It shall be the duty of landowners in this state, or tenants of such landowners when in possession, owning or occupying lands through which a watercourse, slough, drainage ditch or drainage course lies, runs or has its course, to clean such watercourse, slough, drainage ditch or drainage course at least once a year, between March 1 and April 15, of all rubbish, weeds or other substance blocking or otherwise obstructing the flow of the water in such watercourse, slough, drainage ditch or drainage course, whenever such obstruction is caused by any of the acts of said owner or tenant, or with his knowledge or consent; Provided, however, this and sections 31-225 and 31-226 shall not apply to drainage ditches under control of any drainage company or corporation.