ISHS Acta Horticulturae 779: International Symposium on Growing Media
TREE-SEEDLING COMPOST AS A COMPONENT IN SPHAGNUM PEAT-BASED GROWING MEDIA FOR CONIFER SEEDLINGS: PHYSICAL AND CHEMICAL PROPERTIES |
| Authors: | A.-M. Veijalainen, J. Heiskanen, M.-L. Juntunen, A. Lilja |
| Keywords: | density, forest nursery, germination, nutrients, organic matter, particle-size distribution, water-retention capacity |
| Abstract:
Approximately 150 million forest tree seedlings are delivered for planting annually in Finland. The seedlings affected by plant diseases or pests, or not meeting the quality requirements, as well as the used growing media, weeds, clipped grass and fallen leaves comprise the biodegradable waste formed in forest nurseries. Currently there is an increasing political and economical pressure on minimizing the generation and landfilling of waste materials. A practical solution for forest nurseries would be composting of biodegradable waste on-site, and then using the compost as a component of growing media for seedling production. Before this, the suitability of composted tree-seedling waste for growing media in tree-seedling production needs to be assured. In this study, growing-media mixtures were (by volume): 100% light sphagnum peat (100P), 100% tree-seedling compost (100C) and peat mixtures with 25 or 50% of compost (75P25C and 50P50C, respectively). Particle-size distribution, bulk density, water-retention capacity, particle density, loss on ignition, pH, electrical conductivity, total and plant available nitrogen (N), phosphorus (P) and potassium (K) concentrations, as well as the germination capacity of Norway spruce were studied. The tree-seedling compost was found to have a relatively fine texture and high density compared with peat. These physical properties may lower the air-filled porosity and oxygen-diffusion rate, and thus have a negative effect on the germination and growing in the mixtures with a high compost content. The results indicate that tree-seedling compost has a potential to be used as a minor component in growing media in tree nurseries, although the irrigation and fertilizer requirements need further studies. | |
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