Azolla
a green goldmine
Green
a green goldmine
Coordinators Tesla
J. Buis
J.J.W.Buis@uva.nl
B. Tulleners
bertus.tulleners@therockgroup.biz
Academic Supervisor
Dr. F. Oosterhuis
Frans.Oosterhuis@vu.nl
Supervisor Commonland
S. Kruijt
Sanne.Kruijt@commonland.com
Tesla Team Green Gold
T. Bakker
Tijmen.Bakker1@gmail.com
+31620070975
T. van Dijk
Tessavdijk@hotmail.com
+31630172670
M. Heinemans
Mirjam.Heinemans@student.uva.nl
+31650567636
Azolla
Green
G ld
Team4
Summary (NL)
Het westen van Nederland is beroemd om zijn uitgestrekte ingepolderde weiden met historische molens en grazende koeien. Op het eerste gezicht lijkt er niks mis met deze polders, maar ze zijn langzaam aan het verdwijnen. Dit komt doordat het waterpeil op 60cm onder het maaiveld gehouden om de grond bruikbaar te maken voor de boeren die het land gebruiken. Als gevolg oxideert de bovenste laag van de grond, die uit veen bestaat, door contact met zuurstof. Veenoxidatie leidt tot inklinking, uitstoot van broeikasgassen, stijgende bemalings- en onderhoudskosten, en uiteindelijk tot vernietiging van vruchtbare gronden. Om dit tegen te gaan moeten er nieuwe, innovatieve oplossingen bedacht worden die ervoor zorgen dat het veen behouden wordt, terwijl de boeren op een duurzame manier hun brood kunnen verdienen.
De stichting Commonland, die zich bezig houdt met landschapsherstel, is een project begonnen om de problemen in het veenweide gebied aan te pakken. Het Tesla project, uitgevoerd door drie UvA-studenten, is een onderdeel van het grotere veenweide project. Tijdens het Tesla project gekeken naar mogelijke oplossingen voor het veenweide probleem. Uit deze analyse kwam naar voren dat natte landbouw, oftewel paludicultuur, bij kan dragen aan het behoud van het veen. Eén gewas leek hiervoor bijzonder geschikt, aangezien het voor de boeren direct te gebruiken viel als krachtvoer; de kroosvaren Azolla.
In theorie heeft Azolla twee grote voordelen met het oog op veenbehoud, deze zijn dat het op water geteeld wordt en het veen niet kan oxideren en dat het een hoge groeisnelheid heeft, dus er een relatief klein oppervlak nodig is voor de beoogde hoeveelheid Azolla productie. Dat zorgt er voor de rest van het land extensiever gebruikt kan worden, wat de restauratie van natuurgebieden of incorporatie van natuur in agrarische gebieden faciliteert. Azolla geeft daarom een kans op een alternatief voor de Nederlandse boeren, terwijl de natuur tegelijkertijd van Azolla kweek kan profiteren.
Er is veel onderzoek gedaan naar de mogelijkheden van Azolla, maar er is tot op heden nog geen praktische kennis over hoe het gewas het beste te verbouwen. Daarom is er besloten om in maart 2017 een pilot te starten op de zorgboerderij De Marsen. Tijdens deze pilot zal er onder anderen onderzocht worden of Azolla in het veld groeit en of het praktisch haalbaar is om het als veevoer te kweken. Het ultieme doel van dit project en deze pilot is om de boeren en andere belanghebbenden te inspireren om hun huidige landgebruik te heroverwegen en om ze samen actief te laten bijdragen aan herstel en behoud van het mooie Nederlandse landschap.
5
Summaries
Summary (ENG)
The western part of the Netherlands is famous for its vast drained peat meadows, with majestic windmills and grazing cows. At first sight it nothing appears to be wrong with these drained meadows, but they are slowly disappearing. This is because the water level is kept 60cm under the ground level to keep the land useable for farmers that use the land. As a consequence the top layer of the ground, which primarily consists of peat, oxidizes upon contact with oxygen from the air. Peat oxidation leads to subsidence, emission of greenhouse gasses, increased drainage and maintenance costs and ultimately to the destruction of fertile lands. To prevent this, new innovative solutions have to be found to ensure peat conservation and the income of farmers simultaneously.
The Commonland foundation, working on landscape restoration, started a project to tackle the problems concerning the peat meadows. The Tesla project, executed by three UvA-students is part of the bigger peat meadow project. During the Tesla project possible solutions to the peat meadow problem have been explored. From this exploration it was concluded that wet agriculture, or paludiculture, could contribute to the peat preservation. One crop seemed to be especially appropriate, since farmers could use it directly as concentrates. This is the aquatic fern Azolla.
In theory Azolla has two main benefits concerning the peat preservation, these are that it is cultivated on water and therefore peat cannot oxidize and that it has a high growth rate and therefore a relatively small area is needed to produce the required amount of Azolla, which ensures that the rest of the land can be used more extensively. This allows the restoration of nature areas or the incorporation of nature within agricultural areas. Azolla therefore provides an opportunity to an alternative for the Dutch farmers, while nature will benefit at the same time.
There have been many studies towards the possibilities of Azolla, but up to this point there has been no practical knowledge on how to cultivate the crop. It has therefore been decided to start a pilot on care farm De Marsen in March 2017. During this pilot the growth of Azolla in the field, as well as the practical aspects to produce it as animal feed will be investigated. The ultimate goal of this project and pilot is to engage and inspire farmers and stakeholders in such a way that they will reevaluate the way in which the land is currently being used and that they will actively collaborate on the restoration and conservation of the beautiful Dutch landscape.
