Opportunities and Challenges of Sphagnum Farming & Harvesting

Gilbert Ludwig

Master’s thesis December 2019 Bioeconomy Master of Natural Resources, Bioeconomy Development

Description

Author(s) Type of publication Date Ludwig, Gilbert Master’s thesis December 2019 Language of publication: English Number of pages Permission for web 33 publication: x Title of publication Opportunities & Challenges of Sphagnum Farming & Harvesting

Master of Natural Resources, Bioeconomy Development

Supervisor(s) Kataja, Jyrki; Vertainen, Laura;

Assigned by International Peatland Society Abstract Sphagnum sp. moss, of which there are globally about 380 species, are the principal peat forming organisms in temperate and boreal peatlands. Sphagnum farming & harvesting has been proposed as climate-smart and carbon neutral use and after-use of peatlands, and dried Sphagnum have been shown to be excellent raw material for most growing media applications. The state, prospects and challenges of Sphagnum farming & harvesting in different parts of the world are evaluated: Sphagnum farming as paludiculture and after-use of agricultural peatlands and cut-over bogs, Sphagnum farming on mineral soils and mechanical Sphagnum harvesting. Challenges of Sphagnum farming and harvesting as a mean to reduce peat dependency in growing media are still significant, with industrial upscaling, i.e. ensuring adequate quantities of raw material, and economic feasibility being the biggest barriers. Development of new, innovative business models and including Sphagnum in the group of agricultural products eligible for subsidies, could in the future open up new and sustainable livelihood opportunities for landowners and peat extraction professionals, and ultimately may be key in reducing the peat dependence of growing media.

Keywords/tags (subjects)

Peat, peat alternatives, paludiculture, growing media, sustainability, Sphagnum sp., Sphagnum farming, Sphagnum harvesting, climate change Miscellaneous (Confidential information)

Description

Tekijä(t) Julkaisun laji Päivämäärä Ludwig, Gilbert Opinnäytetyö, YAMK Joulukuu 2019 Julkaisun kieli English Sivumäärä Verrkojulkaisu 33 myönnetty: x Työn nimi Rahkasammaleen viljelyn ja keruun mahdollisuudet ja haasteet

Tutkinto-ohjelma Biotalouden edistäminen YAMK Ohjaaja(t) Kataja, Jyrki; Vertainen, Laura;

Toimeksiantaja International Peatland Society/Kansainvälinen Suojärjestö ry Tiivistelmä Rahkasammalet ovat laaja sammalten suku, jotka muodostavat maatuessaan turvetta, ja sen viljelyä ja keruuta pidetään yhtenä lupaavana ja ilmastoystävällisenä soiden käyttömuotona. Kuivattuna raaka-aineena rahkasammal on ihanteellinen erilaisten kasvualustojen ainesosana. Tässä opinnäytetyössä selvitin rahkasammalviljelyn ja -keruun nykytilaa sekä tulevaisuuden näkymiä sekä haasteita eri puolilla maailmaa.

Rahkasammal on nopeasti uusiutuva raaka-aine, jolla on vahva potentiaali kasvualustojen turveriippuvuuden vähentämisessä, mutta sen tuotannon nostaminen teolliselle tasolle, eli riittävien raaka-ainemäärien varmistaminen, sekä taloudellisuus ovat vielä suuri haaste. Uusien innovatiivisten liiketoimintamallien ja teknologian kehittäminen sekä muutokset maatalousstrategioissa voisivat tulevaisuudessa avata viljelijöille ja maanomistajille uusia ja kestäviä toimeentulomahdollisuuksia.

Avainsanat Turve, turvevaihtoehdot, paludikulttuuri, kasvualustat, kestävyys, rahkasammal, sphagnum sp. Peat,Muut tpeatiedot alternatives, paludiculture, growing media, sustainability, Sphagnum sp., Sphagnum farming, Sphagnum harvesting, climate change

Contents

1 Background ...... 4

2 Objectives...... 7

3 Methods ...... 7

4 Results...... 9 4.1 General ...... 9

4.2 Sphagnum farming as paludiculture and after-use of of agricultural peatland and cut-over bogs (Germany, Canada, Sweden) ...... 10

4.3 Sphagnum farming on mineral soils (China) ...... 14

4.4 Mechanical Sphagnum harvesting (Finland, Sweden) ...... 18

5 Conclusions ...... 20 5.1 Environmental Dimensions of Sphagnum Farming & Harvesting ...... 20

5.2 Economic Dimensions of Sphagnum Farming & Harvesting ...... 23

5.3 Societal Dimensions of Sphagnum Farming & Harvesting ...... 24

5.4 Technology Dimensions of Sphagnum Farming & Harvesting ...... 25

6 Discussion...... 26

References ...... 27

Figures

Figure 1. Global peatland distribution derived from PEATMAP (Xu et al. 2018.) ...... 5 Figure 2. Experimental Sphagnum cultivation site, Hankahauser Moor, Rastede, Germany. Image by Gilbert Ludwig ...... 11 Figure 3. Sample of Sphagnum from first year harvest in Sweden. Image courtesy of Sabine Jordan ...... 14 Figure 4. Upper left: Dense Sphagnum growth, before harvest (Image courtesy of Zhu Longjin). Upper right: Annual growth (Image courtesy of Zhu Longjin). Bottom: Sphagnum cultivation site on former rice paddy, after harvest (Image courtesy of Gilbert Ludwig). All images Qiannan Prefecture, Guiding, Guizhou...... 16 Figure 5. Mechanical harvesting in Finland. Image courtesy of Hannu Salo...... 19 Figure 6. Peatland uses in Finland as % of total surface. Adapted from Rantanen (2019a) ...... 20

