I'd like to know the exact word in English for the agricultural machine for digging and cleaning ditches (to facilitate the flow of water). I think bulldozer is not the right one for this.
I would probably use one of these to dig or maintain a ditch. In Britain, we might call such a machine more formally, a mechanical excavator or mechanical digger, or less formally, just a 'digger'. The first well known British digger was made in the 1950s by a company called JCB, and many British people still call a digger of any make a 'JCB'. I believe Americans would call one of these machines a 'backhoe'.