Miscanthus sinensis gigantheus crop ready for harvesting in spring (2015) (Andrei Vrinceanu (INCDPAPM-ICPA Bucharest))

Cropping perennial grasses (Miscanthus sinensis gigantheus) on soils contaminated with heavy metals (Romania)

Cultivarea cu Miscanthus a solurilor poluate cu metale grele (Romanian)

Description

Miscanthus sinensis gigantheus is a perennial warm-season grass used as a commercial energy crop on soils contaminated with heavy metals.

Cropping Miscanthus sinensis gigantheus mainly addresses the problem of land contamination with toxic materials namely soil pollution with heavy metals due to industrial activities. Miscanthus is a perennial warm-season grass used as a commercial energy crop. The plant is a sterile hybrid, unable to produce viable seed, vegetative propagation being by rhizomes, therefore reducing the risk to become invasive. Its special type of photosynthesis (C4) implies the return of the nutrients in the rhizomes during the cold season. As temperatures cool in the fall, the dark green foliage fades to buff and drops, leaving the stems which are the most important commercial part of Miscanthus. Regarding cropping on contaminated soils, research has shown that the amount of heavy metals uptaken by Miscanthus is extremely low, making the plant unsuitable for phytoextraction but allowing it to be used for green energy or in various other fields like pulp and paper industry, without any risk. Miscanthus sinensis gigantheus stands for an alternative crop, from which an annual income can be obtained, instead of food crops and fodder that can represent a risk for human and animal consumption in areas with soils contaminated with heavy metals.

The aim of this technology is to assure a sustainable use of polluted soils with heavy metals through cultivation of energy crops with economic value and very few risks for humans, animals and environment. Studies of Miscanthus sinensis gigantheus behaviour on contaminated soils with heavy metals showed that very small amount of Pb (Lead) and Cd (Cadmium) were detected in the upper parts of the plants. In comparison, higher amounts of heavy metals is being retained at root level in rhizomes, which in time will decrease when root system will develop deeper, in less affected soil horizons as roots can reach 2-3 m in depth. The applied technology increases overall soil quality in terms of organic matter, nutrients and structure. Miscanthus cropping enhances the nutrients cycle in the plant–soil system. As a result of the high input of leaves, rhizomes and roots, the alluvial sandy loam soils, on which Miscanthus is currently croped, can benefit of increased organic carbon amount.

The establishment phase takes place on arable land (annual cropland) which after implementation will become a permanent cropland with perennial (non-woody) cropping, as the crop has the potential to be in the ground for at least 15 years. Miscanthus cropping technique consists of the following: weeding the site in July-August by spraying herbicides for controlling perennial weeds, deep ploughing in October-November to improve subsoil structure and soil aeration possible affected by compaction or hardpan, harrowing in February-April to ensure an adequate seedbed for rhizomes and planting in March-May. Early planting is being recommended as it takes advantage of spring time soil moisture and allows an extended first season of growth. The operation can be made using a modular potato planter or specialized planter like Miscanthus ETPM4. The planting rate is 10 000 rhizomes per hectare in order to provide a good crop density required to achieve optimal yields from year three onwards and effective weed suppression through competition. Rhizomes need to be planted at a depth of 8-15 cm and at 1m x 1m wide spacing. The crop is harvested annually during February-March, typically with conventional farm machineries or specialized ones like Miscanthus CRM Harvesting Cropper. The crop needs 3 to 4 years to reach a mature yield between 15-18 t/ha. The technology requires mechanized agricultural operations and investments in specialized equipment, if necessary.

The technology is applied mainly on alluvial sandy loam soils (Fluvisols), with deep depths, on low lands with flat-gentle slops (0-5%), placed in valley floors/floodplains. The climate is temperate, semi-arid, with an average annual rainfall between 550-600 mm. The plots cropped with Miscanthus are privately owned but leased. Size of crop land where the technology is applied is usually small up to 2 ha. The farmers receive agricultural subsidies and the production system is mechanized and market oriented.

