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Friday 25 April 2014

Applications of Agro-Textiles | Manufacturing Processes of Agro Textiles


Textile in Agriculture

Saiful Sabuz
Department of Textile Engineering
Ahsanullah University of Science & Technology (AUST)
Email: saifulsabuz.tex23@gmail.com
Cell: +88016-77057646 
Facebook: Saiful Islam



Introduction:
Agriculture, forestry, horticulture, floriculture, fishing segments, landscape gardening, animal husbandry, aquaculture & agro-engineering all these sectors combined together are popularly called as Agro-tech sector. Agro textiles are the application of textile materials in those sectors. It is a very much important segment of Technical Textile. The word “AGRO- TEXTILES” is now used to classify the woven, non-woven and knitted fabrics, applied for Agro-tech sector including livestock protection, shading, weed and insect control and extension of the growing season. With the continuous increase in population worldwide, stress on agricultural crops has increased. So it is necessary to increase the yield and quality of agro-products. But it is not possible to meet fully with the traditionally adopted ways of using pesticides and herbicides. Today, agriculture and horticulture has realized the need of tomorrow and opting for various technologies to get higher overall yield, quality and tasty agro-products. [Ref- 1 & 3]

Fibers used for Agro Textiles:
Man made (synthetic) fibers are preferred for agricultural product than the natural fibers due to their high strength, durability and other suitable properties of agricultural applications. On the other hand natural fiber based agro-textiles not only serve the specific purpose but also after some year degrade and act as natural fertilizers. Fibers used in agro-tech sectors are as follows:
  • Nylon
  • Polyester
  • Polyethylene
  • Polyolefin
  • Polypropylene
  • Jute
  • Wool
  • Coir
  • Sisal
  • Flax
  • Hemp
Though man made fibers (like poly-olefins) are preferred for agro-textiles than the natural fibers mainly due to their favourable price performance ratio, light weight with high strength and long service life, but natural fibers can be used in agro-textiles in some specific arena where characteristics like high moisture retention, wet strength, biodegradability are effectively exploited.

Properties Required for Agro-Textiles:
  • Tensile Strength: The tensile strength of shade nets can be a deciding factor of its long term durability and service life. Hence good tensile strength is necessary parameter for shade nets. 
  • Withstands solar radiation: Agro textiles are laid over the cultivated areas immediately after sowing or planting. For such application Agro-textiles has to withstand solar radiation with varying surrounding temperature.
  • Withstands ultraviolet radiation: The Non visible radiations include ultraviolet radiations (UV) radiation leads to degradation of molecular chains. No single material is resistant to all radiations .polypropylene and polyester are more resistant to UV radiations when used as an outdoor material, polyethylene is treated with the appropriate UV stabilizers. Potential to reduce the impact of UV radiation on plants by light absorbing or light‐reflecting non-woven (light permeability: 80 to 90% to allow photosynthesis to take place).
  • Bio degradability: Natural fibers like wool, jute, cotton are also used where the bio-degradability of product is essential. Natural polymer gives the advantage of bio-degradation but has low service life when compared to the synthetics. 
  • Abrasion Resistance: The abrasion to which a shade net is subjected may be of the material itself (material to material) or stray animals .abrasion of the shade net would result in holes though which animals and pests could enter the structure and harm the crops .good abrasion resistance is required of shade nets. 
  • High potential to retain water: This is achieved by means of fiber materials which allow taking in much water and by filling in super-absorbers. While non-wovens meant for the covering of plants show a mass per unit area of 15 to 60 gm/m2, values between 100 and 500 g/m2 are reached with materials for use on embankments and slopes. 
  • Protection property: It must have the properties of protection from wind and creation of a micro‐climate between the ground and the non-woven, which results in temperature and humidity being balanced out. At the same time, temperatures in the root area rise. This is what causes earlier harvests, sufficient stiffness, flexibility, evenness, elasticity, biodegradability, dimensional stability and resistance to wetness. Fungicidal finish (up to 2% of the total mass), which avoids soil contamination. 
  • Resistance to microorganisms: It must resistant to microorganism to protect the living being.
  • Stable construction: The construction must be such that it must be stable for any application.
  • Lightweight: The weight of the fabric should be such that it will bare by the plant.
History of Agro Textile:
Agriculture is the backbone of our country. Now it is saying that textile can be the backbone of agriculture. Textile fabrics have a long history of use in agro-tech sectors to protect, gather and store products. Between the 18th century and the end of the 19th century, agricultural development was occurred, which saw a massive and rapid increase in agricultural productivity and vast improvements in farm technology. From then, Textiles have always been used extensively in the course of food production, most notably by the fishing industry in the form of nets, ropes and lines but also by agriculture and horticulture for a variety of covering, protection and containment applications.

