Production of natural geotextile products

The process technologies for producing nonwoven and woven fabric are already well described in the widely available teclmical hterature on textile technology or textile engineering. It is therefore appropriate to restrict our considerations in this chapter to a general overview for the reader unfamiliar with the subject area, while citing suitable references for further study. 

If the nonwoven geotextile is to be used as a mulch, then plant seeds can be introduced into the fibrous web prior to needling. The fabric would thereby act as a vehicle for the distribution of seeds in the soil and prevent erosion during seed establishment and early plant growth. Suggested insertion rates range from 2000 to 4000 wildflower seeds per m for fabrics of 340 to 680 g m .  

If required, two yarns may be twisted together to achieve increased yam strength and to produce a heavier woven fabric. The resultant yarn is called a two-fold, a doubled or a plied yarn and its linear density would be twice that of the individual component yarns. 

The strength of the fibres must be, of course, effectively utilised by the spun yam. A yam can never have the same strength as its constituent fibres because of the fact that to withstand an applied load, the yam depends on the frictional contact between the overlapping lengths of fibres to transfer the load to all the fibres. The higher the twist the better the frictional contact and the stronger the yam, but for each fibre type there will be an optimum twist to obtain maximum yam strength [8]. 

Both weft and warp crimp of a fabric are important to the fabric modulus [25], in that the higher the crimp is, the lower the modulus will be. 

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