ISHS Acta Horticulturae 664: IV International Symposium on Irrigation of Horticultural Crops
COMBINING TECHNIQUES TO STUDY EVAPOTRANSPIRATION IN WOODY CROPS: APPLICATION TO SMALL AREAS - TWO CASE STUDIES |
| Authors: | M.I. Ferreira, T.A. Paço, J. Silvestre |
| Abstract:
Information on water use of woody crops is scarce because of experimental and modelling limitations related to the size and structure of roots and shoots. The eddy covariance (EC) micrometeorological method is considered relatively reliable and adequate, but it requires large uniform areas. The alternative is the use of sap flow (SF) methods to quantify transpiration (T), which is usually the dominant component of evapotranspiration (ET). Sap flow methods also allow the distinction between T in small plots submitted to different treatments (in relation to water, fertilisers, pruning, etc). However, none of the sap flow methods seem to provide good absolute values in all circumstances. This paper shows two case studies on the use of a combination of EC and SF methods to quantify ET of small areas. One study was in a peach orchard, where ET could be indirectly obtained for different treatments (irrigated and stressed plot). The other study was in a vineyard where water usage was compared in three locations with different slopes (3%, 10% and 17%) but the same aspect throughout a season. The measurement strategy gave good results and identified treatment differences of good quality in an appropriate time scale. | |
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