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ContentsContents
04
15
11
19
Summaries
04
05
Summary (NL)
Summary (ENG)
Project team
15
16
16
16
17
Tesla team green gold
Tesla coordinators
Academic supervisor
Client contact
Client
Introduction
11
12
12
The invisible problem
Peat meadow project
Azolla pilot
Methodology
19
20
21
Goal and deliverables
Research methods
The 4 Returns, 3 Zones, 20 Years
approach
8
25
39
35
51
Consequences of
peatland drainage
26
27
27
28
30
32
33
Drainage of the peatlands
Changes in biodiversity
Greenhouse gas emissions
Disappearing cultural heritage
Maintenance costs
Decrease in water quality
Consequences in short
Azolla: a contribution
to peat preservation
41
41
42
46
47
49
Paludiculture with Azolla
Characteristics of Azolla
Environmental effects of Azolla
cultivation
Marketable products of Azolla
Azolla in comparison to other feed
Azolla in short
Dairy farming on
peatlands
35
36
Revenues from dairy farming
Future of dairy farming
Azolla pilot
52
55
56
57
Pilot setup
Pilot partners
Risk analysis
Legal aspects of Azolla as livestock
feed
9
59
73
63
Advice for the peat
meadow project
59
60
61
Further research
New contacts
Future prospects
Appendices
73
76
Appendix I- All explored innovation
options
Appendix II - In-depth explored
innovation options
Acknowledgements
67
References
CO2 CO2 CO2 CO2 CO2 CO2 CO2 Ground water Peat Vegetation
Mechanical drainage for dairy farming, causing oxidation of peat and release of CO2
60 cm
Landsubsidence due to peat oxidation
Drainage costs are increaseing and more CO2 is released
60 cm
11
Azolla: a green goldmine - Tesla 2016
The invisible problem
Since the medieval ages the Dutch people have conquered the wet peatlands by building dikes and polders. Dewatering the peatlands created fertile meadows on which dairy farmers have been living for generations. The peat meadows in the Netherlands are still mainly used for dairy farming and form a unique landscape with cultural and environmental importance on both national and international scale. On first sight these peatlands seem a green and stable landscape, but due to long-term intensive dewatering of the areas they are in danger of disappearance.1,2 In the
western part of the Netherlands, the groundwater level is consistently kept about 60 centimeters below ground level, in order to be able to grow grass and pasture the cows.1 As a consequence the upper part of the land is exposed to air, which causes the
peat in the ground to oxidize and to literally evaporate.3,4 This results in a subsidence
of the ground, which in turn forces the farmers to decrease the water levels even further.1This vicious cycle of dewatering and land subsidence for dairy farming has been going on since the 10th century. Intensification of agriculture in the 1960’s and ‘70’s has resulted in a 2-5 fold increase of annual land subsidence.1 Currently, the land
has subsided up to seven meters in some areas and it continues to subside about 1 centimeter per year.1
Peat oxidation has several other negative consequences. Peat is a major source of carbon and nitrogen, and consequently when it oxidizes these elements are released into the air as carbon dioxide (CO2) and other green houses gasses.5 Thus, peat oxidation
contributes significantly to greenhouse gas excretion.5 For example, around 1.5
Megatons CO2 is yearly emitted as a consequence of peat oxidation in the Netherlands, which is equivalent to the CO2 emission of 1.3 million cars driving around for a year.6,7
Furthermore, the usage of peatlands for dairy farming has negative consequences for the water quality due to over-fertilization and intensive dewatering.8,9 Water pollution is
This report was written to give a clear overview of the peat meadow problem. In the sections ‘Project team’ the involved parties are described and in ‘Methodology’ the approach of the project is written. Afterwards, an overview of the problem is given in ‘Effects of peatland drainage’ and ‘Dairy farming on peatlands’. Finally the possible solutions for the problem are explained, as well as a project plan for a pilot study with Azolla on a farm.
Introduction
12
problematic since it decreases the biodiversity in the areas and it threatens the quality of the drinking water of The Netherlands.9 Finally, land subsidence as a consequence
of dewatering increases maintenance costs of dykes, roads and cities enormously. It has been calculated that this will cost the Dutch government up to 110 billion euros from now until 2090.10,11
In short, subsidence of the peatlands is an ongoing process that will ultimately result in increased maintenance costs, loss of fertile lands, loss of water quality, loss of native wildlife, and increase in emission of CO2 and other greenhouse gasses. To prevent this from happening, new – sustainable – alternatives for the current ways of land use and dairy farming have to be developed.
Peat meadow project
The non-profit organization Commonland initiated the ‘peat meadow’ project, ‘veenweide project’ in Dutch, in order to preserve the peatlands and encourage people to more sustainable land use. The project described in this report, performed by students from the Tesla minor, see section ‘Project team’ for further explanation, is part of the bigger peat project and will be referred to as the ‘Tesla project’. The Tesla project was set up to provide Commonland with alternatives to the current use of the peat meadows that ensure sustainability from an economic, social and environmental perspective.
Azolla pilot
In the first part of the Tesla project an extensive list of potential options were provided for further exploration. For more detailed information on these options see Appendix I.11 During the second part of the Tesla project three of these options were explored
in depth; land heightening, wastewater treatment wetlands, and paludiculture. The general findings on the three options are included in this report; see section ‘Azolla: a contribution to peat preservation’.
During the research on different paludiculture crops, Azolla turned out to be especially interesting for several reasons. It was therefore decided to investigate Azolla in-depth and to provide all necessary information to run a pilot on a farm with this fern. The results of this research and the specifics of the pilot can also be read in this report. The pilot itself is planned to start in March 2017, the beginning of fern’s growing season.
Figure 1. Restoration of the Loess Plateau (before in 1995 (a), and after 2009(b)) in Shaanxi province, Northwest China. The ecological and economic transformation of this area demonstrates what can be achieved if different stakeholder groups work together. Figure adopted from Ferwerda et al. 2015.14
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Tesla team
During this project the students are given the opportunity to apply their scientific skills outside of academia. These skills can be combined with knowledge the program provides by means of trainings, workshops and practical advice. This Tesla team consists of the following people: Mirjam Heinemans, Tessa van Dijk and Tijmen Bakker. All three have a different academic background.
Mirjam successfully finished her bachelor in veterinary medicine at the Utrecht University. After obtaining her bachelor’s degree she switched to the master Brain and Cognitive Sciences at the UvA.
Tessa has obtained her scientific knowledge at the Wageningen University, where she studied Biology. She has a background in Behavioural Ecology and specialized herself in Medical Entomology.
Tijmen did an inter-disciplinary bachelor Beta-Gamma with a major in chemistry and economics and is currently doing a double masters, one in the field of Science for Energy and Sustainability and one in the field of Molecular Design, Synthesis and Catalysis.
Project team
The current project is part of the Tesla minor program from the Institute of Interdisciplinary Studies at the University of Amsterdam. The aim of this program is to bring students at a master level of education with different scientific backgrounds together to work on a ‘real-world’ problem for one of the collaborating companies or foundations.
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Tesla coordinators
Joris Buis (first picture) and Bertus Tulleners (second picture) are the coordinators of the Tesla minor program. Together with the client Commonland they developed this project for the minor. They have supervised the team with regards to all practical aspects such as time management, how to approach the issue, how to optimize teamwork, and how to efficiently communicate internally and externally (e.g. with different stakeholders). Furthermore they provided the team with feedback about the content and progress of the project, in order to optimize the planning and processes during different phases.
