Designing, making and installation of weighted lysimeter for water demand determination of trees and shrubs in arid zones

Weighting lysimeters are good instruments and direct method to plants water needs (evapotranspiration) in arid zones. This research practiced at Yazd Shahid-Sadooghi Desert Research Station. Ten galvanized iron lysimeters (120 cm. diameter & 170 cm. high) were made and constructed after covering with a glass-wool layer to minimize the effect of the environment temperature variation on them. Four hatchways installed at different depths (30, 60, 90 and 120 cm) of lysimeters for root and soil sampling and estimating of soil moisture content by TDR instrument. These containers became full with disturbed local soil (l.s tex.), planted and irrigated respectively at the beginning. Lysimeters weighted by a portable liftract which was linked to a powerful (5000 kg. capacity) and accurate (0.1 % sensitivity degree) balance. Drainage water also collected from outlet tubes below of lysimeters occasionally. Results has shown that this procedure have had a good efficiency because achieving to objectives of this research was available. Saving and analyzing of information by computer and with change of weighting method, would also be probable in the future.