lysimeter A device for the direct estimation of evapotranspiration. Typically it comprises a vegetated block of soil 0.5–1 m³, to which the amount of water added is known, and from which the amount lost as run-off or percolation may be measured. Recording the changing weight of the soil vegetation system (keeping vegetation change resulting from growth static or monitored) reveals the amount of water retained by the system, and thus by difference the amount lost as evapotranspiration. For geographic comparisons, easily standardized, short, grass vegetation cover is used. For water-budget experiments, vegetation cover may be varied to simulate different crop types or semi-natural communities.

lysimeter A device for the direct estimation of evapotranspiration. Typically it comprises a vegetated block of soil 0.5–1 m³, to which the amount of water added is known, and from which the amount lost as run-off or percolation may be measured. Recording the changing weight of the soil vegetation system (keeping vegetation change due to growth static or monitored) reveals the amount of water retained by the system, and thus by difference the amount lost as evapotranspiration. For geographic comparisons, easily standardized, short, grass vegetation cover is used. For water-budget experiments, vegetation cover may be varied to simulate different crop types or semi-natural communities.

lysimeter (evaporimeter) Device for the direct estimation of evapotranspiration. Typically it comprises a vegetated block of soil of volume 0.5–1m³, to which the amount of water added is known, and from which the amount lost as run-off or percolation may be measured. Recording the changing weight of the soil-vegetation system (keeping vegetation change due to growth static or monitored) reveals the amount of water retained by the system, and thus, by difference, the amount lost as evapotranspiration. For geographic comparisons an easily standardized, short, grass vegetation cover is used. For water-budget experiments, vegetation cover may be varied to simulate different crop types or semi-natural communities.

Lysimeter

A device for 1) measuring percolation and leaching losses from a column of soil under controlled conditions, or 2) for measuring gains (precipitation, irrigation , and condensation) and losses (evapotranspiration ) by a column of soil. Many kinds of lysimeters exist: weighing lysimeters record the weight changes of a block of soil; non-weighing lysimeters enclose a block of soil so that losses or gains in the soil must occur through the surface suction lysimeters are devises for removing water and dissolved chemicals from locations within the soil.

lysimeter An instrument used to measure the loss of water from an area of land covered with vegetation. Water that evaporates from both the soil and from the plants can be determined.