As someone who has read widely about climate change mitigation methods and who has been immersed in the world of biochar for eight years, I was stunned to read an article in Biochar Today this July 21. It described a four year (2021 to 2024) field trial of biochar plus foliar-applied dilute salicylic acid (SA) on a fig grove in a semi-arid region of Iran that resulted in a 300% increase in fig yields and a 13.5 times (3.99 vs 0.29) improvement in the benefit-to-cost ratio, compared to the control plots, which had no SA or biochar.

These results included major improvements in fruit taste and size, nutrients, and in 21 other plant metrics. Charged biochar alone and SA alone each produced about a 100% increase in yield. When combined, the yield increased by over 300%, along with fruit quality, taste, and marketable grade (AA vs. B)!

You can download the full peer-reviewed research paper, which was published on July 8, 2025, in the prestigious Journal of Soil Science and Plant Nutrition, here. I had never before heard of such significant yield and benefit-to-cost ratio increases in a long-term field study! (I am a bit of a junky when it comes to reading biochar research reports.)

This made me realize that plant hormones could be important, and I should learn more about them. My only knowledge of salicylic acid was that it is the active ingredient in skin creams for treating eczema and that it is somehow related to aspirin.

It turns out that plant hormones, of which six are known, control virtually everything that plants do. Salicylic acid is unique in that it is the only plant hormone that triggers a plant’s defense responses to various stressors, including drought, heat, soil pollutants such as salt and heavy metals, as well as pests. The resilience responses can often be substantial, immediate, and long-lasting.

Biochar and salicylic acid (SA) can be applied to crops to create a cost-effective way to rapidly scale biochar production in drought-prone areas, which now cover about 40% of the globe. SA can be applied as a very dilute (about 1 part in 10,000 parts water) foliar spray, or in significantly diluted irrigation water, or as a seed coating for priming. It’s widely available globally as a powder and is inexpensive to buy, ship, and apply. When diluted to the appropriate amount, it is almost free.

Unlike biochar, which can take two or more years to show increases in yields, SA works in the first season and can even be applied to counter immediate threats. SA works synergistically with biochar — by strengthening the plant from the inside, while charged biochar improves the soil, including its water-holding capacity, texture, and nutrient availability. Synergy means 1 + 1 = 3 in terms of yields and other plant health metrics. That’s all music to a farmer’s ears, whether in America, Europe, Asia, Africa, or elsewhere.

These claims are backed up by “about 605” research reports available on Google Scholar, using the keywords “biochar”, “salicylic acid”, and “increased yield” in their titles and/or texts.

Given that most of the world’s farmland is now suffering from poor soil, heatwaves, and/or prolonged drought, this approach should work rapidly and cost-effectively almost anywhere in the world.

The Many Ways SA Increases Farmers’ Incomes, Reduces Their Costs, and Improves the Environment

Because SA is a unique, low-cost plant hormone that acts inside the plant but can be applied externally, it works in ways that complement other crop improvement methods. Its fast results are also unique and very valuable.

Consider the following benefits:

• SA, by itself or in combination with biochar, significantly increases crop yields, as well as fruit, nut, and vegetable size, taste, nutrient content, and many other plant metrics.
• SA significantly reduces farmers’ costs for buying and applying chemical fertilizers and pesticides, and reduces their environmental damage.
• SA reduces the soil compaction associated with the application of chemical fertilizers and pesticides.
• SA reduces farmers’ needs for buying and pumping scarce irrigation water, along with the environmental degradation that it causes, e.g., further lowering already low nearby surface waters and aquifers.
• SA’s rapid response makes it ideal for countering sudden and immediate stressors, such as heatwaves, extended droughts, and pest attacks.
• SA improves the environment by reducing the need for chemical fertilizers, which produce runoff that leads to harmful algal blooms (HABs) that contaminate rivers, ponds, lakes, reservoirs (and thus also drinking water supplies), and the ocean.
• Since about 70% of surface water is used by agriculture, significantly more water will be left for urban dwellers, as well as commercial and industrial users.
• The cost of testing any of these claims in the field or in a greenhouse is low, since SA is inexpensive to buy, then to highly dilute, and to apply.

Facing the Facts of Climate Change

Biochar, a natural climate solution, has proven to be by far the most cost-effective and scalable way to remove atmospheric CO2, while simultaneously providing a multitude of co-benefits. But we need to dramatically accelerate the pace and scale of biochar adaptation if we are to avoid the worst consequences of climate change.

Fortunately, salicylic acid is the perfect partner for biochar. SA is the plant hormone that is uniquely capable of stimulating the plant’s own short and long-term resistance to abiotic and biotic stressors, e.g., drought, heat, soil pollutants like salt and heavy metals, as well as pests.

Biochar typically requires more than one season to yield results. SA shows results in the first season and can even be used to address sudden stressors, like a heat wave or insect attacks.

Biochar, by itself, can be too expensive for many farmers to justify. However, SA is very inexpensive to purchase and apply. Due to their synergistic partnership (1+1=3), they can be economically attractive together to farmers worldwide.

If you’d like to learn more, please download a free copy of my open-source paper below. Please feel free to contact me with any questions or if you would like to initiate trials. I will be offering further guidance and support in the near future. Stay tuned to my LinkedIn page.