However, modern textile materials are also opening up new applications. Lightweight Spun bonded fleeces are now used for shading, thermal insulation and weed suppression. Heavier non-woven, knitted and woven constructions are employed for wind and hail protection. Fibrillated and extruded nets are replacing traditional baler twine for wrapping modern circular bales. Capillary non-woven matting is used in horticulture to distribute moisture to growing plants. Seeds themselves can be incorporated into such matting along with any necessary nutrients and pesticides.

The bulk storage and transport of fertilizers and agricultural products is increasingly Undertaken using woven polypropylene FIBCs (flexible intermediate bulk containers – big bags) in place of jute, paper or plastic sacks. Today, modern textile materials and constructions have helped to increase the strength, lightness and durability of traditional products, as well as open up completely new markets.

Manufacturing Processes of Agro-Textiles:
Several techniques of fabric production can be used to produce agro-textiles. Each method offers specific advantages for particular product. The techniques are:

Weaving and woven products
Woven products are manufactured by using weaving machines especially Sulzer projectile weaving machines. The range of light to heavy and wide width fabric production is possible with Sulzer projectile weaving machine. The machines with weaving width of 540 cm to 846 cm are available for the production of agro-textiles. The nets with a mesh width of 1.8 mm to 40 mm can be produced. Other methods of fabric manufacturing such as air-jet and rapier weaving machines are not preferred for the manufacture of such fabrics as they do not have required weaving width.

Knitting
Warp knitting technique is most widely used in comparison to weft knitting. Warp knitted protective nets are used in different sectors, which are produced on Raschel machines. Agro nets are produced in various constructions or lapping. Here, the construction or lapping is a way in which individual yarn systems are converted into fabrics.

Non-woven
There are many techniques to produce non-woven fabrics.

Spun bonding and needle punch techniques are mainly used for the production of non-woven agro-textiles. The spun bonded fabric has high and constant tensile strength in all directions. It has also good tearing strength.

Needle punched fabric plant bags provide advantages over conventional fired clay pots. All natural fibers offer an added advantage of that the container decomposes after being planted in the ground. Thermal Bonding, Stitch-bonded, Hydro entangled & Wet non-wovens are also used.

Advantages:
Agro-textiles decrease the requirement of fertilizers, water, harmful pesticides and herbicides and render a healthy farming culture and are an eco-friendly technique. They prevent the soil from drying out increase crop yield. Thermal protection textiles are treated with ultraviolet ray stabilizers & it can save up to 40% on energy in heating greenhouses. Their use prevents staining and improves uniformity of color. They increase the early maturing of crops and non seasonal plants & protect from climatic changes and its effect. Agro textiles avoid branches from breaking, increase the cleanliness of the crop, make harvesting easy & give large space. Agro textiles for its excellent environmental resistance, mechanical properties, easy process ability and durability characteristics can improve quantity, quality and safety of agricultural products.