Academic supervisor
The academic level of the project is revised by Drs. Frans Oosterhuis, senior researcher at the department of Environmental Economics at the Institute for Environmental Studies (IVM) at VU University. He has a background in economics and has experience in working with people from various disciplinary backgrounds. His recent work fields include: the impact of environmental policies on innovations in the field of energy, transport, climate, air, water, waste and biodiversity. With his expertise in economic analysis, assessment of environmental policies and design of economic instruments he provided our team with valuable advice.
Client contact
The contact person of the client Commonland is Sanne Kruijt. She is part of the ‘Dutch Peatland’ team within Commonland. Sanne studied Future Planet Studies at the University of Amsterdam majoring in ecology and evolution. After her bachelor she studied earth and environment at the Wageningen University majoring in biology and chemistry of soil and water. She has been working for Commonland since August 2015. Communication with Sanne has been very helpful, since she translated the needs and expectation of the client, ensuring a smooth progress of the project.
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Client
Commonland is a young non-profit organization that has been founded in 2014 by Willem Ferwerda. Ferwerda is Executive Fellow Business & Ecosystems at the Rotterdam School of Management and special advisor of the IUCN (International Union for Conservation of Nature) Commission Ecosystem Management in Switzerland. Commonland is based in the Netherlands and the organization’s core activity is to mobilize stakeholders into actively participating in landscape restoration. Landscape restoration comprises both restoration of nature and ecosystems in a landscape and implementing sustainable forms of land use and agriculture for the people living on that land. A successful case of landscape restoration that inspired Ferwerda is shown in Figure 1 at the beginning of this section.
Commonland aims to restore landscapes by establishing a vast network of stakeholders and bringing them into contact with each other. At the beginning of each project, Commonland organizes a co-initiation workshop and invites all stakeholders to evaluate problems and to collectively form prototypes of solutions. Commonland realizes that landscape restoration cannot be done from a top-down approach but rather needs a bottom-up approach. It therefore focuses on relatively small communities and regions to set up projects specific to that region or communities. Up to this point they have set up three successful projects in Spain, South Africa and Australia and started their fourth project in the Netherlands. An example of the South African project is described in Box 1.
In September 2015 Commonland started with preparing a new project to restore the Dutch peatlands. Their main focus has been to identify all the stakeholders in the area and to search for ‘leaders’, people who are already trying to implement sustainable use of peatlands in the Netherlands. With these people they organized a co-initiation workshop on June 26th and 27th of 2016 in order to start a movement towards conservation of the peat landscape. During these days the different stakeholders formed several
prototypes that could
contribute to peatland restoration. Currently, several groups of stakeholders are cooperating to implement these prototypes.
Box 1: An example of the Commonland method
To further illustrate the methods of Commonland, an example of the South African project will be given. In the Baviaanskloof near Port Elizabeth in South Africa, Commonland has collaborated with goat farmers to engage in a holistic approach to farming. The farmers degraded their lands by overgrazing and this in turn caused financial problems. To counteract the degradation, the farmers and Commonland established the idea to develop a new business case that would be beneficial for the land and the farmers. The previous goat farmers changed their business by growing Lavandin on the lands. These plants are rich in oils that are desired by the growing cosmetics industry and can therefore be transformed into a lucrative business. A collaboration of farmers is setting up this industry and will share the profits. The farmers will greatly increase their profits and in the process the land will be restored.
Urban area
Water
Other
Waterland
Vechtplassen
Amstelland
Key areas
Amsterdam
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In this section an overview of the methodology will be given. This includes the goal and deliverables, research methods, and the approach of the project.
Goal and deliverables
The main goal of Commonland’s Dutch peat meadow project is the restoration and preservation of the peatlands in the Netherlands. The Tesla project described in this report is part of this peat meadow project of Commonland. The main goals of the Tesla project were to provide an overview of the innovations that can aid the peatland restoration and to implement one such innovation in pilot form.
The final deliverables of this project are therefore:
1. An overview of the peatland problem
2. An overview of innovations that can aid peatland restoration
3. A foundation for a pilot of an innovation contributing to peatland
restoration
4. Advice for the peat meadow project
The presented deliverables are included in this report and are set out in agreement with the 4 Returns,3 Zones, 20 Years framework of Commonland, see section ‘4 Returns, 3 Zones, 20 Years approach’.
The focus areas of the Commonland project are the peat meadows surrounding Amsterdam. These areas are depicted left in Figure 2: Waterland, Vechtplassen and Amstelland.12 As can be seen in the figure these areas are mainly peat meadows,
which are used for dairy farming.13 It must be mentioned that the three regions fall
under different provincial and municipal authorities and thus have slightly different regulations concerning water level, nature preservation and agriculture. The solutions provided within this project are tailored to these specific regions and not directly translatable to other regions.
Methodology
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Research methods
In order to get to a proper solution within the given timeframe of five months, the project was subdivided into four phases:
1. Exploration phase
2. Choice and Research phase
3. Implementation phase
4. Final documentation phase
The exploration phase lasted for four weeks and was meant to provide a clear and exhaustive overview of the problem. This was done by a combination of literature research and interviews with experts in the field. Furthermore, an overview of all possible categories of solutions was developed. See section ‘Azolla: a contribution to peat preservation’ for further details. Again, this was done by interviewing experts and by reading scientific literature about wetland use. After collecting all the information, a table was created in order to visualize all advantages and disadvantages of the three in-depth explored options. This is included in Appendix II.
The next phase was the research phase. At the beginning of this phase it was decided, in agreement with Commonland, that three solutions had the highest potential: peatland use for paludiculture, heightening of the land and wastewater wetlands. These three options were investigated in-depth to assess the viability of implementing one of them as a pilot in the field. This was done by desk research and by interviewing farmers and other stakeholders to assess their willingness to cooperate. At the end of this phase it was decided that a pilot with Azolla had the highest potential, therefore it was decided to implement this in the next phase.
During the implementation phase, all practical aspects of the implementation of the ‘Azolla pilot’ were taken care of. The goal of this phase was to realize the pilot and let everything concerning the pilot run smoothly. This involved multiple meetings with all stakeholders, gathering practical information about costs and workload for the pilot and providing all necessary knowledge for all the stakeholders, as to ensure a smooth launch in March 2017.
The final documentation phase was the last phase of the project. During this phase, all the gathered information was documented in such a way that it will be useful in the future for Commonland and its partners. This report is the result of the documentation phase and an extensive overview of the problem is included the report, as well as the findings on the three high-potential solutions and all scientific and practical information about the pilot with Azolla.
