Effect of Changing Substrate Density and Water Application Method on Substrate Physical Properties and Container-Grown Seedling Growth

The quality of container-grown seedlings is influenced by the air and water properties of the substrate. These properties are closely tied to the amount and frequency of water supplied through sprinkler systems in nurseries, as well as the density of the substrate in the container cells. Throughout the entire growing season, this study examined how various parameters of Scots pine, Norway spruce, European beech, and pedunculate oak seedlings cultivated in HIKO V120SS and V265 containers were affected by two factors. Firstly, the study analyzed the impact of increased substrate density when filling the containers. Secondly, it explored the precise dosing of water applied by the sprinkler system, which was determined based on substrate sensors and meteorological conditions surrounding the seedlings. The results revealed that increased substrate compaction led to a long-term reduction in air capacity and an increase in water capacity within pine, spruce, and beech containers. However, oak seedlings were not affected by the increased substrate density. Additionally, the higher density of the compacted substrate positively influenced the growth parameters of pine seedlings but did not affect the other species. As a result, the current substrate compaction level used in the nursery where the measurements were taken appears to be optimal for spruce, beech, and oak seedlings. Furthermore, precise control over the amount of water applied during irrigation allowed for a reduction in water consumption by about 8%. This control also resulted in improved seedling sturdiness quotient and a more developed root system in the case of pine seedlings. However, no significant differences were observed for the other species.