1 Background

With the world population expected to reach 10 billion by 2050, the demand of vegetables, fruits and flowers is increasing rapidly. According to Hunter, Smith, Schipanski, Atwood & Mortensen (2017, 386), global food production will have to increase by up to 70% from current production levels by 2050, with vegetable production needs being likely even higher. At the same time, expansion of traditional agriculture is increasingly difficult and needs to be prevented (Ranganathan, Waite, Searchinger & Hanson 2018.). Intensive and large-scale production of vegetables and fruits in greenhouses using standardized high-quality growing media mixtures, or substrates, allow uniform high-quality plant seedlings to be grown economically with very high productivity (Altman 2008.). As an example, following its agricultural crisis in the end of the 20th century, China is increasingly shifting its production of vegetable, fruit and rice seedlings to controlled greenhouse plantations, resulting in a gradually increasing demand of growing media (Meng 2019.). According to Meng (2019), Chinas demand of growing media will increase from currently 2 mio m3 to 100 mio m3 within the next 10 to 20 years. Globally, growing media demand is expected to increase from 60 mio m3 in 2018 to 240 mio m3 by 2050 (Blok 2019.). Ensuring availability of raw materials in order to keep up supply of growing media is therefore a big challenge (Hofer 2019.), but also a necessity.

The challenge is exacerbated by the fact that, for decades, Sphagnum peat (mostly white peat) has been, and still is, the single most important ingredient of most growing media mixtures, comprising commonly 60-90% of growing media mixtures. The unique physical and chemical properties, such as low pH, nutrient and nitrogen immobilization, its structural properties, slow decomposition, low bulk density, high porosity and unique water retention capacities, the fact that it is relatively free of weeds and pathogens, and, after all, its low price, make peat the most important constituent of professional high-quality growing media mixtures that allow easy adjustment to requirements of individual plants (Schmilewski & Köbbing 2016, Schmilewski 2008).

The sustainability of peat based growing media, however, is an increasing concern of environmental lobbying. Covering over four million km2, or about 3% of the world’s

5 terrestrial & freshwater surface (Fig. 1), peatlands store and sequester more carbon than any other terrestrial ecosystem, about one quarter of the worlds soil carbon. Drained peatlands make up about 16% of the world’s peatlands, or 0.5% of the Earth’s land surface, yet their contribution to global greenhouse gas and cropland emissions are 5% and 32%, respectively (Joosten et al. 2016, Carlson et al. 2017). Peatlands and peatland use make therefore an important contribution to global climate change mitigation (Biancalani, Salvatore & Tubiello 2014.), the significance of rewetting and restoration of drained peatland is increasingly acknowledged (Leifeld & Menichetti 2018.). FAO (UN Food and Agriculture Organization) are actively promoting replacement of peat in growing media through sustainable peatland concepts. As a result, the use of peat as raw material is increasingly criticized, and the environmental agenda demands global phase out of peat by 2050 in order to contribute to the climate targets set by the Paris 2015 agreement (Günther et al. 2019.).

Figure 1. Global peatland distribution derived from PEATMAP (Xu et al. 2018.)

There is a wide range of other known growing media constituents, such as e.g. coconut choir, wood fibre and bark, compost, perlite or stonewool, to name a few (Schmilewski 2018, 65.). While all of those substituents have advantages and disadvantages, complete peat free growing media have so far failed to meet the needs and standards of professional growers, with availability, quality (and consistency thereof), high price and health issues being the main concerns (Hofer 2019.). Nevertheless, the pressure to develop growing media solutions that use less,

6 or no peat at all, is increasing rapidly. However, considering the increasing importance of growing media for food security in many parts of the world, one may argue that measures for climate protection should be limited at the point when they endanger the existential needs for food of the world population, at least until viable alternative solutions are developed.

Sphagnum sp. are a large genus of moss comprising about 380 species (The Plant List 2016.) commonly called peat moss, and are the principal peat producing organism on mires such as raised bogs or blanket bogs (Gorham 1957, 145-166.). Sphagnum may retain water as much as 16 to 26 times as their own dry weight, decompose very slowly due to conditions of waterlogging, oxygen deficiency, high acidity and nutrient deficiency, and eventually form the bulk of the surface organic layer called peat that is typical of peatlands in the temperate, boreal and sub-arctic regions (Bold 1967, 225.). Sphagnum moss have unique physical and chemical properties that are comparable to white peat, making them an increasingly valued constituent of horticultural growing media (Emmel 2008, Wichmann, Prager & Gaudig 2018), and a potential candidate to reduce the peat dependency of growing media in horticultural applications (Gaudig et al. 2014.). Caron & Rochefort (2015) consider Sphagnum an indispensable raw material for a wide range of horticultural products, and highlight that demand is increasing despite increasing availability and supply of other peat alternatives. Furthermore, Gaudig et al. (2018) found that a proportion of up to 50% Sphagnum biomass (by volume) poses no problems to most growing media applications. For vegetables, growing experiments with Sphagnum have been succeeded successfully with seedlings of e.g. cauliflower (Brassica oleracea var. botrytis), Chinese cabbage (Brassica rapa ssp. pekinensis), cucumber (Cucumis sativus), lettuce (Lactuca sativa), or tomato (Solanum lycopersicum) (Gaudig et al. 2018.).

Sphagnum farming is a form of paludiculture (Gaudig et al. 2017.). Paludiculture can be described as the use of wet or rewetted peatlands for the purpose of cultivating biomass, be it or agriculture or forestry, under conditions where peat is conserved Wichmann, Schröder & Joosten 2016.).

