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2288242 
Journal Article 
Computation and prediction of the buffering capacity of organic amendments and fertilisers 
Masso, C; Khiari, L 
2013 
1 
Canadian journal of soil science
ISSN: 0008-4271
EISSN: 1918-1841 
93 
5 
595-606 
French 
WOS:000327675100005 
is also published as 5255599 Expression et prédiction du pouvoir tampon des amendements et des engrais organiques
The buffering capacity (BC) of organic substrates used in agriculture as soil amendments or organic fertilizers are of high interest to prevent adverse effects of mineral fertilizers in the application band near seeds or juvenile seedlings. This is the effect of ammonia, nitrous or aluminum toxicity caused by the sudden and temporary pH flux due to the application of these fertilizers. However, to our knowledge there is no standard method for computing of the BC of organic substrates. In this study, a method by integral calculation, called BCI, was developed and tested on 30 organic amendments and fertilizers (OAF) commonly used in agriculture in Quebec. These OAF were titrated with variable rates of diluted H2SO4 or NaOH. A linear and a punctual methods found in the literature were compared to BCI. The integral method was found more appropriate to OAF titration curves, particularly for determining the global BC, integrating the curves obtained during both the acid and alkaline treatments, which was not possible with the other two methods found in the literature. On average, the potential alkalinity of the 30 OAF was higher than the total exchangeable acidity. The globol BCI could be predicted with total Ca, exchangeable Ca, and total Al (r(2) = 0.79). Likewise, the BCI to acidity could be predicted using total Ca, exchangeable Ca, and pH(CaCl2) (r(2) =0.78). 
Acidity; alkalinity; buffering capacity; Organic amendments and fertilizers