Archive for the ‘general methodologies’ Category

Quantifying biochar impact on soil

December 3, 2010

Discussions with IRRI gave some simple assumptions which can be used when assessing the impact of biochar addition on the soil.

If biochar analysis is available, then the impact of a known volume of biochar to soil can be calculated. For example, if one square metre of soil is amended with 4 kg of biochar (this is a 40 t/ha application rate), then we can assume that this represents 4% of the soil weight. This is because in 1 m at a 10 cm depth there is 100 litres of soil with an approximate bulk density of 1, which is 100 kg of soil. The properties of the biochar can then be assumed to be diluted in the soil at a 4% rate.

This assumption was then applied to the CEC (Cation Exchange Capacity) where rice husk biochar is added to the research farm soil in Siem Reap, Cambodia.
The soil has a CEC of 18.44 cmol+/kg
Biochar has a CEC of 44.5 cmol+/kg.

Therefore the CEC of the soil can be assumed to be raised to (18.44*0.96)+(44.51*0.04) = 19.48

This is a rough assumption, and should not substitute using actual data, and it assumes that there are no interactions between the soil and the biochar which could influence the CEC of the soil.


End of project meeting, Cambodia

December 2, 2010

Although this won’t be the end of blog posts yet, we held the end of project meeting in Siem Reap 26-27.11.2010.

The aim of this meeting was to put together the end of project document, to discuss findings, and identify further areas for research. The partners from all participating countries attended: ARTI (India), IRRI (Philippines) and University of Edinburgh (representing Cambodia).

The meeting was productive, and some interesting discussions occurred, and a focused assessment of future research requirements was discussed. Particular issues where more work is required include:
– Methane emission measurements from alternative feedstock use (including degradation in the rice husk heap)
– Long term measurements on managed biochar field trial plots
– Introduction of high value cash crops (including soy beans and peanuts) into biochar trials
– Investigation into the economics of feedstock prices – for example the potential for a more developed market in rice husk following successful deployment of gasification units
– More work on the potential of biochar production from rice straw (there is relatively more work on rice husk biochar).

We are actively seeking funding to ensure that biochar research is comprehensive in that covers all potentially useful functions of biochar, and also is able to answer some of the unknowns in order to reduce risk of biochar application and production.

Change to India biochar pot trials

August 27, 2010

The egg plants which were transplanted into the biochar amended pot treatments were removed since almost ¼ did not survive (disease). Instead cabbage will be used for the pot trials, which will also make monitoring the results easier. The harvest will be biomass, and only one value will need to be recorded, which will be on the same day when all the plants are uprooted. With crops like egg plant which have multiple harvest, a more intensive monitoring and recording method is required, and there becomes a level of uncertainty with the research interference as to at which time the fruit / vegetables are ready to be harvested. A total of 75 days should be required for this study.

Crop yield data collection… Lettuce

June 17, 2010

After the lettuce were harvested from the pot trials at the research farm, they were taken to be measured at the office. Plant length, number of leaves, total biomass and root biomass were measured.

Weighing lettuce from Tuk Vil, 17.06.2010.

Practicalities of biochar application…

June 8, 2010

….. onto a flooded field.

Today we added biochar to a flooded paddy in Krabeil Reil, Pouk District. This farm could have been drained, but this was not part of his usual land preparation routine since it is easier to plough when the land is wet. So we went ahead and added biochar on the field which was submerged in about 20cm of water.

08.06.2010 Adding biochar to a field in Phum Popis village, Krabeli Reil commune, Pouk district, Siem Reap province. Picture by Vichida Tan.

Plots were marked out, and the bags put into the plots where they needed to be spread, however the bags quickly soaked up the water in the field and became heavier so were more difficult to spread than on a dry field. After the bags had been emptied, and during this process roughly spread across the plots, it was also more difficult to see how evenly the biochar had been spread.

The flooded paddy meant that incorporation by hand would have been more difficult, but the land will still be ploughed again which will incorporate the biochar sufficiently, then the farmer expects to plant in about one week. The layout of this plot is as in the nearby trial in Krabeil Reil.

There was no sign of the biochar moving from the plots, since most of it sank quickly after application. Some appeared to float for a while before sinking, but since the water was not moving, it was not thought that the biochar was moving away from the plot.

More information on biochar addition and incorporation.

Mid-term progress workshop 24.05.2010

May 30, 2010

The mid-term progress workshop was held for the team working on the Asia-Pacific Network for Global Change Research project ‘biocharm’.

This began with a visit to field trials in Phaltan, Satara District, Maharastra State, managed by ARTI. The maize is growing well, and at present it is possible to see an increase in germination rate with the maze grown in the biochar treatments.

Biocharm 2009

February 10, 2010

The initial visit to Cambodia in November and December 2009 was a great success.

This was a scoping visit to investigate potential crop trial locations. Some great contacts were made, and the first deployment of biochar was made on the 19th December. Lessons were learned about the logistics of moving truck loads of biochar around Cambodia, and methods of application to different soils were tested.

Biochar was added to 5 field sites, which comprised of a total of 17 plots (including controls).

Things were also set in motion for the next stage to begin in January 2010.