The invention discloses a trenching device of a ploughing and
sowing combined
machine. The trenching device comprises a casing, a stirring
barrel and a
sowing barrel, rollers are arranged in the lowerends of the two sides of the casing respectively, the stirring
barrel is arranged in the casing, the
sowing barrel is arranged on right of the stirring barrel, a water tank is arranged on right of the sowing barrel, a feed port is arranged in the upper end of the stirring barrel, and a first motor is arranged on right of the feed port and connected with a stirring
paddle. During use of the trenching device of the ploughing and sowing combined
machine, a mixture of
fertilizer and water is poured into the stirring barrel, when a barrier rod moves rightwardly, a discharging
pipe is opened, a seed output
pipe is closed, fertilizing is started and sowing is stopped, a rotary blade can implement trenching, the
survival rate of sowing can be improved, a connecting rod is fixed, a covering shovelcan combine soil in the two sides of fertilizing and sowing trenches into the trenches, the
fertilizer and the seeds are buried, a pressure roller compacts the loosening soil to certain tightness, and thus, trenching, fertilizing and sowing are completed.