Besides of its use in growing media applications, paludiculture in the form of Sphagnum cultivation, but without harvesting, is also proposed as means to

7 transform peatlands, which have been formerly extracted or used as agricultural pastures, into climate-smart after-use environments, thereby contributing positively to climate change mitigation (Gaudig et al. 2017.).

2 Objectives

The main objectives of this study are to evaluate the current state of both Sphagnum farming and Sphagnum harvesting in different parts of the world, its challenges and opportunities, from an environmental, economic and societal perspective, as a means to

a) Reduce the peat dependence in growing media b) Develop climate-smart after use of cut-over bogs or peatlands used in agriculture c) Develop alternative sources of income for farmers and landowners, or peat extraction professionals

3 Methods

The status of Sphagnum farming and Sphagnum harvesting in different parts of the world is evaluated using information from the following sources:

a) Review of recent scientific literature, including congress abstracts b) Review of popularizing articles and online contributions c) Discussions & emails and with people from the branch, including both academic and industrial representatives: a. Hannu Salo, Bioenergia ry, discussions & emails, Jan-Nov 2019 b. Dr. Sabine Jordan, SLU Uppsala, several discussions and emails, Jan- Nov 2019 c. Josef Gramann, Gramoflor, Discussion, Field & Company visit, January 2019 d. Dr. Silke Kumar, Moorwek Ramsloh, Discussions Hankhauser Moor January 2019, Bad Zwischenhahn 2019 & emails

e. Prof. Xianmin Meng, Institute for Peat and Mire Research, Northeast Normal University, Changchun, China. Several discussions (China April & September 2019, Bremen 2019 & emails f. Dr. Jan Köbbing, Klasmann-Deilmann, Discussion, Bremen 2019 & emails g. Dr. Niko Silvan, LUKE, Discussion & Field visit Kihniö & Aitoneva, June 2019 & emails h. Dr. Franziska Tannenberger, University of Greifswald. Meetings May 2019 Isle of Vilm & 17.10.2019, Greifswald, Germany. Several emails. i. Dr. Sandrine Hogue-Hugron, University of Laval, Discussion and Field visits, Quebec, Canada, June 2019 j. Professor Line Rochefort, University of Laval, Discussion and Field visits, Quebec, Canada, June 2019 k. Teppo Rantanen, CEO Biolan, Discussion Qingdao 2019 and emails l. Zhu Longjin, 3 day visit with field visits & discussions, September 2019, Guiding & Qingdao, China, discussions via wechat & email m. Professor Hans Joosten, University of Greifswald. Meeting 17.10.2019, Greifswald, Germany. n. Dr. Greta Gaudig, University of Greifswald. Meeting 17.10.2019, Greifswald, Germany. Several emails. o. Dr. Sabine Wichmann, University of Greifswald. Meeting 17.10.2019, Greifswald, Germany. d) Attendance of symposia and trade fairs relevant to the topic: a. IPM Shanghai (World’s largest horticultural Trade Fair), Shanghai/China, April 2019 b. IPS Convention 2019 - Economy meets Environment & Society: Future Use of Peat and Substitutes in Horticulture, Bremen/Germany, May 2019 (IPS 2019a.) c. International Symposium on Peat for Food & Quality of Life, Qingdao/China, September 2019 (IPS 2019b) d. Hortichina 2019 – 1st China International Peat Product and Technology Expo, Qingdao/China, September 2019

e) Field visits a. Hankhauser Moor, Rastede, Germany: Sphagnum Farming on agricultural peatlands, January 2019 b. Several field sites in Quebec/Canada: Sphagnum farming and peatland restoration, June 2019 c. Aitoneva & Kihniö, Finland: Sphagnum harvesting, June 2019, esim Silvan (2012) d. Guizhou/China: Sphagnum farming on mineral soils, September 2019 The study focuses on, and is restricted to:

a) Sphagnum farming as paludiculture and after-use of agricultural peatlands and cut-over bogs (Germany, Canada, Sweden) b) Sphagnum farming on mineral soils in (China) c) Mechanical Sphagnum harvesting (Finland, Sweden

4 Results

4.1 General

Results are presented in three parts: a) Sphagnum farming as paludiculture and after-use of of agricultural peatland and cut-over bogs (Germany, Canada, Sweden), b) Sphagnum farming on mineral soils (China) and c) Mechanical Sphagnum harvesting (Finland, Sweden). For the first part, a short background on German and Canadian Sphagnum farming is given on the basis of recent literature, supplemented with information from discussions and emails with specialists from the field (Germany, Canada, Sweden). Results on Chinese Sphagnum farming is largely derived from discussions and email with Xianmin Meng & Zhu Longjin,a s well as on a presentation given by Zhu (2019a) in Qingdao, September 2019. Results on Swedish Sphagnum farming are largely based on discussions and emails, as well as on Kling & Jordan (2019). Results on Sphagnum harvesting Finland are based on recent scientific and popularizing literature, as well as a field visit and discussions with Hannu Salo and Niko Silvan. Discussion & Conclusions are presented in the context environmental, economic and societal impact of the presented results.