Location

Location: Sibiu/Axente Sever, Romania/Transylvania, Romania

No. of Technology sites analysed:

Geo-reference of selected sites
  • 24.19, 46.11132

Spread of the Technology: evenly spread over an area (0.14 km²)

In a permanently protected area?:

Date of implementation: less than 10 years ago (recently)

Type of introduction
Arable lands affected by heavy metals pollution near industrial emission stacks (Andrei Vrinceanu (INCDPAPM-ICPA Bucharest))

Classification of the Technology

Main purpose
  • improve production
  • reduce, prevent, restore land degradation
  • conserve ecosystem
  • protect a watershed/ downstream areas – in combination with other Technologies
  • preserve/ improve biodiversity
  • reduce risk of disasters
  • adapt to climate change/ extremes and its impacts
  • mitigate climate change and its impacts
  • create beneficial economic impact
  • create beneficial social impact
Land use

  • Cropland
    • Perennial (non-woody) cropping
    Number of growing seasons per year: 1
Water supply
  • rainfed
  • mixed rainfed-irrigated
  • full irrigation

Purpose related to land degradation
  • prevent land degradation
  • reduce land degradation
  • restore/ rehabilitate severely degraded land
  • adapt to land degradation
  • not applicable
Degradation addressed
  • soil erosion by water - Wt: loss of topsoil/ surface erosion
  • soil erosion by wind - Ed: deflation and deposition
  • chemical soil deterioration - Cp: soil pollution
SLM group
  • improved ground/ vegetation cover
  • integrated soil fertility management
SLM measures
  • vegetative measures - V2: Grasses and perennial herbaceous plants
  • management measures - M2: Change of management/ intensity level, M4: Major change in timing of activities

Technical drawing

Technical specifications
Schematic diagram indicating the spatial distribution of Mischantus rhizomes (1 m between plants) - part of the planting technology
Technical knowledge required for land users: moderate
Main technical functions: increase of biomass (quantity), retain heavy metals at roots level
Secondary technical functions: improvement of ground cover, improvement of surface structure (crusting, sealing), improvement of topsoil structure (compaction), improvement of subsoil structure (hardpan), increase in organic matter, reduction in wind speed
Aligned: -linear
Vegetative material: C : perennial crops
Number of plants per (ha): 10000
Vertical interval between rows / strips / blocks (m): 1
Spacing between rows / strips / blocks (m): 1
Vertical interval within rows / strips / blocks (m): 1
Width within rows / strips / blocks (m): 1
Perennial crops species: Miscanthus sinensis gigantheus
Change of land use practices / intensity level: from rotational cropping to mono-cropping
Major change in timing of activities: from land preparation and planting in the first year to only harvesting from year 3 to 15
Author: Petru Ignat, INCDPAPM-ICPA Bucharest

Establishment and maintenance: activities, inputs and costs

Calculation of inputs and costs
  • Costs are calculated:
  • Currency used for cost calculation: Lei
  • Exchange rate (to USD): 1 USD = 4.0 Lei
  • Average wage cost of hired labour per day: 12.00
Most important factors affecting the costs
The price of rhizomes (seeds) per hectare and harvesting activity involving special machines that cut and chop stems are the most determinate factors affecting the costs.
Establishment activities
  1. Treatment with herbicides (Timing/ frequency: month VII -VIII)
  2. Deep ploughing (Timing/ frequency: month X-XI)
  3. Soil preparation by harrowing (Timing/ frequency: month II-IV)
  4. Planting (Timing/ frequency: month III-V)
Establishment inputs and costs
Specify input Unit Quantity Costs per Unit (Lei) Total costs per input (Lei) % of costs borne by land users
Labour
ha 1.0 102.0 102.0 93.0
Equipment
machine use ha 1.0 237.0 237.0 93.0
Plant material
seeds ha 1.0 2180.0 2180.0 93.0
biocides ha 1.0 62.0 62.0 93.0
Total costs for establishment of the Technology 2'581.0
Total costs for establishment of the Technology in USD 645.25
Maintenance activities
  1. Harvest (Timing/ frequency: month II-III)
  2. Harvest (Timing/ frequency: month II-III)
Maintenance inputs and costs
Specify input Unit Quantity Costs per Unit (Lei) Total costs per input (Lei) % of costs borne by land users
Labour
ha 1.0 25.0 25.0
Equipment
machine use ha 1.0 124.0 124.0
Total costs for maintenance of the Technology 149.0
Total costs for maintenance of the Technology in USD 37.25

