Stinging nettle

Stinging nettle: a neglected species
with a high potential as multi-purpose crop
Nicola di Virgilio, PhD
National Research Council of Italy – Institute of Biometeorology
CNR-IBIMET
[email protected]
Summer school of FIBRA
FIBRA - Fibre Crops as sustainable source of biobased material for
industrial products in Europe and China
Catania-Italy
21-27 July 2013
www.fibrafp7.net
Research Team
Laura Bacci:
project
coordination
Stefano
Predieri:
Sara Di
Lonardo:
Nicola Di
Virgilio:
Edoardo
Gatti:
propagation
coordination,
mutagenesis
fibre
processing,
Life Cycle
Assessment
agronomy,
field trial
layout, in vivo
propagation
in vitro trials,
propagation
and
mutagenesis
Lorenzo
Albanese:
agronomy,
Life Cycle
Assessment
Silvia Baronti, Piero Battista, Francesco Sabatini (IBIMET Firenze), Giorgio Mastromei (Dipartimento Biologia Evoluzionistica
dell’Università di Firenze).
Dipartimento di Scienze Farmaceutiche ‐ Università di Firenze: Annalisa Romani, Patrizia Pinelli, Pamela Vignolini, Francesca Ieri, Arianna
Scardigli, Elena Agostino, Margherita Campo, Lisa Banelli, Marco Michelozzi (Istituto di Genetica Vegetale CNR Firenze)
Projects carried out at IBIMET (2005 - 2012)
LAMMATEST (2005-2007):
“The textile processing chain
in Tuscany", supported by
Tuscany Region; Scientific
responsible: Laura Bacci >>>
Handbook on stinging nettle
cultivation and first
processing for textile use
NATURAL.TEX (2006):
"Natural fibers in textile
processing chain of Tuscany",
supported by Tuscany Region;
Scientific responsible: Laura
Bacci
ICCOG (2008-2009):
"Identification and
characterization of some
clones of nettle and Spanish
broom for textile and
phytotherapic fields",
supported by Tuscany Region;
Scientific responsible: Laura
Bacci
Propagation, field trial establishment, fibre extraction trials, fibre
quality, environmental impact analysis.
PRIN 2009 (2010-2012):
“Medicinal and dyeing-plants
natural extracts:
characterization, and
innovative poly-use of nettle,
daphne , lavender and
chesnut tannins”, supported
by the Italian Ministry of
Research; Scientific coresponsible: Laura Bacci
Randomized
block design
Field of Irradiated
plants
(mutagenesis)
Prato (43◦53N, 11◦06E) in Tuscany, 1 ha
Silt loam soil: 15% clay, 72% lime, 13% sand, pH 6.9, organic
matter 20.6 g kg−1, total N 1.4 g kg−1, assimilable P2O5 140.6
mg kg−1, exchangeable K2O 66.3 mg kg−1.
Clone 13 Bredemann (1959).
Agency of Agriculture in the province of
Thuringen in Germany, Thuringer Landesanstalt fur Landwirtschaft in Dornburg
Block 3
Plot detail
Harvest 2
Block 1
Harvest 1
Block 2
50 X 75 cm. 2.6 plants m-2
Establishment - Autumn
Establishment - Springtime
Measurements: biomass traits, biomass and fibre yields,
phenology, fibre quality
Most common fibre crops
Flax
Linaceae > (Linum usitatissimum L. FLAX)
Cotton
Malvaceae > (Gossypium spp. COTTON; Hibiscus cannabinus L. KENAF)
Tiliaceae > (Corchorus spp. JUTA)
Kenaf
Juta
Amaryllidaceae > (Agave spp. SISAL)
Ramiè
Cannabaceae > (Cannabis sativa L.) HEMP
Stinging nettle
Leguminosae > (Spartium junceum D. BROOM)
Hemp
Urticaceae > (Boehmeria nivea (L.) Gaud. RAMIE’;
Urtica dioica L. STINGING NETTLE)
… Abaca, Agave, etc.
Broom
Interest on fibre crops
New land use. Cotton replacement using lower environmental impacting crops.
Decrease paper market pressure on forests.
Customer rediscovery of Natural fibres against synthetic fibres: demand of biological anallergic
natural fibres.
