Use of remote sensing in zoning's studies for terroir and precision viticulture: Implementation in DO Ca Rioja (Spain) / Uso de la teledetección en los estudios del terroir para la viticultura de precisión: Aplicación en la DO Ca Rioja (España)

Abstract

There are two principal ways of plot/exploitation management: Traditional or Conventional Managing (MC) and Precision viticulture (VP). Even though the technological requirements from these systems are different, in both cases, the Zoning or Variability Map for the Terroir (MVT) is required. MVT is a detailed mapping of the plot and enables to know the delineation and characterization of several sectors which make up its variability. The VP manages independently and optimized each of these sectors, allowing, among other things, optimizing the plantation's layout, rootstocks' selection, tillage, cover crop management, fertilization and maintenance programs, adjustment of water needs, diagnosis and pests and diseases management, monitoring of ripening, the harvest timing, etc. and all so in a localized manner according to the characteristics of each sector. Direct Method (MD) is the natural way to get the MVT. The map made from Direct Method defines and characterizes the different sectors indeed, and also provides some information about the terroir characteristics, which allow diagnosing the causes of heterogeneity and thus, handle them properly. Maps obtained by remote sensing from Spectral High Resolution Imaging (IEAR) provide relevant information, they are very affordable, and with an easy accuracy limits and they are obtained quicker than those made from MD. However, this kind of maps split the areas whose differentiation is due to the plant response in a specific situation that may be caused by a nearly endless options, and therefore, they vary with them. These maps are unable to discriminate sectors by the properties according to environmental factors (climate, lithology, geomorphology, soil) that affect the terroir variability, forbidding any direct action on them. Doing a MVT performed through a MD is expensive on large scales (very detailed studies) due to the gap about adequate perform delineations (net fixed error is related to sides length). However, IEAR technology provides a map which is obtained allowing to buffer this problem and also, reducing the costs. Both in maps obtained from MD or IEAR, the sampling quality is a key point. Both density of observations and the number of properties involved in the study determine its utility and the relative directives, when is possible under an international procedure (such as, OIV), must be a quality guarantee. In fact, both methodologies (MD and IEAR) are complementary for doing the MVT and, once the map (done through MD) is available, the right interpretations of the IEAR maps are possible, whether annual, seasonal, depending on the phenological status or any other circumstance that may affect the variability (pests, stress, ...). MVT obtained like that, allows to the viticulturist address the most ambitious goal: the product optimization and homogenization. Specifically, in a short or medium term and by the management carried out with the VP's performance on the terroir's properties in different sectors of the parcel/plot, resulting in the highest uniformity as possible, and also, in the product. In this work, we worked on terroir's variability and the vineyard management systems (MC and VP), highlighting the relevance of mapping, the need for MVT and its complementary performance related to the MD, and the use of remote sensing systems (IEAR) as another discriminative method.