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The 4 Returns, 3 Zones, 20 Years
approach
When thinking about restoring the peatlands and preserving the remaining peat, one must think about all the different purposes this landscape serves currently and will still need to serve in the future, such as provide revenue for the farmer, provide historic scenery for tourists, and provide a habitat for wildlife. The 4 Returns, 3 Zones, 20 Years framework is a handy tool that can be used to evaluate the different scenarios of landscape restoration that affect these purposes.14
4 Returns
In most agricultural businesses, there is a pursuit of maximizing the financial return of investment (ROI).15 This leads to degradation of landscapes in the long run due
to exploitation, as can seen in the Dutch peat meadow landscape.14 According to
Commonland, in order to use land in a sustainable manner, the ROI should not comprise only the financial returns, but other returns as well: return of inspiration, return of social capital, and return of natural capital. Together with the return of financial capital these returns are the 4 Returns that form the total ROI of any landscape. Combining these four returns will result in an optimal and ROI for farmers, entrepreneurs, or companies and will lead to restoration of the landscape and its ecosystem. Therefore, to find a sustainable solution for the peatland problem, all four returns should be taken into account.
3 Zones
According to Commonland, three functionally different zones can be identified in any landscape: the natural zone, the combined zone and the economic zone. The natural zone comprises all areas that are not used by human beings in any way; it is only nature. The focus of the natural zone is the restoration and preservation of original landscapes and their biodiversity. This zone includes all nature reserves and is a minor zone in the project, since most of the peatland is used for agricultural purposes or as urban construction sites. Urban construction sites always belong to the economic zone and agricultural land can be put in either the combined or economic zone. The agricultural land surrounding Amsterdam mainly belongs in the economic zone, since the farming on this land is intensive and there is little room for landscape or biodiversity restoration.
Increasing the sustainability of the land use, as well as increasing the degree of landscape restoration, could change this area from an economic zone into a combined zone. This transition from economic to combined zone will have numerous positive effects on for instance the landscape restoration, biodiversity restoration and yields for farmers in
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the long run. Several options to achieve this can be identified: extensification of dairy farming, changing to a different type of agriculture or changing to a different kind of land use altogether.
20 Years
In previous projects it took about twenty years to entirely restore a landscape. This illustrates the importance of long-term commitment of the parties involved in the restoration project. Furthermore, it has to be taken into account that any change towards a new landscape and balance will include a transition period in which changes will gradually take place. This is both relevant for the expectation the project team, the client, and the stakeholders; all three parties must be convinced that the pilot that will be implemented is relevant, even if the effect on the peatland is not observed instantly.
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The peatlands in the Netherlands have been drained for centuries and today the anthropogenic effects have become visible to many farmers and numerous other stakeholders. The draining of the peatlands has great economical, biological, social, ecological and cultural consequences, mainly due to land subsidence. If these peatlands continue to be exposed to the air, the effects will persevere and worsen over the next couple of decades. The cost of draining the peatlands will continue to increase and more lands will succumb to saline upward water seepage and will become unsuited for agriculture. It is therefore of the utmost importance to find solutions to the depletion and destruction of these Dutch peatlands. More information about the problem can be found in this section. For a short introduction on peat terminology, see Box 2.
Consequences of peatland
drainage
Box 2: Peat terminology
Peatlands and can be distinguished in two different types based on how they are formed: bogs and fens.20 A bog is a peatland receives water mainly from
precipitation, while a fen receives its water primarily from the ground. A bog is therefore relatively acidic and poor in minerals, as rainwater contains virtually no minerals, while a fen is mainly alkaline and rich in minerals.
Another word for peatland is mire; these terms can be used used interchangeably. The only difference between a mire and a peatland is that a peatland can be wet or dry, a mire however is always wet. The focus of this project is on both wet and dry peatlands. Dry peatlands are also called peat meadows, since most of the time grass grows on top of it.
Peat can only accumulate in wet peatlands, since it is formed through anaerobic decomposition of dead organic material, see foto on the left.5,19 The difference
between the growth rate and the decomposition rate of plants determines the growth rate of the peat layer. Usually it takes thousands of years to grow one meter of peat in boreal areas.23 It is therefore an extremely long process to form
thick peat layers. Peat will be preserved as long as it stays under water. Due to pressure from accumulated peat on top, the lower peat layers will slowly change into lignite (brown coal) and later anthracite (black coal).89
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Drainage of the peatlands
The Dutch peatlands have been formed in the past 5,000 to 10,000 years as a result of the combination of a rising sea level and poorly leaching sediment.16 Most parts
of the Netherlands used to be wet peatlands before medieval times, especially in the northwestern and eastern parts of the country.17
During the medieval ages the Dutch found ways to drain the peatlands to increase the support of these grounds and use the areas for agriculture and urban construction sites. With smart engineering of windmills and clever water management by building dikes, the Dutch turned the peatlands into highly fertile peat meadows on which dairy farmers have been living for generations.18 The consequence of draining these ancient
lands was that the upper 60 cm of the land came into contact with the air. Due to the presence of oxygen the land started to slowly evaporate.1 The average decline over time is visualized in Figure 4. This figure shows the history of peatland drainage and the consequent land subsidence.
At the same time the Dutch also learned that they could dry the peat and generate turf. The turf could be used to burn in order to heat houses during the harsh Dutch winters. However, it was not until the industrial era when the turf was extracted on a massive scale.19 This era caused tons of peat to be extracted from the land for
industrial purposes allowing for an even faster degradation of the land.19 At the end of
the industrial era the extraction of peat has been halted due to the availability of the better burning coal and oil.19 Currently, mainly drainage of the peat meadows plays a
role in peatland degradation.1
-3.0 m -2.0 m -1.0 m Sea level 1.0 m 2.0 m Drainage by windmills Mechanical Drainage Deep Drainage 1000 1200 1500 1850 1950 2100 Land subsidence Ditches Dike construction Year
Figure 4. Average land subsidence in the Netherlands over the past millennium. Adapted from N. Pieterse et al., 2015.10
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Changes in biodiversity
Before the peatlands were drained, they possessed a wide, unique and rich biodiversity because of the anaerobic water.20 The water is anaerobic due to the low photosynthetic
activity of plants living in the water. This water was ideal for several types of mosses, ferns and plants that need an anoxic environment to grow. These plants and the humidity of the area attracted a wide range of spiders and insects.21,22 The presence of
insects made these peatlands in turn an ideal habitat for a wide variety of unique birds, reptiles, amphibians, fishes and small mammals.21
Nowadays, peatlands in the Netherlands are mainly found as dewatered peat meadows used for dairy farming. The more solid surface of the meadows, combined with highly fertile grassland and nutrient rich waters provide a habitat to species that are different from the wetland types.23 Peat meadows form a unique landscape with environmental
importance on both national and international scale, due to the presence of a wide variety of meadow wildlife, including multiple endangered species of migratory birds and rare floral species.24 Due to the intensification of dairy farming, the pressure on
these endangered species increases and they are in great danger of disappearing.25
By extensification of dairy farming on these meadows, the pressure on the wildlife and ecosystem of the area could be preserved. This is a perfect example of how the 4 Returns framework enhances sustainable land use: even though the return of financial capital decreases with extensification, the return of natural capital increases. Therefore the net total return of financial and natural capital combined is higher when you extensify the dairy farming. Furthermore, by combining wet and dry agriculture, a mozaique landscape is created that provides habitats for both wetland and peat meadow bound species. This could increase the natural return even further.