Income differentiation for farmers.
Use of fibre in several industrial applications (multi-purpose crops), from textile to biocomposites to
energy production from by-products.
Interest for stinging nettle
Good quality fibre
Natural fibre crop feasible using organic production
Perennial crop (10-15 years)
Low input requirements (low chemicals use)
Nettle could answer to current problems in agriculture relating to over-fertilised soils, netle thrives on nitrogenous soils
Good in soil erosion control
Use of marginal lands
Increase farmer biodiversity
Common and spread plant, possibility to be gronw under several pedo-climatic conditions
Development of local production chain
Possibility to transform a common weed plant in a commercial crop, with large application oppotunities using stem, leaves,
roots and seeds (fibre, food, cosmetic).
Perennial, nitrophilous herb containing sclerenchymatic fibers in the bark,
widely distributed throughout the temperate regions of the world.
It has been used for textile purposes until the Second World War as substitute of Cotton,
during ’40, 500 hectares have been cultivated in Germany and Austria for textile production
Nettle become a weed in the modern intensive agriculture > Neglected and underused crops
Most of the modern literature related to the use of nettle as fibre crop is in German language, some projects have been
carried out in Germany and Austria on the production of organic fibre:
• From nettle to textile I + II (1997-2000, 2001-2003).
• Nettle-reintroduction of stinging nettle cultivation as a sustainable raw material for the production of fibers and cellulose FAIR.ST8356 and FAIR-CT98-9615 (1999-2001).
• Natural textiles made of nettle-innovative technology and product development for the textile industry (1999-2002).
There is not a real market for nettle fibre in EU, there are only some pioneer examples on the use of nettle fibre
also in blend with cotton and silk.
Fam. Urticaceae (Urtica dioica L.)
Temperate region of Europe, Asia and North America.
On ruderal sites, at the edges of forests and in wooded areas of
riverline floodplains
Dioic herbaceous perennial, dense axillary inflorescences, plants
flower in late spring or early summer and seeds form by late August or
early September
1 to 2 m tall
Simple, opposite, sharply toothed leaves (5-10 cm long)
Stinging hairs, trichomes on leaves and stems
Widely spreading rhizomes and stolons, superficially
Growing from seeds and rhizomatously. The stem roots at the nodes
and erect shoots initiate in the spring
Rich soils in forest clearings, stream banks, old fields and waste places
Adapted to a wide range of climatic conditions in Europe (600-800 day
degrees to over 3,250 day degrees, base T of 5.5ºC)
female flower
Hairs, trichomes
male flower
male plant
female plant
seeds
Fibre crop
Nettle has a vast number of potential applications, most are similar to those of hemp and flax. Potential
uses include fibre, protein, culinary, medicinal, biomass, oil, repellent and waterproofing.
It was suggested in 2000 that stinging nettle is one of the most undervalued of economic plants with
potential applications in a wide range of uses. If technical problems are solved the nettle has greatest
potential for long fibre pulping and textile markets.
As a fibre source nettle is a useful alternative or complementary product to other natural fibres such as
hemp, linen and cotton, they will play an increasing role in the next 5-7 years.
It is thought that nettle fibre has was used to make thread and fabric as far back as 2000 years.
Nettles are currently used in the production of a silky fabric known as ramie. The nettle fabric is currently
available in some Italian fashion houses.
Other applications for the fibre from the nettle plants include rope, cloth and paper.
Fibre quality
Cross section of Nettle (10X)
Stinging nettle bark contains fibre similarly to hemp and flax.
Good anti-static, thermoregulatory and transpiration charatcteristics.
Not lignified cell wall.
Soft and resistant fibres with low specific weight.
For some application, as replacement for glass or carbon fibers as
composite in the automotive industry, or in the replacement of
asbestos fibres, some characteristics of nettle fibre are superior to flax
fibre.
