ISSN 1064-2293, Eurasian Soil Science, 2012, Vol. 45, No. 1, pp. 68–79. © Pleiades Publishing, Ltd., 2012. Original Russian Text © I.N. Kurganova, V.O. Lopes de Gerenyu, J.F. Gallardo Lancho, C.T. Oehm, 2012, published in Pochvovedenie, 2012, No. 1, pp. 82–94. 68 INTRODUCTION The mineralization of the organic matter(OM) in soils mostly is a microbiological process [5], and the characterization of the soil OM according to its avail- ability to soil microorganisms and the activity of car- bon’s participation in the transformations in the soil seems to be important [13, 15]. The active pool of soil OM, the turnover time of which comprises several days to several years [15, 38], not only sustains the micro- bial activity but also controls the short-term carbon cycle in the soil. Carbon dioxide and water are the final products of the microbial transformation of the soil OM; therefore, the biokinetic method, which is based on the analysis of the intensity of the carbon dioxide emission from soil under the incubation experiments of different lengths, became popular in the study of the processes of the OM mineralization [13, 14, 22, 26, 32, 40]. The rate of the organic matter mineralization in the soil depends on the combination of hydrothermal conditions with all other the factors being equal. A moisture deficit as well as its excess can make slow the processes of plant residues' destruction [28, 29, 43], and the intensity of the OM mineralization increases as a rule as the temperature increases but with different rates in different temperature intervals [8, 26–29]. The conditions that are commonly supposed to be the most favorable (optimal) for the functioning of the microbial cenoses in soil are the following: a tempera- ture of 22–25°С and a moisture content of 60–65% of the field water capacity (WHC) [1]. The rate of the СО 2 emission from soils under these conditions char- acterizes the potential rate of the OM mineralization (PR min ), which corresponds to its potential biological activity or to the rate of the basal respiration (V basal , the respiration of nonenriched soil). Since PR min is deter- mined under artificial laboratory conditions, this value can characterize most conventionally the real devel- opment of microorganisms in soils and the processes connected with their activity, while, at the same time, it allows correctly performing the comparative analysis of soils both in terms of the soil profile and in relation to the conditions of the soil formation [6]. This study was aimed at (1) the comparison of the potential rates of the OM mineralization in soils of Evaluation of the Rates of Soil Organic Matter Mineralization in Forest Ecosystems of Temperate Continental, Mediterranean, and Tropical Monsoon Climates I. N. Kurganova a , V. O. Lopes de Gerenyu a , J. F. Gallardo Lancho b , and C. T. Oehm c a Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Moscow oblast, 142290 Russia b Instituto de Recursos Naturales y Agrobiologia de Salamanca, Spanish C.S.I.C., IRNASa, C/Cordel de Merinas 40, Salamanca, 37080 Spain c University Tübingen, Institut für Geoéokologie, Sigwartstrasse 10, Tübingen, 72076 Germany Received October 20, 2010 Abstract—The processes of the organic matter (OM) mineralization in forest soils developed under temper- ate continental (Moscow oblast, Russia), Mediterranean (the central and western parts of Spain), and trop- ical monsoon (southern Vietnam) climates were studied under laboratory conditions. The potential and spe- cific rates of the OM mineralization (PR min and PR min /C org , respectively), the ecophysiological parameters of the microbial communities status (C mic , qCO 2 , and C mic /C org) , and the sensitivity of the rate of the OM min- eralization to the rise in temperature were evaluated by the temperature coefficients (Q 10 ) determined in the humus horizons (0–10 cm, without forest litter). The average values of PR min for the climatic zones decreased in the following order: Mediterranean (57.1 ± 10.6 mg C/kg per day) > temperate continental (23.8 ± 7.1 mg C/kg per day) > tropical monsoon (10.4 ± 1.6 mg C/kg per day). The lowest resistance of the soil OM to min- eralization as evaluated by the PR min /C org values was found in the Albeluvisol and Phaeozem of the temperate continental climate and in the Acrisol of the Mediterranean climate. The highest Q 10 coefficients were attrib- uted to the OM mineralization in the forest soils of the temperate continental climate. This allowed us to con- clude that the observed and expected climate changes with an increase in the mean annual air temperature should lead to the maximum intensification of the OM mineralization processes in the forest soils of northern regions. DOI: 10.1134/S1064229312010085 SOIL CHEMISTRY