Biochar Trials Show 23% and 52% Yield Gains in Yardlong Beans and Tomatoes in Java

Recent field trials in Java, Indonesia, have provided clear evidence of how biochar can improve crop yields, soil health, and resilience. The program is a collaboration between WasteX, Yayasan Bina Tani Sejahtera, and Adakarbon, supported by the P4G Partnerships initiative.

Yardlong Bean Yields Rise 23% in Batang

In Batang, Central Java, farmer Kodri tested biochar on his yardlong bean plots. Both plots received fertilizer, but the biochar plot used 20% less, and it is used to charge biochar instead of applying it directly to the soil.

The results were striking:

• Control: 17.4 tons of yardlong bean per hectare.

• Biochar-treated: 21.4 tons of yardlong beans per hectare.

• Outcome: 23% higher yield with reduced fertilizer

Farmers also noted darker, crumbly soil in the biochar plot—an indicator of better water retention, aeration, and microbial health.

Demonstration plots of yardlong beans, with biochar vs no biochar

Tomato Harvests Improve 52% in Pasuruan

In another trial in Pasuruan, East Java, WasteX worked with farmer Suyono to test biochar’s effects on tomato crops.

The biochar trial used the same approach: 20% less fertilizer and pre-charged biochar.

The results surpassed expectations:

• Control: produced 1.82 tons

• Biochar-treated: produced 2.27 tons

• Outcome: 52% higher yield with reduced fertilizer use

Shared Benefits Across Trials

Beyond higher yields, farmers in both Batang and Pasuruan reported additional advantages from using biochar:

• Resilience to weather stress: Crops with biochar were better able to withstand heavy rainfall and heatwaves.

• Improved soil structure: Biochar-treated soils appeared darker and more crumbly, signaling healthier soil conditions.

• Better water retention and aeration: Enhanced soil properties contributed to stronger root development.

• Increased microbial activity: More active soil life supported overall plant growth and resilience.

  
  

These improvements highlight biochar’s role not only in boosting productivity but also in making farming systems more climate-resilient. This is a critical point as farmers face more unpredictable growing seasons due to climate change.

Implications for Farmers and Climate

The trials provide early evidence that biochar can simultaneously cut fertilizer dependence, lower input costs, and strengthen food security. For Indonesian farmers facing rising fertilizer prices and increasingly unpredictable weather, biochar offers a practical path forward—improving yields while protecting long-term soil health.

With positive results in yardlong beans and tomatoes, additional trials are planned across Java for other crops. WasteX and its partners aim to create a replicable model that supports sustainable farming, reduces chemical reliance, and strengthens rural livelihoods.