22 Agro and Geo Textiles

S. Amsamani

1. AGROTEX

1.1 INTRODUCTION

Agricultural and textiles are the most important industries in India. They are inter- linked with each other. Like every other field even in agricultural, farming, marine and forestry use textiles either in the form of fiber, yarn or fabric. Decrease in the availability of resources such as land, water, energy and increase in population pressure along with high standard of living and pollution has resulted in the use of agro textiles. It can control climate, ecological degradation, and result in efficient use of water, reduce use of pest control chemical, save energy and can even improve production quality. Some of the technical textile products covered under Agro tech is shade-nets, mulch-mats, crop-covers, anti-hail nets, bird protection nets and fishing nets. The consumption under Agro tech in India is estimated at around Rs 487 crore. Agro tech segment is estimated to provide employment to 65,000 people. The demand for Agro tech products like shade nets, Mulch mats depends upon the performance of agriculture sector and also on the awareness and acceptance of these products by the farming community. The Indian government has taken several steps to increase the production and consumption agro textiles. One such step is the introduction of subsidies towards usage of Agro tech. National Horticulture Mission (NHM) has been actively promoting products through annual.

DEFINITION

All the textile goods intended for use in the agricultural production compassing farming, horticulture, animal husbandry and forestry can be considered as agro-goods. Any type of fiber yarn or fabric used for the production or enhancement of the shelf life of any product agro product is called as an Agro-Tech or Agro Textiles. .

1.2 OBJECTIVES

At the end of the session the learner will be able to

• To gain knowledge about various textile materials used in the production of agricultural products
•  Understand the importance in the use of agro textiles.

1.3 TYPES OF AGRO TEXTILES

1.3.1     Shade nets/Fabrics

The shade nets are woven or knitted fabrics used for the protection of the plants from wind, extreme weather conditions for reduce water evaporation. India is the second largest producer of flowers, fruits and vegetables therefore the used shade nets is very significant. Shade nets have widespread applications in the cultivation of vanilla, tea plantations, processing and drying of agricultural -products, growing and persevering flowers, fruits and vegetables. Roses, orchids, grapes, cabbage, pepper, are some of the major fruits and vegetable crops which use shade nets. Shade nets are also used in cattle-sheds, feed and grain storage areas, parking lots and water pools as covers against dust. It is also used to maintain humidity in greenhouses and plant nurseries which in turn increases the time for presences of water content in the soil.

Shade nets are usually made of woven or knitted polypropylene and sometimes with cotton, jute, coir and polyester as blends. Medium texture and thickness, high tear, elongation resistant and light weight are common physical properties of shade-nets. The standard sizes of nets vary from 2, 3, 4 and 8 meters in width with 25, 50 and 100 meters in length. The most common dimensions of these nets are 3 m (width) by 50 m (length) with GSM of 120 to 180. Green and black are the common coolers used for the manufacture of shade nets. The in depth in the color varies from 25 percent to 90 percent which indicates the degree of shade provided by the shade-nets. The shade depth percentage also depends upon the application and type of plants under cultivation.

1.3.2     Mulch Mats or Ground covers

Textile materials used to cover the soil around the plants to prevent the escape of soil moisture and nutrient loss and weeds control is called ground cover commercially and as mulch mat technically. This helps in the deduction of chemicals as fertilizers and also aids in the maintenance of the soil temperature. A mulch mat can reduce run-off, increase penetration of rainwater, controls erosion and corrects the chemical balance of the soil. It acts as barrier between the pests and the seeds or plants. This sheet of fabric can also prevent the plants from being attacked by diseases. Apart from these major results mulching produces secondary effects such as improvement of soil structure, increase in micro-activity, earthworm populations and root systems. Germination and growth of weed seeds is better prevented by the black film in contrast to clear film. It also absorbs more heat and energy from the sun which is retained for a longer period. Generally mulch mats are used for vegetable and fruit crops with short life period. The planting areas are covered with mulch film. Small holes are made and required distances, where the seed are put in. The main advantage of the mulch sheet is that it decreases the growth or unwanted weeds.

Wool, jute and coir are the common natural fibers and different types of polymers and their blends with other natural fibers are used for the production of mulch mats. Weaving and non-woven techniques are used to make munch mats. Mulch mats can be made as thin films also. Wool fiber is used for designing non-woven mulch mat where as jute and cotton fibers are used for woven mulch mats. Polymer is used for making mulch films, which vary in thicknesses and microns. Depending upon the type of fibers used the mulch sheet can be biodegradable or non biodegradable.