4.2 Sphagnum farming as paludiculture and after-use of of agricultural peatland and cut-over bogs (Germany, Canada, Sweden)

Gaudig et al. (2018) highlight three types of Sphagnum “activities”. Firstly, restoration of Sphagnum vegetation on drained cut-over peatlands, with no intent of harvesting, as a means of e.g. carbon sequestration and climate mitigation, or nature conservation (e.g. Gonzalez & Rochefort 2014, Clarkson, Whinam, Good & Watts 2017, Karofeld, Müür & Vellak 2016.). Secondly, Sphagnum harvesting is the manual or mechanical collection of Sphagnum from largely unmanaged, wild populations. Manual harvesting is done in e.g. Chile (Diaz & Silva 2012.), Australasia (e.g. Buxton et al. 1996.) and mechanical harvesting in Finland (Silvan et al. 2012.). Thirdly, Sphagnum farming is the active management and cultivation of Sphagnum biomass for harvest. Biomass was originally intended to be used as donor material for restoration projects (Money 1994.) but is increasingly targeted as raw material for growing media. Sphagnum farming normally occurs on degraded bogs (bogs used in agriculture and cut-over bogs). Sphagnum can, however, also be cultivated successfully on mineral soils, e.g. on former rice paddies in Southern China (Zhu 2019a.).

The idea to convert formerly extracted bogs into climate smart land-use was originally inspired by Canadian studies providing guidelines to restore and re- naturalize bogs that were extracted for horticultural peat (Quinty & Rochefort 2003.). During the restoration process, Sphagnum material is collected from a new upcoming extraction area and is spread densely over the rewetted cut-over area. In order to avoid losses due to drying or freezing, Sphagnum are covered with straw during the first year, allowing the Sphagnum to establish itself. This method has proved successful and recent result of over 10 years of greenhouse gas dynamics monitoring showed that restored bogs turn from carbon sources to carbon sinks within 10 years (Roulet 2019.).

The first outlooks on Sphagnum farming for horticultural purposes in Germany comes from Gaudig & Joosten (2002), and the first pilot project dates back to 2004 (Gaudig, Krebs & Joosten 2014, 1.), and similarly farming intents, with the aim to collect Sphagnum as biomass, have been conducted in Canada since 2004 (Landry &

Rochefort 2009). The two methods of Sphagnum farming in Germany and Canada differ between each other due to differences in the extent of humification and permeability (Robert et al. 2019.). In essence that means that German Sphagnum farming implies a higher degree of water level control in order to stabilize the water table. Gaudig et al. (2014, 2018) provide excellent outlooks on Sphagnum farming in general and on the different stages from species selection to the production of growing media. Long-term studies on farmed Sphagnum growth on cut-over bogs in NE Germany are presented in Gaudig, Krebs & Joosten (2014). Figure 2 shows the experimental Sphagnum farming at Hankhauser Moor, Rastede, Germany, in January 2019.

Figure 2. Experimental Sphagnum cultivation site, Hankahauser Moor, Rastede, Germany. Image by Gilbert Ludwig

As a summary German farming experiments reveal that (Gaudig et al. 2014, Gaudig et al. 2018, Gaudig, Krebs & Joosten 2014):

- Sphagnum is an excellent biomass and suitable, renewable raw material for growing media - Sphagnum palustre is possibly the single most promising species for both farming and growing media applications - Sphagnum can be farmed on re-wetted peat areas with varying water levels, but risks such as insufficient water availability or expansion of parasitic fungi and vascular plants need to be identified - Sphagnum is overall still in an early developmental stage, especially its industrial upscaling and large-scale commercialization

Possibly a critical success element in the process of upscaling of Sphagnum farming is whether or not Sphagnum moss may be included in the group of agricultural products eligible for Agricultural funding, or subsidies, on national or EU level. According to initial evaluation by the Greifswald ire Centre, as permanent crops and on the basis of Sphagnum production as agricultural products, Sphagnum are eligible under Chapter 06 of the Brussels Tariff Scheme. Likewise, the Federal-State- Association (Bund-Länder-AG „Direktzahlungen/InVeKoS”) considers eligibility to be probable. Although DG Agri in Brussels confirms the eligibility of paludiculture in the first pillar, it says there may be an exception for Sphagnum (Gaudig 2019.). There is no case submitted for application for Sphagnum agricultural funding yet, neither on EU nor German level. Kumar (2019) states, however, that a first case of submission for such funding is imminent. There is an amendment by the European Parliament's Agriculture Committee calling for the explicit direct payment of paludiculture areas in the new CAP (European Parliament 2019.) is important to mention however, that subsidies, if available, could only be directed to actual Sphagnum farming, not harvesting or gathering (Gaudig et al. 2018.).

According to estimates, it is assumed that the replacement of the white peat used in Germany (about 3.5 million m³y-1) would require around 35’000 ha of net production area (Wichmann et al. 2017). If the assumptions for this assessment are also applied to black peat, then almost twice the area would be necessary (about 65,000 ha) to cover the entire peat in Germany's substrate production (about 6.5 million m³y-1 peat for 8.5 million m³y-1 of growing media). This estimate strongly depends on the productivity (or yield) and volume bulk density of the Sphagnum moss. These assumptions are rather conservative, so there may be much potential for optimization.

In Canada, Caron & Rochefort (2013) highlight that peat will continue to be the key constituent due to its unique properties, but Pouliot, Hugnon & Rochefort (2015) highlight the increasing need to substitute with peat, with Sphagnum biomass being the closest to peat in terms of performance in growing media. In addition to its use in growing media, they also suggest uses such as floral moss, plant packaging material and as moss reintroduction materials for peatland restoration projects. In their Sphagnum farming experiments in New Brunswick in Canada they found that

Sphagnum productivity was, in average, similar or higher than in restored peatlands, but fluctuation between years and sites was large due to variations in water table and intrinsic properties of plant interactions, highlighting, similarly to German studies, the importance of integrated water level control. Chirino, Campeau & Rochefort (2006) state that conditions in the first year are critical and may permanently influence Sphagnum growth. In both German and Canadian studies, the ideal harvesting interval varies and is difficult to predict, with cycles of 5-7 years being common.

