DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 5-6/2023 str. 33 <-- 33 --> PDF |
During the air sampling, soil temperature was measured by soil thermometer at the depth of 5 cm. Soil moisture content was determined by gravimetric method. The soil samples were taken and put into aluminium tins. Afterwards, the samples were dried to constant weight in the oven at the temperature between 103-105 oC. The relationship between CO2 emission, soil temperature and soil water content was analysed through Pearson’s correlation test, simple and multiple linear regressions. Statistical analysis of the obtained data was carried out by Statistica 12 program package and R statistical software. Microsoft Exel 2016, “ggplot2” (Version 3.3.2), (Wickham, 2016) and “scatterplot3d” (Version 0.3-41), (Ligges and Mächler, 2003) packages in the R environment were used for the graphic design. RESULTS REZULTATI Soil temperature at the depth of 5 cm and soil water content are given in Figure 3. The values of soil temperature and soil water content were changing distinctly during the research period. The highest soil temperature values were recorded on the 14th of July (34 oC) and 4th of August (33 oC), (Figure 3). The lowest soil temperature was measured at the beginning of the research period. The soil water content ranged from 4.81% to 30.32%. The decrease of soil water content was followed by an increase of soil temperature. Sharp decline of soil moisture was recorded when the highest values of soil temperature were measured (Figure 3). The inverse correlation was found between soil temperature and soil moisture (r = -0.533, p < 0.05), where after a rainfall, soil water content was considerably increased and affected the reduction of soil temperature. Soil respiration at Plot 1, Plot 2 and Plot 3 ranged from 4.28-10.86 g CO2 m-2 day-1, 5.22-17.96 g CO2 m-2 day-1 and 3.60-15.29 g CO2 m-2 day-1, respectively (Figure 4). At the beginning of study period, the emission of CO2 within the second plot (Plot 2) was slightly higher than CO2 emission within the third plot (Plot 3), while CO2 flux within the control plot (Plot 1) was the lowest. At the end of June, the greatest value of flux was recorded on Plot 3 and was higher for 40% compared to other two plots. The values of soil respiration were similar on 2nd of July at all three plots. In the middle of July, soil respiration from Plot 3 was greater compared to the other research plots, while the highest value of flux was recorded in the last decade of July within the second plot. The study showed that the greatest difference in the CO2 emission between plots was recorded on 4th of August when the value flux on the third plot was over 50% higher than on Plot 1 and Plot 2. At the end of the study period, the values of CO2 flux were very similar within all experimental plots. During sampling period, the greatest value of CO2 emission was measured at Plot 2, while the values of CO2 flux were very similar in the middle of July and in the first decade of August within the third location. The emissions of CO2 within the control plot were |