Thursday, 25 December 2014

Report: Biochar on acidic agricultural lands in Indonesia and Malaysia

I've been aware of a collaborative biochar research program that has been running over a number of years, led by Gerard Cornelissen from the Norwegian Geotechnical Institute with participation from researchers in Malaysia and Indonesia. I have now discovered that this work has been extensively documented here and the final report from the Malaysia / Indonesia component of this research was released earlier this year...

"Biochar is the charcoal product obtained when biomass (preferably organic waste, not wood) is heated without access to oxygen (pyrolysis). Most of the biochar matrix is likely stable when mixed into soils, and thus represents carbon that is actively removed from the short-lived carbon cycle and thus contributes to climate change mitigation. Biochar combines a number of important “wins” such as: i) climate change mitigation: carbon sequestration and reduction of other GHG emissions (mainly N 2 O), ii) soil fertility improvement, iii) pollutant immobilization, iv) waste management and v) energy production. In this project we investigated two of these “wins” in an Indonesian /Malaysian context: soil fertility improvement and biochar technology /energy production. In addition, physical and chemical properties of biochar were evaluated.

General findings: Co-synthesis of toxic polycyclic aromatic hydrocarbons (PAH) during biochar production has oft en been reported as a potential impediment to biochar implementation. We found however, that for 60 biochars, PAH contents were low and so strongly bound that they were almost unavailable for uptake in plants and soil organisms. We also investigated potential undesired co-effects of biochar on soil biota in a biochar-soil system, and found that these were modest. In addition, earthworms preferred biochar over other soil amendments (activated carbon and an iron-based metal sorbent) in avoidance tests. 

Soil fertility improvement: In pot trials in Kalimantan, (Indonesia) hardly any biochar eff ect on rice and maize growth was found for acid sulphate and peat soils. In contrast, positive biochar eff ects were seen for clay soil in West-Timor and oxisol in Sulawesi (both Indonesia). 

Biochar technology: An upscale Belonio top-lit updraft gasifier was developed and used to prepare biochar for field trial applications in Malaysia. In Sulawesi clean cooking stoves run on biochar generated by improved retort kilns were implemented.

Life-cycle and cost-benefit analysis: these analyses were centered around our case study in the village of Ngata Toro in Sulawesi. The most important finding of both these analyses was that soil amendment for improved soil fertility is a better way to use biochar than burning it as briquettes for cooking purposes. The main reasons are that i) polluting gases generated during biochar production are not off set by carbon sequestration in the briquetting alternative, and ii) briquetting is much more labor-intensive than applying biochar to agricultural soil. 

This research project has paved the way for large-scale implementation of biochar in Indonesia. The biochar will be prepared using environmentally-friendly retort kilns, and mainly applied to degraded lands where yield increases can be expected.

In addition, this project has led to several spinoff projects in other countries: Nepal (biochar from an ubiquitous weed, spontaneous farmer adoption), Zambia (maize biochar in conservation farming), Tanzania (rice husk biochar used as soil amendment, made in retort kilns where energy is used for bread baking by housewife groups) and Uganda (village electrifi cation by gasification with biochar as by-product)."

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