Suitability of thermal treated sawdust as replacements for peat moss in horticultural media

Abstract

An experiment was conducted to study the potential of thermal treated oak sawdust(steamingand steam explosion) as horticultural medium component in plug seedlings production ofChinese cabbage(Brassica campestris L.). This study involves the chemical, physicalcharacterization and growth test of thermal treated oak sawdust(steaming and steam explosion) inorder to evaluate their use as components of horticultural media. A commercial peat moss andoak sawdust were used as control. The total carbohydrate, C/N ratio, pH, phenolic compound,total porosity and water holding capacity were 45.1g/100g dry wt, 425.1, 4.4, 141.8mg/g wt,82.5%, 47.1% in oak sawdust and 39.2g/100g dry wt, 300.3, 4.7, 131.7mg/g wt, 84.9% and49.2% in steamed oak sawdust and 30.3g/100g dry wt, 247.8, 5.7, 40.8mg/g wt, 92.3% and51.7% in steam exploded oak sawdust, respectively. The mixtures of the horticultural mediawere prepared using different substrate as peat moss, oak sawdust, steamed oak sawdust, steamexploded oak sawdust and perlite to grow Chinese cabbage in a greenhouse. The seedgermination, stem height and leaf area were 68%, 2.2cm, 1.1cm2 in OSP(containing 90% oaksawdust and 10% perlite) and 69%, 2.5cm, 1.5cm2 in SMP(containing 90% steamed oak sawdustand 10% perlite) and 87%, 3.0cm, 2.2cm2 in SEP(containing 90% steam exploded oak sawdustand 10% perlite), respectively. The leaf area SEP(containing 90% steam exploded oak sawdustand 10% perlite) was higher than that of PP(containing 90% peat moss and 10% perlite). Thisresearch indicates that steam exploded oak sawdust may be utilized as a suitable replacementfor peat moss in horticultural media component for Chinese cabbage.