%0 Research Notes %T The size and condition of ditches made by ploughs and tractor diggers in drained peatlands %A Timonen, Erkki %D 1983 %J Suo - Mires and peat %V 34 %N 2 %U http://suo.fi/article/9567 %X Changes in the dimensions of ditches made by heavy ploughs or tractor diggers were followed during a 15 yearperiod after digging. The material consists of 102 experimental ditches (each 20 m in length) dug using either the plough or tractor digger method on four main site types. The results showed that the diminishing of the ditch dimensions was not significantly affected by the digging method, but rather by depth, water content and humification of peat. Vegetation completely covers the peat surfaces of ditches after 15 years. The worst hindrances for water movement are shrubs (Salix, Betula pubescens, B. nana), but also sedges (Carex rostrata) and mosses (Polytrichum) lower the efficiency of ditches. The cleaning of ditches made by either methods seems necessary approximately 20 years after digging.