Source Variation in Physical and Chemical Properties of Coconut Coir Dust

Summary

This comparative analysis of coconut coir dust samples from multiple tropical sources identified substantial variation in horticultural properties that would affect suitability for growing media applications. Physical properties such as bulk density and water-holding capacity differed significantly, as did chemical properties including pH, electrical conductivity, and elemental composition—particularly potassium and chloride, which ranged over 50-fold. These findings highlight the need for source-specific characterisation and quality control in coir dust procurement for commercial horticulture.

Regional applicability

Whilst this study examined Asian-sourced coir dust, coconut coir is widely imported into the United Kingdom for horticultural use in container production and as a peat alternative. The demonstration of substantial source-to-source variation has direct relevance to UK growers and suppliers, suggesting that specifications and testing protocols should account for origin and processing methods to ensure consistent growing media performance.

Key measures

Bulk density, air-filled pore space, water-filled pore space, total pore space, total solids, water-holding capacity, particle size distribution, pH, electrical conductivity, elemental concentrations (Fe, Mn, Zn, B, Cu, Ca, Na, K, Mg, Cl, N species), cation exchange capacity

Outcomes reported

The study characterised significant variation in physical properties (bulk density, pore space, water-holding capacity, particle size distribution) and chemical properties (pH, electrical conductivity, nutrient concentrations, cation exchange capacity) across coconut coir dust samples from the Philippines, Sri Lanka, and Indonesia. Bulk densities ranged from 0.04 to 0.08 g·cm⁻³, water-holding capacities from 750% to 1100% of dry weight, and potassium concentrations from 19 to 948 mg·L⁻¹.

Supporting research

Characterises the chemical and physical properties (K, Na, Cl, cation exchange capacity, micronutrients) of coconut coir dust, the growing medium used in soilless fruit production.

Limits: Measures the substrate itself across twelve coir sources; it reports no crop growth, yield or fruit composition.

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