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Cotton: a flow cycle to exploit
Industrial Crops and Products 11 (2000) 173 – 178 www.elsevier.com/locate/indcrop
Cotton: a flow cycle to exploit Maria Proto *, Stefania Supino, Ornella Malandrino Uni6ersita` degli Studi di Salerno, Facolta di Economia, Dipartimento di Studi e Ricerche Aziendali, Via Ponte don Melillo, Cattedra di Merceologia, 84084 Fisciano, SA, Italy Accepted 8 October 1999
Abstract The relation between agricultural resources, industrial activities and the environment has complex aspects because of many dynamic interrelationships. Among the sectors that are showing a certain environmental sensibility, there is the textile one, and particularly the cotton sector. Cotton is one of the most important non-food crops in the world. Its products are destined to different industries: textiles, food, chemicals and so on. In Italy, cotton cultivation encounters economic problems that makes its development quite difficult. In this paper, the development opportunities in agricultural and manufacturing processes are analysed in view of new trends that are characterised by sustainable life-cycle assessments. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Cotton; Flow cycle; Non food crops; Life cycle assessments
1. Introduction Cotton, included in the genus ‘Gossypium’1, is economically the most important vegetable fibre. Botanically, the cotton fibres are the protective
* Corresponding author. Tel.: +39-89-963146; fax: + 3989-963505. 1 The most important species included in the Gossypium are hirsutum, barbadense, arboreum and herbaceum. It is very easy to distinguish each type by using a microscope or chemical staining. The average cotton plant is a herbaceous shrub with a normal height of 4.5–6.0 m (Villavecchia Eigenmann, 1973).
covering of the seeds in a cotton plant. The cotton fibre, in its pure form, and also in blends, is the principal clothing fibre of the world, accounting for about 50% of total world fibre production (Shariq, 1995). Cotton fibre production depends on many factors, including soil productivity, climate2, cost of production, market conditions, government programs, etc. This paper analyses the biomass balance related to the cotton crop, and aims at underlining how it is possible to obtain a large variety of different products utilised in various fields from this interesting renewable resource.
2 The most favourable growing conditions for this plant is a warm climate (21 – 30°C mean temperature).
0926-6690/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 6 - 6 6 9 0 ( 9 9 ) 0 0 0 6 0 - 6
174
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
Table 1 Distribution and main uses of cotton Botanical name
Distribution
Gossypium spp. including many hybrids, e.g.: short fibre, Gossypium herbaceum; long fibre, Gossypium barbadense
USA, former USSR, South Amer- Textiles, clothica, China, Africa, India, West ing Indies, Egypt, Sudan
2. Cultivation and production report The use of cotton dates back to a remote period. It has been used as a fibre in spinning and weaving for over 5000 years. It was originally used in India, later spread to China and Central Asia, and then reached Italy (Sicily), Spain and Africa (Sarno, 1987). As trade flowed from the East into Europe, cotton products became a valuable commodity. In Great Britain, the textile industry began to develop quite rapidly after 1500, with most of the technological advances in spinning and weaving originating in that country. As regards Italy, the diffusion of cotton cultivation dates back to about 1850 when the Italian textile industries, like those in other European countries, had a crisis scarcity of the raw material. During the following decades, the history of the culture of cotton in Italy suffered various problems. After periods of crises, improvements and downfalls, cotton production has almost completely disappeared. Today, the world production of raw cotton — a renewable resource from which it is possible to obtain textiles, pulp and paper, but also different products in the field of chemical, pharmaceutical, cosmetics, food, zootechnics, etc., that are obtained from cotton-seed oil — is about 53× 106 tons, and the most important producers are the USA, the former USSR, South America, China and India, which together contribute to almost 80% of total production. Other important producers are East Africa, Egypt and the Sudan (Table 1) (Shariq, 1995). The most important world raw cotton producing countries (total amount about 20× 106 tons) are reported in Table 2.
Main uses
Other uses Oil makes up 20% of the seed. Cotton-seed oil is used in margarine and soap. Cotton-seed cake, the residue after milling, is a valuable stock feed.
