In the arid regions of the world, like Fujairah in the UAE, extreme environmental conditions pose a significant challenge to local food production. Over-reliance on chemical fertilizers to increase crop yield has, in many cases, caused adverse environmental effects. A recent study published in the journal Scientific Reports by François Mitterand Tsombou and colleagues introduces a sustainable strategy: converting plant parts of the abundant date palm into biochar and testing its effect on the hydroponic growth of sweet basil (Ocimum basilicum). This research addresses the dual challenge of sustainable food production and the efficient utilization of large volumes of agricultural waste generated from date palm cultivation. The researchers produced biochar from three parts of the date palm—leaflet, petiole, and fruit—using a low-cost, sustainable drum method that heated the plant materials to a maximum of 500−600∘C. They then evaluated the biochars’ physicochemical composition and their ability to enhance O. basilicum growth at 0%, 1.5%, and 3% concentrations, both with and without Hoagland nutrient solution.

The study found a strong, positive link between the date palm biochar and plant growth. The best overall performance for sweet basil was achieved when plants were treated with a combination of 3% leaflet biochar and the standard Hoagland nutrient solution. This treatment resulted in significantly higher plant metrics compared to the control groups and other treatments, including a shoot length of 16 cm, leaves number of 14.25, and a shoot dry weight of 0.34 g. Interestingly, while the combination with Hoagland maximized most growth parameters, root length was actually longest ( 26.75 cm) when 3% leaflet biochar was used without the Hoagland solution. This suggests different biochar types and concentrations can be optimized for specific plant needs.

The physiochemical analysis revealed why the different biochar types performed differently. The leaflet and petiole biochars had higher values of macro elements like calcium and potassium compared to the fruit biochar. These elements are vital for plant health, with calcium involved in processes like stomatal movement and potassium essential for enzyme activation and protein synthesis. The leaflet biochar was also noted for its high calcium content, while the petiole biochar had notably higher potassium levels, as well as significantly higher pH (8.38) and EC (3452.66 μS/cm) without Hoagland. The high EC (Electrical Conductivity) values are considered a proxy for nutrient availability in the media, suggesting the biochar successfully increased the negative charges in the media, enhancing the retention of positive nutrient ions.

A unique aspect of this research was the investigation of the electrical properties (voltage and current) of the biochar and their correlation with plant development. To the best of the authors’ knowledge, no prior research has evaluated the electrical current and voltage of biochar derived from date palm residues. The results showed that voltage (ranging from 0.62 to 0.98) and current (ranging from 0.73 to 0.95) were strongly and positively correlated with all measured sweet basil plant growth parameters, including leaf width and shoot dry weight.

The researchers theorize that increasing biochar levels leads to a rise in voltage and current in the solution. Voltage is seen as the energy transferred to the solution, while current is the rate of electrical charge flow. These electrical changes could increase the biochar buffer capacity and facilitate cation exchange capacity (CEC), essentially helping the plants take up more nutrients from the media. This suggests that biochar doesn’t just act as a physical or chemical amendment but also as an electrochemical enhancer in hydroponic systems.

This study successfully demonstrates a two-pronged solution for arid regions. First, it provides an environmentally sound way to manage date palm waste, an abundant resource in the UAE. Second, it offers a sustainable, waste-derived amendment that significantly improves crop productivity in hydroponic systems. The final outcome is a viable strategy for enhancing food security in challenging environments, paving the way for biochar-based hydroponic solutions in sustainable agriculture. Future research will focus on optimizing biochar compositions and application methods for broader use.

Source: Tsombou, F. M., Ali Alhmoudi, A. M. S., Al Dhanhani, A. S. S. J., Alhmoudi, M. A. S. M., Mirza, S. B., Engracial, M. J., & Ridouane, F. L. (2025). Biochar from date palm enhances hydroponic growth of Ocimum Basilicum under arid conditions of Fujairah. Scientific Reports, 15(1), 34238.