1a.Objectives (from AD-416):
Determine the feasibility of measuring grapevine water use during deficit irrigation using capacitance probes monitored remotely.
1b.Approach (from AD-416):
Capacitance probes used to monitor soil water content will be installed on three treatments at 4 locations that are part of the NIFA-SCRI research project to evaluate yield response to deficit irrigation. Data will be collected using a cellular phone and internet protocol. Data will be downloaded and processed daily and compared to the irrigation treatments to evaluate the system.
This project supports objective 2 of the parent project. The project is in support of the NIFA-SCRI project “Developing Sustainable Vineyard Water Management with Limited and Impaired Water Supplies”. One deliverable in the project is evaluating the effect of deficit irrigation on the yield and quality of table, raisin and wine grapes. An important component in the evaluation is determining variation in soil water content in response to the irrigation treatments. This can be done using neutron probes, soil matric potential sensors and a variety of other devices. The limitation with most of these methods is they require the data be taken manually or at least downloaded from a datalogger manually. We developed an alternative system that enables the data to be collected from remote sites using wireless technologies. This equipment uses the capacitance type soil water measurement technique and continuously stores data that is downloaded wirelessly through the internet. This facilitates data collection from sites up to 200 miles from the office. It also provides a continuous record of changes in soil water content in 1 foot intervals to a depth of 5 feet. The system also measures irrigation events and provides weather data over the grape canopy. Systems were installed on each of the 3 irrigation treatments in the research sites at Delano, Caruthers, Paso Robles and Mecca, California. The initial data from the first installed site clearly demonstrated a response to irrigation. These data indicated when the irrigation began and ended as well as changes in the soil water content. The soil water content responds to irrigation by increasing and decreasing in response to crop water use. The sensors still need to be calibrated for each site. These systems will significantly improve our understanding of grape water use in response to deficit irrigation.