PEAT-REDUCED SUBSTRATES WITH MINERAL COMPONENTS FOR GROWING OF WOODY PLANTS

Cultivation methods influence growth of woody plant seedlings in a nursery as well as their development and prosperity after planting. The aim of this work was to evaluate the effect of substrate composition. Seedlings of native woody plants: Abies alba, Betula pendula, Crataegus monogyna, Fagus sylvatica, Quercus petraea, Tilia cordata were cultivated outdoor in containers with different kinds of low-peat or peat-free soil-based mixtures (ratio by % vol.): soil, green compost, peat (50/30/20); soil, green compost, composted spruce bark (50/30/20); soil, green compost, crushed rockwool (50/30/20); soil and green compost (70/30) and with peat and soil (90/10) as a control. Chemical properties (pH, EC, available nutrients) of the components and the substrates were analysed according to European Standards. A sand box in the range of -0.23 to -10 kPa and a pressure membrane apparatus in the range of -500 to -1500 kPa were used to determine retention curves and other physical properties as bulk density, air pore space, proportion of available and unavailable water. At the end of the growing season the growth of plants was evaluated and the plants were used for a following experiment which was a part of a landscape restoration project established to monitor the subsequent development of the plants in field conditions. The results showed that peat-based substrates were generally the best ones for the growth of woody plants in containers. Soil based substrates were better for the post-transplant growth in field conditions in some cases but these results have been based on two-year evaluation only. Further research is in progress.