Greenhouse gas emissions
Dairy farming and peatland drainage are two important sources of greenhouse gas (GHG) emission.3 GHG play an important role in global warming, since they retain heat
in the atmosphere.26 The three main GHG are carbon dioxide (CO
2), methane (CH4), and
nitrous oxide (N2O)3; together they account for 98% of the total GHG-emission.27 The
effect of a GHG on global warming is usually expressed as ‘global warming potential’
(GWP).26 GWP is a relative measure that compares the amount of heat trapped by a
certain mass of a gas with the amount of heat trapped by the same mass of CO2, whose GWP is standardized to 1.26 The unit of GWP is CO2-equivalent.26
28
In Figure 5, the emission CO2, CH4, and N2O are given for three different types of peatlands: wet peatlands, dry peatlands with a high groundwater level and dry peatlands with a low groundwater level. From this figure and the explanation above it becomes apparent that peatlands play a considerable role in greenhouse gas emission in the Netherlands. Since emission of greenhouse gasses is the major cause of the current global warming, which is causing severe damage to the environment, it is crucial to find ways to reduce greenhouse gas emission.28 One obvious way to
reduce the emission would be to increase the water level and rewet the peatlands. Peatlands could be changed from a greenhouse gas emitter to a greenhouse gas sink and can therefore greatly contribute towards the solution of global warming and the greenhouse effect.
A simple calculation illustrates the positive impact of peatland rewetting. The CO2 emission through peat oxidation is about 1.5 Megaton CO2 per year; equivalent to 1.3 million cars driving around for a year.29 In comparison, if these peatlands would be
under water and would actively accumulate peat again, they would absorb around 13.7 Megaton CO2 on a yearly basis, which equals to the CO2-emission of 11.7 million cars driving around for a year.6,7,29 From a quick calculation it becomes clear that the
difference in yearly CO2 emission between a dry and a wet peatland is around 15.2 Megaton CO2.6,29 A comparison study was performed in ‘Het Groene Hart’ that showed
that the yearly CO2 emission from peat oxidation was higher than CO2 emission from domestic use, as depicted in Figure 6.
The transition from greenhouse gas emitter to sink is a clear example of increasing the return of natural capital of the peatlands. Obviously, this is not as straightforward as it sounds, because, as will be explained next, many people live on the lands or use them, and peatlands are of cultural importance as well.
Disappearing cultural heritage
As described above, peatlands are of environmental importance because of their function as GHG sink and because of the unique biodiversity of the lands. Next to environmental importance of the peat meadows, they are also of cultural importance, since many of the Dutch people identify the peatlands as part of their history and surroundings.30 Furthermore this landscape attracts tourists. The windmills combined
with green grasslands grazed by several cows can be identified as Dutch heritage. A cultural heritage can be translated in economical value, defined as the amount of material or immaterial welfare that heritage generates for society.31 The material
value comprises the housing comfort value, while the immaterial value looks at the recreational perception value and the bequest value.30 The housing comfort value is
29
30 20 10 0 -10 -20 CO2 CH4 N2O TotalEmission (ton CO2-equivalents ha
¯1 yr¯1
Wet peatlands Peat meadows with
variable water levels Peat meadows withlow water levels
Figure 5. Emission of greenhouse gasses in peatlands with different groundwater levels. Adapted from
1.3 million ton
Peat oxidation
Houses
by land subsidence in “het Groene Hart”
1.4 million ton
Yearly CO2 emission
Houses
by all houses in “het Groene Hart” (electricity, gas,
Yearly CO2 emission
and water)
Peat Oxidation
Figure 6. A comparison between CO2 emission from peat oxidation and CO2 emission from domestic use in ‘Het Groene Hart’. Adapted from N. Pieterse, 2015.10
30
located near cultural heritage sites. Therefore the cultural aspect of the peat meadows should not be neglected when evaluating these lands, since it can provide various values.30 The recreational perception value is the additional value that can be created
trough the exploitation of both domestic and international tourism. The bequest value is the value of satisfaction gained from the preservation of a natural or historic environment for present and future generations.32 These immaterial values are more
subjective measures. They are obtained through questionnaires and interviews with people who make use of the land.
If the land subsidence continues at the current rate, the western parts of the Netherlands will disappear under water within the next 100 years.10 Preserving the lands is also
important for the Netherlands from a cultural perspective, since disappearance of the landscape would be a loss of social capital as well. However, preservation of the present landscape is conflicting with the maximal increase in natural capital, for which the solution was to put the meadows entirely under water. That would significantly decrease the cultural heritage value of the peat meadows. This conflict between different returns illustrates the complexity of the problem with the peat meadows and explains why all four returns should be incorporated in any solution for the problem.
Maintenance costs
Even though the current landscape has a cultural-economical value for the Dutch people, it also comes with costs. Since the beginning of 1900, the land has subsided up to 9 meters in some areas. Due to this oxidation, 20% of the peat in the Netherlands has been oxidized and the total amount of peat in the country decreased from 5350 Megatons to 4230 Megatons.1,6,7 The subsidence continues with an average speed of
1 cm a year. In Figure 10a the amount of subsidence from 2010 until 2050 is depicted. It shows that the western parts of the Netherlands will subside at least 10-60 cm. This increases the maintenance costs in these areas enormously.1,10 The costs for the coming
ninety years are summarized in Table 1 and illustrated by Figure 8. It shows that the continuous land subsidence will cost the
Dutch government on average €1.23 billion per year on top of the regular maintenance costs. Next to these costs there are also maintenance costs of privately owned houses and farms. An example of damage of a farm due to subsidence is depicted in Figure 7. These costs can be regarded as loss of social capital, since the land subsidence destroys the public utilities and forces the government to spend extra money on them.