In Table 3, the percentage of the world production of cotton fibres, reduced to half during our century, is confronted with wool and chemical fibres (artificial and synthetic). The chemical composition (%) of dry weight of cotton fibres is shown in Table 4. A renewed interest in this crop is manifested by Italy and the EU — today the importers of 338 000 and 952 000 tons, respectively (Rapporto sull’industria Cotoniera e Liniera, 1998) — because cotton crop can be seen as a useful renewable resources from which to obtain fibres and other derived products3. The best known by-product of the cotton plant is lint; that is the hairs that grow on the seed coat yeld. Another very valuable product is in the form of oil, which makes up 20% of the seed. Cottonseed oil is used for cooking, margarine and soap, but also for chemical and pharmaceutical uses. Cotton-seed cake, the residue after milling, is a valuable animal feed (Villet, 1994).
3. Problems and perspectives on cotton crop The relation between agricultural resources, industrial activities and the environment has complex aspects because of many dynamic interrelationships. The cotton textile sector is 3 Chemists recognise several different types of cellulose, namely pure or holocellulose and hemicellulose. Cellulose is a long chain polymer made up of glucose residues joined one to another; the hemicelluloses have shorter chains and are sometimes described as ‘encrusting’ material or gums. Cellulosic and hemicellulosic substances are employed in a large variety of traditional and innovative fields, such as pulp and paper, textiles, chemicals, etc. (Proto et al., 1996b).
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
175
Table 2 Main producers of cotton in the world Producers/countries
Thousands of tons 1997-98
1998-99a
2.636 305 90 792 2 1.447
2.890 345 119 760 2 1.664
3.033 415 89 799 2 1.728
8.461 22 3.850 2.198 165 11 42 24 1.870 221 5 53
9.182 22 4.200 2.771 200 8 51 16 1.589 245 25 55
9.088 22 3.800 2.800 160 8 51 17 1.900 260 13 57
9.114 22 4.000 2.711 151 8 48 18 1.859 227 10 60
1.418 115 77 65 12 60 115 240 150
1.615 172 73 88 16 74 95 343 200
1.796 171 98 92 16 90 130 346 229
1.801 171 78 96 17 73 115 338 229
1991–92
1992-93
1993-94
1994-95
1995-96
Europe Greece Spain Turkey Eastern countries C.S.I.
3.334 183 77 565 9 2.500
3.266 260 62 606 9 2.329
3.018 318 32 580 4 2.084
3.104 320 30 610 4 2.140
3.075 380 20 770 4 1.901
Asia Afghanistan China India Iran Iraq Israel Myanmarb Pakistan Syria Thailand Other Countries
10.201 22 5.663 1.955 114 1 23 21 2.142 180 39 41
10.311 22 5.472 2.190 112 2 30 19 2.200 183 33 48
7.571 22 3.739 2.095 91 4 27 17 1.312 213 6 45
8.811 18 4.500 2.261 113 4 37 28 1.581 207 14 48
Africa Benin Burkina Faso Cameroon Central African Republic Cameroon The Ivory Coast Egypt Mali Morocco Mozambique Nigeria South Africa Sudan Tanzania Togo Uganda Zaire Zimbabwe Other countries
1.290 75 70 50 10 75 90 293 114 7 6 13 45 31 86 100 35 11 73 106
1.299 65 65 48 12 70 110 281 135 2 3 13 63 42 91 70 35 13 81 100
1.287 116 51 52 7 37 116 411 101
15 32 27 53 51 33 4 60 121
1.395 120 60 60 10 60 120 340 128 1 1 13 60 36 83 34 40 8 92 129
America Argentina Brazil Colombia El Salvador Guatemala Mexico Nicaragua Paraguay Peru USA
5.666 275 831 143 4 33 180 25 230 66 3.819
4.886 221 751 70 3 21 50 2 179 48 3.484
4.468 227 428 53 4 13 24 1 125 45 3.515
5.343 275 571 60 1 9 102 1 147 51 4.080
1996-97
11 85 30 122 74 50 10 2 102 98
23 80 36 97 54 45 18
12 90 49 109 65 61 34
13 81 63 111 67 62 48
93 108
85 119
108 131
5.966 353 653 83
5.253 300 368 53
5.251 425 400 33
5.278 419 425 51
4 181 5 168 66 4.412
2 247 2 49 58 4.126
168 1 110 43 4.010
179 4 110 51 3.970
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
176 Table 2 (Continued) Producers/countries
Thousands of tons 1991–92
Venezuela Other countries Oceania
b
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99a
25 35
24 33
18 15
22 24
16 25
22 26
18 43
20 49
359
339
329
329
310
614
622
577
World total a
1992-93
20.850
20.101
16.671
18.982
19.230
19.300
19.647
19.803
%
Total
%
12 22 39 48 48 52 53 55
3.893 5.460 9.173 14.934 21.840 29.625 40.075 43.551 43.625 47.793
100 100 100 100 100 100 100 100 100 100
Estimated dates. Ex Burma.
