Precision irrigation based on soil moisture awareness gives 25% water saving potential – SWAMP Cartagena pilot completed

SWAMP Cartagena pilot focused on optimising irrigation water consumption when growing baby-leaf spinach in semi-arid area close to Cartagena, Spain. The idea was to measure the soil moisture data from three depths of the field, i.e. 5cm, 10cm, and 15cm, to feed the data to our SWAMP smart water management platform, create soil moisture forecasts and irrigation plans, and to irrigate the soil with IoT based automated sprinkler irrigation system.

As we all know, the COVID-16 pandemic with its almost global lockdowns destroyed these plans. we were not able to access the fields, and plans had to changed.

We had collected the soil moisture data and weather data, and we decided to simulate the soil moistures with various irrigation scenarios.  The soil moisture forecast model was created based on collected soil behaviour data. The model predicted how water flows through different soil layers from surface up to 50cm deep. As we had the weather data collected from pilot field from the February 2020, we simulated that time period with several irrigation scenarios. In the scenarios were varied in the irrigation parameters and irrigated the crop trying to maintain the root zone within target soil moisture range that was known to be good for baby-leaf spinach. Then we calculated how much water was needed.

The figure above illustrates the soil moisture development of all 10 5cm layers in the simulation case when initial irrigation to the dry soil was 80mm at February 1st, and the minimum time between irrigations was 12 hours after the seeding of spinach at February 6th. Irrigations were stopped at February 26th when crop was harvested.

We simulated about 40 such scenarios and compared the results to the real farming data at the same time period. In the real farming time period, the soil moisture data and irrigation recommendations were not used. Based on the results, we can say that 25% of water saving is possible with very little risks. Even then we lose water to the deeper layers of the soil, but it cannot be avoided by changing irrigation strategy alone.

IoT and soil moisture measurement improves the knowledge of crops’ water needed and helps in saving the water that is a scarce resource in Cartagena and many other parts in this planet. Even with the simple automation, the sustainability of food production can be improved.




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