The sensor network is monitoring the soil water and electrical conductivity (EC) at three positions within each 72" x 12" bag of perlite, which is used as the substrate. Current plant density is 56 plants per bag.
Additionally, we are sensing soil temperature, canopy air temperature and relative humidity and photosynthetically active radiation (PAR) on a 5-minute time interval for each block.
Data from the network show that matric potentials in the mature summer crop (at right) are cycling between aproximately -7 kPa in the early morning to less than -1 kPa when plants are irrigated during the day.
This information (at right) indicates to us that plants may be exhibiting mild water stress early in the morning, and that irrigations should probably start earlier (around 7am) during hot dry weather.