ISHS Acta Horticulturae 707: VII International Symposium on Modelling in Fruit Research and Orchard Management
A GRAVIMETRIC LYSIMETER FOR MODELING TRANSPIRATION IN YOUNG CHERRY TREES |
| Authors: | A. Antunez, C. Stöckle, M.D. Whiting |
| Keywords: | Modeling, transpiration, Prunus avium, lysimeter, water use, water stress |
| Abstract:
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. | |
Download Adobe Acrobat Reader (free software to read PDF files) | |
