Alternative irrigation simulation test device and method for plant

The invention relates to an alternative irrigation simulation test device and method for a plant. The alternative irrigation simulation test device comprises a bucket body and a water observation unit, wherein the upper part of the bucket body is opened, and the bottom of the bucket body is closed; a partition perpendicularly arranged in the middle divides the interior of the bucket into 2 spaces;a gap is formed in the middle position of the upper edge of the partition and serves as a position for planting and root division of a test plant; a water supply hole is formed in one side of the bucket bottom, and a water overflow hole is formed in the other side of the bucket bottom; and the water observation unit comprises a plurality of soil water sensors and data acquirers. The method realizes horizontal alternative irrigation by respectively watering soil on the left and right sides in the bucket through a watering sprayer; and water is supplied through the water supply hole in the bucket bottom or the watering sprayer simultaneously waters the soil on the left and right sides in the bucket, so as to realize dry-wet alternative irrigation for the soil on the lower and upper layers in the bucket body. The device disclosed by the invention can simultaneously develop an alternative irrigation experiment for a root system of the plant in a horizontal direction and a perpendicular direction.