Effects of mulching with compost on growth and physiology of Acer campestre L. and Carpinus betulus L.

The aim of this work was to evaluate the effects of mulching with compost on growth and leaf gas exchange of two widely-used ornamental trees in comparison to local nursery management standards. In addition, effects on soil respiration, soil temperature and water evaporation from soil were determined. An equal number (180 each) of uniform hedge maple (Acer campestre L.) and 180 hornbeam (Carpinus betulus L.) were planted in an experimental plot located in Pistoia. Treatments compared were: 1) chemical weeding by herbicides; 2) natural grass cover, mowed twice per year; 3) harrowing once a year; and 4) mulching with mixed compost (50% green+50% from household waste, 5 to 10 cm thick). Over a two-year period, stem diameter, shoot extension and leaf gas exchange were measured. In the second year leaf chlorophyll content, chlorophyll fluorescence, soil respiration, soil evaporation content and soil temperature were also recorded. Mulching with compost influenced shoot extension and stem diameter growth of field maple and white hornbeam. Plants grown with natural grass cover had, generally, smaller stem diameters and shoot growth than the other treatments. Leaf gas exchange, chlorophyll content and chlorophyll fluorescence were influenced by the different treatments. Soil respiration was unaffected by the different treatments while soil temperature was significantly lower in mulched plots.