1.3.3     Anti Hail Nets

Anti-hail nets are used to protect the crops like apple, litchi, etc from hails high altitude and hilly areas like Himachal Pradesh, Jammu & Kashmir, Uttar Pradesh and North-eastern states like Assam and Manipur. The anti hail nets are normally provided for each individual tree. These are woven from high modulus polyethylene and high performance polyethylene yarn or are combination of monofilament. Even knitted tapes with finish against UV rays are available in the market. These nets are flexible, light, strong and easy to spread, and can be placed on simple support structures. These nets are transparent in color with small hole like structures. Their GSM varies from 60 to 100size.

1.3.4 Bird protection nets

Most of the fruit farmers face the major problem of fruits being bitten by birds which results in heavy loss of crops and income for which bird protection nets are the right solution. This is a net like fabric which is used covering the fruit such that the birds are unable to pick it. This is designed in such a manner with small holes which allows the movement of bees and air to maintain shade, prevent rotting or fungus formation. It also allows penetration of light required for the growth of the fruit.

Bird protection nets are manufactures with a GSM of 25 -40.These are light weight knitted fabrics with tough, durable, tear resistant properties. . The standard sizes of nets available are 1, 2, 3 & 6 meters in width and 10, 20, 50 and 100 meters in length. The fibers used are high performance polyethylene yarns of monofilament yarn. Generally these fabrics are given UV protection finish. The common colors used are green, blue and white.

1.3.5 Crop covers

The major role of crop-covers is to create an exceptional microenvironment for seed germination and growth of small plants. A crop cover is a large sheet of mesh like fabrics with small holes placed over the entire area of the crops to protect them from extreme heat or cool temperatures. Sometimes these are also placed over newly planted saplings which are transferred to the fields. This helps to maintain the humidity needed for the crops to grow. On a over view it is said that the crops show a rapid growth, resulting in early harvest when covered under crop covers unlike the plants which are exposed to natural conditions directly. These cover also protect the plants from insects, heavy rain, hail, snow and wind. One of the major advantages of the crop cover is cross pollination which in turn results in improves crop quality.

Crop covers are available in woven, non woven and sheet or film structures. The fibers commonly used are polypropylene. These are light weight, white material with a GSM of 17- 19 for hot climates and 20-30 for cold climates. Great care has been taken to keep the weight of the fabric low which will prevent the crops from been crushed. These fabrics are available in the form of rolls of three meters width 450-500 meters length.

1.3.6    Fishing nets

One of the most important textile materials used in the fishing industry is fishnets. Fishing nets are mesh like knitted of knotted fabrics used for marine and inland fishing by fisherman and fishing boats. Generally fishnet construction are single, double and U-knots. The main purposes of these nets are to allow fishes to enter into them when thrown into the water bodies and hold them when drawn out of the water bodies. The size of the mesh or holes varies from 10 mm to 2,000 mm based on area and type of fish likely to catch. The main property of the fishing nets are high tensile and knot breaking strength, high abrasion resistance and low drag resistance. The fishing nets used in oceans and seas are transparency and invisibility in water. The fibers used are high performance polypropylene and nylon. These fibers are made into thick ply yarns or mono-filament and multi-filament tape yarns. These nets are available in 100 m, 250 m, 500 m, 600 m and 1000 m spools.

1.4    CONCLUSION

An Agro textile is a fast growing area were a number of researches to improve the quality of crops and fruits are carried out. It also yields a huge amount of income through exports. In India the making and use of agro textiles is limited unlike European and American countries. The awareness of the technical production and use of agro textiles has just stepped into India hence there is a huge potential for research and manufacturing of agro textiles.

2. GEO TEXTILES 2.1 INTRODUCTION

     The term Geotech is new to the field of textiles. It is known to the industry only for the last 20 years. But as per the reviews it is clear that the term is new unlike its use age which dates back to the 17 th century where in jute fabrics where used to with hold sand from flood water. The development of geo textiles has always been an ‘industry-led’ science. Geo textiles are manufactured fabrics that are used to withstand and/or support the environment of the earth and its movement’s earth like floods, earthquakes such that the damage caused to life and asses is minimum or zero percent. Geo textiles are particularly refers to porous synthetic woven or non-woven material. These fabrics are specifically engineering material to suit a particular application. The very first type of geo textile was made by the Dutch which was a woven heavy steel wires into polypropylene textiles to manage coastal land reclamation. Later on these fabrics were made into specific composite materials to suit civil engineering purposes. The establishment of the International Geo textile Society in 1978 led to a coordinated and coherent approach to international development of geo textile design and utilization.

2.2 OBJECTIVES

At the end of the session the learner will be able to

•  Know the significant role of geo textiles in construction and engineering structures.
•  To gain knowledge about different geo textile products, its application and benefits.

2.3 GROWTH OF GEO TEXTILES

First Generation Geo Textiles: The first generation geo textile fabrics are fabrics manufactured for carpet and industrial sacking which did not have any technical production process. The fibers were just spun and woven in the simplest manner and used in limited applications.

Second Generation Geo Textiles: The second generation geo textile fabrics are fabrics manufactured by choosing specific textiles material, processes and finishes suitable for geotechnical purposes using the conventional manufacturing techniques. The manufacture of inlayed composite just by compression is an example for the second generation geo textiles.

Third Generation Geo Textiles: The third generation textiles are specifically designed and developed with a new a purpose of geotechnical application following technically new process and finish. Here in the application is defined first, then the properties required are listed and them the fabric is designed to suit the application with the particular properties.

  2.4 DEFENITION

• Any permeable textile material used for filtration, drainage, separation, reinforcement and stabilisation purposes as an integral part of civil engineering structures of earth, rock or other constructional materials…….(source: textile terms and definitions).
• Geo.textiles is permeable fabrics which, when used in association with soil, have the ability to separate filter, reinforce, protect or drain……..(source: Wikipedia).
• Woven, nonwoven or knitted fabrics generally known as geo.textiles made from synthetic fibres of polyamide, polypropylene, polyester and polyethylene. They are used in civil engineering works as drainage blankets and as a means of improving the stability and load-bearing quality of soft soils……(source: dictionary of geo technics).

  2.5 Classification of Geo Textiles

Geo textiles are mainly classified into two groups passed upon its property as porous (permeable) and non porous (impermeable) textile materials. In simple terms these are fabrics which will allow air and liquid to pass through and ones which will not allow. Examples for porous geo textiles are geo grids, geo nets and for non porous geo textiles are geo composites.

2.6 Materials Used for Geo textile Manufacturing

The most common material used in the manufacturing of geo textiles is grouped as natural and synthetic fibers. The common natural fibers and synthetic fibers used for geo textiles are jute, hemp, coir cotton and PET, polypropylene, polyethylene, and glass fibers respectively. Generally natural fibers are used for the making of porous geo textiles and synthetic are used for nonporous geo fabrics.

2.7 FUNCTIONS OF GEOTEXTILES

The major functions of Geo textiles are

• Confinement: The major property of Geo textiles namely porosity, toughness and strength enhance the fabric to divide two types of soil or other materials from mixing with each other.
• Filtration: Filtration is the process of separation of two state of matter. It is considered as a very important application in industries and civil work. Geo textiles is used for filtration in ditch lining, beneath roads, water disposal areas and drainage basements
• Reinforcement: In many case the strength of the soil /earth or a particular area which is weak needs to increased. Geo textiles made with soil and jute bonding provide this property hence it is used as a soil fabricator improving the quality of soil.
• Drainage: Water is carried across vertically and horizontally along the earth from one place to another. Geo textiles facilities this movement of water without damaging the surrounding area with its function of the permeability.
• Protection: Landslides, entry of river water during floods and storms cause huge damage to the crops and wash away the soil. This can be prevented through the application of geo textiles.

2.8 PROPERTIES REQUIRD FOR GEO TEXTILES

• The three main properties required for geo textile are its mechanical responses, filtration ability and chemical resistance.
•  Mechanical responses are the ability of a textile to perform work in a stressed environment and to resist damage in any tough environment.
•  Filtration ability is the capacity to transfer of liquid from solid and limiting the passage of solids that are hanging around in a liquid medium.
•  Chemical resistance ability to with stand against erosion caused by chemical and effluent which pass through the geo textile fabrics.

2.9 APPLICATION AREAS OF GEO TEXTILES

• Civil Engineering – Geo textiles are used in roads and pavement laying, strengthen of slopes, protection of tunnels rail way tracks, drainage and ground and plantation bed stabilization.
• Marine Engineering- Geo textiles are used in soil erosion control and embankment protection and water way protection.
• Environmental Engineering– Geo textiles are used in landfills and waste management.

