terclim by ICS banner
IVES 9 IVES Conference Series 9 GiESCO 9 Comparing different vineyard sampling densities and patterns for spatial interpolation of intrinsic water use efficiency

Comparing different vineyard sampling densities and patterns for spatial interpolation of intrinsic water use efficiency

Abstract

Context and purpose of the study – The need to rationalize agricultural inputs has recently increased interest in assessing vineyard variability in order to implement variable rate input applications, so-called ‘precision viticulture’. In many viticultural areas globally, precision viticulture is already widely used such as for selective harvesting and variable rate application (VRA) of inputs such as irrigation and/or fertilizer. Robust VRA relies on having a geostatistically accurate map (of one or more vineyard attributes) requiring high sampling densities, which can be cost- and time-prohibitive to obtain. Previous work on spatial interpolation using kriging have upscaled ground-based measurements, but such upscaling strategies are applicable only when vineyard conditions are spatially continuous and satisfies the assumption of second-order stationary processes. Alternatively, mixed models that combine kriging and auxiliary information, such as the regression kriging (RK) method, are more instructive for spatial predictions. In order to improve prediction accuracies, it is therefore necessary to incorporate additional information to achieve accurate spatial patterns with low error. Here, we used a hybrid approach where information derived from multiple sources – point (ground-based) and high resolution remote sensing (aerial, continuous) – was used to spatially interpolate leaf-level intrinsic water use efficiency (WUEi) in a South Australian Shiraz vineyard to improve the prediction accuracy and lower the error estimates of WUEi.

Material and methods – We utilised a upscaling approach where aerial imagery was used to improve the accuracy of spatially-interpolated ground-based measurements to obtain a reliable geostatistical (kriging) model with respect to error rates. We also compared different sampling densities and distributions; gridded vs. stratified sampling distribuitions were compared viz. upscaling UAV images in order to obtain a geostatistically accurate estimate of WUEi. Relationships between UAV altitude and number of ground sampling points were obtained vs. kriging error rates. To the best of our knowledge, this is the first study reporting on the spatial prediction of WUEi from multiple data sources.

Results – The integration of UAV images with ground data of WUEi effectively improved the spatial accuracy of WUEi through the RK technique. We found that kriging WUEi  based on stratified sampling had a lower interpolation error compared to gridded sampling. We found that gridded sampling error rates increased more rapidly with increasing flight altitude (or higher ground spatial distance) than stratified sampling. Our findings could help viticulturists to rapidly develop highly accurate spatial maps of vine performance parameters.

DOI:

Publication date: July 5, 2023

Issue: GiESCO 2023

Type: Poster

Authors

Alessandro MATAFFO1, Boris BASILE1, Vinay PAGAY2*

1Department of Agricultural Sciences, University of Naples Federico II, Viale Italia, 83100 Avellino, Italy
2School of Agriculture, Food & Wine, The University of Adelaide, PMB 1, Glen Osmond, SA 5064, Australia

Contact the author*

Keywords

grapevine, kriging, water use efficiency, UAV, geostatistics, sampling distribution

Tags

GiESCO | GIESCO 2023 | IVES Conference Series

Citation

Related articles…

IMPACT OF HARVEST DATE ON THE FINE MOLECULAR COMPOSITION OF MUST AND BORDEAUX RED WINE (VAR. MERLOT, CABERNET SAUVIGNON). FOCUS ON ACIDITY AND SENSORY IMPACT AFTER FIVE YEARS OF AGING

Climate change has brought several impacts that are becoming increasingly intense during the last few years and put at risk the quality of the berries or even the plant’s sustainability. Such extreme climatic events impact the composition of the wine while modulating its quality and the consumer preferences (Tempère et al., 2019). The three most important changes that take place in the must are: 1) decrease acidity, 2) increase of the concentration of sugar, hence increase of alcohol in the wine, and 3) modification
of the sensory balance and the development for example of cooked fruit aromas.

IMPACT OF CLIMATIC ZONES ON THE AROMATIC PROFILE OF CORVINA WINES IN THE VALPOLICELLA REGION

In Italy, in the past two decades, the rate of temperature increases (0.0369 °C per year) was slightly higher compared to the world average (0.0313 °C per year). It has also been indicated that the number and intensity of heat waves have increased considerably in the last decades. (IEA, 2022). Viticultural zones can be classified with climatic indexes. Huglin’s index (HI) considers the temperature in a definite area and has been considered as reliable to evaluate the thermal suitability for winegrape production (Zhang et al., 2023).

A synthesis approach on the impact of elevated CO2 on berry physiology and yield of Vitis vinifera

Besides the increase in global mean temperature the second main challenge of a changing climate is the increase in atmospheric carbon dioxide (CO2) in relation to physiology and yield performance of grapevines. The benefits of increasing CO2 levels under greenhouse environment or open field studies have been well investigated for various annual crops. Research under free carbon dioxide enrichment on field-grown perennial plants such as grapevines is limited to a few studies. Further, chamber and greenhouse experiments have been conducted mostly on potted vines under eCO2 conditions.

Microbial ecosystems in wineries – molecular interactions between species and modelling of population dynamics

Microbial ecosystems are primary drivers of viticultural, oenological and other cellar-related processes
such as wastewater treatment. Metagenomic datasets have broadly mapped the vast microbial species
diversity of many of the relevant ecological niches within the broader wine environment, from vineyard
soils to plants and grapes to fermentation. The data highlight that species identities and diversity
significantly impact agronomic performance of vineyards as well as wine quality, but the complexity
of these systems and of microbial growth dynamics has defeated attempts to offer actionable
tools to guide or predict specific outcomes of ecosystem-based interventions.

Searching for the sweet spot: a focus on wine dealcoholization

It is well known that the vinification of grapes at full maturation can produce rich, full-bodied wines,
with intense and complex flavour profiles. However, the juice obtained from such grapes may have very
high sugar concentration, resulting in wines with an excessive concentration of ethanol. In addition, the decoupling between technological maturity and phenolic/aromatic one due to global warming, exacerbates this problem in some wine-growing regions. In parallel with the increase of the mean alcohol content of wines on the market, also the demand for reduced alcohol beverages has increased in recent years, mainly as a result of health and social concerns about the risks related to the consumption of alcohol.