A GRAVIMETRIC LYSIMETER FOR MODELING TRANSPIRATION IN YOUNG CHERRY TREES

This paper reports on the design and preliminary testing of a novel, above-ground, load-cell weighing lysimeter for estimating transpiration from young sweet cherry trees (Prunus avium L.). Each system was comprised of a rigid copolymer Polypropylene PP U.V. stabilized bin (ca. 1.21 m x 1.21 m x 0.60 m) and a high precision, 4-load-cell floor scale coupled to a datalogger.
Soil evaporation was practically eliminated by sealing the top of the bin with a 5 cm thick polystyrene isolating layer.
An opening for the trunk was sealed with closed-cell foam.
Bin mass was determined intermittently and tree transpiration was estimated by applying the mass balance equation to the system:

Transpiration = W – Irrigation

This system was able to resolve 0.1 kg changes in mass.
To evaluate the system, we correlated transpiration estimates from our lysimeter with calculated values using the FAO-56 Penman-Monteith reference crop (ET₀). Under well-watered conditions, canopy transpiration ranged from 10 to 13 kg m^-2 day^-1 (leaf area based) while Penman-Monteith reference ET₀ ranged between 5 to 6 kg m^-2 day^-1 (ground area based). We observed a dramatic transpiration decrease during incremental water stress.
Preliminary results show: 1) the scale lysimeter facilitates the measurement of young fruit tree transpiration and, 2) transpiration was positively related to soil water content.

VII International Symposium on Modelling in Fruit Research and Orchard Management

A. Antunez, C. Stöckle, M.D. Whiting

Modeling, transpiration, Prunus avium, lysimeter, water use, water stress

https://doi.org/10.17660/ActaHortic.2006.707.15