Natural environment

Average annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Agro-climatic zone
  • humid
  • sub-humid
  • semi-arid
  • arid
Specifications on climate
573 mm/year; May and June register the highest amount of rainfall during the year: 85-100 mm
Thermal climate class: temperate
Slope
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitude
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.
Technology is applied in
  • convex situations
  • concave situations
  • not relevant
Soil depth
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil)
  • coarse/ light (sandy)
  • medium (loamy, silty)
  • fine/ heavy (clay)
Soil texture (> 20 cm below surface)
  • coarse/ light (sandy)
  • medium (loamy, silty)
  • fine/ heavy (clay)
Topsoil organic matter content
  • high (>3%)
  • medium (1-3%)
  • low (<1%)
Groundwater table
  • on surface
  • < 5 m
  • 5-50 m
  • > 50 m
Availability of surface water
  • excess
  • good
  • medium
  • poor/ none
Water quality (untreated)
  • good drinking water
  • poor drinking water (treatment required)
  • for agricultural use only (irrigation)
  • unusable
Water quality refers to:
Is salinity a problem?
  • Yes
  • No

Occurrence of flooding
  • Yes
  • No
Species diversity
  • high
  • medium
  • low
Habitat diversity
  • high
  • medium
  • low

Characteristics of land users applying the Technology

Market orientation
  • subsistence (self-supply)
  • mixed (subsistence/ commercial)
  • commercial/ market
Off-farm income
  • less than 10% of all income
  • 10-50% of all income
  • > 50% of all income
Relative level of wealth
  • very poor
  • poor
  • average
  • rich
  • very rich
Level of mechanization
  • manual work
  • animal traction
  • mechanized/ motorized
Sedentary or nomadic
  • Sedentary
  • Semi-nomadic
  • Nomadic
Individuals or groups
  • individual/ household
  • groups/ community
  • cooperative
  • employee (company, government)
Gender
  • women
  • men
Age
  • children
  • youth
  • middle-aged
  • elderly
Area used per household
  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Scale
  • small-scale
  • medium-scale
  • large-scale
Land ownership
  • state
  • company
  • communal/ village
  • group
  • individual, not titled
  • individual, titled
Land use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Water use rights
  • open access (unorganized)
  • communal (organized)
  • leased
  • individual
Access to services and infrastructure
health

poor
x
good
education

poor
x
good
technical assistance

poor
x
good
employment (e.g. off-farm)

poor
x
good
markets

poor
x
good
energy

poor
x
good
roads and transport

poor
x
good
drinking water and sanitation

poor
x
good
financial services

poor
x
good

Impacts

Socio-economic impacts
land management
hindered
x
simplified

energy generation (e.g. hydro, bio)
decreased
x
increased


Miscanthus is an energy crop cultivated for generation of heat and biofuels

expenses on agricultural inputs
increased
x
decreased


Usually from year two no agricultural inputs (fertilizers and pesticides) are required. In case of establishment losses, additional planting is needed to achieve the plant density for optimal yields.

