Abstract
The carbonate content in the agricultural soils is very important, and sometimes causes a critical problems regarding to the plant nutrition. CO2 the information about the soil carbonate content should note. The Calcimeter method is a simple and convenient method to give reliable estimates of carbonate in different soil types and horizons as well. Calcimeter apparatus was used to determine the dissolution kinetics of calcium carbonate (CaCO3) in three different Hungarian soil types (originated from Iregszemcse, Szeged-Othale and Ozsak-Puszta) using non-selective acid reagent HCl of 10%. Three processes of carbonate dissolution were investigated under laboratory conditions, and the processes were examined by a non-linear regression computer programme, given the followings: very fast reaction (Q a constant parameter), faster (k1, A1) and a slower (k2, A2) order of kinetic reactions. The soil samples divided into four soil sub-samples according to the texture (sand I, sand II, silt, and clay). Based on the technique used and depending on the volume of carbon dioxide and time require for dissolution, the following information can pointed out: • The results documented that the method described is simple and can reasonably estimate the carbonate content of soil sub-samples, and does not require special equipment. This technique can be readily adapted to routine soil analysis without the need for long preparation of additional chemicals. • The amounts of carbonate present in the soil sub-samples by this intercept method was higher in sand soil sub-sample than in clay one. • The smallest value of the constant rate of the faster reaction (k1) was found in the sub-sample of Iregszemcse (Clay {k1 = 0.4711}), while the highest value was in the sub-sample Ozsak-Puszta (Sand I {k1 = 1.67677}). Meanwhile, the value of constant rate of slower reaction (k2) was at maximum with the sub-sample Ozsak-Puszta (Sand I {k2 =0.314106}), and the minimum (k2) value was found in the sub-sample Szeged-Othale (Sand I {k2 = 0.0}). • It was found that the highest percentage of CaCO3 in faster reaction (A1) was found in the Sand I {A1 = 19.2715} soil sub-sample at Iregszemcse region. While the lowest percentage (A1) was obtained in Silt {A1 = 1.6075} at the same region. Moreover, in the slower reaction, the lowest value of the maximum CaCO3 (A2) was calculated in Clay {A2 = 0.0} soil sub-sample at Szeged-Othale region, and the highest value was obtained in the Sand I {A2 = 5.1768} soil sub-sample at Ozsak-Puszta region. On the based of results, it is easy to make a schematic research work points for the future as the following: (1) CaCO3 deposition model for modelling the processes and easily parameterized for sites and useful for long-term simulations. (2) Validate to model with field observations. (3) Consider the roles of state factors in controlling CaCO3, and (4) Role of some environmental factors (biotic and abiotic) affecting the carbonate dissolution in soils.