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VRANOVA, V., HOLIK, L., POSCHL, M., REJSEK, K., FORMANEK, P.: Selected amino acids uptake by microorganisms in soil of diff erently managed mountain meadows. Acta univ. agric. et silvic. Mendel. Brun., 2011, LIX, No. 1, pp. 263–268 This work was aimed at determination of the eff ect of 13 years abandonment of previously long-term mown mountain meadows on uptake of L-glutamic acid (CO2H[ CH2]2[NH2] CO2H) and L-alanine (CH3 CH[NH2] CO2H) by microbial community of Ap horizon (3–13 cm). The study plots has been located near to the experimental stand “Bilý Křiž“ which is located in the Moravian-Silesian Beskids Mountains (N 49°30’17”, E 18°32’28”), on a slope with an elevation of 825–860 m a. s. l. and southeast orientation, and soil classifi ed as an Oxyaquic Hapludalf. The study was performed to test method for measurement of 14C-labelled amino acids uptake by soil microbial community and to increase knowledge on particular processes of N-transformation in soil of these ecosystems. The results obtained in this work showed that 13 years abandonment of mountain meadow did not signifi cantly (P > 0.05) infl uence rate of glutamic acid or alanine uptake by soil microbial community. Further research including determination of amino acids use by soil microbial biomass with expression of their partitioning between production of new microbial biomass and energy metabolism is necessary. soil, amino acids, uptake, glutamic acid, alanine, meadow, management Socio-economic changes in the Czech Republic towards the end of the last century have lead to considerable changes in environmental conservation management of nonforest ecosystems. The local population has moved away from mountainous regions where traditional farming and mowing of meadows was practised. Abandonment of meadows has initiated secondary succession with re-colonizing shrubs and tree species (Formanek et al., 2008a). Plant biomass in abandoned or uncut meadows is steadily increasing. Changes in belowand aboveground plant biomass due to abandonment bring about diff erent physical-, chemicaland biologicalsoil properties, for example, soil moisture, amount of O2, temperature and amount of nutrients (Huhta, 2001; Vranova et al., 2007; Formanek et al., 2008 a, b; Vranova et al., 2009 a,b). Some studies have shown that reducing or abandoning management e.g. enhance soil erosion (Paldele, 1994; Korner, 1999; Tasser et al., 1999, 2003; Coppus et al., 2003). Organic material on the soil surface increases while the pH decreases, resulting in a shi from mull to moder humus forms (Seeber and Seeber, 2005). The measured soil chemical variables were linked not only to the natural fertility of the site, but also to long-term management inputs. These relationships between species richness, soil and management were found by Schellberg et al. (1999), and Myklestad (2004). The abandonment of meadows slows down nutrient cycling. In our previous works, we have evaluated the eff ects of thirteen years abandonment of previously traditionally mown mountain meadows on total carbon and nitrogen content in soil and its stand heterogeneity, activity of selected enzymes, nitrogen mineralization, availability of amino acids in soil, cleavage of proteins or kinetics of heterotrophic 264 V. Vranova, L. Holik, M. Poschl, K. Rejsek, P. Formanek soil respiration (Formanek et al., 2006a,b; Vranova et al., 2007; Formanek et al., 2008a, b; Vranova et al., 2009a, b). In this study we aim to test a method for measurement of uptake of 14C-labelled amino acids by soil microorganisms and to determine the eff ect of thirteen years abandonment of previously long-term mown mountain meadows on kinetics of selected amino acids uptake by microbial community from Ap horizon of these ecosystems. As well as comparison of glutamic acid and alanine uptake on diff erently managed mountain meadows was performed as a new parameter to more understand the processes related to N-transformations in soil of these ecosystems. MATERIAL AND METHODS The experimental stand “Bilý Křiž“ is located in the Moravian-Silesian Beskids Mountains in the northeast part of the Czech Republic (N 49°30’17”, E 18°32’28”), on a slope with an elevation of 825– 860 m a. s. l. and southeast orientation. The local subcontinental climate is characterised by the mean annual air temperature of 4.9 °C, mean relative air humidity of 80 % and by mean annual precipitation of 1100 mm. Number of days with snow cover is 160 per year. The experimental meadow (1 ha) was originally mowed regularly once a year, the hay removed and stored as winter feed for livestock. This traditional management ceased 13 years ago on half of the meadow (abandoned meadow), whilst the remaining half has been permanently mown (once a year). Mown meadow plant community belongs to the Nardo-Callunetea class PREIZING (1949) (Zelena in Formanek et al., 2008a), mowing treatment in season 2006 was applied there on the 3rd of August. Abandoned meadow is characterised by higher representation of forbs and community belongs to the Molinio-Arrhenatheretea class TUXEN (1937) (Zelena in Formanek et al., 2008a). The soil is classifi ed as an Oxyaquic Hapludalf with the following sequence of horizons Oi-Oa-OeAp-BAt-Bt1-Bt2-Cg (USDA-NRCS, 2006). Mixed samples (1 sample = 5 sub-samples randomly taken within whole plot forming together 0.5 kg) were taken from both meadows in depth of 3–13 cm (Ap horizon) in August 2006. Sampling was performed using boring bar. A er transportation in cool box, the samples were sieved through 5 mm mesh size and stored at 6 oC untill analyses. Selected physical, physical-chemical and chemical properties of Ap horizon of both meadows were calculated from 3–8 repetitions on each of the meadows (expressed as Mean ±SD) are shown in Tab. I. Amino acids uptake was measured using modifi ed procedure described by Vinolas et al. (2001). For these purposes two amino acids, L-glutamic acid (CO2H[ CH2]2[NH2] CO2H) and L-alanine (CH3 CH[NH2] CO2H) were used. One hundredfi y microlitres of alanine solution (15.7–717 μM) or glutamic acid solution (9.2 to 588.3 μM) was briefl y mixed with 0.3 g wet soil in a 15-ml polypropylene tube. Within these ranges, the natural concentrations of “free“ L-glutamic acid and L-alanine in Ap horizon of the studied meadows was determined (Formanek et al., 2008a, b). To each sample tube, 1M NaOH (1 ml) was added to capture respired CO2 and the sample tubes were sealed with a gas-tight stopper and incubated at 14.5 oC for 3 hours. Subsequently, the soils were extracted with 0.5M K2SO4 to remove unutilized amino acid (10 min, 200 revolutions min−1) followed by centrifugation (3,550 rpm, 20 min) and counting the 14C label remaining in the supernatant solution. As preconditions for parametric testing (test normality and homogeneity of variance) were not fulfi lled to fi nd diff erences between meadow treatment (mown versus abandoned), statistical analysis was performed through the nonparametric KruskalWallis ANOVA and Dannet’s t-test. All statistical analyses were undertaken using the Statistica 9.0 program. RESULTS AND DISCUSSION Results obtained in this work showed that 13 years abandonment of the traditional management of mountain meadows did not signifi cantly (P > 0.05) I: Selected physical, physical-chemical and chemical properties of Ap horizon on moderately mown and abandoned meadow (Mean ± SD; n = 3–8). The diff erent letters mark signifi cant (P 0.05) higher in Ap horizon of abandoned meadow (Vranova et al., 2009b). Glutamic acid was found to be dominant in pool of “free“ amino acids in soil of both studied meadows and was signifi cantly higher on abandoned plot only when data from season nm ol g -1 d w h -1 9.2 36.7 73.5 147.1 294.1 588.3 0 10 20 30 40 50 60 70 80 90

Selected amino acids uptake by microorganisms in soil of differently managed mountain meadows