Table 3 World production of cotton wool and chemical fibresa Years
1900 1920 1940 1960 1970 1980 1990 1995 1996 1997 a
Thousand of tons/(%) Cotton
%
Wool
%
Chemical fibres
3.162 4.629 6.907 10.113 11.784 13.844 18.997 19.962 18.960 19.580
81 85 76 68 54 47 47 45 44 42
730 816 1.134 1.463 1.659 1.599 1.927 1.485 1.456 1.450
19 15 12 10 7 5 5 3 3 3
1 15 1.132 3.358 8.397 14.182 19.151 22.104 23.209 26.763
Rapporto sull’industria Cotoniera e Liniera, 1998.
demonstrating a certain environmental awareness in its production cycle. To determine the environmental impact connected to a product, it is necessary to estimate inputs and outputs of its productivity cycle. Today, the Life Cycle Analysis (LCA), with a ‘cradle-to-grave’ approach, is increasing, but it is still often incomplete and approximate (Proto et al., 1996). The first step of this flow cycle includes agricultural activities, where many important challenges are turned towards the reduction of pesticides used to control insects, disease and weeds, and defoliants to facilitate harvest. In most areas, cotton production consumes more pesticides than any other agricultural crop (Bacheler, 1996). Cotton fresh from the bale has the appearance of ‘cotton wool’ mixed with pieces of dead leaf and other debris. Hand-picked cotton is, however,
cleaner than machine-picked cotton. Samples from different sources vary greatly in cleanliness, staple length and colour. Table 4 Composition of typical cotton fibres Constituent
Cellulose Protein (% N×6.25)a Pectic substances Ash Wax Total sugars Pigment Others
Composition (% dry weight) Typical
Range
94.0 1.3 1.2 1.2 0.6 0.3 Trace 1.4
88.0–96.0 1.1–1.9 0.7–1.2 0.7–1.6 0.4–1.0
a Standard method of estimating percentage of protein from nitrogen content (% N).
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
177
Fig. 1. Cotton crop: global balance of biomass (moist weight) (1 ha). For the source, see Proto et al., (1996a).
