Showing papers by "Simone Priori published in 2013"

Improving Wine Quality through Harvest Zoning and Combined Use of Remote and Soil Proximal Sensing

Abstract: Successful adoption of precision viticulture at the farm level depends on the appreciation of vineyard spatial variability. Knowing the spatial variability of soil properties is a challenge, often very expensive and labor intensive. An alternative approach could be the combined utilization of proximal and remote sensors. This study combined proximal (Geonics EM38-MK2) and remote (normalized difference vegetation index, NDVI) sensing aimed at mapping homogeneous zones (HZs) of two 3.5-ha vineyards in the Chianti wine district (Italy). Two HZs in each vineyard were obtained by a k-means clustering of the first two factors of the principal component analysis performed on four maps: (i) apparent electrical conductivity, obtained by EM38-MK2 at 0 to 75 cm (ECa₁) and (ii) 0 to150 cm (ECa₂); (iii) topographic wetness index (TWI), calculated from a digital elevation model; and (iv) NDVI extrapolated by multispectral airborne images. Only ECa₁ and ECa₂ were correlated with some physical (silt and gravel content) and hydrologic (available water capacity) features of the soils. These two variables could also better discriminate the two HZs with respect to NDVI and TWI. The grapes (Vitis vinifera L.) of the selected HZs were separately harvested and vinified to test the differences in the wine quality. Significant differences emerged between the wines produced from the two HZs, especially in terms of color intensity, dry extract, and anthocyanin content. A wine tasting after 6-mo aging of the wines confirmed the differences between the wines produced in the two zones, especially in terms of color, structure, and total score.

Using the ARP-03 for high-resolution mapping of calcic horizons

Abstract: A b s t r a c t. The aim of this work is to present a fast and cheap method for high-resolution mapping of calcic horizons in vineyards based on geoelectrical proximal sensing. The study area, 45 ha located in southern Sicily (Italy), was characterized by an old, partially dismantled marine terrace and soils with a calcic horizon at different depths. The geoelectrical investigation consisted of a survey of the soil electrical resistivity recorded with the Automatic Resistivity Profiling-03 sensor. The electrical resistivity values at three pseudo-depths, 0-50, 0-100 and 0-170 cm, were spatialized by means of ordinary kriging. A principal component analysis of the three electrical resistivity maps was carried out. During the survey, 18 boreholes, located at different electrical resistivity values, were made for soil description and sampling. The depth to the calcic horizon showed a strong correlation with electrical resistivity. The regression model between calcic horizon and the principal component analysis factors with the highest correlation coefficients was selected to spatialise the calcic horizon values. An Normalized Difference Vegetation Index map was used to validate the calcic horizon map in terms of crop response to different soil rooting depths. The strengths of this method are the quick, non-invasive kind of survey, the relevance for vine vigour, and the high spatial resolution of the final map. K e y w o r d s: precision viticulture, soil conservation, irrigation, Mediterranean, geophysics

A combined geophysical-pedological approach for precision viticulture in the Chianti hills

Abstract: The aim of the present work was to test and develop a combination of both geophysical and pedological survey techniques devoted to the definition of a correct plan for precision viticulture. In particular, the objective of the study was to evaluate the potentiality of a combined use of these techniques to identify areas with uniform soil properties within 4 test vineyards of the “Barone Ricasoli” farm, located in the Chianti wine district (Tuscany, central Italy) and to evaluate the relationships between soil properties and wine quality. Two different geophysical methods based on the measurement of the electrical conductivity were used: an electro-magnetic induction method and electric resistivity tomographies; these were combined with detailed pedological analyses and with the evaluation of remote sensing maps. All results were compared and discussed, and finally a cluster analysis based on the evidences of geophysical tests and on pedological data was performed. For each of the identified uniform areas, a separate winemaking was successively made, and the quality of the wines is discussed and correlated to the geophysical-pedological results. The study has shown that the approach used is suitable for mapping and understanding the anomalies in soil distribution which partially reflects in the quality and effectiveness of wine production. Moreover, it was demonstrated that the geophysical data alone are not able to provide any pedological information because, in the investigated area, electrical conductivity is affected by various soil properties in a complex manner; however, these methods are very useful to integrate and complement pedological data in the aims of precision viticulture.

Unexpected relationships between δ 13 C and wine grape performance in organic farming

Abstract: Aim: To evaluate the relationship between carbon isotope ratio (δ13C) and wine grape viticultural and oenological performance in organic farming.Methods and results: The study was carried out for four years in the Chianti Classico wine production district (Central Italy), on five non irrigated vineyards conducted in organic farming. The reference variety was Sangiovese. Eleven sites were chosen for vine monitoring and grape sampling. The performance parameters were alcohol and must sugar content, sugar accumulation rate, mean berry weight, and extractable polyphenols. δ13C, stem water potential, and soil water availability were also monitored. Finally, soil nitrogen as well as yeast available nitrogen in the must were measured. δ13C was directly related to stem water potential and soil water deficit, and indicated a range of water stress conditions from none and moderate to strong. However, its relationship with viticultural and oenological results was contrary to expectation, that is, performance linearly increased along with soil moisture. On the other hand, the worst performance was obtained where both water and nitrogen were more limiting.Conclusions: The unexpected relationship between δ13C and Sangiovese performance was caused by low nitrogen availability. The studied sites all had low-fertility soils with poor or very poor nitrogen content. Therefore, in the plots where soil humidity was relatively higher, nitrogen plant uptake was favoured, and Sangiovese performance improved. Macronutrient being the main limiting factor, the performance was not lower in the plots where soil water availability was relatively larger. Therefore, the best viticultural result was obtained with no water stress conditions, at low rather than at intermediate δ13C values.Significance and impact of the study: Water nutrition is crucial for wine grape performance. δ13C is a method used to assess vine water status during the growing season and to estimate vine performance. A good performance is expected at moderate stress and intermediate δ13C values. A better knowledge of the interaction between water and nutrient scarcity is needed, as it can affect the use of δ13C to predict vine performance.

THE POTENTIAL OF γ-RAY SPECTROSCOPY FOR SOIL PROXIMAL SURVEY IN CLAYEY SOILS LE POTENTIEL DE LA SPECTROSCOPIE A RAYONS-γ LORS DE L'ECHANTILLONNAGE PEDOLOGIQUE DE SOLS ARGILEUX LE POTENZIALITÀ DELLA SPETTROSCOPIA DI RAGGI-γ NEL RILEVAMENTO PEDOLOGICO DI SUOLI ARGILLOSI

Abstract: Gamma-ray spectroscopy surveys the intensity and distribution of γ-rays emitted from radionuclides of soils and bedrocks. The most important radionuclides of soils and rocks are: 40 K, 232 Th, 238 U and 137 Cs, the latter due to Chernobyl explosion or radioactive pollution. Distribution and quantity of these radionuclides in the soil are strictly linked to parent material mineralogy and soil cation exchange capacity. The aim of this work was to show the potential results of γ-ray proximal survey spectroscopy within experimental fields of clayey soils in western Sicily. The γ-ray spectrometer used for the fieldwork was “The Mole”, made by “The Soil Company”, “Medusa system” and the University of Groningen, Netherlands. During the survey of eight experimental fields, 55 soil samples were collected for laboratory analysis of particle size distribution, calcium carbonate, organic carbon and total nitrogen content. The results of the work show the statistical correlations between soil features and γ-ray data.