Nettle
Cotton
Tensile strength (cN Tex-1)*
30 - 35
15 - 50
Elongation (%)
2,2 - 2,5
6 - 10
Length (mm)
23 - 27
25 - 40
Homogeneity
+
++
* tex = 1 g
Photo: N. Di Virgilio
Foto: N. Di Virgilio
Photo: C. Giordano
Cross section of hemp stem (4X)
Cross section of Kenaf stem (4X)
photo: F. Pelatti
Cross section of stinging nettle stem (10X)
photo: N. Di Virgilio
Stinging nettle fibre cells (40X)
photo: N. Di Virgilio
photo: N. Di Virgilio
Toluidine Blue
Cross section 5X
fixation, paraffin and methacrylate resin embedding,
microtome cutting
photo: N. Di Virgilio
Cross section 10X
fixation, paraffin and methacrylate resin embedding,
microtome cutting
Cross section 40X
photo: N. Di Virgilio
photo: N. Di Virgilio
Fibre content (% of stalk dry matter) of different stalk portions (2nd cultivation
year) from field trial.
Means followed by different letters within a row are significantly different at P = 0.05 according to ANOVA.
DOY
Stalk portion
Mean
Bottom
Middle
Top
110
5.20.5a
4.80.8a
4.82.2a
4.9
130
5.30.6a
4.10.4b
3.40.6c
4.3
155
6.91.8a
11.30.4b
9.81.1c
9.3
169
9.92.1a
13.41.3b
6.50.7c
9.9
205
8.61.7a
13.22.4b
11.62.0c
11.1
DOY = day of the year
Fibre yield
The fibre content can reach at maximum 16 % of stalk dry matter. Trial carried out in
Tuscany showed 13 % in the second year at 205 DOY (Day Of the Year).
In field trials conducted in Austria the fibre yields ranged from 335 to 411 kg ha-1 in the
second year and from 743 to 1016 kg ha-1 in the third year. The upper stalk part of nettle
has a higher percentage of fibre respect to the woody core.
Influence on fibre content is given by the clone variety, plant density (increasing plant
density increases fibre yield), harvesting time.
Cellulose, hemicellulose and lignin content (%) of the fibers extracted from
different stalk portions (2nd year cultivation and the entire stalk of the 1st year)
from field trial.
Means followed by different letters within a row are significantly different at P = 0.05 according to ANOVA.
2nd year fibre
1st year fibre
Bottom
Middle
Top
Cellulose (%)
83.6 4.5a
79 2.2b
81.3 3.8c
83.5 5.0ac
Hemicellulose (%)
8.3 5.2a
12.5 3.1a
7.2 1.1a
6.5 5.8a
Lignin (%)
4.4 0.4a
3.8 0.9ab
3.5 0.2b
4.1 1.8a
Diameter (μm), length (mm), tensile strength (cN tex-1) and elongation (%) of fibre
extracted by different stalk portions (2nd cultivation year nettle) from field trial.
Bottom
Middle
Top
Mean
Range
47
31-63
32
21-42
19
10-26
Mean
Range
43
27-60
50
39-63
58
40-73
Tensile strength (cN tex-1)
Mean
Range
24
12-40
62.1
38-98
58.7
24-98
2.6
1.5-3
2.3
1.3-3.5
2.5
1-6
Diameter (μm)
Length (mm)
Elongation (%)
Mean
Range
Other potential uses of stinging nettle
Nettle has several medicinal properties; astringent, tonic, anti-asthmatic and diuretic.
Across Europe it is also used for the treatment of gout, dropsy, rheumatism and for weight loss.
Nettle roots are commonly used in hair products to treat eczema and dandruff along with
helping to stimulate hair growth.
The antioxidant capacity of nettle water extract have been applied to improve the shelf life of
ground beef, as well the effects of nettle extracts on insects like aphids.
It is thought that along with the vast number of applications, the water extracts of nettle can
also be used successfully to control angular leaf-spot of cucumber by 32-66%.
Male and female plants vary in quality and composition. The content of polyphenolic acids both in leaves
and rhizomes is higher in male plants, however the chemical composition of female polyphenolic acid
tends to be more complex.
Female plants generally have higher content of assimilation pigments whereas male plants have higher
flavonol and polyphenol acid contents, particularly at the beginning of flowering.
Six compounds which are found in aerial parts of nettle plants are caffeic acid, rutin (rutoside), quercetin,
hyperin, isoquercitrin, lignan and beta-sitosterol.
Nettle is nutritionally high in vitamins A, C and D, also minerals iron, manganese, potassium and calcium.
It contains 21-23% crude protein and 9-21% crude fibre.