Building on the experience of German and Canadian Sphagnum farming experiments, the Swedish University of Agriculture (SLU) in Uppsala has recently launched investigations on climate-smart after-use of cut-over bogs that have come the end of the extraction cycle, evaluating a) the feasibility to rewet, and then restore Sphagnum vegetation of cut-over bogs, and b) the possibilities to harvest Sphagnum as a biomass for use in horticulture (Jordan 2019, Kling & Jordan 2019). A first trial was launched in 2018 on cut-over over bog (2ha), run by Hasselfors Garden an in collaboration with SLU, Rölunda products and SvenskTorv. Growth of Sphagnum and environmental impacts of cultivation are investigated by the team of Sabine Jordan from SLU (Kling & Jordan 2019.). First results show that while re-wetting and restoring gives rise to some methane emissions, it absorbs carbon to the extent of becoming a carbon sink. Based on greenhouse tests, the researchers selected the Sphagnum species with best growth potential and properties for the given conditions. The restoration areas are planned such that harvesting can be done mechanically with a traditional excavator. Results of one year of Sphagnum growth were very promising. Sphagnum grew up to 25 cm in length (Fig. 1) and yield was in the range of 4-8 t dry mass ha-1y-1. According to Jordan (2019), there are currently 12’000ha of cut-over bogs with potential to re-wet and restore, which hence could produce up to almost 100’000 t ha-1y-1.

Figure 3. Sample of Sphagnum from first year harvest in Sweden. Image courtesy of Sabine Jordan

4.3 Sphagnum farming on mineral soils (China)

Methods of Sphagnum moss farming in China are not well known to the general public, and literature is barely available. A presentation given by Zhu Longjin (Zhu 2019a.) at the International Symposium on Peat for Food & Quality of Life, Qingdao/China, September 2019, and a visit hosted by Zhu Longjin to Sphagnum farming sites in Guizhou province, provided a lot of useful information.

There are about 100 species of Sphagnum in China, and while they normally grow on peatlands, wild Sphagnum in China is also found on mineral soils. Chinese Sphagnum farming differs significantly from other experiments because it is cultivated on mineral soils, rather than on peatlands. It is therefore not a form of paludiculture yet may contribute to decrease peat dependency in growing media. Sphagnum plantations are mostly found in Southern China, Guizhou, one of the poorest provinces in China. There is little to no documented knowledge about the suitability of different Sphagnum species for cultivation on mineral soils. Dried samples of the most commonly cultivated Sphagnum species were sent for identification to the laboratory of Greifswald University. The samples were identified as Sphagnum

15 palustre, a species considered as possibly the best suited for farming and for use in growing media (Gaudig 2019.).

Zhu Longjin is a pioneer of Chinese Sphagnum farming. He started his first Sphagnum farming experiments in 1986 by planting fresh Sphagnum material on fields formerly used for rice cultivation. Through his experiments he realized that Guizhou climate as well as the terrace like nature, drainage irrigation systems and the clay like soil of former rice fields, or paddies, provide ideal conditions for Sphagnum growth. The climate is humid, winters are not severely cold, summers not severely hot, and there is abundant rainfall throughout the year guaranteeing adequate groundwater exposure throughout the year (Zhu 2019b.). The majority of Sphagnum farmland is situated in the mountains. The soil layer is thin and yield of other crops like rice are often insufficient and transportation difficult, and hence traditional crop culture such as rice are increasingly is abandoned, providing rich land resources for the planting of Sphagnum moss on mineral soils.

According to Zhu, Sphagnum can be planted in two ways. Donor material is either spread densely and evenly on the soil (similarly to the methods used in Germany or Canada), or single plants are put in a small whole made with the finger, i.e. in the same way rice seedlings are traditionally planted. The latter method is more laborious but also gives better yields, especially in the first harvest.

Sphagnum moss cultivation should choose paddy fields with sufficient water sources, and it is best to have water flowing all year round. Nitrogen, phosphorus and potassium are essential trace elements, both water and soil also require sulfur, and the pH is normally about 4-5.5. A short description of the entire Sphagnum cultivation process, including planting, seedling selection, field management, harvesting and processing is described in Zhu (2019a.). Figures 4 show typical growing areas and harvested Sphagnum palustre, respectively.

Figure 4. Upper left: Dense Sphagnum growth, before harvest (Image courtesy of Zhu Longjin). Upper right: Annual growth (Image courtesy of Zhu Longjin). Bottom: Sphagnum cultivation site on former rice paddy, after harvest (Image courtesy of Gilbert Ludwig). All images Qiannan Prefecture, Guiding, Guizhou.

Once Sphagnum is planted, little is done expect for removal of weeds. Some weed species are left growing, as they are believed to form symbiotic relationships with Sphagnum, increasing thereby the yield, and no pesticides are used. Sphagnum

17 cultivation in Guizhou is essentially organic, and all harvesting is done manually. The irrigation drainage system, which normally is ready in place from former rice cultivation, is dense, so that farmers can collect Sphagnum manually without stepping on the growing area. Most of the harvest occurs in summer months, and harvested material is dried open air. In order to maximize the structural properties (e.g. water retaining capacity) necessary for e.g. growing seedlings of orchid, Sphagnum are left whole and are not crushed. After drying, the moss is put in large bags and is transported to the distributor, where moss material is packed for the market. Sphagnum species in China seem to grow faster than Sphagnum in the German and Canadian experiments, as they can be harvested on an annual basis.

