A large weighing lysimeter for evapotranspiration and soil‐water–groundwater exchange studies

摘要: A large weighing lysimeter was installed at Yucheng Comprehensive Experimental Station, north China, for evapotranspiration and soil-water–groundwater exchange studies. Features of the include following: (i) mass resolution equivalent to 0·016 mm water accurately simultaneously determine hourly evapotranspiration, surface evaporation groundwater recharge; (ii) a area 3·14 m2 soil profile depth 5·0 m permit normal plant development, soil-water extraction, exchanges, fluctuations level; (iii) special supply–drainage system simulate field conditions within lysimeter; (iv) about 30 Mg, including both unsaturated saturated loam. The consists mainly mealy sand light Monitoring vegetated during growing period winter wheat, from October 1998 through June 1999, indicated that contributed 16·6% total water-table 1·6 2·4 below ground surface. Too much irrigation reduced amount upward flow table, caused deep percolation groundwater. Data neutron probe tensiometers suggest soil-water-content profiles soil-water-potential were strongly affected by shallow Copyright © 2000 John Wiley & Sons, Ltd.