Chapter 34

Precision Viticulture

Precision Viticulture Applications

The development and implementation of precision viticulture or site-specific crop management has been made possible by combining the global positioning system (GPS), geographic information system (GIS), and variable rate technology. These technologies enable the coupling of real-time data collection with accurate position information, leading to the efficient manipulation and analysis of large amounts of geospatial data. GPS-based applications in precision viticulture are being used for vineyard design, vineyard mapping, soil sampling, canopy and vigor monitoring, variable rate applications, and yield mapping among other applications.

Canopy and Vigor Monitoring

Canopy and vigor monitoring is the area of greatest adoption by the wine grape growers for several reasons. It is possible to get timely, high-resolution information during the growing period, which may be relevant for canopy management, fertilization, and irrigation. The information can also be used to delineate zones with differences in vigor to target sampling for a better assessment of the yield and/or the quality and eventually to plan a differential harvest according to the measured quality.

Crop Load Management

Crop load management in vineyards is important for the consistent production of both quality fruit and mature wood. "Crop load" is the ratio of exposed leaf area to fresh fruit weight. Too much leaf area promotes shading and reduces fruit quality, and sometimes bud fruitfulness. Too little leaf area per unit of fruit delays ripening and reduces vine size. Measures of crop load are useful to growers in evaluating success of vineyard management practices. The Ravaz index - which uses the ratio of yield to pruning weight to estimate crop load - is one common metric.

Berry Quality Sampling

The NDVI image is an excellent tool to design quality, sampling zones based upon the NDVI classifications.

Harvest Planning

While an idealized goal of management is to provide uniform vineyard blocks, the reality is it takes time, and some blocks will just never be uniform.

Disease Management

Disease from insects, pathogens, and other infectious organisms can become a serious problem. In some cases, disease development on grapevines occur rapidly and results in entire vineyards incurring injury to various degrees.

Vineyard Design

Variation in soil and topography is likely to have a substantial impact on variation in vineyard performance. High resolution soil maps generated through the use of proximal sensors are proving to be useful in providing insights into the spatial variation in soil properties at scales that are relevant to those responsible for designing new vineyards or re-developing older vineyards.

Planting Vines

In recent years, application of centimeter accuracy RTKGPS has received a lot of attention because of its ability to provide extremely precise location information.

Weed Control

Where weeds are found to be “patchy” in the vineyard it is best that they be spot sprayed rather than by treated by broadcast application. Spot treatments are a variation on broadcast treatments where applications target specific weed patches instead of treating the entire vineyard. This is especially useful for controlling slow-spreading weeds, which form dense, patchy infestations.

Yield Monitoring

Given the low additional cost of yield monitoring over and above the cost of harvesting, there has been an increase in the number of growers that have installed yield monitors on their mechanical harvesters. Several yield-monitoring systems have been developed for tracking yield. The sonic beam system uses ultrasonic sensors to measure the volume of grapes passing along the discharge conveyor.

Ground-Based Crop Monitoring

Many ground-based remote sensing systems have been developed for monitoring vineyards, which provide a high-resolution screening of the canopy side across the row coupled with a GPS system for data geo-referencing. One example of these sensors is GrapeSense®, which captures a high-frequency digital image of the canopy side, collecting information on the height and texture of the vines along the row.

Irrigation Scheduling

Irrigation scheduling is commonly based on estimating crop evapotranspiration from atmospheric measurements (temperature, solar radiation, humidity, and wind speed) or from soil moisture monitoring. While one or a combination of the above two methods can be used to successfully determine when to irrigate and how much water to apply, plant-based monitoring using a handheld infrared thermometer (sensor) may be a useful tool.

Fertilization of Grapevines

Tractor-mounted variable-rate fertilizer spreaders for grapevines use sensors, computers, and GPS technology to continuously monitor vines along the row in order to make adjustments to the rate of fertilizer delivered to each vine. Granular fertilizer is accurately placed in independent left and right bands under the vines.

Wireless Sensor Network

Wireless sensor network (WSN) technologies provide a useful and efficient tool for remote and real-time monitoring of important variables involved in grape production, processing the data and transmitting the required information to the users. A WSN is a network of small sensing devices known as sensor nodes, arranged in a distributed manner throughout the vineyard, which collaborate with each other to gather, process, and communicate over wireless channel for collecting data, where the data are stored and accessible to the end user.

Weather Monitoring

A WSN can collect data and continuously transmits physical or environmental conditions at different locations in the vineyard to a remote central data server. A web-based system can enable remote online access to WSN data with interactive data retrieval and visualization functionalities.

Disease Control

Online monitoring of temperature and relative humidity with a WSN assists growers in predicting the occurrence of some crop pathogens, such as powdery mildew, in deciding when a fungicide program should be performed.

Irrigation Scheduling

Wireless sensor networks for irrigation management offer capability of providing continuous, real-time measurements of soil water status and vine sap flow.

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