As a feed component the quality of nettle plants is valuable. At the vegetative stage plants contain 4%
protein and fibre, 50 microg/g carotene, 4 microg/g riboflavin and 10 microg/g vitamin E.
By incorporating nettle into poultry feed it is possible to increase protein intake by 15-20% and vitamin
intake by 60-70%, also green feed requirements can be reduced by 30%.
Multipurpose crop
Field of
application
Use
Part of the plant
Medicine
Hemostatic, diuretic, anti-arthritic, anti-rheumatic anti-itch, antiinflammatory
Dried leaves (tea) and
juice made from
fresh plants
Food
Spinach and soups, carotene extract for vitamin A accumulation,
margarine, tea, seeds (24.9±32.65% oil content), juice made of
fresh plants. During the Second World War used as spinach
replacement, cookies made of leaf flour, vegetable sausage,
dumpling, etc.
Young plants and leaves
Field of
application
Use
Part of the plant
Cosmetics
Soaps, shampoos, hair lotion
Industrial use
Chlorophyll production, use of nettle for paper production
and use of nettle roots as a dye (traditionally, used in
Sweden for coloring Easter eggs)
Seeds, leaves, nettle
shives, whole plant
Forage crop
Used fresh, dried, milled and silaged during periods of
forage shortage before, during and after the First and
Second World Wars; for feeding poultry, cattle, horses
and pigs.
Seeds, leaves, nettle
shives, whole plant
Horticulture
Used in bio-dynamic agriculture (pest control and as a
means to stimulate growth)
Nettle varieties and propagation
Nettle is a common world plant in the temperate region, very variable in characteristics and
probably present as several subspecies.
The fibre nettle can be considered as the cultivated form of the wild nettle (fibre content
increased by breeding, from 5 % to a maximum value of 17 % on stalk dry matter based), long
and not ramified stalks.
Even if some nettle clones has been released and maintained by several Institutes in Germany
and Austria, there are no officially registered varieties.
Propagation by sowing is not suggested, the F1 generation produces high variable plants. Seed
propagation also seems to reduce the fibre content of 2 % respect to mother plants.
Best propagation method is by vegetative propagation. Stinging nettle well suites for both in
vivo and in vitro clonal propagation.
In vivo propagation (cutting)
Through cutting (in vivo propagation), it is possible to obtain a large amount of plant in almost
2 weeks.
It requires large spaces and using mother plants grown in the greenhouse and the seasonality
influence both the rate and the percentage of rooting.
Stocks are grown in rich potting medium with regular fertilisation to ensure healthy nursery
stock is produced.
Percentage of the in vivo rooted plants for
protocol 1 and 2 is almost 100 % in 10-12
days,
while decreasing to 70 % in the case of
protocol 3.
Protocol 4 has to be more deeply
investigated as the showed high influence
of crop stage on cutting production.
IBA (30 s in [3]Hindole-3-butyric acid, solution 2 g L−1)
Thermostatic box with expanded inert silica
Plants transferred in a pot with rich medium
Mother plants stored in the greenhouse
In vitro propagation
Another possibility is the in vitro propagation which actually gives the possibility to
produce big amounts of clones in a short period, reducing spaces and the dependence
from the seasonality.
Trials carried out at IBIMET gave the possibility to define the optimal hormone
concentration for the propagation medium.
In vitro propagation is also interesting for the possibility to apply mutagenesis and test
new clones.
Apical and nodal explants are easy to sterilize.
In vitro cultures well develop in SH medium and the combination of growth regulators induces
the formation of new vigorous shoots.
Medium supplemented with BAP at the concentration of 3.08 2M induces a fast growth of
vigorous shoots and hence adopted as proliferation medium
Cultured shoots well roots in the rooting medium, after three weeks the percentage of rooting is
nearly 100 %.
Components and concentration of the defined medium for propagation and radication
Mutagenesis - Propagation of the irradiated shoots
A
26 7
•H
• N° internodes
• proliferation
24 08
•H
• N° internodes
• proliferation
N
19 6
N
6 7 06
•H
• N° internodes
N
26 7
• H new shoots
• proliferation
24 08
•H
• proliferation
Selection of stable enhanced clones with high quality fibre, optimal grown, frost tollerance, optimal morphology for fibre use (e.g.
single stem, lot of leaves which falls to the soils before harvest, late flowering).