Applications of Agro-Textiles:

1. Agro-textiles for production of crops:
The selection of Agro-textile product is depends on crop needs. Selection of the agro textiles is also greatly influenced by the geographical location. Some of the applications of agro textiles are as follows:
  • Sunscreen: The Warp-knitted nets are used in order to protect fields and greenhouses from the intense solar radiation for healthy plant growth and good harvest. Sunscreen nets with open mesh construction are used to control sunshine and amount of shade required. These net fabrics allow the air to flow freely. So the excess heat does not built up under the screen. The percentage of shadow varies according to the density of threads. The current offer 45%, 65% & approximately 85% shadow.
    Sunscreen net
  • Bird protection nets: Knitted monofilament nets (Open knitted nets for crop protection) offer effective passive protection of seeds, crops and fruit against damage caused by birds and a variety of pests. Open‐mesh net fabrics are used as a means of protecting fruit plantation. The special open structure repels birds, provides minimal shading and excellent air circulation ‐ allowing plants to flourish, whilst avoiding the risk of dangerous mold developing on the fruit. These net are strong yet lightweight and protect the fruit without restricting plant growth. The use of polyethylene tape yarns or mono filament yarns makes the net extremely durable and hard-wearing.
    Bird protection net
  • Plant net: Fruits, which grow close to the ground, can be kept away from the damp soil by allowing them to grow through vertical or tiered nets in order to keep the amount of decayed fruit to a minimum. These are made from polyolefin type of fiber.
    Plant net
  • Ground cover: Ground cover is an extremely versatile landscaping and horticultural fabric for long‐term weed control, moisture conservation and separation. It effectively suppresses competitive weed growth, conserves ground moisture, maintains a clean surface, protects from UV rays and creates a favorable environment for healthy plant growth. Ground covers can reduce the costs and minimizes undesirable herbicide use. It is mainly used in Borders & rockeries, nursery display areas, greenhouse floors, soft fruits beds & orchards, paved areas, horse bridleways & seed harvesting areas. 100% polypropylene is used.
    Ground cover net
  • Windshield /Wind protection nets/Wind-breaks: Windshields are used in farming to protect fields of young plants, fruits, trees or the harvest from being damaged by the wind. Erecting wind-breaks at right angles protects the young seedlings and the mature plants from dying out and being broken. The nets used here reduce the effects of high winds and even help to keep out airborne sand and salt in areas close to the sea. Protecting plants from high winds also encourages plant growth and reduces the number of irrigation cycles required. It also prevents plants being cooled by wind too.
    Wind protection nets
  • Root ball net: It is extremely important for safe and speedy growing of young plants such that root system is not damaged when they are dug up, transported or replanted. Normally the root balls are wrapped in cloth. Elastic net tubes are alternative to this. When the plants are transplanted, the nets on the outside do not have to be removed since the roots can protrude through the nets.
    Root ball net
  • Insect meshes: Various pests like Whitefly, scale insects attack some ornamental plants and vegetables frequently. Clearly, woven and knitted polyethylene monofilament meshes to exclude harmful insects from greenhouses and tunnels, or to keep pollinating insects inside, The fine woven screens protect plants from insect attack (without the use of insecticides).
    Insect meshes net
  • Mulch mat: Mulch mats are used to suppress weed growth in horticulture applications, It covers the soil, blocking of light and preventing the competitive wheat growth around seed links, This also reduces the need for herbicides required for weed control Needle punched non-woven and black plastic sheet are used for this application, Bio degradable and non‐biodegradable types of mulch mats are available.
    Mulch mat
  • Monofil nets: Tough, knitted Monofil, nets for windbreak fences and shading/ privacy screens, A suitable windbreak, set at a right‐angle to the prevailing wind, will protect plants against the harmful effects of blustery weather ‐ which can break young branches, damage flowers and cause leaves to dry or tear. The nets also protect against frosts and help enhance the micro‐climate. This not only safeguards the current harvest but also benefits future crops, since the woody part of the plant are protected too.
    Monofil nets
  • Cold and frost control fabrics: Cold and frost fabric can be laid directly on the plants, unlike plastic covers that can attract frost, and burn any leaf that touches them. These fabrics protect the plant from frost kill during unexpected late cold snaps and unexpected early ones.
    Cold and frost control fabrics
  • Nets for covering pallets: For safe transportation of fruits and vegetables to the market the boxes are covered with large mesh nets and pallets to stop the boxes being turned upside down. This prevents damage of goods during transportation.
    Nets for covering pallets
  • Anti-hailstone nets: Anti-hailstone nets are used to cover plants and fruit orchards to protect them from being damaged by hailstones, but does not restrict their growth. The nets are primarily made from polyethylene monofilaments.
    Anti-hailstone nets
  • Harvesting net: It is extremely helpful to those countries where labour charges are costlier. With the application of such nets for harvesting purpose, the labour cost could be reduced considerably. They are laid on ground or tied under the trees so that fruits fall directly on to them.
    Harvesting net
  • Packing materials for agricultural products: Nets can be used for packaging of farm products for many end uses. It includes packing sacks for vegetables, tubular packing nets for fruits and wrappers for Christmas trees, Net structures are preferred because of their high strength, low weight, air permeability and cheapness.
    Packing materials for agricultural products
2. Agro‐textiles for Horticulture & Floriculture:
Application of textile materials in horticulture is growing fast. Nets, non‐woven mats, movable screens for glass/poly houses, non‐woven sheets, mixed bed for mushrooms, cordage and strings are used in horticulture. Nets are also used for protection against hailstorms, intense sunrays, etc. Light resistant woven and non-woven polyester fabrics are used in the inside of green house to protect the plants from extreme hot or cold conditions. They are also used on the outside of the green houses as screen to control sun light.
Horticulture net
Floriculture net
Some of the agro-textiles that are used frequently for horticultural & floriculture use are as follows:
  • Hail protection fabrics
  • Mulch net
  • Rain protection fabrics
  • Wind control fabrics
  • Harvesting nets
3. Agro-textile for Animal Husbandry:
Nylon and polyester identification belts are used for cows. Textile nets are used to support the large udders. Non-woven fabrics are used to filter the milk in automatic milking systems and as an underlay to reduce mud on cattle paths and trails.

