Archive for the ‘biochar sources’ Category

Is there enough rice husk to make biochar?

November 17, 2010

As a follow on from the previous post, as mentioned many mills have piles of rice husk left from their activities, which is not being used at present.

Discussions with Dr Tan Boun Suy from the Apsara Authority, led us to consider the following question – if biochar is to be promoted as a useful soil amendment (for example at 20t/ha application for rice fields), is there enough?

Assumptions (for a very rough back of envelope calculation!)
– 2 harvests per year of rice at 1t/ha paddy produced per harvest
– 20% of paddy is husk
– 1/3 conversion rate of husk to biochar

2t/ha paddy produced, 0.4 t/ha husk, 0.13t/ha biochar per year.
Therefore in 150 years, enough biochar would be produced for a 20t/ha application rate.

Of course if biochar can increase harvest, then this would lead to more biochar availability!!


Is there any ‘waste biomass’ in a rice system?

November 17, 2010

Harvesting rice 14.11.2010 (Picture by Vichida Tan)

Last week, we had a practice run harvesting rice in trial plot formation. It is essential to ensure that each plot harvested is the same size (for example the same border is left to account for the border effect in each plot), and that the area harvest matches exactly with the area where the biochar was applied (not so easy when the plots are in 1.5 feet of water! The harvested straw with rice was then weighed, then the rice thrashed (in this case using the traditional method involving stamping on the harvested straw), and the paddy (rice with husk) weighed. After this the paddy is dried, and then milled to remove the husk. Other processes such as polishing the rice, or colour sorting can be done in more high technology mills.

So what happens to the ‘waste biomass’ (and is there even such a thing as waste biomass in this system)?

– Straw – used as feed for cattle (which are used for ploughing the field),
– Husk – used to make rice wine (then the then the char put in the field),
– crop stubble – Left in the field and ploughed in (soil amendment)

Rice straw is used as cattle feed. 14.11.2010

In this case there is no biomass which is either left to rot, or burned for no purpose. However where rice is taken to other mills, the husk is often left in large piles, and where this is not all used for gasification, we can call it ‘waste’.

Biochar collection 10.05.2010

May 13, 2010

Biochar was distributed for rice trials. It was delivered to two farmers in Pouk District, one in Chireav, Harmony Farm in Beng Melia, and the Nagathom base near Kralanh, to be distributed to their outgrowers later.

Rice husk biochar was picked up as before from Kralanh, at a gasification unit which produced gas to power EAP SOPHAT ice factory.

Biochar bagging 10.05.2010, EAP SOPHAT, Kralanh.

A brick making factory was also visited to pick up some rice husk ash. This was different in texture and colour from the biochar, even though the feedstock is the same due to being fully combusted in the kilns. See the biochar production pages for more info on SME’s production and the brick factory.

Picking up burned rice husk at the brick factory, Kralanh. 10.05.2010.

Gasification unit

February 13, 2010

A SME gasification unit at EAP Sophat ice factory, in Kralanh District Town.