Original material: fibre clones 13, first selected by Bredemann (1959). Bredemann clone cultured in vitro and treated with increasing
doses of gamma radiations (25, 30, 35, 40 Gy).
Surviving plants deriving from irradiation after an in vitro selection are transferred in open field for a selection based on morphological
an physic-chemical properties linked to the management aspects and commercial uses.
Sprout lenght (mm) after 20 days of two clones vs Radiation doses.
70
mm
orti bon
orti max
60
50
40
30
20
10
0
0
20
40
60
80
dosi
Field layout of Clonal plants
15/05/2008 establishment
30/06/2008 Irradiated plants
Induction of mutations in stinging nettle (Urtica dioica L.) for increasing fibre yield and
antioxidant content by using in vitro culture and gamma irradiation
Stefano Predieri · Edoardo Gatti · Nicola Di Virgilio · Laura Bacci · Di Lonardo Sara · Albanese Lorenzo · Pinelli Patrizia · Romani
Annalisa
Acta Horticulturae, under revision
Abstract
Mutants were obtained from a perennial stinging nettle (Urtica dioica L.) clone selected for high fiber content
through in vitro mutagenesis of in vitro propagated plantlets. Gamma-irradiated (20, 25, 30, 35 and 40 gray)
shoots were micropropagated for three cycles (M1V3), to separate mutated from non-mutated sectors and limit
the risk of obtaining chimeral plants. A further propagation was performed in vivo and about 1200 plants were
obtained to establish a selection field. DNA fingerprinting demonstrated that DNA variations existed among
the original clone and selected mutants. Mutants exhibited changes in vigour, plant and leaf shape, fiber
content. Mutant exhibited great differences in phenolics both in total concentration, ranging from 0.7 to 8.4
mg/g of fresh weight, and as related to the relative presence of the two principal classes of phenolics detected,
hydroxycinnamic acid derivatives and flavonoids.
Keywords: stinging nettle, Urtica dioica, mutation induction, tissue culture, hydroxycinnamic acid derivatives, flavonoids.
Cultivation
Information on cultivation of nettle crops are limited
Soil and field preparation
The ideal soil for nettle is with high organic carbon and rich in N, well drained and
with a no acid reaction. Before transplanting, the soil can be prepared according to
the methods used for the cultivation of herbs or vegetables.
The plant prefers loose soil, preferably with a layer of organic matter to encourage
growth. The plant is thought to be responsive to nitrogen and require high
phosphate levels for rapid growth rates.
Sowing and planting
Seeds can be drilled as a method of sowing, but high level of heterozygosis will produce an
inhomogeneous field in particular in terms of plant and fibre maturity, which will affect
overall yield and fibre quality during harvest.
Best method, even if more time spending, is transplanting of cuts, also mechanically, using
machines used in horticulture, e.g. for tomato field establishment or conventional cabbage
planting machinery.
Field establishment can be carried out during springtime (from April to May) or in early
autumn, at least in Central Italian conditions.
Young plants can be planted at 50 cm X 50 cm, or at wide row spacing, e.g. 70-100 cm
between rows, in order to implement a mechanical weed control.
Before nettle establishment, it can be suggested to plant hemp because his effectiveness in
suppressing weeds, which can be a problem in the first year (plants are small and do not able
to cover the whole inter-row).
Also legumes are welcome for their ability to fix nitrogen.
High Density 50x50 cm vs Low Density 50x75 cm
100 vs 85 stalks m-2
Stalk density Height
Treatment
(n. m-2)
(cm)
Diameter
(mm)
Bottom Middle
Dry Biomass
(g m-2)
Top
Stems
Leaves
Fibre
content
(% )
Fibre yield
(g m-2)
High Density
103.4
210.5
9.0
6.0
3.3
1284.5
148.8
12.8
166.8
Low Density
84.7
194.6
8.3
5.6
2.9
981.1
124.9
13.4
127.5
*
*
n.s.
n.s.
n.s.
**
n.s.
n.s.
n.s.
