Phytoremediation in

Presented during the Soil Remediation Workshop (With special presentation on Nextgen sequencing), Pretoria, SA, 27 - 28 May 2014

By Damase Khasa Centre for Research and Institute for Integrative and Systems Biology, Université Laval, Québec Canada G1V OA6 Outline of Presentation

Part I: Temperate /subtropical AF systems

Part II: Potential use of Agroforestry in phytoremediation Part I: Temperate AF systems

Definitions

Classification of temperate agroforestry systems Definition of AF AF is defined as a dynamic, ecologically based, natural resources management system that, through the integration of woody perennials on farms, ranches, and in other landscapes, diversifies and increases production and promotes social, economic, and environmental benefits for land users (Orlando declaration, 02 July 2004). Agroforestry practices help landowners to diversify products, markets and farm income; improve soil and water quality; sequester carbon, and reduce erosion, non-point source pollution and damage due to flooding; and mitigate climate change. I. Temperate/subtropical Agroforestry Systems

- Systems - Windbreak Systems - Silvopastoral Systems - Integrated Riparian Management Systems - Systems Forest Farming systems

Mycoforestry: cultivation of edible mushrooms in woodlots Fruitiforestry: Cultivation of plants bearing edible fruits

• e.g., blueberries, cranberries, etc.. Cultivation of blueberries in managed forest

Quebec is the only one Canadian province experimenting this concept Advantages: • windbreaks • Temperature buffer effect • Reduction of soil erosion and flowers frost

Source: MRNF 2006 Pharmacoforestry: Cultivation of medicinal plants e.g., name "ginseng" is used to refer to both American (Panax quinquefolius) and Asian or Korean ginseng (Panax ginseng) Herboforestry: Cultivation of ornemental, aromatic and edible herbs

• (e.g., Ferns, Sweet Gale - Myrica Gale, Labrador Tea, Ledum groenlandicum ) II. Windbreak Systems

Source : www2.sbf.ulaval.ca

11 III. Silvopastoral Systems IV. Integrated Riparian Management Systems Benefits of Streambank - Control erosion - Nutrient filtering - Shading effects on streams / modification of aquatic habitat - Food for invertebrates - Enhance stream denitrification - production - Wildlife corridors - (4-5 ODT ha y-1 ) v) Intercropping Systems OLD field with a LOW [P] content (Université Laval research site)

FC AF

8 m 8 m

Forestry Control (without crop) AgroForestry (poplars with soybean crop) Part II: Potential use of Agroforestry in phytoremediation

Riparian buffer systems

Intercropping systems

Woodlot management/soil sanitation short rotation woody crop (SRWC) fallow systems Riparian buffer Systems/Areas

•Riparian areas are parts of the landscape that are strongly influenced by water • Periodic flooding, erosion, sediment deposition, alterations by wildlife • Agricultural operations, waste disposal, discharge of effluents, grazing, vegetation removal Nitrogen and Phosphorus

• N and P: two of the main nutrients of environmental concern • In surface water eutrophication and groundwater contamination

Lake Winnipeg Integrated Pest Management (IPM)

Monitoring soil nutrient level Preventative Fertilizer/pesticide application Proper pesticide mixing and loading BMPs management Smart sprayer technology Pesticide reformulation

Types of Ag Constructed wetlands and ponds BMPs Conservation tillage

Cover crops Edge-of-field Vegetative filter strips (VFS) buffers Field borders / margins Mitigative Contour strips Vegetative Windbreaks / Hedgerows Vegetative Grassed waterways BMPs buffers waterways Vegetative ditches Riparian buffers

Polyacrylamide (PAM) Tailwater treatment Source: Zhang 2009 Landguard Vegetated ditch Riparian buffer

Vegetative filter strip Hillside contour PAM

Hedgerow field-border Windbreak Tailwater pond Main functions: Slow runoff, Increase infiltration, Trap pollutants (Zhang 2009) Figure 3. The traditional three zone riparian buffer. Source: Reprinted, with permission, from Schultz et al. (2000). © ˜2000 by American Society of Agronomy Riparian buffers

Multi-species vegetation established at the interface between croplands and surface-water to remove sediments and chemical pollutants in run-off and shallow water from agricultural land. • Filtration zone for streams and lakes • Effective in controlling run-off erosion • Preserve biodiversity (wildlife & aquatic species) • The success of riparian buffers for phytoremediation depends on the species used • Examples Riparian buffers

