Improved Performance of Zero‐Tension Lysimeters

Published collection efficiencies (volume of water collected divided by percolating volume calculated from a water balance) of zero‐tension lysimeters are <10%, suggesting that samples collected by such lysimeters may not be representative of the water percolating downward. By increasing catchment area to 2500 cm 2 , and by pushing the lysimeter rim upward into the soil, collection efficiency was increased to 36% under grass and 17% under forest; failure rate (proportion of lysimeters yielding <50 mL) was decreased from 60 to 6% under grass and to 23% under forest.