* P<0.05 e ** P<0.01
Crop management after sowing
Ideal situation for nettle is when rainfall or irrigation is distributed homogenously
during the growing period, anyway there are no data in the literature about the exact
water requirement of fibre nettle.
During the field experiment carried out in Tuscany in 2006, very low rainfall during
summer season (June: 0.8 mm, July: 0 mm) required two rescue irrigations, which was
not required during the 2007 growing season as there was enough rainfall (June:
56mm, July: 0 mm)
Fertilization
Nettle is a perennial crop which require large amount of N. Several studies investigated the
optimal amount of N and way of applying it, ranging from 20 to 160-240 kg N ha-1.
Under intensive cultivation, some researchers used very high rates of chemical N fertilizer (i.e.,
160±240 kg N ha-1 or 250±300 kg Nha-1 yr-1 as CaNO3) and close plant spacing (50 cm X 50
cm). The extremely high rates of chemical N fertilizer is neither allowed in organic farming, nor
is it acceptable for environmental reasons.
Good results both in terms of yields and from the environmental point of view, have been
obtained coupling intersowing of white clover with applications of manure and slurry, which
produced up to 4.4 t ha-1 dry biomass.
Weed & pest management
Weed control is essential in the first year. Narrow plant spacing promotes early covering
of the inter-row for suppression of weed, while wide row spacing (up to 150 cm) gives
also the possibility of repeated mechanical inter-row cultivations.
Pest and diseases are not a real problem for nettle. He is host for many butterflies and
other insect, but only producing local damages and plant easily recovers.
Once established the plant is very competitive, thus weed control should not be a
problem.
Certain varieties, particularly the taller ones, are thought to be resistant in the most part
to weeds and pests, thus lowering the use of chemicals during the growth period.
It is anyway yet unknown how potentially damaging pests and diseases are to the crop.
Harvest
Nettle stalks do not achieve the quality required for fibre processing in the first year of
cultivation, also the stalks are too thin and branched.
A cutter bar can be used for harvesting, or alternatively the same harvesting chain of flax or
hemp.
Harvest can start from the second year and can be carried out also according to the final
destination of the crop. For fibre production harvest can be carried out between July and
August.
If the main product is leaves, harvest time can be carried out when plant are younger.
A fibre nettle crop duration is mentioned to be around 4 years. In the literature is reported
also 10 or 15 years, 4 years is the optimum from the economic point of view.
4 year (large interrow and repeated mechanical control of weeds)
10 years (intensive cultiveation with high fertilization level).
Double harvest during one growing season is also possible.
Multi-purpose strategy:
- first cutting at the end of April, used for fodder, medical uses or for industrial purposes,
such as chlorophyll production;
- second cutting at the end of June to be used for fibre production;
- third cutting in September
loss of crop vigor and reduced fibre quality, due to the short growing period preceding the cutting
and branched, thin stalks.
or
-
First year cut for other application then fibre
Following year for fibre.
First harvest can be carried out in July for fibre destination, and a second harvest in
September for collection of leaves.
Yields
Yield values that can be found in the literature are very variable, an average stalk dry
matter yield can be 3 to 4 t ha-1.
Higher values has been observed, depending on stalk density and intensive or organic
management.
Under intensive management value around 11 t ha-1 has of dry stalks has been reported.
Yield increases during the year thanks to the increasing amount of n° of stalks and of
plant height.
In the experience carried out in Tuscany, yield levels at second years was 15.42 t ha-1 as
total dry biomass of which 1 t ha-1 of dry leaves (stalk density of 131.7 n m-2, height of
170.8 cm, bottom stem diameter of 8.1 mm)
50
3 – 5 t ha-1 (2nd year without N
fertilization)
t ha
-1
40
30
20
6 – 10 t ha-1 (3rd year)
10
0
Fresh
Stem
Fresh
Leaves
Dry
Stem
Dry
Leaves
0.14 - 1.28 t ha-1 dry weight
Stalk density, height and diameter, fresh and dry biomass of
stalks and leaves (2nd year)
Stalk density Height
(no m-2)
(cm)
Diameter
(mm)
Bottom Middle
Top
Fresh biomass
(g m-2)
Stalks Leaves
Dry biomass
(g m-2)
Stalks
Leaves
Mean
S.D.
131.7
170.8
8.1
5.2 2.7
4226.0
375.0
1542.1
108.9
16.8
25.7
1.6
1.0 0.7
625.2
86.0
287.6
27.2
height:
100 – 150 cm (1st year)
200 – 300 cm (from 3rd year)
Generally male plants appear to produce slightly
greater mass than the female plants.
Processing methods
Fibre of stinging nettle is similar to all the other herbaceous stalk fibres, as hemp or kenaf. The fibre
processing, industrially, can follow same procedures used e.g. for hemp or flax,
i.e. biological retting, mechanical or physico-chemical methods.
Apical part is more rich in fibre: apical part for textile, basal stalk for technical uses of fibre.
Some experiences anyway revealed that nettle stalks are prone to overretting (decrease of fibre
quality)
Decortication and fibre processing tests
Good degree of separation between fibers and shives obtained by mechanical scutching applied on stalks
stored for 1 year, probably resulting from natural retting processes occurring during the storage.
Microbiological retting (anaerobic plus aerobic bacteria) of entire stalks and/or unretted decorticated fiber
produced fibers with a higher quality than water retting.
Both enzymes used (Viscozyme L and Pectinex Ultra SP-L), improved fiber quality if EDTA was added.
Unretted
mechanically
decorticated fiber
Laboratory scutcher: timing rollers on the timing belt (left) and
harsh brush placed at the end of the timing
belt (right)
Fabric manually realized with nettle fibre (C. Ciuoli, Photo: S. Baronti)
On the market …
Stoffkontor Kranz AG (German company)
http://www.stoffkontor-ag.de/
http://www.nettleworld.com/
“MOECO la casa secondo natura”
www.gzespace.com
http://www.moecoitalia.it/
Underclothes ortica amica - IT
Constraints upon Production
Establishment costs are currently high
Although vegetative propagation with cuttings is simple the process is very labour intensive, particularly in
the case of large scale production.
Mechanical harvest chain is undefined.
Although the plants produce good fibre commercial extraction of fibre fine enough for high quality fibre has
not yet been achieved. Mechanical extraction methods are currently available in Germany, these however
have not yet produced a fibre fine enough for spinning.
Retting is the other major constraint to increased production of nettle plants, enzyme retting has been
attempted but much care needs to be taken. Used in too high concentrations or for too long the cellulose
begins to dissolve and the fibre strength is lowered. Important factors to be considered in this process are
enzyme concentration, temperature, pH value and duration of treatment, all may have an effect on the fibre
quality if not used correctly.
Retting in water has been proven to be successful but is not always practical.
Research
Attempts to improve agronomic aspects of the nettle crop are currently being undertaken,
main areas include establishing a good crop, nutrition requirements, maintenance work
and harvesting techniques.
Processing techniques also need to be reviewed to become more effective, extraction,
spinning and weaving are the key areas.
Further information needs to be gathered relating to wear resistance, fineness of the fibre
and also effects on the skin before products become more widely available.
Also establishment from seed should form the primary basis for further research in order to
reduce establishment costs.
Some main international references
Propagation:
Di Virgilio N., Predieri S, Gatti E, Bacci L, Baronti S, Romani A, et al. The Stinging Nettle (Urtica dioica L.): a Neglected, Multifunctional Species for a Low-impact
Land Use. Italian Journal of Agronomy, 3 Suppl. 2008. p. 443.
Luna, T. (2001) Propagation Protocol for Stinging Nettle (Urtica dioica). Native Plants Journal 2 (2) 110-111
Agronomy and fibre uses:
Vogl CR, Hartl A. Production and processing of organically grown fiber nettle (Urtica dioica L.) and its potential use in the natural textile industry: A review.
American Journal of Alternative Agriculture [Internet]. Cambridge University Press; 2009 Oct 30 [cited 2013 Jul 8];18(03):119.
Bisht S, Bhandari S, Bisht NS. Urtica dioica ( L ): an undervalued , economically important plant. Agricultural Science Research Journals. 2012;2(5)(May):250–
2.
