Lysimeters to Study Soil Water Movement and Crop Water Use Under High Water Table Conditions

A system of 6 drainage lysimeters was constructed to conduct studies of water use and water movement in 3 different soils influenced by high water tables. The lysimeters were equipped with control mechanisms that accurately maintained a water table at any desired depth and permitted the contribution of the water table to crop water use to be calculated. A tensiometer-pressure transducer data acquisition system that permitted soil water redistribution and extraction to be closely monitored was also installed in the lysimeters. Inherent limitations of drainage lysimeters and various system errors prevented daily water use from being measured. However, errors in the overall water budget were less than 2%, permitting monthly water budgets to be accurately measured. Contributions of the water table to monthly crop water use of tomatoes and continuous records of soil water potential fluctuations are presented.