farm income
decreased
x
increased

diversity of income sources
decreased
x
increased

farm energy independence
None
x
None

Socio-cultural impacts
food security/ self-sufficiency
reduced
x
improved

conflict mitigation
worsened
x
improved

Ecological impacts
surface runoff
increased
x
decreased

evaporation
increased
x
decreased

soil moisture
decreased
x
increased

soil cover
reduced
x
improved

soil crusting/ sealing
increased
x
reduced

soil compaction
increased
x
reduced

nutrient cycling/ recharge
decreased
x
increased

soil organic matter/ below ground C
decreased
x
increased

biomass/ above ground C
decreased
x
increased

animal diversity
decreased
x
increased

habitat diversity
decreased
x
increased

emission of carbon and greenhouse gases
increased
x
decreased

fire risk
increased
x
decreased

wind velocity
increased
x
decreased

Off-site impacts
wind transported sediments
increased
x
reduced

Cost-benefit analysis

Benefits compared with establishment costs
Short-term returns
very negative
x
very positive

Long-term returns
very negative
x
very positive

Benefits compared with maintenance costs
Short-term returns
very negative
x
very positive

Long-term returns
very negative
x
very positive

Climate change

Gradual climate change
annual temperature increase

not well at all
x
very well
Climate-related extremes (disasters)
local rainstorm

not well at all
x
very well
local windstorm

not well at all
x
very well
drought

not well at all
x
very well
general (river) flood

not well at all
x
very well
Other climate-related consequences
reduced growing period

not well at all
very well
Answer: not known

Adoption and adaptation

Percentage of land users in the area who have adopted the Technology
  • single cases/ experimental
  • 1-10%
  • 11-50%
  • > 50%
Of all those who have adopted the Technology, how many have done so without receiving material incentives?
  • 0-10%
  • 11-50%
  • 51-90%
  • 91-100%
Number of households and/ or area covered
1 land user family
Has the Technology been modified recently to adapt to changing conditions?
  • Yes
  • No
To which changing conditions?
  • climatic change/ extremes
  • changing markets
  • labour availability (e.g. due to migration)

Conclusions and lessons learnt

Strengths: land user's view
  • High economic value of the crop
  • Simple agricultural technique
  • Low-cost of maintenance / recurrent activities
Strengths: compiler’s or other key resource person’s view
  • This technology allows a sustainable land use of contaminated soils with heavy metals with minimum risk for humans, animals and environment
  • It is very effective for biomass production with multiple uses: biofuel, animal bedding or cellulose production
  • Miscanthus sinensis gigantheus is a phytoexcluder with low heavy metal uptake from contaminated soils
Weaknesses/ disadvantages/ risks: land user's viewhow to overcome
  • High costs for initial establishment. The cost of rhizomes (seeds) represents 85% of total initial investment costs Initial costs could be reduced if a proportion of the crop is used as a “mother crop” for the production of rhizome cuttings
  • High costs for purchasing special machines for harvesting activity Subsidizing
  • Undeveloped energy crop market Support for creating local or regional markets for energy crops
Weaknesses/ disadvantages/ risks: compiler’s or other key resource person’s viewhow to overcome
  • Low suitability on lands without phreatic input Selecting sites with good groundwater availability
  • Relatively long period (three to four years) for achieving a mature yield Maintaining the energy crop subsidies

References

Compiler
  • Andrei Vrinceanu
Editors
Reviewer
  • Deborah Niggli
  • Alexandra Gavilano
Date of documentation: June 18, 2015
Last update: Sept. 5, 2019
Resource persons
Full description in the WOCAT database
Linked SLM data
Documentation was faciliated by
Institution Project
Key references
  • Barbu, C.H., Pavel, P.B., Sand, C.; Pop, M.R., 2013. Reduced uptake of Cd and Pb by Miscanthus sinensis x giganteus cultivated on polluted soil and its use as biofuel, Environmental Engineering & Management Journal (EEMJ), Vol. 12 Issue 2, pp: 233-236:
  • Barbu, C.H., Pavel, P.B., Sand, C.; Pop, M.R., 2009. Miscanthus sinensis gigantheus’ behavior on soils polluted with heavy metals, Metal Elements in Environment, Medicine and Biology, Tome IX, Cluj University Press, pp: 21-24:
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