A COMMENT ON INTER-FIELD SPATIAL EXTRAPOLATION OF VINE (VITIS VINIFERA L.) WATER STATUS

Aim: Recent work has identified strong inn-field relationships of pre-dawn leaf water potential (Psi(PD)) between paired sites. This study investigates if these relationships exist at the inter-field level when soil types between fields are constant or different in a vineyard in Southern France. Method and result: Nine fields were sampled for Psi(PD) on 6 dates over two growing seasons. When general assumptions of uniformity in climate. growing conditions and soil moisture were able to be met, a linear relationship between the mean Psi(PD) responses of different fields was observed. The relationship was no longer linear when the soil moisture regime between fields differed. Conclusion: The results indicate that it should be possible to extrapolate a reference Psi(PD) value across a production region (syndicate/co-operative) defined on a similar soil type. Significance and impact of study: These intra-field relationships may minimise the need for Psi(PD) sampling to define irrigation/crop management in areas planted to similar soil types. The poor fit between fields with differing soil moisture regimes indicates that the original intra-field model may be flawed in larger fields or vineyards with heterogeneous soil moisture conditions.