2.10      TYPES OF GEO TEXTILE

•  Geo grids
•  Geo nets
•  Geo membranes and
•  Geo composites

2.10.1 GEOGRIDS: Geo-grids represent a rapidly growing segment within the geo textiles area. Geo grids are plastics filaments, rovings, and tapes etc formed into a very open, grid like configuration having large opening unlike woven, nonwoven or knit textiles. These apertures may vary in size from 1 to even more than 10 cm. They can be mono-axial or bi-axial which means they are stretched in one or two directions for improved physical properties. Both the mono or uni -axial and bi-axialare made of high-density Polyethylene and are used as reinforcement. The major functions of geo grids are stabilizing soil mass, creates a composite soil mass of increased strength, reinforcing steel to concrete and ability to carry higher loads by the soil structures.

Application of geo grids – can be listed as

•  Retaining Walls
•  Steepened slopes, repairing slope failures/landslides
• Embankment fills/earth dams or over soft soils
• Stability in Landfills
•  Void Bridging
•  Pavement Reinforcement
•  As inserts between geo textiles and geo membranes

2.10.2 GEO NETS

Geo nets are usually formed by a continuous extrusion of parallel sets of polymeric ribs at acute angles to one another. When the ribs are opened, relatively large gap are formed into a netlike arrangement Geo nets are made of polypropylene (PP) or Polyethylene (PE). Geo nets are used almost exclusively for their drainage capability for applications like water drainage behind retaining walls, seeping rock slopes, beneath sport fields, building foundations; drainage of landfill side slopes, above landfill liners and surface water drainage.

2.10.3 GEO-MEMBRANES

Geo-membranes are impermeable membranes; used where the primary functions is to have a solid barrier for fluids. Geo membranes are made from continuous polymeric sheets that are very flexible, but at the same time they should be solid without deformed when exposed to stressful environment. Geo membranes are used in applications such as liners for water canals, waste canals, solid waste landfills, covers for solid-waste landfills, waterproofing within tunnels, to control odors in landfills, to prevent infiltration of water in sensitive areas, and beneath asphalt overlays as a waterproofing layer.

2.10.4 GEOSYNTHETICS

In the field of civil engineering, membranes used in contact with, or within the soil, are known generically as ‘geo synthetics’. This term encompasses permeable textiles, plastic grids, continuous fibers, staple fibers and impermeable membranes.

2.10.5 GEOCOMPOSITE

Geo composites are polymer products, made by connecting two or more types of geo synthetics. The best features of different materials are combined in such as way that the benefit/cost ratio is maximized. The major properties of geo composite are high tensile strength in the warp and weft directions, low elongation, ability to with stand excellent temperature range, good anti-age and  alkali-resistance, Reduce construction cost, extend service life of road and prevent deflection cracks.

Application of geo composite

•  Separation
•  Reinforcing function
•  Pavements (especially for repairs).

2.11      GEO TEXTILES CONSTRICTION METHODS

Geo textiles are made by woven, Knitted and non-woven methods Woven geo textile is made with natural and polypropylene fibers with specific ends and picks. They have good tensile strength, grab strength, puncture resistance, elongation, thermal, and stabilization and UV resistance. They are not affected by mildew, fungus and chemicals. The woven fabrics cater the functions of separation, stabilization, filtration, erosion control and marine protection. The application of woven geo textiles range from road construction, retaining wall and embankment, airport runway, slope reinforcement, landslide control, beach reclamation and marine construction

The knitted geo textile is featured with high tensile strength, even deformation in length and breadth, high water penetration and softness. These are used in drainage of dam and river water, reinforcement of dam, filters in industrial and soil blocks.

The non woven geo textiles are classified as based on the type of bonding namely mechanical, chemical and thermal. In case of mechanical bonding spun laced fabrics, needled punched and stitch bond fabrics are manufactured. Whereas chemical bonded fabrics are made with application of chemicals and thermal boned fabrics are made by the application of heat. These fabrics are by a width of 2 m to 6.5 m and GSM OF 100 TO 1000.Generally these are many layer fabrics. UV protection and resistance against aging is given to the geo nonwoven fabrics. These fabrics are used for separation, filtration, drainage, reinforcement, protection, and liquid barrier.

2.12      CONCLUSION

Geo textiles are an upcoming field with much number of applications, due to its varied properties new application are seen and can be improved through researches. Countries across the globe are concentrating on the production of geo textiles especially for road ways and control of natural calamities. In a nut shell geo textiles can help India to find income generating activities and researches.

Web links

• www.technicaltextile.net › Articles › Agro Textiles
• www.fibre2fashion.com › Knowledge › Article
• www.indiantextilejournal.com/articles/FAdetails.asp?id=1999
• https://www.journals.elsevier.com/geotextiles-and-geomembranes
• https://www.masterbuilder.co.in/data/edata/Articles/October2013/88.pdf