientific community as well as for publication in scientific journals. However, without a position as member of an institution, it becomes very challenging to be published. I hope that this handicap do not overshadow the value of my work and the intellectual rights represented by the license of attribution attached are respected and considered by the scientist involved in this line of research. Any comment and feedback aimed to be constructive is welcome. In this blog I publish pieces of research focused on addressing relevant environmental questions. Furthermore, I try to break the barrier that academic publications very often offer isolating scientific findings from the general public. In that way I address those topics which I am familiar with, thanks to my training in environmental research, making them available throughout my posts. (see "Framework and Timeline" for a complete index). At this moment, 2017, I am living in Spain with no affiliation attachments. Free to relocate geographically worldwide. If you feel that I could be a contribution to your institution, team and projects don´t hesitate in contact me at d.fdezsevilla (at) or consult my profile at LinkedIn, ResearchGate and Also, I'd appreciate information about any opportunity that you might know and believe it could match with my aptitudes. The conclusions and ideas expressed in each post as part of my own creativity are part of my Intellectual Portfolio and are protected by Intellectual Property Laws. Licensed under Creative Commons Attribution-NonCommercial conditions. In citing my work from this website, be sure to include the date of access. (c)Diego Fdez-Sevilla, PhD, 2016. Filling in or Finding Out the gaps around. Publication accessed 20YY-MM-DD at
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