effect of four types of mulches including wood chips, municipal compost, sawdust and gravel in three different thickness on the growth of platanus orientalis l.

abstract to study the effects of four types of mulches including wood chips, municipal compost, sawdust and gravel in three different thicknesses on growth of platanus orientalis during two years, an experiment was conducted in mashhad area with semi-arid climate. the research was conducted as split plot based on a completely randomized block design with four replications. treatments included control (no mulching) and four types of mulch including wood chips, municipal compost, sawdust and gravel in three thickness (5, 10 and 15 cm). during the study, soil moisture and temperature, total leaf number, fresh and dry weight of leaves, tree height, fresh weight of tree, trunk circumference at height of 20 cm from soil surface was measured. sawdust mulch with 15cm thickness had highest soil moisture and lowest soil temperature. all factors in sawdust mulch with 15cm thickness showed the highest growth characteristics. in all factors (tree fresh weight, leave fresh and dry weight, tree height, total number of leaves and trunk circle at 20 cm height) increasing of mulch thickness led to increased rate of growth and the best results was observed at 15cm thickness of all kinds of mulches. there were no significant difference among mulch types on height of the tree but all mulch types had significant difference with control. in the other measured factors including total leaf number, fresh and dry weight of leaves, fresh weight of tree, trunk circumference at height of 20 cm from soil surface, the highest growth was related to sawdust, wood chips, compost, gravel and control, respectively. it seems that sawdust with keeping soil moisture and reducing drought stress could help better growth of the plants compare to other mulches in dry and semi-arid areas.