This glossary is a work tool, and any constructive proposals for a better understanding of the terms will be welcomed. This glossary is not presented in alphabetical order: it is to read as is, prior to reading any document on liming. Underlined terms used in the definitions are defined in the glossary. In some cases, remarks are added to the definition to make a clarification for the reader. Finally, we found it necessary to quote a number of terms that should not be used because of the confusion that their use generates.
Notions on the ground
adj. : Refers to a chemical entity likely to give H + (proton) to another chemical entity which is then called a base. Also used for a solution or a soil whose effective acidity or salt replaceable acidity is considered high.
Note: This quality is subjective, use with caution.
Change resulting from the addition of acid or acid-producing reactions (or consuming bases).
This action or these changes may lead to more or less long term lowering of the pH.
Note: This concentration depends on what is referred to as “ground solution”. It depends on the exchange soil acidity but also the dilution ratio (or soil water content) and the composition of the solution. The measurement method of this magnitude must always be specified. (See pH).
Note: This amount depends on the neutral salt used.
Note: The titratable acidity depends on the pH (initial and final) of the provided base and the cation associated with the solution (suspension in water, KCl, …), the contact time …
Changes resulting from the provision of a base or reactions consuming protons.
Note: The main advantage of a basic amendment is to neutralize all or part of the acidity of a soil.
Note: In practice, the provision of a base neutralizes the H+ and thus reduces soil acidity.
Note: BEB VN is expressed in units (in kg CaO / ha). The part of acidity to neutralize can be estimated in many ways.
This quantity is estimated by a chemical or conventional physicochemical measure performed on a soil sample.
Note: Conditions (pH, type and concentration of cations and anions, …) greatly affect the result; it is necessary to indicate the method used. See Adsorption, effective CEC, CEC “Metson” exchangeable cations, cmol + kg-1 soil, permanent load, variable load, load pH dependent.
Note: The three main methods use chlorides hexaammine cobalt or “Cohex”, barium and potassium salts.
Note: This method is not usable for the calculation of the need for bases.
Note: See Electrical Neutrality, Adsorption. The analysis method affects the results: in the presence of CaCO3 method “Metson” overestimates the content of exchangeable calcium.
Note: In general, the CEC Metson overestimates the effective CEC for acid soils and underestimates for basic soils. See Load pH dependent.
See variable or proton load.
In dilute solution, pH = log10 [H+] (or [H+] = 10 pH) with [H+] expressed in mol/l
Note: The values of pHwater and pH 0.01M CaCl2 are different, and both are different from that of the soil solution.
Note: cations and S are in cmol+ .kg-1 or cmol+ / kg.
(2) a subsequent loss of sorbed by the sorbent is called desorption;
(3) in common language, absorption is in use in the most general sense to enter or leave a liquid or a gas in its own substance.
This term is quantitatively equivalent to the kilogram. However, we prefer to use the units for the nutrients and kilograms for products made.
Example: a contribution of 100 kg of KCl grading 60 K2O corresponds to a contribution of 60 units of K2O.
Note: Do not use this term.
Note: The neutralizing value is a conventional chemical measurement that expresses the potential ability of a basic amendment to neutralize the acidity of soil. The expression of this potential depends on environmental conditions, and in certain cases, of the finesse and hardness of amendment particles.
Symbols and Abbreviations
example: 1 + cmol is the load carried by 1/2 cmol Ca2+ or K+ 1 cmol.
Note: the result is numerically equal to the old term in milliequivalents per 100 grams of soil (mis / 100g or meq / 100g).
Terms to avoid