The valorisation of coarse and crossbred wool from EU sheep farming and butchery industry has been the aim of a number of efforts financially supported from local and EU Development Plans.
Nevertheless, only niche applications have been proposed till now, whilst the exploitation of the bulk of the low quality coarse wool clip still remains an unsolved problem.
However, in spite of these attempt, coarse raw wool from landscaping sheep still remains perceived as a by-product and is mostly disposed of, or illegally thrown over. Indeed, management costs and early processing costs (scouring and carbonising) are economically unsustainable without public financial support. Furthermore, the high amount of dead fibres (kemps) in the fleece of most native crossbred makes their wool unserviceable for textile uses, since cheaper and better quality wools from Overseas are available for textile applications. Thus, raw wool management costs (annual shearing, storage, transportation and disposal in accordance with the current EU Commission Regulation No 142/2011 for Class 3 Materials) heavily weigh on the profit of sheep farming.
Use of wool as a fertiliser
Literature shown that wool can be used as amendment-fertilizer with excellent results; its slow-release nitrogen and high water holding capacity can potentially benefit uses in agriculture. Grease (unclean) raw wool is rich in nutrients that are released over a long time fluently. Wool contains elements such as carbon (50 %), nitrogen (16-17 %) and sulphur (3-4 %) which play an essential role in plant nutrition (W. Von Bergen, Wool Handbook Vol.1, New York-London, John Wiley & Sons,1963, 3rd Ed.).
Wool fibres absorb and retain moisture very effectively; this property can be a benefit when applied to soils where it can reduce runoff of contaminants such as pesticides, and can aid in water conservation. Wool when added to the soil, greatly increases the yield (wet and dry matter) of grass grown. The suitability of wool wastes as fertiliser is confirmed by elevated levels of essential elements such as nitrogen (19%), sulphur (19%) and magnesium (7%) in the grass grown on wool fertilised plots as compared to the control grass (McNeil, S.J.; Sunderland, M. R.; Zaitseva, L. I. “Closed-loop wool carpet recycling”, Resources, Conservation & Recycling 51(1), (2007), 220-224). The known disadvantages to using wool fibrous wastes in direct grassland application are the inherent handling problems, lack of ready availability of nutrients, weed problems and low bulk density. (Das, K.C.; Tollner, E.W.; Annis, P.A. Georgia-Tech. Conf. “Recycling of fibrous Textile abd Carpet Waste Conference”, 4/11/97). The slow release of nitrogen from wool indicates that the soil micro-organisms could not easily digest the chemical fibre structure, which is made of keratin, one of the most abundant non- food, animal proteins, being the major component of hair, feathers, nails and horns. The modification of keratin structure can be achieved by chemical, physical and enzymatic treatments, with cleavage of disulfide bridges (sulphur–sulphur cystine bonds) and peptide bonds.