Figure 7 .Dutch farm affected by subsidence. (Tesla team)
31
Sewages system Electricity cables
CO2
Drainage Barrages Flood defenses
Houses Roads Governmental Expenses Private Expenses 2010 – 2100 2010 – 2050 € 8 200 € 15 000 € 28 000 € 5 800 € 5 800 € 2 200 € 5 000 € 1 500 € 150 € 800 € 150 Total Expenses € 20 000 € 1 100 € 50 € 250 € 50
Figure 8. A schematic overview of the expenditures due to land subsidence. Adapted from N. Pieterse, 2015.10
Expense
Additional costs in million
€
Drainage costs 311
Barrage costs 1,700
Electricity cables maintanance 311
Flood defenses 3,100
Sewage system maintenance 10,400
House maintenance 12,000
Road maintenance 31,200
CO2 costs 51,900
Total over 90 years 110,900
Total per year 1,230
Table 1. Overview additional expenses due to land subsidence.
32
Decrease in water quality
As explained in the section ‘Drainageof the peatlands’, the water in the Netherlands is drained in order to keep the land dry and to increase the support of the ground.33 The drained
water is a combination of surface water and groundwater. When water is pumped out of the ground, groundwater from surrounding areas slowly seeps through again, due to differences in pressure between the areas. With the continuing land subsidence the upward pressure of groundwater becomes relatively higher, i.e. the weight of the land decreases, causing increased upward water seepage, ‘kwel’ in Dutch, see Figure 9.34 This has two major negative
effects.
Firstly, with increasing upward water seepage it becomes increasingly difficult and costly to keep the ground dry enough for farming and to build on it. If the land continues to subside, the upward water seepage will become greater and it will become impossible to drain the water any longer.33 When this will happen depends on
the speed of the subsidence and the level of the groundwater in the area.35 See Figure
10b for an overview of water seepage in the Netherlands.
Secondly, upward water seepage often translates to saltwater intrusion in the western parts of the Netherlands, since most of the groundwater there is highly saline due to earlier oceanic floods; see Figure 10c.36,37 This is problematic for farmers, since high
saline concentrations decrease the fertility of the ground.37
Both problems can be counteracted by increasing the water level of the subsiding areas. The increased water level decreases the relative upward pressure of groundwater and salinity of the groundwater decreases due to diluting the salt in a larger water body. Increasing the water level would therefore be a way to decrease the loss of natural capital: it ensures preservation of fertile land. It would however decrease the direct financial return of the land, since higher water levels make the land less suited for dairy farming. It is thus essential to look for other ways of making profit from these rewetted lands in the future. How this can be achieved will be discussed in the section ‘Azolla: a contribution to peat preservation’.
Figure 9. Upward water seepage in a peatland meadow. (Tesla team)
33
Consequences in short
In this section different effects of peatland drainage have been explained. Drainage leads to peat oxidation, which has several negative consequences. It causes environmental problems such as GHG emission, land subsidence, a decrease in water quality and a threatened biodiversity. The major problems for society are the significant increase in maintenance costs due to subsidence and the threat of losing the cultural Dutch landscape. Evidently, all these problems are severe and something should be done to prevent them from becoming any bigger. However, no preventive measures have been taken up to this point. The reason why no measures have been taken will be explained in the next section. Furthermore, important stakeholders of the problem
Decrease > 60 cm Decrease 40-60 cm Decrease 30-40 cm Decrease 20-30 cm Decrease 10-20 cm Decrease 2-10 cm Decrease till 2 cm No change Increase till 2 cm Increase > 2 cm < -1.0 Upwater seepage -1.0 - -0.5 -0.5 - -0.1 -0.1 - 0.1 0.1 - 0.5 0.5 - 1.0 >1.0 Infiltration No data a) Land subsidence b) Upwater seepage
-750 - -650 -650 - -550 -550 - -450 -450 - -350 -350 - -250 -250 - -200 -200 - -150 -150 - -100 -100 - -75 -75 - -50 -50 - -40 -40 - -30 -30 - -20 -20 - -10 -10 - 0 c) Salt water level below sealevel
Meters below sealevel
Figure 10. a) Land subsidence between 2000 and 2050. Adopted from G. De Lange and J. Gunnik, 2011.35 b) The rate of upward and downward water seepage in the Netherlands. Adopted from NHI,
2009. 90 c) Depth of salt water below sealevel. Adopted from R. Stuurman and G. Oude Essink, 2007.91 Consequences of peatland drainage
35
Revenues from dairy farming
The dairy industry plays an important role in the Dutch economy and its international trade. A total of 18,000 farms and 1.6 million cows produce 12.7 billion kilos of milk per year, which amounts to two glasses of milk a day for almost 100 million people.39
Around 98% of the Dutch raw milk is processed into dairy products like cheese, butter, pasteurized milk and milk powder. Most of the dairy products of the Netherlands are exported to countries all over the world; the Netherlands is the largest exporter of dairy products of the countries both within and outside the European Union.38
In 2014 the Dutch farming industry and the dairy industry had a production value of 5 billion and 7 billion euros respectfully.39 The sector comprises of 45,000 fulltime jobs,
even after the automation took over a significant part human labor. The Netherlands has a leading role in dairy farm automation, through which the yield per cow is significantly increased and which causes the production per cow to be in the global top. Furthermore, the expertise in dairy farming technology is another major export product of the Netherlands.40
In short, the Dutch dairy industry is so successful and important to the country that a lot of effort is put into keeping the industry as it is.38 This includes keeping the water levels
at 60cm below ground level and intensification of the dairy farms i.e. increasing the number of animals per hectare. Unfortunately this can only be a short-term solution, since these practices are exhausting the lands quickly. As can be read in the next section, the current circumstances for dairy farmers can be used as an opportunity to look for more sustainable alternatives.
