|Authors: ||P. Noguera, M. Abad, V. Noguera, R. Puchades, A. Maquieira|
|Keywords: ||Cocos nucifera L., coir waste, containerised plants, growing media, sustainable agriculture, waste reclamation|
Selected physical and chemical properties of thirteen coconut coir wastes (pith plus short-to medium-length fibres) commercially produced in six countries from Africa, America and Asia, were evaluated as growing media or growing media constituents for containerised plants.
Coir waste was evaluated as a lightweight material and showed a high total porosity, over 94 % (vol). It exhibited a very high air content together with fairly low easily-available water.
Total water-holding capacity in coir waste was lower than peat. pH was slightly acidic and salinity varied between 0.4 and 6.0 dS m-1. Cation exchange capacity ranged from 32 to 95 m.e./100 g and C/N ratios averaged 117. Coir waste contained more lignin and cellulose, but less hemicellulose when compared with peat.
The amount of naturally-occurring available nutrients was low, especially mineral nitrogen, calcium and magnesium.
On the other hand, indigenous phosphorus and potassium contents in coir waste were extremely high.
Remarkable differences were observed between sources with respect to physical and chemical properties.
Two individual coir waste samples from Mexico and Sri Lanka were manipulated in order to prepare suitable coir waste-based container media for growing Calendula officinalis and Coleus blumei. The removal of excess salts by controlled leaching did not improve plant growth and development in comparison with unleached coir waste.
No N immobilisation was found in coir waste-based media with a conventional fertilisation programme.
As a consequence of the particular chemical properties of coir waste, nutritional regimes may need to be adjusted on a crop-by-crop basis.
The two plant species tested grew equally well or better in the best coir waste media than in the control mix composed of 3:1 (vol:vol) Sphagnum peat and vermiculite.
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