Temperature

The temperature of the root zone is not always measured or controllable. It is however very important and root temperatures should be kept between 18 ^oC and 25 ^oC.

For Oxygen availability

As the temperature of the root zone increase the availabily of oxygen from the irrigation water decreases. At root temperatures of over 25 ^oC especially if root distribution is poor this combined with competition between roots can lead to root death. This opens up the possibility of secondary infection by root pathogens such as Pythium.

Measurement is knowledge so measure to know what is happening with the slab temperature.