When reading about the consequences of peatland drainage, the question “why do the Dutch continue to do this?” arises. To find an answer to this question, one must take a further look into the current state of the dairy industry in the Netherlands. Historically, the farmers on Dutch peatlands specialized in dairy farming, because peat soil is suited for grass cultivation, but not very suitable to grow other crops like grain.1 Nowadays the dairy farmers still use around 60% of the total peatland surface in the northwestern
parts of the Netherlands.38
Dairy farming on peatlands
36
Future of dairy farming
In the past years there have been some adversities for dairy farmers, of which the abolishment of the milk quota in April 2015 has had the biggest impact.38 With the
abolishment most of the farmers have expanded their farms investing vast amounts of money in their farms.41 The result is an oversaturation of the market and a decrease of the milk price. Consequently, the farmers do not have enough money for new investments and have to work very hard to be able to survive in the dairy business. Currently a growing number of dairy farmers are looking for new ways to add value to their product instead of continuing to increase their milk production. The large ‘dead-end’ investments they made on their farm force them to look for solutions of the subsiding land within the dairy farming sector.38
Another important factor in the dairy farming is the so-called ‘fosfaatplafond’-law, which is literally translated as ‘phosphate ceiling’ from Dutch, implemented by the European Union.42 This law prescribes a legal maximum of manure production per
hectare of land owned by a farmer, in order to prevent further phosphate-pollution of (agricultural) grounds and water. The abolishment of the milk quota (leading to expansion of dairy farms) caused the farmers to exceed the phosphate limit for the first time in five years in 2015, which is shown in Figure 11.43
2010 2011 2012 2013 2014 2015 0 50 100 150 200 250
Cattle Poultry Pigs Others Phosphate ceiling
Phosphate production through manure (million kg)
Figure 11. The phosphate production in animal manure over the past five years in relation to the phosphate ceiling of the Netherlands. Adapted from CBS, 2016.43
37
Due to the phosphate ceiling farmers cannot expand their businesses any further and due to the milk quota the farmers do not earn nearly as much money as they used to do. As one can imagine, this is an unstable situation that asks for a change towards more sustainable business models of dairy farming, where the focus is no longer only on higher milk production.44 This could for instance be achieved by incorporating
collaboration with nature preservation organizations, water authorities, or other (governmental) institutions. This way farmers could earn money with ‘nature services’ such as shelters for endangered and land for water storage.44 The 4 Returns model of
Commonland provides a very useful framework for the farmers to incorporate all these forms of land use in their business.
39
During the exploration phase of the Tesla project, different innovations have been assessed for their impact and feasibility. The innovations can be grouped in the categories: extensification of dairy farming, from dairy farming to other agricultural businesses, or from farming to different land use, see Appendix I. From these innovations, three different solutions seemed the most interesting and promising:
1. Wastewater treatment by wet peatlands
2. Landmass heightening with Topsurf
3. Paludiculture on wet peatlands
Wastewater treatment is a way to go from dairy farming to another form of land use, landmass heightening can be an addition to extensification of dairy farming and paludiculture enables the farmer to switch from dairy farming to another agricultural business. The three ideas have been examined in depth during the research phase. The results of this research is summarized in Table 2, for more extensive information on all three options, see Appendix II.
Azolla: a contribution to peat
preservation
40
Idea
Short
exlanation
Positive
impact
Practical
drawbacks
Conclusion
Wastewater
treatment
Wastewater can be purified and filtered by the unique ecosystem of wet peatlands45 Creating, restoring and maintaining wet peatlands while purifying wastewater 1.Implementation is not yet viable from an economical perspective2.Pollution in urban wastewater is usually too high to purify it only through wastewater wetlands
3.No clear profit for landowners Major drawback is that wastewater treatment is not economically viable for farmers
Landmass
heightening
with Topsurf
Topsurf is made from materials obtained from waste streams: manure, dredging and mowing surplus Application of Topsurf would allow an increase of the water level, preventing further subsidence1.Product is yet not legal in the Netherlands 2.Much uncertainty about the effects of the product More research is needed before it can be applied safely and be legalized
Paludiculture
on wet
peatlands
Agriculture with crops that grow under wet circircumstances46Paludiculture is a way to make profit from a wetland
1.There are many different crops to choose from 2.The market for paludiculture products is virtually nonexistent Azolla was chosen as an example of paludiculture to show the possibilities of wet agriculture Table 2. A summary of the three options that have researched in-depth.
41
Paludiculture with Azolla
Based on Table 2 it was concluded that paludiculture in general would be the most viable option for a pilot, since a substantial amount of research has been done on possibilities and business models of different forms of paludiculture,47 whereas there
were too many unknown factors for the other two options. Subsequently, different forms of paludiculture were explored. Based on these results it was decided that the aquatic fern Azolla was a very interesting option for a pilot. A major advantage of this crop is that Azolla contains high concentrations of nutrients and is therefore is highly suitable as cattle feed. This makes it interesting for dairy farmers to grow the product for their animals. As mentioned in the ‘20 Years’ section, a landscape restoration project has to comprise a transition phase. Azolla can play an important role in the transition phase of this project, since farmers do not have to adapt radically to a new situation. Instead, they can first use the crop for their dairy business. Another advantage for the farmers is that it is relatively cheap and easy to grow Azolla and no large investments have to be done to start growing Azolla.
To get a better understanding of the fern, some technical aspects of the plant will be described, since it gives an excellent description of the plant’s potential. After this the different possible applications of Azolla will be discussed.
Characteristics of Azolla
Azolla filiculoides, the Azolla-subspecies focused on in this report, is an aquatic fern that can be found in freshwater locations in warm-temperate, subtropical and tropical regions in the world. Azolla can be found in the Americas from southern South America through western North America to Alaska.48 The species used to be native in Europe,
but was destroyed during the last ice age. This species has been reintroduced in Europe around 1880 and is generally considered to be naturalized on the continent.49,50 For a
more extensive history of Azolla, see Box 3.
In Table 3 it is shown that the fern is only found in certain countries in Northern Europe, including the Netherlands.50 Interestingly, based on this table, the plant does not seem
extremely invasive, since it is not distributed over the whole continent and where it is found it is only found to be ‘common’, but never ‘very common.’50 This means that even
though the plant grows very fast, it has not spread uncontrollably over the Europe.50
Azolla lives in symbiosis with the green-blue algae Anabaena Azollae.51 These algae
are made from beadlike highly pigmented vegetative cells that are approximately 6 μm in diameter and 10 μm in length. They have the ability to fixate nitrogen in a fast
42
rate, which can be used by Azolla.51 The fern can therefore survive in water with low
nitrogen levels and is mainly dependent on phosphor concentrations in the water.52
Due to its variety of light-harvesting pigments present in both Azolla and Anabaena, they can capture a wide range of the photo-electric spectrum, which allows the plant to achieve photosynthetic rates higher than most plants.52 Laboratory studies at the
International Rice Research Institute in the Philippines have shown that Azolla can double its mass within 3 to 5 days, while growing in a nitrogen-free solution.53
Box 3: History of Azolla
To evaluate the history of Azolla, one needs to look back thousands of years ago, all the way back to the Eocene. Sediments of the Eocene were successfully recovered during an expedition in 2004 at the most northern location on Earth, which was only 250 km from the North Pole (87o52’N, 136o10’E). In this sediments dark-clay and light-clay layers were found and it was within these light-clay layers that high concentrations of Azolla spores were found.92 This indicated that Azolla
grew, reproduced and thrived in the Eocene Arctic Ocean. This left scientist quite puzzled, since Azolla we know today grows in warm temperate to tropical fresh water bodies and can only withstand salinities of a maximum of 5.93 It therefore
suggests that the arctic during the Eocene was warmer and less saline; otherwise Azolla could not have lived there.