Mr. Zhu Longjin is the biggest and most important distributor of Sphagnum in Guizhou, and also the originator of the technology of planting Sphagnum moss on mineral soil. He and his company work closely with Sphagnum farmers from entire Guizhou province. His current company is located in Guiding County, Qiannan Prefecture, Guizhou Province and was founded in 2006.

There is a growing demand of Sphagnum, in order to grow seedlings of different ornamentals, orchids in particular. Orchids are among the most important ornamentals in China and are sold in high quantities especially for the Chinese New Year. Sphagnum is also used for cultivation of some food plant seedling, e.g. blueberry shrub (Liheng 2019.). Demand of Sphagnum is consistently higher than possible supply. Sphagnum is sold to Chinese growers, but a significant part is also exported to Japan, Taiwan, Vietnam, Indonesia, Malaysia, Thailand, United States, Canada and Europe.

Getting exact data on current cultivation area and annual production of Sphagnum is not easy. According to Zhu (2019a), current growing area in Guizhou province is about 2300 ha, and annual yield in 2018/2019 are about 1800-2500t dry material. However, in a presentation given in Qingdao, Zhu (2019a) presented maximum possible yields of 750g m-2y-1, i.e. 7.5t ha-1y-1, which would translate into maximum annual yield of 17’250 t. Zhu (2019a) reports a production value of as high as 19’000€ ha-1y-1, with costs being around 5’000€ ha- a1y-1, which would give net revenue (before tax) of 15’000€ per hectare and year!

The shift from traditional rice cultivation to Sphagnum farming is slow but steady. Traditional attitudes related to the agricultural lifestyle of Guizhou and the complexity of Chinese bureaucracy are the likely reasons of this slow transition. Rice production in Guizhou has a long tradition, but in respect to total rice production in China Guizhou is marginal at best, as rice production on the industrial scale occurs in other provinces. Hence, rice production in Guizhou is more a life-style thing and mostly provides self-sufficiency of rice to farmers, with only little income. According to Zhu (2019), one hectare of Sphagnum produces in average an income that is eight times higher than correspondingly one hectare of rice production.

In recent years the increase in Sphagnum cultivation area has been about 200 ha y-1. According to Zhu (2019b.), the potential of expansion is very significant, but its accurate evaluation and mapping challenging at best. Sphagnum farming has also been introduced to Guizhou as a poverty alleviation program, allowing unemployed people to gain new knowledge on possible new livelihoods.

4.4 Mechanical Sphagnum harvesting (Finland, Sweden)

Silvan et al. (2012) present and describe a method of mechanical harvesting of wild Sphagnum in Finland. On the basis of these results, Finnish company EcoMoss OY, which is part of Biolan Group, has been piloting a mechanical Sphagnum harvesting production chain since 2016 (Satakunta 2016.). Harvesting is done by removing the moss from the bog surface with a specially designed bucket loader (Figure 5). The machine is built on top of a forestry logging machine and its patented equipment is used to squeeze most of water out of the moss on site. In this way, water is returned to its original biotope. Sphagnum moss, mostly Sphagnum fuscum, is removed to a depth of 20-30cm, allowing enough spores and buds to remain in the top layer for future propagation, hence Sphagnum is growing back naturally, without the need for spreading donor material after harvest.

Rantanen (2019a) states that renewal of Sphagnum moss after collection has been very quick, with the state of carbon sink and near original environmental conditions being reached within 5 to 10 years. Re-harvesting may be done in ca. 20 years from former harvest. On the basis of their study in 2012 (Silvan et al. 2012.), Silvan et al.

(2017) demonstrated a quick recovery of Sphagnum carpet and carbon sequestration. They concluded that mechanical Sphagnum biomass harvesting is comparable to forestry management than peat excavation, which causes severe long-term changes to the functioning of peatlands.

Figure 5. Mechanical harvesting in Finland. Image courtesy of Hannu Salo.

Sphagnum harvesting in Finland is restricted to bog areas that are already disturbed or drained, i.e. harvesting from natural or near natural mires is not recommended. In this way Sphagnum biomass conforms to the same conditions as those of peat in the RPP (Responsibly Produced Peat 2019.) certification scheme.

Since the 1960’s, more that 50% of Finnish peatlands have been drained for forestry purposes, with varying success. According to Rantanen (2019a), around 700’000 ha of drained peatlands that are unsuitable for forestry, of which 300’000 ha are considered suitable for Sphagnum harvesting (Figure 5). Considering a cut frequency of 20 years, annual production could be as high as 15 mio m3y-1.

Figure 6. Peatland uses in Finland as % of total surface. Adapted from Rantanen (2019a)

According to Rantanen (2019a), the process chain from Sphagnum harvest to final product is now being commercialized. Another Biolan company, Novarbo, specialized in the production of professional grade growing media, have developed a peat free growing media mixture based on Sphagnum harvested by EcoMoss. This moss-based substrate, called Mosswool®, has a wide range of applications for food production (Rantanen 2019a.). Sphagnum in Mosswool also replaces stonewool, another growing media constituent. Stonewoool is a problematic constituent, since after use it becomes problematic waste which does neither decompose nor burn. Mosswool can be composted or recycled locally (Rantanen 2019a).

5 Conclusions

5.1 Environmental Dimensions of Sphagnum Farming & Harvesting

Gaudig et al. (2018) conclude that Sphagnum farming provides sustainable and climate-smart after-use solutions for degraded peatlands. Besides of climate-change mitigation (Günther et al. 2017.), it also contributes to improvement related to

21 nutrient & water retention (Temmink et al. 2017) and biodiversity (Gaudig & Krebs 2016.) in Germany. It also efficiently halts the continuous process of land subsidence as a result of drainage (Joosten & Clarke. 2002.).

