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Comparison of different grapevine water status measurements
- Hessdörfer, D., Schwab, A., Gruber, B. R.
- Acta horticulturae 2014 no.1038 pp. 351-358
- Vitis, field experimentation, microirrigation, sap flow, water potential
- The feasibility of continuous in-situ measurements of grapevine stem water potential by means of stem hygrometers was investigated. The comparison with pressure chamber measurements as reference method revealed close correlations at pre-dawn as well as during the day. It was possible to monitor the short term recoveries caused by drip irrigation. However, while absolute values of hygrometer and pressure chamber measurements at pre-dawn were on the same level, stem hygrometer values during the day tended to indicate more intense stress than pressure chamber measurements. Stem water potential continuously measured by stem hygrometers in field experiments showed a very close correlation to ambient VPD. In addition, sap flow rates of grapevine could be estimated by the daily courses of the water potential gradient between stem and pre-dawn water potential. Remounting of stem hygrometers due to exudates was necessary in intervals of several weeks.