Precision pneumatic seed drill and method of regulating same

A precision pneumatic seed drill for sowing seeds into the ground, the seed drill comprising:

• at least one sowing element having a seed selector device housing a rotating perforated selector disc which selects the seed and has opposing faces subject to a pressure differential;
• a sowing duct associated with the seed selector device and having an intermediate region located at a distance from the seed selector device;
• a pressurization device associated with the selector disc and applying the pressure differential to the opposing faces of the selector disc;
• a compressed air dispenser for feeding compressed air, the compressed air dispenser being independent from the pressurization device;
• an ejector positioned in the intermediate region of and fed by the sowing duct and fed compressed air by the compressed air dispenser for pneumatically accelerating the seeds singled out by the seed selector device along the sowing duct;
• a pressure-varying device for varying the pressure of compressed air fed to the ejector, the pressure-varying device configured to be calibrated according to the typology of the seed to be sown;
• a measuring system for measuring the speed of forward movement of the seed drill with reference to the ground being sown in order to vary the rotational speed of the selector disc according to the speed of forward movement measured by the measuring system;
• and
• a computer and a storage unit configured to store a plurality of calibration curves of the pressure-varying device according to a typology of the seed to be sown, the computer being configured to set the pressure variation carried out by the pressure-varying device according to the calibration curves.