Mechanical Sphagnum harvesting leaves significant marks in the peatland landscape especially in the year of harvest, and obviously removes carbon in the form of Sphagnum biomass. Moss carpet, however, and the overall aesthetics of peatlands, has been shown to recover quickly (Silvan 2017.). The hydrological system of the area remains largely untouched, i.e. no water is channelled away from the area (Silvan. 2019a,b), and carbon sink properties restored in 5-10 years. However, to argue that the harvested area returns from a state of carbon source to carbon sink, even if true, is tricky. Joosten (2017) criticizes the approach, stating that the “story” of mechanical Sphagnum harvesting in Finland is full of false claims. Although Sphagnum indeed is renewable, he concludes that the activities of mechanical harvesting are not climate “neutral”. Regrowth would not restore the bogs’ function as carbon sink, but rather would halt the peatland environment from being a carbon sink during the period between moss removal and the re-establishment of a full moss cover. The process also removes part of the carbon reserve previously accumulated by the vegetation. It is true that in pristine Sphagnum mires, carbon is stored in the vegetation not only during its cycle as living organisms (such as in crops) but also thereafter. Other land- based carbon sequestration options in soil or vegetation, such as afforestation, reforestation, agroforestry, soil carbon management on mineral soils, or carbon storage in harvested woods products do not continue to sequester carbon forever, but peatlands can continue to sequester carbon for centuries. As Silvan (2017, 2019) points out, Sphagnum farming can be compared to forestry management, and this is probably true. Sphagnum harvesting in that sense would belong to the former group. Even if it achieves a state of carbon sink at some stage after harvesting, the sink effect is offset after harvest. The system of Sphagnum harvesting may therefore not be climate positive, but still climate “smart” in term of compensation, since the removed biomass compensates itself through regrowth. Additionally, since only ca. 10% of the carbon containing in living Sphagnum material is stored into a long-term store, i.e. peat, and ca. 90% is anyhow decomposed and released into the atmosphere (Clymo 1984.). Thus, if we compared Sphagnum harvesting to peat

22 production, where almost all of the removed peat material belongs to long-term carbon store, Sphagnum harvesting will produce only at most 10% of the peat production’s climatic effect.

This situation could be compared to the production of biogas. While the combustion of biogas, e.g. in cars or CHP plants, produces emissions, the emissions are said to be compensated through continuous rebuild of organic material that is being used for further biogas production. In that sense of compensation, Sphagnum farming could be considered climate “neutral” in the strict sense, and certainly much more climate friendly than traditional white peat extraction. And, to be fair, carbon is also removed during the harvest of Sphagnum in paludicultural cultivation. With the same reasoning it would be best to leave Sphagnum growing and let the peat layer build up.

The carbon question in China is different, because Sphagnum is grown on mineral soils just as other agricultural crops. Hence, the growing environment is not supposed to work like a mire and does not sequester carbon of biomass long-term. It merely replaces another crop (rice), and its environmental effect should be evaluated in terms of e.g. use of water or pesticides. As mentioned earlier, Sphagnum cultivation in China is essentially organic. No fertilizers are used, water is provided abundantly through natural precipitation and hence water needs are not competing with the need of drinking water. Sphagnum farming may also provide protection against soil impoverishment and erosion, e.g. after rice cultivation is abandoned. Harvesting is done manually without damaging the environment. Also, drying of moss is environmentally friendly.

Overall, it is safe to say that Sphagnum farming, as paludiculture or on mineral soils, as a means to grow biomass or to restore degraded peatlands into functioning peatlands, is by all means environmentally sustainable. Mechanical harvesting is more criticized. Considering the current and projected trends in the demand of growing media, however, mechanical Sphagnum harvesting is currently the only method that comes even marginally close to the industrial needs in terms of quantity. The entire production chain is still under development. Vapo has been investigating possibilities of mechanical Sphagnum harvesting for several years and

23 are in the process of developing a harvester that minimizes physical damage made to the ground (Pennanen 2019.).

5.2 Economic Dimensions of Sphagnum Farming & Harvesting

The economic impact of Sphagnum farming in Europe and Canada may be significant, but implies an upscaling of the production process chain, including its commercialization and economic optimization, to fit industrial needs. In their review, Wichmann et al. (2017) stated that investment costs of setting Sphagnum farming sites in northern Germany are high, especially for founder material, but underline that there is large potential to reduce and minimize costs. Subsidies will likely play an important role.

Upscaling and economic optimization are therefore, so far, and by far, the biggest obstacle of Sphagnum farming success in the long run, and its potential to reduce peat dependence in growing media. The need for such upscaling is increasingly imminent. In Germany, authorities likely will not grant new permits for peat harvest anymore. Sphagnum farming may therefore be a future way of securing not only availability of necessary resources, but also a way to secure the future of both peat extraction and growing media companies, which, not uncommonly, are traditional family businesses (Kling & Jordan 2019.). Sphagnum farming may also open up new business opportunities for farmers and landowners.

The economic potential of Sphagnum harvesting in Finland is described as promising. To the landowner, Sphagnum harvesting may produce a revenue of around 1000€ h- 1y-1 (Rantanen 2019a).