4. Fishing and aquaculture nets:
Fishnets are used for fishing and in fish farming. Warp knitted knotless nets results in low energy expenditure when the net is used for fishing. They are mainly produced from Nylon monofilament, multifilament or HDPE.
Fishing net
Aquaculture net
Markets of Agro Textile:
Agro-textiles is one of the smaller categories of technical textiles, with consumption accounting for around 8.2% by volume and 6.4% by value of the global technical textiles market in 2010. However, this sector is among those with the strongest growth predictions based on the projected increase in global population and the demand for higher quality food. Internationally, the agro‐textile market is expected to grow from 1615000 tons (US$6.5 billion) in 2005 to 1958000 tons (US$8.1 billion) in 2010, at an average growth rate of 3.9% per annum. Developing countries like China, Brazil and India with CAGR of 7.8%, are expected to witness a surge in demand for agro textiles. The global end‐use consumption of agro-textiles will increase from 3.3% in 2000 to 3.9% by 2010; according to a David Rigby Associates’ (DRA) study. Unbounded fabrics are increasing in agricultural applications at the expense of woven fabrics. Textile is only a relatively small branch, cost‐based reasons, the global textile market in agricultural produce about 200 million tons, valued at 5 billion U.S. dollars, an increase of potential. In textiles, agricultural development, production and Applications will become an increasing concern.

Comments:
Today agro textile plays a significant role to control environment for crop production, eliminate variations in climate, weather change and generate optimum condition for plant growth. Adopting the hi-tech farming technique, where textile structures are used, could enhance quality and overall yield of agro-products. Textile structures in various forms are used in shade house/ poly house, green house and also in open fields to control environmental factors like temperature, water and humidity. The need of textile goods in the field of agriculture has been stressed and their role in the reduced usage of harmful pesticides and herbicides to render a healthy farming culture underlined. Unique manufacturing techniques and properties of this blend of agro-textile sector products whose cost is lesser than that of pesticides and chemical herbicides have been emphasized. ‘Agro textiles’ gives multidimensional views and solutions to the problems being faced by agro industry. Textiles prove to be flexible in their suitability for specific geographical locations. So now it is our turn, to carefully and beautifully shape this infant technology, to contribute to the nation’s economy.

References:

Books:
  • Agro-textile Products & Their Usage By- Mrs. Manisha A. Hira Scientist C Sasmira, Mumbai
Links:  

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