A greatly improved understanding of the dynamic behavior of salinity of soil solutions is now possible due to the recent installation of a Soil Salinity Monitoring Station at Dubai. Hourly data logging of soil salinity and temperature using soil salinity sensors connected to a “Smart Interface” enables direct and dynamic monitoring of soil salinity EC in units of dS/m corrected to 25°C. This system was installed, and training in operation and data interpretation was carried by Dr Peter Cull from ICT International; an Australian company which specializes in soil moisture, salinity and plant water use monitoring instrumentation.
Each salinity sensor is fitted with an external Smart Interface that includes an integrated microprocessor. This interface contains all the required information to allow autonomous operation of the sensor, including power requirements and logging interval. The Smart Interface resolution is 16 Bit offering highly precise and accurate recording of the salinity sensor.
A feature of this salinity monitoring field station is that is does not require any knowledge of electronics or computer programming. To operate the salinity station simply plug in a salinity sensor and the Smart Logger will then search the DataBus and automatically identify the number of salinity sensors connected and begin logging them at hourly intervals. For custom configuration of the Smart Logger or salinity sensors a simple menu system can be accessed through HyperTerminal that provides complete control over each individual sensor’s set-up. Instantaneous readings from sensors can be viewed on the logger’s display directly in the field without the need for a laptop. Data can also be accessed in the field by memory stick or remotely using a mobile phone modem. This data is then available for graphing and interpretation in Excel.
The monitoring is taking place in a field which is being irrigated with 10, 20 and 30 dS/m salinity water. Salinity sensors have been buried at 30 cm and 60 cm. The dynamic changes of soil salinity within an irrigation cycle are showing the effect of the salinity of the irrigation water on the salt concentration in the rootzone of the grass and how this is constantly changing under irrigation.
The soil temperature is recorded enabling the correction of the soil salinity EC to units of dS/m at 25°C. However the soil temperature readings can also be used to give assistance with interpretation of soil moisture movement as no soil moisture sensors were installed. This soil temperature data shows:
The soil salinity data in the Distichlis shows:
The soil moisture (tensiometer) was data logged in only one treatment 10 dS/m at 30 cm in Sporobolus (Figure 3).