Its generally seen that addition of biochar generally increases the pH of the acidic soil. So does it also increases the pH of the alkaline soil?
Yes, I got very positive effects for soybeans in Alkaline soils with low temperature biochar
Impact of biochar on alkaline soil pH depends on initial pH of biochar and pH buffer of soil. In that case, biochar could maintain, increase or decrease alkaline soil pH.
Dear Ondo, you are right. Moreover, biochar provides considerable amount of intrinsic nutrients which might be limited in the alkaline soils. In some cases, biochar increase nutrients holding capacity by increasing CEC, although it takes time to develop. Nevertheless, low temperature biochar contain a good proportion of labile carbon that increases CEC
In general biochar is alkaline in nature and thus it may not work in highly sodic soils of the NW parts of the IGP, India.
Dear Colleagues Take a look at MacDonald et al. 2014. Plant growth response to biochar addition. Biol. & Fert. Soils 50(7)
As you have commented many biochars are quite alkaline and work best for acid soil infertility issues the Australian works supports that.
The alkalinity of the biochars in alkaline sodic environments may be concerning. In relation to that concern the adjusting of biochar temperature in pyrolysis can eliminate the generation of extreme alkaline generation.
If the char temperature is less than 450 centigrade the resulting char will be neutral rather than extremely alkaline.
In leached ferrasols the biochar in an alkaline state is optimally effective for its liming ability. In Alkaline and sodic environments biochar can be useful especially if generation conditions give a neutral but not alkaline product. The excess alkalinity will contribute to increased severity of micronutrient deficiency the Carbon however should have some capacity to help in relation to moderate to slight sodicity based on adsorption of Sodium on the Carbon matrix reducing its activity in solution.
Some thoughts.
Response of biochar in alkaline soils of varying texture ( Loam alluvial versus black clay ) will be of differential order . As Dr Hepperly very rightly said about the quality of biochar is largely dependent on the charring temperature . The impact of biochar will surely be reduced on alkaline soils , especially on fine textured soils.
In some case, due to carboncious material. But we do not find any negative effect concerns with plant.
most of biochar produced in high temp above 400 will be high pH
we have done some work on biochar produced under different temp and found interesting results>
https://www.researchgate.net/publication/235396461_Pyrolysis_temperature_induced_changes_in_characteristics_and_chemical_composition_of_biochar_produced_from_conocarpus_wastes
Article Pyrolysis temperature induced changes in characteristics and...
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