The journal IOP Conference Series: Earth and Environmental Science recently published a study by PA Mandasari, NI Triwardani, S Supriyadi, and A Amzeri regarding the benefits of using composted biochar for vegetable production. Their research focuses on how these soil amendments can overcome the challenges of farming on marginal lands, particularly in coastal regions like Madura, Indonesia. By testing different amounts of composted biochar alongside diluted seawater irrigation, the authors demonstrate a practical path for maintaining food security in areas facing freshwater scarcity and soil degradation. The findings suggest that traditional waste products, when processed correctly, can become powerful tools for modern sustainable agriculture.

The most striking result of the research is the significant boost in plant growth measured by leaf count and height. When fifteen grams of composted biochar were added to the soil, the lettuce plants developed nearly 20 percent more leaves compared to plants grown without the amendment. This increase in vegetative growth is primarily due to the high nutrient content of the composted biochar, which is rich in nitrogen and potassium. These elements are essential for early plant development, fueling processes like cell division and leaf expansion. Furthermore, the porous structure of the biochar improves the physical properties of the soil, allowing roots to spread more easily and absorb water more efficiently.

In addition to leaf growth, the study highlights a 15.9 percent increase in plant height for those treated with the highest dose of biochar. This growth trend was consistent across both fresh and dry biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More measurements. The total fresh weight of the lettuce reached its peak at over 48 grams per plant with the fifteen-gram biochar treatment, which is a substantial improvement over the control group. This indicates that the biochar does not just make the plants taller but also significantly denser and more productive. The researchers attribute this to the biochar’s ability to reduce nutrient loss from leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More and its role in stimulating beneficial microbial activity in the root zone.

A critical aspect of this study is the investigation into diluted seawater as an alternative irrigation source. While high salinity usually stunts plant growth, the research found that a 3 percent seawater concentration did not negatively impact the lettuce when combined with biochar. In fact, the interaction between the two treatments produced the tallest plants in the entire study, reaching over 29 centimeters. This suggests a synergistic effect where the biochar acts as a protective buffer, mitigating the osmotic stress caused by salt. By holding onto essential minerals and moderating the availability of toxic ions, the biochar allows the plants to thrive even under conditions that would otherwise be unfavorable.

The study also examined the physiological health of the plants by measuring chlorophyll levels. Interestingly, the interaction between biochar and diluted seawater specifically helped maintain chlorophyll b content, which is a key indicator of photosynthetic efficiency. While salt water on its own tended to reduce these levels, the addition of composted biochar helped stabilize them. This means the plants were not only larger but were also maintaining the internal biological processes necessary for high-quality produce. These results provide a strong scientific basis for using biochar to expand agricultural production into coastal environments where fresh water is a limited and precious resource.

Source: Mandasari, P. A., Triwardani, N. I., Supriyadi, S., & Amzeri, A. (2026). Effects of composted biochar and diluted seawater on growth, yield, and chlorophyll content of green lettuce. IOP Conference Series: Earth and Environmental Science, 1591, 012010.