Cotton picking is highly labour-intensive, and on a large scale is often carried out by machinery. In many parts of the world, however, picking is carried out by hand. Since cotton must be picked at weekly intervals to prevent discoloration of the lint in the field, it is a very laborious task: smallholders average only 9 kg per day. The first stage in processing the cotton bales into fibre suitable for spinning is the removal of the cotton seeds by ginning. The mechanical ginning process, invented by Ely Whitney in 1793, is the principle applied today to remove foreign matter and moisture, and to separate cottonseed from raw seed cotton. To obtain lint cotton, various impurities must be removed before the manufacturing process. These are than transformed and later employed as high added-value products. Once the cotton is grown, ginned and manufactured, the textile processing necessary to provide the colourful fabrics desired requires the use of numerous environmentally dangerous materials. In fact, the dying and finishing processes consume huge amounts of energy and water, mixed with various chemical substances. Scientists are engaged in the process of identifying and isolating useful genes from various sources
and evaluating them in the possibility of improving cotton. Most current genetic-engineering attempts are targeted at conferring agronomic traits such as insect herbicide and stress tolerance. Transgenic varieties resistant to both insects and herbicides are expected to be available within the next few years (Bacheler, 1996). An American researcher (Maliyakal, 1994) developed the first naturally coloured cotton, considerably reducing the environmental impact. Today, the production of organic cotton is about 5000 tons. However, in the light of the high environmental impact of the cotton cycle, it is necessary not only to improve photosynthetic efficiency of the crop and to introduce new genetic engineering but also to utilise all the by-products obtained from processed cotton. In order to analyse the most important substances deriving from the cotton cycle that may be employed in a large variety of industrial sectors4, the global biomass balance of these resources is reported (Fig. 1). 4 Cotton cultivation has declined since the appearance of synthetic fibres; but new markets have developed: use of the oleoprotinaceous seeds in the food and pharmaceutical-industry.
178
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
may be obtained through the diffusion, on large quantities of cotton products, of the European Ecolabel, introduced in Regulation 880/92. Today, the European Commission has placed the environmental criteria on the elaboration of a life-cycle analysis for bed linen and T-shirt only. It is obvious, therefore, that one of the cotton sector’s prime future aims is to achieve certification of its environmental quality.
References
Fig. 2. Traditional and innovative uses of cotton plant.
The most important uses of these materials are reported in Fig. 2. Until more attention is placed on the relative problems concerning the environmental quality of products and processes, it is essential to identify suitable ways of creating correct eco-management policies and outlining appropriate instruments in order to solve the current difficulties. These derive principally from the scarce harmonisation of instruments suggested up to now (life-cycle analysis, environmental balances, ecolabels, etc.). Their results are not comparable and, above all, are not very ‘transparent’, particularly for the final consumer. In the textile sector, the diffusion of ‘ecological private labels’, only disorientate and complicate the market, rather than facilitate commercial exchanges. On the contrary, opposite contributions
.
Bacheler, J.S., 1996. Cotton insect scouting guide, Center for IPM, April 1996, http://ipmwww.ncsu.edu/cotton/insect/ scout – insect.htlm. Maliyakal, E.J., 1994a. Cotton futures. Chemtech 24 (10), 27 – 30. Proto, M., Malandrino, O., Supino, S., 1996. Environmental quality management: tools for sustainable development, Proceedings of Fifth International Commodity Science Conference ‘Quality for European Integration’, Poznan, 19 – 21 September 1996, 151-154. Proto, M., Malandrino, O., Supino, S., 1996a. ‘Il cotone: una filiera da non sottovalutare’, Atti del XVII Congresso Nazionale di Merceologia Merceologia e cicli produttivi nel settore agroindustriale alle soglie del 21° secolo, Lecce, 3 – 5 October, 1996a, 230 – 238. Proto, M., Malandrino, O., Supino, S., 1996b. Disponibilita` e impieghi di cellulosa in Italia: realta` e prospettive, Atti del XVII Congresso Nazionale di Merceologia ‘Merceologia e cicli produttivi nel settore aggroindustriale alle soglie del 21° secolo, Lecce, 3 – 5 October, 1996b, 239 – 248. .Rapporto sull’Industria Cotoniera del Lino e delle Fibre Affini, September – October 1998. Sarno, R., 1987. Situazioni e prospettive tecnico-economiche della coltivazione del cotone in Sicilia, Economia e Credito 1, 55 – 81. Shariq, K., 1995. ‘Cotton’, Chemical Economics Handbook, 540.3000 A 540.3000 S, SRI International. Villavecchia Eigenmann, 1973. Nuovo Dizionario di Merceologia e Chimica Applicata, Hoepli Editore, 3, 1137 – 1145. Villet, R.H., 1994. Increasing the value of agricultural feedstocks. Chemtech 24 (9), 44 – 48.
