The ICT supported experiments at Dubai, United Arab Emirates and Cairns, QLD, Australia showed that continuous monitoring of the soil moisture and salinity levels in the soil profile would allow a good understanding of the soil water movement and salt accumulation in the soil profile to better design plant growth, efficient water and nutrient management of irrigated crops.
Dubai, United Arab Emirates and Cairns, QLD, Australia
The results of the experiment at Dubai displayed the time of the day for high salt accumulation in the soil profile. From the experiment, it was noted that the soil tension levels are 0 kPa from 4:00 pm to 9:00 am each day indicating that the soil at 30 cm is at field capacity overnight. Each day the tensiometer first increases suction at the 9:00 am reading as the soil begins to dry from plant water use. The soil suction is driest at 1:00 pm each day and typically prior to the rainfall events 2-4 kPa at 1:00 pm. After this time the soil suction declines due to upward flux of water from depths below 30 cm at a rate sufficient to satisfy the demands of plant water use. This flux will impact the salinity levels within the profile and indicates the necessity to monitor closely soil water movement and soil salinity dynamics at the same time.
The optimisation of irrigation in parkland requires knowledge of the soil properties, plant characteristics, weather conditions and management practices. With this known, the Cairns Regional Council, in conjunction with Central Queensland University (CQU), commenced the Smart Urban Irrigation Project with the aim of optimising irrigation via the integration of best available irrigation equipment, real time monitoring data and the latest irrigation software.
To establish the benchmark measurements, Dual Electromagnetic (Dual-EM) surveys were undertaken to determine the soil moisture content. Additional infiltration measurements were also made, and these were used to classify park regions as low, medium, and high moisture zones.
Two parks, the Eastern Lagoon and Fogarty Park, were selected for intensive investigation. The grasses in these parks have shallow root systems (<20cm depth) due to compaction and low soil infiltration rate, and currently require frequent irrigation.
Sensors and communications employed: