Physical properties and water uptake in peat-based growing media containing green compost.

摘要

The physical properties of a green compost destined for use in growing media were investigated. This compost was produced by co-composting of indigenous Irish waste materials including green wastes (pruning material, clippings, discarded plants), spent roasted malt grains, fruit and vegetable discards, and sludge from a dairy waste water treatment plant. In terms of air volume (AV), easily-available water (EAW) and total porosity (TP), few differences were seen with compost amended media at up to 50% by volume in comparison to a pure peat medium, although total pore space (TPS) declined significantly with incremental addition of green compost. Media amended with green compost absorbed water far more readily than a pure peat medium, and at rates of 40% and 50% (vol/vol), almost achieved similar uptakes to peat amended with a commercial wetting agent. These properties are allied to a high, stable organic content and relatively low bulk density, compared to other green composts from Ireland and the U.K. This, plus the inherent presence of major and minor nutrients, has led to large scale production of this compost and its routine inclusion at up to 40% as a peat diluent for both Irish and U.K. markets.