1. Poplars and forage grasses in multi-species buffer zones phytoremediate atrazine and phosphorus (Chang et al. 2005; Lin et al. 2008; Kovar and Claassen, 2009). 2. Willow cultivars tend to promote some bacterial groups and early ectomycorrhizal species (Pezizomycetes, Sphaerosporella brunnea) in hydrocarbons (HC) contaminated soils (Bell, Hassan et al.2014). 3. Panicum virgatum L. a grass that is grown on riparian buffer systems has a good potential to uptake, degrade and detoxify atrazine in the rhizosphere (Lin et al., 2008). 4. species in riparian buffer zones in Peninsular Malaysia produced a large amount of woody biomass and substantially removed sediments in channels leading into headwater streams (Gomi et al. 2006). 5. ( Bambusa vulgaris), a non-timber valued in handicraft, is grown in tropical riparian zones. Riparian buffers

 The phytoremediation property of vegetative grasses involves many processes (Lin et al. 2005; Dosskey et al. 2010) : –Soil microbial activities for herbicide degradation –Denitrification of groundwater –Phytostabilisation, phytoextraction, rhizodegradation –Nutrient uptake by fast-growing species. N cycling in a monocrop N cycling in a tree/crop intercropping system

Short-rotation woody crop woodlot system or soil sanitation fallow

Utilization of fast-growing with metal-extraction potential including poplars, eucalypts, and N-fixing trees to remediate contaminated soils. • Ameliorate degraded soils • Extract and accumulate contaminants (only at low level) • Can create soil water deficit • Examples Short-rotation woody crop system

1. Poplars and eucalypts • Poplar-based agroforestry systems are common in India (Das and Chatuverdi, 2005). • Eucalypts are used as fast-growing shade trees in coffee in the tropics (Schaller et al. 2003). • Eucalyptus spp. and Populus spp. that are cultivated at close spacing for rotations of 10 years or less can be used in phytoremediation (Rockwood et al. 2004). 2. Bamboos (presentation by Mr. Jan Van Zyl) 3. N-fixing trees such Acacias, Casuarinas, Leuacaenas Alley cropping/intercropping systems

1. Fast-growing nitrogen-fixing species • Acacia angustissima, Acacia mangium, Inga edulis and Albizia sp. are used in alley cropping in the tropics. • Have potential for heavy-metal extraction and accumulation. • However, less is known on the phytoremediation potential of alley cropping. • More work needs to be done to to identify systems that have a large potential for phytoremediation, while providing local people with food and other benefits. Hydraulic lift

Plant roots can redistribute water from wet zones deeper in the soil, to dry soil zones close to the surface in dry regions, a process known as hydraulic lift (Richards and Caldwell 1987). Deep roots absorb water when transpiration is high during the day, and re-distribute the absorbed water to the rhizosphere in drier layers when plant transpiration is low (at night). Figure.

Hydraulic lift

Phenomenon used in agroforestry for water redistribution between woody species and crops, and to assist in phytoremediation of contaminated soils. Rewetting the rhizosphere in the shallow soil layers : –Keeps microbes active for biodegradation of organic chemicals in soils. –keeps fine roots wet, which facilitates the absorption of pollutants by roots. –Enhances the release of chemicals, thereby facilitating their acquisition by hyperaccumulators (or metallophytes) (Liste and White 2008). Hydraulic lift

Examples : –Acacia tortilis (Ludwig et al. 2003; Dhillon et al. 2008), Eucalyptus (Bafeel 2008; Caldwell et al.1998; Hamada et al. 2003), Dalbergia sissoo, Melia azedarach, Morus alba, poplars, Szygium cumini and Terminalia arjuna (Dhillon et al. 2008) have been found to phytoremediate contaminated soils that benefit from hydraulic lift. Next steps

• Much more research is needed to understand the phytoremediation potential of agroforestry systems especially in mining areas to secure for local people • For example: *design agroforestry systems that minimize competition for water while favoring hydraulic lift. *assessment of decontamination potential of agroforestry tree and shrub species for polluted soils. *include phytoremediation potential in the criteria of tree selection for introduction in agricultural landscapes *more work should be done on the phytoremediation properties of the association between agroforestry species and microsymbionts on contaminated soils by either organic or inorganic compounds AF at Université Laval

 Unique in Canada ! Since 1997, formal M.Sc (48 credits including internship in tropical or temperate AF (unique in Canada)  PhD sur mesure also possible  Within and between collaborations (U. Moncton, U. Guelph, U. Saskatchewan, U. Alberta, PFRA)  MOUs (CATIE, WAC, CIFOR) New textbook published

37 Acknowledgements

Members of the Biomonitoring and Remediation Groups, EME, NRC-Montreal Funding

39 Acknowledgements THANK YOU VERY MUCH FOR YOUR ATTENTION

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