Dreyer, J., Dreyling, G. Feldmann, F., (1996) Cultivation of stinging nettle Urtica diocia L. with high fibre content as an raw material for the production of fibre
and cellulose: Qualitative and quantitative differentiation of ancient clones. Journal of Applied Botany. 70 (1-2) 28-39
Fibre yield and quality:
Bacci L, Baronti S, Predieri S, di Virgilio N. Fiber yield and quality of fiber nettle (Urtica dioica L.) cultivated in Italy. Industrial Crops and Products, 29(2-3):480–
4.
Bacci L, Di Lonardo S, Albanese L, Mastromei G, Perito B. Effect of different extraction methods on fiber quality of nettle (Urtica dioica L.). Textile Research
Journal;81(8):827–37.
Hartl A, Vogl CR. Dry matter and fiber yields, and the fiber characteristics of five nettle clones (Urtica dioica L .) organically grown in Austria for potential textile
use. 2002. American Journal of Alternative Agriculture: 17,(4): 95–200.
Kavtaradze, N. Sh., Alaniya, M.D. & Aneli, J.N., (2001) Chemical components of Urtica dioica growing in Georgia. 37 (3) 287
Pinelli P, Ieri F, Vignolini P, Bacci L, Baronti S, Romani A. Extraction and HPLC analysis of phenolic compounds in leaves, stalks, and textile fibers of Urtica
dioica L. Journal of agricultural and food chemistry [Internet]. 2008 Oct 8;56(19):9127–32. Available from: http://www.ncbi.nlm.nih.gov/pubmed/18778029
No fibre uses:
Vogl CR, Hartl A. Production and processing of organically grown fiber nettle (Urtica dioica L.) and its potential use in the natural textile industry: A
review. American Journal of Alternative Agriculture [Internet]. Cambridge University Press; 2009 Oct 30 [cited 2013 Jul 8];18(03):119.
Gaspari M, Lykouressis D, Perdikis D, Polissiou M, (2007) Nettle extract effects on the aphid Myzus persicae and its natural enemy, the predator
Macrolophus pygmaeus (Hem., Miridae). J Appl Entomol 131(9/10): 652-657
Alp E, Aksu MI (2010) Effects of water extract of Urtica dioica L. and modified atmosphere packaging on the shelf life of ground beef. Meat Sci 86:468–
473
Riehemann K, Behnke B, Schulze-Osthoff K (1999) Plant extracts from stinging nettle (Urtica dioica), an antirheumatic remedy, inhibit the
proinflammatory transcription factor NF-kappa-B. FEBS Lett. 442:89-94
Guil-Guerreroa JL, Rebolloso-Fuentes MM, Torija Isasa ME (2003) Fatty acids and carotenoids from Stinging Nettle (Urtica dioica L.). J Food Compost
Anal 16:111–119
Gülçin OI, Küfrevioğlu M, Oktay, Büyükokuroğlu ME (2004) Antioxidant, antimicrobial, antiulcer and analgesic activities of nettle (Urtica dioica L.). J
Ethnopharmacol 90:205–215
Krishnaiah D, Sarbatly R, Nithyanandam R (2011) A review of the antioxidant potential of medicinal plant species. Food Bioprod Process 89:217-233
http://www.lammatest.rete.toscana.it/lammat
est/documenti/manuale_ortica_200705.pdf
Web sites
Supported by LaMMa-TEST project “Technologies for the Textile Chain”, founded by the Tuscany Region in collaboration with the
National Research Council and the Province of Prato. www.lammatest.rete.toscana.it
IENICA: http://www.ienica.net/crops/nettle.htm
http://www.ovop.go.ke/index.php/ovop-groups/central-region/nyeri-county/113-nettle-world
http://www.osservatoriokyoto.it/userfiles/newsletter/NewsKyoto_0902_007.pdf
http://www.stampa.cnr.it/documenti/cnrWeb/2006/Mag/15_mag_06_11.htm
http://www.dmu.ac.uk/faculties/art_and_design/research/team/sting/index.jsp - STING (Sustainable Technology In Nettle Growing)
Project. Expired.
http://www.defra.gov.uk/farm/acu/fibres/fibres.htm - Industrial Crops: Fibres; includes regular updates on recent developments and the
future. Also provides access
to useful related reports. Expired.
http://www.nettletex.com - Produce fibre nettle cuttings (Urtica dioica L.). Useful literature list. Expired.
Thank you for your attention
Nicola Di Virgilio, PhD
[email protected]