The Mediterranean regions, as well as other areas of the world, are currently facing a serious water stress problem.
Very low rainfall, combined with prolonged periods of drought, significantly limits water availability. In addition, extreme weather events disrupt agricultural production and cause soil erosion. This, combined with the increasingly common occurrence of soils with high salinity and low fertility, seriously hinders the growth of many crops.
However, there are crops, such as the carob, which have proven over decades to be particularly well-suited for combating desertification and stabilizing degraded soils thanks to their drought resistance. This is also due to its ability to grow in nutrient-poor soils. Furthermore, this tree’s potential for carbon sequestration makes it a highly effective tool for promoting climate change mitigation.
However, at present, it is still There is significant room for improvement in their productivity.
Although it has traditionally been a rain-fed crop, studies have been conducted on the impact of implementing the Sub-surface Drip Irrigation (SDI) as an effective irrigation method to maximize water efficiency and improve crop yields without compromising natural resources. RGS represents a paradigm shift and a transformation in the agricultural management of this crop.
The RGS system allows water to be applied directly to the root zone, which reduces evaporation losses and ensures the most efficient use of water resources.
Implementation of RGS in Carob Cultivation
As part of the research project CICLICA PRIMA, in 2021, work was carried out to convert an 8-hectare commercial plot of 7-year-old rainfed carob trees. The conversion was based on the implementation of the SUB-SURFACE DRIP IRRIGATION with a dripline AZUD PREMIER PC AS 16 at a depth of 30 cm. A filtration system was also installed AZUD LUXON to ensure the quality of the nutrient solution supplied and prevent clogs in the irrigation emitters.
For the experimental monitoring of this plot, soil probes were installed to measure substrate moisture, temperature, and conductivity; plant sensors were used to measure the trees’ physiological response; and a weather station was set up to provide detailed information on the plot’s environmental conditions.
All of these sensors were connected to a device AZUD DLOG 600 which enabled comprehensive and continuous monitoring of weather conditions and the entire crop environment, allowing for real-time tracking from any device.
Under these conditions, The RGS proved to be an effective strategy for ensuring efficient water use and providing water without losses due to evaporation or runoff.
The RGS made the crop more resilient to drought. It also helped minimize the negative effects of salinity in irrigation water, allowing the carob tree to tolerate water with a salinity of up to 4 dS/m.
Under conditions of severe rainfall scarcity (< 200 mm of annual precipitation), the RGS helped improve the carob tree’s vegetative growth and increase fruit weight. It also helped maintain more stable production, even increasing yield in some cases.
Under moderate rainfall conditions (400–550 mm of annual precipitation), the RGS helped improve production and stabilize the harvest, allowing for a more predictable and consistent yield, which consequently reduced the financial risks associated with the harvest.
Impact of SUB-SURFACE DRIP IRRIGATION
As a result of this transition from rain-fed carob cultivation to irrigated cultivation using SUB-SURFACE DRIP IRRIGATION, the following results were obtained:
- Optimizing Water Use: The RGS system enables highly efficient water use without evaporation losses.
- Greater water stability: The RGS resulted in trees that were better hydrated and experienced less water stress.
- Weed Control: The RGS prevented the growth of unwanted weeds.
- Better adaptation to salinity: RGS increased the carob tree’s resilience to irrigation water with high electrical conductivity.
- Positive environmental impact: The RGS system allowed for irrigation with limited and reduced water consumption, which led to the optimization of the crop’s water footprint.
- Increased profitability: The RGS ensured more stable and higher-quality production, which led to lower financial risk.
The use of soil, plant, and weather sensors, meanwhile, made it possible to ensure more efficient resource management through continuous and accurate monitoring on the system’s climatic and environmental conditions. This information enables real-time decision-making, which directly impacts the optimization of water application volumes, ensuring that the crop receives the appropriate amount of water based on its actual needs.
In short, the RGS has proven to be an effective and sustainable solution for increasing the productivity of carob cultivation in the context of climate change and limited water resources.
For this reason, the adoption of efficient irrigation technologies is key to the future of the agricultural sector.
The CICLICA project is part of the PRIMA program and is funded by the European Union and the Center for Technological and Industrial Development (CDTI).