Cotton: a flow cycle to exploit Maria Proto *, Stefania Supino, Ornella Malandrino Uni6ersita` degli Studi di Salerno, Facolta di Economia, Dipartimento di Studi e Ricerche Aziendali, Via Ponte don Melillo, Cattedra di Merceologia, 84084 Fisciano, SA, Italy Accepted 8 October 1999
Abstract The relation between agricultural resources, industrial activities and the environment has complex aspects because of many dynamic interrelationships. Among the sectors that are showing a certain environmental sensibility, there is the textile one, and particularly the cotton sector. Cotton is one of the most important non-food crops in the world. Its products are destined to different industries: textiles, food, chemicals and so on. In Italy, cotton cultivation encounters economic problems that makes its development quite difficult. In this paper, the development opportunities in agricultural and manufacturing processes are analysed in view of new trends that are characterised by sustainable life-cycle assessments. © 2000 Elsevier Science B.V. All rights reserved. Keywords: Cotton; Flow cycle; Non food crops; Life cycle assessments
1. Introduction Cotton, included in the genus ‘Gossypium’1, is economically the most important vegetable fibre. Botanically, the cotton fibres are the protective
* Corresponding author. Tel.: +39-89-963146; fax: + 3989-963505. 1 The most important species included in the Gossypium are hirsutum, barbadense, arboreum and herbaceum. It is very easy to distinguish each type by using a microscope or chemical staining. The average cotton plant is a herbaceous shrub with a normal height of 4.5–6.0 m (Villavecchia Eigenmann, 1973).
covering of the seeds in a cotton plant. The cotton fibre, in its pure form, and also in blends, is the principal clothing fibre of the world, accounting for about 50% of total world fibre production (Shariq, 1995). Cotton fibre production depends on many factors, including soil productivity, climate2, cost of production, market conditions, government programs, etc. This paper analyses the biomass balance related to the cotton crop, and aims at underlining how it is possible to obtain a large variety of different products utilised in various fields from this interesting renewable resource.
2 The most favourable growing conditions for this plant is a warm climate (21 – 30°C mean temperature).
0926-6690/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 6 - 6 6 9 0 ( 9 9 ) 0 0 0 6 0 - 6
174
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
Table 1 Distribution and main uses of cotton Botanical name
Distribution
Gossypium spp. including many hybrids, e.g.: short fibre, Gossypium herbaceum; long fibre, Gossypium barbadense
USA, former USSR, South Amer- Textiles, clothica, China, Africa, India, West ing Indies, Egypt, Sudan
2. Cultivation and production report The use of cotton dates back to a remote period. It has been used as a fibre in spinning and weaving for over 5000 years. It was originally used in India, later spread to China and Central Asia, and then reached Italy (Sicily), Spain and Africa (Sarno, 1987). As trade flowed from the East into Europe, cotton products became a valuable commodity. In Great Britain, the textile industry began to develop quite rapidly after 1500, with most of the technological advances in spinning and weaving originating in that country. As regards Italy, the diffusion of cotton cultivation dates back to about 1850 when the Italian textile industries, like those in other European countries, had a crisis scarcity of the raw material. During the following decades, the history of the culture of cotton in Italy suffered various problems. After periods of crises, improvements and downfalls, cotton production has almost completely disappeared. Today, the world production of raw cotton — a renewable resource from which it is possible to obtain textiles, pulp and paper, but also different products in the field of chemical, pharmaceutical, cosmetics, food, zootechnics, etc., that are obtained from cotton-seed oil — is about 53× 106 tons, and the most important producers are the USA, the former USSR, South America, China and India, which together contribute to almost 80% of total production. Other important producers are East Africa, Egypt and the Sudan (Table 1) (Shariq, 1995). The most important world raw cotton producing countries (total amount about 20× 106 tons) are reported in Table 2.
Main uses
Other uses Oil makes up 20% of the seed. Cotton-seed oil is used in margarine and soap. Cotton-seed cake, the residue after milling, is a valuable stock feed.
In Table 3, the percentage of the world production of cotton fibres, reduced to half during our century, is confronted with wool and chemical fibres (artificial and synthetic). The chemical composition (%) of dry weight of cotton fibres is shown in Table 4. A renewed interest in this crop is manifested by Italy and the EU — today the importers of 338 000 and 952 000 tons, respectively (Rapporto sull’industria Cotoniera e Liniera, 1998) — because cotton crop can be seen as a useful renewable resources from which to obtain fibres and other derived products3. The best known by-product of the cotton plant is lint; that is the hairs that grow on the seed coat yeld. Another very valuable product is in the form of oil, which makes up 20% of the seed. Cottonseed oil is used for cooking, margarine and soap, but also for chemical and pharmaceutical uses. Cotton-seed cake, the residue after milling, is a valuable animal feed (Villet, 1994).
3. Problems and perspectives on cotton crop The relation between agricultural resources, industrial activities and the environment has complex aspects because of many dynamic interrelationships. The cotton textile sector is 3 Chemists recognise several different types of cellulose, namely pure or holocellulose and hemicellulose. Cellulose is a long chain polymer made up of glucose residues joined one to another; the hemicelluloses have shorter chains and are sometimes described as ‘encrusting’ material or gums. Cellulosic and hemicellulosic substances are employed in a large variety of traditional and innovative fields, such as pulp and paper, textiles, chemicals, etc. (Proto et al., 1996b).
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
175
Table 2 Main producers of cotton in the world Producers/countries
Thousands of tons 1997-98
1998-99a
2.636 305 90 792 2 1.447
2.890 345 119 760 2 1.664
3.033 415 89 799 2 1.728
8.461 22 3.850 2.198 165 11 42 24 1.870 221 5 53
9.182 22 4.200 2.771 200 8 51 16 1.589 245 25 55
9.088 22 3.800 2.800 160 8 51 17 1.900 260 13 57
9.114 22 4.000 2.711 151 8 48 18 1.859 227 10 60
1.418 115 77 65 12 60 115 240 150
1.615 172 73 88 16 74 95 343 200
1.796 171 98 92 16 90 130 346 229
1.801 171 78 96 17 73 115 338 229
1991–92
1992-93
1993-94
1994-95
1995-96
Europe Greece Spain Turkey Eastern countries C.S.I.
3.334 183 77 565 9 2.500
3.266 260 62 606 9 2.329
3.018 318 32 580 4 2.084
3.104 320 30 610 4 2.140
3.075 380 20 770 4 1.901
Asia Afghanistan China India Iran Iraq Israel Myanmarb Pakistan Syria Thailand Other Countries
10.201 22 5.663 1.955 114 1 23 21 2.142 180 39 41
10.311 22 5.472 2.190 112 2 30 19 2.200 183 33 48
7.571 22 3.739 2.095 91 4 27 17 1.312 213 6 45
8.811 18 4.500 2.261 113 4 37 28 1.581 207 14 48
Africa Benin Burkina Faso Cameroon Central African Republic Cameroon The Ivory Coast Egypt Mali Morocco Mozambique Nigeria South Africa Sudan Tanzania Togo Uganda Zaire Zimbabwe Other countries
1.290 75 70 50 10 75 90 293 114 7 6 13 45 31 86 100 35 11 73 106
1.299 65 65 48 12 70 110 281 135 2 3 13 63 42 91 70 35 13 81 100
1.287 116 51 52 7 37 116 411 101
15 32 27 53 51 33 4 60 121
1.395 120 60 60 10 60 120 340 128 1 1 13 60 36 83 34 40 8 92 129
America Argentina Brazil Colombia El Salvador Guatemala Mexico Nicaragua Paraguay Peru USA
5.666 275 831 143 4 33 180 25 230 66 3.819
4.886 221 751 70 3 21 50 2 179 48 3.484
4.468 227 428 53 4 13 24 1 125 45 3.515
5.343 275 571 60 1 9 102 1 147 51 4.080
1996-97
11 85 30 122 74 50 10 2 102 98
23 80 36 97 54 45 18
12 90 49 109 65 61 34
13 81 63 111 67 62 48
93 108
85 119
108 131
5.966 353 653 83
5.253 300 368 53
5.251 425 400 33
5.278 419 425 51
4 181 5 168 66 4.412
2 247 2 49 58 4.126
168 1 110 43 4.010
179 4 110 51 3.970
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
176 Table 2 (Continued) Producers/countries
Thousands of tons 1991–92
Venezuela Other countries Oceania
b
1993-94
1994-95
1995-96
1996-97
1997-98
1998-99a
25 35
24 33
18 15
22 24
16 25
22 26
18 43
20 49
359
339
329
329
310
614
622
577
World total a
1992-93
20.850
20.101
16.671
18.982
19.230
19.300
19.647
19.803
%
Total
%
12 22 39 48 48 52 53 55
3.893 5.460 9.173 14.934 21.840 29.625 40.075 43.551 43.625 47.793
100 100 100 100 100 100 100 100 100 100
Estimated dates. Ex Burma.
Table 3 World production of cotton wool and chemical fibresa Years
1900 1920 1940 1960 1970 1980 1990 1995 1996 1997 a
Thousand of tons/(%) Cotton
%
Wool
%
Chemical fibres
3.162 4.629 6.907 10.113 11.784 13.844 18.997 19.962 18.960 19.580
81 85 76 68 54 47 47 45 44 42
730 816 1.134 1.463 1.659 1.599 1.927 1.485 1.456 1.450
19 15 12 10 7 5 5 3 3 3
1 15 1.132 3.358 8.397 14.182 19.151 22.104 23.209 26.763
Rapporto sull’industria Cotoniera e Liniera, 1998.
demonstrating a certain environmental awareness in its production cycle. To determine the environmental impact connected to a product, it is necessary to estimate inputs and outputs of its productivity cycle. Today, the Life Cycle Analysis (LCA), with a ‘cradle-to-grave’ approach, is increasing, but it is still often incomplete and approximate (Proto et al., 1996). The first step of this flow cycle includes agricultural activities, where many important challenges are turned towards the reduction of pesticides used to control insects, disease and weeds, and defoliants to facilitate harvest. In most areas, cotton production consumes more pesticides than any other agricultural crop (Bacheler, 1996). Cotton fresh from the bale has the appearance of ‘cotton wool’ mixed with pieces of dead leaf and other debris. Hand-picked cotton is, however,
cleaner than machine-picked cotton. Samples from different sources vary greatly in cleanliness, staple length and colour. Table 4 Composition of typical cotton fibres Constituent
Cellulose Protein (% N×6.25)a Pectic substances Ash Wax Total sugars Pigment Others
Composition (% dry weight) Typical
Range
94.0 1.3 1.2 1.2 0.6 0.3 Trace 1.4
88.0–96.0 1.1–1.9 0.7–1.2 0.7–1.6 0.4–1.0
a Standard method of estimating percentage of protein from nitrogen content (% N).
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
177
Fig. 1. Cotton crop: global balance of biomass (moist weight) (1 ha). For the source, see Proto et al., (1996a).