Deeper research into this suggested that Azolla occupied the entire artic from 49.3 million years ago to 48.1 million years ago.94 Even more interesting are the
enhanced greenhouse conditions during this time, with CO2 concentrations ranging between 400-3000 ppm.95 This is of great interest in the modern age since
mankind first witnessed the CO2 concentration exceeding 400 ppm in 2015.96
During the Eocene when Azolla was thriving, it fixated an enormous amount of CO2. When the Azolla plant died, it sank to the bottom of the ocean, thus effectively removing CO2 from the atmosphere. This event is now referred to as the Azolla event and is been considered as an important, if not the most important factor causing the cooling of the planet into the quaternary glaciation, or ice age we recently experienced.95
This research on the history of Azolla demonstrates the power of this fresh-water fern, especially in relation to CO2 fixation. The research also led several scientists to further investigate Azolla as a candidate in a bio-based economy and as a measure to counteract the greenhouse effect.
43
Country
Not found
Not established Rare
Local
Common
Austria Belgium Denmark Estonia Russia Finland Faroe Island Germany Greenland Iceland Ireland Latvia Lithuania Netherlands Norway Poland SwedenTable 3. The frequency and establishment of Azolla filiculoides in Northern Europe. Legend for this table: Not found - The species is not found in the country; Not established - The species has not formed self-reproducing populations (but is found as a casual or incidental species); Rare - Few sites where it is found in the country; Local - Locally abundant, many individuals in some areas of the country; Common - Many sites in the country. Adopted from the NOBANIS invasive alien species factsheet, 2010.51
44
Environmental effects Azolla
cultivation
Azolla cultivation is a form of paludiculture that can contribute to peat preservation; the peat underneath the Azolla will not get in contact with air and oxidized. The fact that it can be used as animal feed makes it interesting for farmers to grow this: it is cheaper than importing other forms of concentrates such as soybeans, and it is relatively easy to harvest. Scientific research on the properties of the plant has shown that Azolla can be used for several other purposes, which further increases the potential value of the crop.51,52,54–58 Azolla tillage has multiple consequences for the environment, which are
shortly explained below and summarized in Table 4.
Greenhouse gas reduction
From the history of Azolla it can be seen that it has great potential as a CO2 fixating agent. The tremendous growth rate due to its high photosynthetic activity can contribute to the goals to reduce the carbon footprint in 2020 and 2050, which was stated in previous sections. Growing Azolla is therefore a quick way to produce biomass while fixating CO2 by using light from the sun.
Peat preservation
Since Azolla has to be grown on water, the water level has to be increased in order to be able to grow it. Because of this, the peat underneath the Azolla cannot come in contact with air and will be preserved as long as the water level stays high.1 This is a
major reason why Azolla growth in the northwestern part of the Netherlands can help with preserving the landscape. However, it is only preserving the peat, not restoring it. In order to fully restore the peat landscape, Azolla growth should be combined with other solutions.
Wastewater filtering
The exceeding of the phosphate ceiling, which was discussed in the ‘Future of dairy farming’ section, leads to an excess of phosphate in Dutch surface water. The water quality based on phosphor concentrations is depicted in Figure 12a. 59 Since Azolla has a
high phosphor absorption capability, it can be used to filter phosphor from the surface water.57,60 The fact that Azolla binds only atmospheric nitrogen can be a disadvantage if
nitrate levels in the water are high. As shown in Figure 12b, the water quality based on the nitrate concentrations in the surface water is average, while based on phosphate levels it is bad. Since phosphate in surface water seems to be a more pressing problem than nitrogen, Azolla would be an interesting option for wastewater treatment.59
45
b) Nitrogen Excellent Good Moderate Below everage Bad a) PhosphorFigure 12. Water quality in the Netherlands based on a) phosphor concentrations and b) nitrogen concentrations measured from 2010 to 2014. Adopted from: Compendium voor leefomgeving59
Effect of Azolla
growth
Based on which
characteristics?
Potential problems
Advantage or
disadvantage?
GHG reduction
-CO2 absorbtion-Water prevents peat oxidation
None Advantage: GHG
emission is a major problem worldwide
Peat preservation
-Water prevents peatoxidation No peat restoration, only preservation Advantage: peat oxidation is a major problem in the Netherlands
Wastewater filter
-High phosphateabsorption from water High phosphate absorption from water Advantage: phosphate levels in The Netherlands are above EU-limit
Decrease
biodiversity
63 -Decrease of sunlight in water -Oxygen decrease in water Loss of biodiversity in areas with Azolla growthDisadvantage: choice between Azolla and biodiversity
Table 4. Summary of the effects of Azolla tillage for the environment.
46
Influence on ecology
There are a lot of unknowns about the effects of Azolla on water ecology. There is evidence that Azolla growth changes the nutrient composition of the water, therefore it is reasonable to expect the biodiversity will change as a consequence of Azolla growth.62 There is one study that shows that the presence of a thick mat of Azolla on
the water almost completely suppressed the number of mosquito larvae in these water bodies, thus allowing for the control of these populations.63 This could be an indication
that Azolla can remove other aquatic organisms due to its intense growth rate.
Marketable products of Azolla
Azolla can be processed into several marketable products, which are summarized in Table 5. The multi-functionality of the crop is its main advantage, since this means farmers can start growing it for their cattle and could decide later that they switch entirely from dairy farming on Azolla diet to growing Azolla for other purposes. This fits perfectly with the transition phase in landscape restoration as shown in the ’20 Years’ section.
Livestock feed
In the past two decades many research has been done towards the use of Azolla as animal feed. From the composition section of Azolla it can be seen that Azolla is very rich in proteins and can therefore be used as a replacement for the expensive supplements that farmers use today. Chickens, ducks, cows, pigs and many other animals have shown to thrive on Azolla feed.62,63 Up to this point no systematic
research has been conducted towards the exact effects of Azolla on cows, but the LPP Foundation has plans to conduct these soon (Peter Bijl, president LPP Foundation, personal communication, 5 July, 2016).
Biofuel
Several researches have been exploring the potential of Azolla as a biofuel.64 Due to the high growth rate and the non-competitiveness for food production, Azolla is an excellent candidate. The production of fuel can be achieved in three distinct ways. First the production of biomass to be used in a furnace seems to be possible but highly inefficient.65 Secondly is the production of the highly energetic hydrogen, which can be achieved using a “trickling-medium” column bioreactor to obtain a production rate of 83 ml hydrogen per gram fresh weight per day.66 Finally Azolla can be used
to produce methane gas when used in a biogas generator in combination with cow dung. The amount of methane generated seems to be the highest when Azolla is used and it is therefore a very viable option.54
