Modernized agriculture has high demand on crop growth microenvironment,irrigation time,quantity,control zoon,and water-fertilizer regime,while automatic irrigation control engineering technique is a foundational support to realize agricultural modernization.

Aiming at the problem of wasting water and time in the vegetable irrigation,an automatic negative pressure irrigation system,in which the water-supply pressure was set at negative pressure and the effect of automatic irrigation and water-saving was achieved based on the characteristic of auto-water-absorbing of soil,was designed in this paper.

The automatic irrigation system is designed chiefly according to various cultivating methods,the water need regulation of flowers as well as the characteristics of programmable logical controller.