Due to emissions trading and increases in emission taxes, the demand of energy peat in Finland is projected to decrease 50% by 2030, and up to 90% by 2040 (Salo 2019.), and as a result many extraction companies will eventually have to close down. Re- wetting and cultivation of Sphagnum can thereby offer new ways of income to persons or companies that own such areas, and that have previously depended on peat extraction. In addition to the harvesting process in Finland, the example in Sweden is encouraging. With similar environmental and climatic condition than Sweden, the same method could work in Finland as well.

Alternatively, restoration of cut-over or otherwise disturbed bogs through cultivation of Sphagnum, but without harvesting, could be used for carbon compensation schemes, such as e.g. hiilipörssi in Finland (Toopakka 2019.). Sphagnum could also be cultivated with the intent to be sold as founder material.

The economic value of Sphagnum farming on mineral soils in Guizhou, China, is very significant, at least in respect to individual incomes. Sphagnum cultivation produces individual incomes that are about eight times higher than rice cultivation on the same area (Zhu 2019b.). According to Zhu (2019a) net revenue (after costs, before tax) may be as high 15’000€ h-1y-1, i.e. 15 time higher more than revenue of Sphagnum harvesting in Finland. It is, however, important to understand that Chinese Sphagnum is a high value “luxury” product, because it is almost exclusively used in the production of another high value product: Orchids. If the same mosses were used for the production of standard growing media, the price, and hence revenues, would collapse. Zhu (2019a, b.) stated that demand of Chinese moss is consistently higher than possible supply, and hence his company is interested in importing Sphagnum from e.g. Finland. Evaluating samples of Sphagnum fuscum, the species most commonly harvested in Finland, Zhu concluded that the species is very much suitable for Orchid cultivation. However, for orchid cultivation Sphagnum media needs to be as intact as possible, i.e. must not be crushed or cut into fractions. This implies that the moss is dried as whole, as they do in China. The current production chain of EcoMoss, however, do not have yet a method to dry Sphagnum as whole bulk material (Rantanen 2019b.).

5.3 Societal Dimensions of Sphagnum Farming & Harvesting

When it comes to Sphagnum farming and harvesting, societal impacts are very much related to the economic impacts. Sphagnum farming in Germany and elsewhere may seem yet as a distant revenue option for peat extraction professionals, farmers or landowners, because it is still new, uncommon, and also unpredictable. Pioneer spirit and an attitude of “never say never” as well as long-term resilience is needed. The process of Sphagnum farming cannot be made economical unless it is seriously tried out and optimized on the large scale, and on the long-term. A successful future of sustainable Sphagnum farming implies a major paradigm shift, a new mind-set, and

25 development of new business models. But one thing is clear: Demand of Sphagnum biomass as raw material for growing media and other products is on the rise.

In Finland and other Nordic countries, especially in rural areas, land is often privately owned, and the cultural spirit of “living of the fat of the land” (Steinbeck 1964.) is strong. Sphagnum farming for harvesting may offer new ways to keep rural populations connected to their roots and their culture of living of “the fat of the land”.

The social impact of Sphagnum farming in China is significant already. Thanks to the long-term resilience and true dedication of the work of pioneers like Zhu Longjin, rural development in poor areas like Guizhou has received major boosts, by innovating new ways of sustainable agricultural production, and hence new ways of revenues. Development of Sphagnum farming has also led to clear improvements in infrastructure, e.g. new roads have been built to make remote areas accessible. Hence, Sphagnum farming in Guizhou combines efficiently the dimensions of environment, economy and society, and by doing so, it already achieves a number of the UN Sustainable Development Goals. In China, RDI work is needed to a) investigate other potential applications of currently farmed species and b) to investigate the suitability to grow other Sphagnum species in Guizhou environmental conditions. With global, and especially Chinese demand for Sphagnum and growing media increasing rapidly, Chinese Sphagnum farming may gain significant importance in the future.

5.4 Technology Dimensions of Sphagnum Farming & Harvesting

Water level control is a crucial element of successful Sphagnum farming, as shown especially in the German and Canadian studies. New innovations involving e.g. remotely controllable IoT technology may improve automatic water control, by using both real time information as well as e.g. regional weather forecast information. For harvesting, there is a need for more advanced and lighter harvesting technology that optimize both harvesting process and minimize environmental damage. Also, considering the high demand for whole dried Sphagnum (for orchid cultivation), RDI

26 is needed to develop a process chain that harvests Sphagnum without much damaging it and dry it as whole bulk.

6 Discussion

There is no doubt that the demand of growing media is going to increase significantly in next 20 to 30 years. At the same time, it is expected that availability and supply of peat, the most important constituent of growing media, is going to decrease as a consequence of political decisions in order to reach climate targets of the Paris Agreement. It is therefore likely that we will witness an increasing discrepancy between demand and availability of peat. This means that as long as growing media for professional growing applications is dependent on peat, the shortage of raw materials will increase. According to Hofer (2019), the shortage of peat may be as high 50 mio m3y-1 by 2050.

It has been shown that Sphagnum can replace white peat used in many applications of growing media, and hence may reduce the peat dependence in growing media. However, the quantities of Sphagnum currently produced are nowhere close to enough to satisfy the needs of the industry. For this, a serious upscaling of Sphagnum farming and harvesting will be necessary.

Sphagnum farming, and paludiculture in general, provides a climate-smart alternative for after use of cut-over bogs or peatlands used in agriculture. Considering the importance of peatlands in climate mitigation, and the urge for climate action, Sphagnum farming deserves a lot of attention. Whether Sphagnum is farmed for biomass use, or simply as climate-smart after use, its potential to be as an alternative source of income and livelihood for farmers and landowners, or peat extraction professionals, should not be underestimated.

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