Research findings from Indonesia including biochar in rice growing

Dynamics of N-NH4 +, N-NO3 -, and total soil nitrogen in paddy field with azolla and biochar - IOPscience

I'm not really sure what to make of this... I could not find any description of the biochar or how it was prepared for the research.  I suggest that most biochar proponents would high-light issues around using raw biochars in short term trials. I'm not sure if this was the case here.