The invention concerns an irrigation system (2) comprising a tank (4) in its turn provided with a water feeding inlet (6), a water outlet (8), and optionally a closing element (10), and comprising a sprinkling unit (12) provided with a water inlet opening (14) and a water outlet jet (16), as well as a connection element (18) suited for transferring a liquid. The inlet opening (14) of the sprinkling unit (12) is connected, with respect to the direction of said water flow, downstream of the tank (4) through the connection element (18) with the outlet (8) of the tank (4), in such a way that the water flowing out of the tank (4) enters the sprinkling unit (12) through the inlet opening (14). The invention concerns also a corresponding irrigation plant and method and a corresponding dispenser tank. The invention can be applied for treating different types of soil, in particular agricultural areas, gardens and flower beds, and sports grounds.