Cotton picking is highly labour-intensive, and on a large scale is often carried out by machinery. In many parts of the world, however, picking is carried out by hand. Since cotton must be picked at weekly intervals to prevent discoloration of the lint in the field, it is a very laborious task: smallholders average only 9 kg per day. The first stage in processing the cotton bales into fibre suitable for spinning is the removal of the cotton seeds by ginning. The mechanical ginning process, invented by Ely Whitney in 1793, is the principle applied today to remove foreign matter and moisture, and to separate cottonseed from raw seed cotton. To obtain lint cotton, various impurities must be removed before the manufacturing process. These are than transformed and later employed as high added-value products. Once the cotton is grown, ginned and manufactured, the textile processing necessary to provide the colourful fabrics desired requires the use of numerous environmentally dangerous materials. In fact, the dying and finishing processes consume huge amounts of energy and water, mixed with various chemical substances. Scientists are engaged in the process of identifying and isolating useful genes from various sources
and evaluating them in the possibility of improving cotton. Most current genetic-engineering attempts are targeted at conferring agronomic traits such as insect herbicide and stress tolerance. Transgenic varieties resistant to both insects and herbicides are expected to be available within the next few years (Bacheler, 1996). An American researcher (Maliyakal, 1994) developed the first naturally coloured cotton, considerably reducing the environmental impact. Today, the production of organic cotton is about 5000 tons. However, in the light of the high environmental impact of the cotton cycle, it is necessary not only to improve photosynthetic efficiency of the crop and to introduce new genetic engineering but also to utilise all the by-products obtained from processed cotton. In order to analyse the most important substances deriving from the cotton cycle that may be employed in a large variety of industrial sectors4, the global biomass balance of these resources is reported (Fig. 1). 4 Cotton cultivation has declined since the appearance of synthetic fibres; but new markets have developed: use of the oleoprotinaceous seeds in the food and pharmaceutical-industry.
178
M. Proto et al. / Industrial Crops and Products 11 (2000) 173–178
may be obtained through the diffusion, on large quantities of cotton products, of the European Ecolabel, introduced in Regulation 880/92. Today, the European Commission has placed the environmental criteria on the elaboration of a life-cycle analysis for bed linen and T-shirt only. It is obvious, therefore, that one of the cotton sector’s prime future aims is to achieve certification of its environmental quality.
References
Fig. 2. Traditional and innovative uses of cotton plant.
The most important uses of these materials are reported in Fig. 2. Until more attention is placed on the relative problems concerning the environmental quality of products and processes, it is essential to identify suitable ways of creating correct eco-management policies and outlining appropriate instruments in order to solve the current difficulties. These derive principally from the scarce harmonisation of instruments suggested up to now (life-cycle analysis, environmental balances, ecolabels, etc.). Their results are not comparable and, above all, are not very ‘transparent’, particularly for the final consumer. In the textile sector, the diffusion of ‘ecological private labels’, only disorientate and complicate the market, rather than facilitate commercial exchanges. On the contrary, opposite contributions
.
Bacheler, J.S., 1996. Cotton insect scouting guide, Center for IPM, April 1996, http://ipmwww.ncsu.edu/cotton/insect/ scout – insect.htlm. Maliyakal, E.J., 1994a. Cotton futures. Chemtech 24 (10), 27 – 30. Proto, M., Malandrino, O., Supino, S., 1996. Environmental quality management: tools for sustainable development, Proceedings of Fifth International Commodity Science Conference ‘Quality for European Integration’, Poznan, 19 – 21 September 1996, 151-154. Proto, M., Malandrino, O., Supino, S., 1996a. ‘Il cotone: una filiera da non sottovalutare’, Atti del XVII Congresso Nazionale di Merceologia Merceologia e cicli produttivi nel settore agroindustriale alle soglie del 21° secolo, Lecce, 3 – 5 October, 1996a, 230 – 238. Proto, M., Malandrino, O., Supino, S., 1996b. Disponibilita` e impieghi di cellulosa in Italia: realta` e prospettive, Atti del XVII Congresso Nazionale di Merceologia ‘Merceologia e cicli produttivi nel settore aggroindustriale alle soglie del 21° secolo, Lecce, 3 – 5 October, 1996b, 239 – 248. .Rapporto sull’Industria Cotoniera del Lino e delle Fibre Affini, September – October 1998. Sarno, R., 1987. Situazioni e prospettive tecnico-economiche della coltivazione del cotone in Sicilia, Economia e Credito 1, 55 – 81. Shariq, K., 1995. ‘Cotton’, Chemical Economics Handbook, 540.3000 A 540.3000 S, SRI International. Villavecchia Eigenmann, 1973. Nuovo Dizionario di Merceologia e Chimica Applicata, Hoepli Editore, 3, 1137 – 1145. Villet, R.H., 1994. Increasing the value of agricultural feedstocks. Chemtech 24 (9), 44 – 48.