Эмиссия СО₂, микробная биомасса и базальное дыхание чернозема при различном землепользовании

The relationship between the CO2 emission and microbiological properties was studied in Haplic Chernozem of steppe, forest, bare fallow of the reserve area and in Urbic Technosols of Kursk city. The CO2 emission from the soil surface (EMsurf) and two subsoil layers (at the depths of 10 and 20 cm: EM10, EM20) were monthly measured (May–October) together with simultaneous measurements of the soil temperature and water content. Overall, 360 soil samples were taken from the layers of 0–10, 10–20, and 20–30 cm for determining microbiological properties (microbial biomass carbon, Cmic basal respiration, BR). Soil chemical properties (the contents of organic C, total C, N, P, K, and Ca; and pH) were measured in samples taken in July. The EMsurf of steppe averaged 24 g СО2/(m2 day), which was 1.6, 1.5 and 6 times higher than that of forest, urban, and fallow soils, respectively. In the forest, EM10 and EM20 were two times higher than reference EMsurf they were similar in the fallow and urban soils; and they were 34% lower in the steppe soil. The CO2 emission from the soils of studied ecosystems during the growing season weakly depended on the soil temperature and moisture. The Cmic and BR (0–10 cm) of undisturbed ecosystems (steppe, forest) were higher by, on average, 3–5 and 2–4 times, respectively, that those of the disturbed (fallow, urban) ecosystems. The positive correlations between EMsurf and Cmic, BR (0–10 cm) were found (r = 0.56 and 0.74, respectively). The seasonal average EMsurf for different land uses was mainly (78%) controlled by their BR (linear regression). Therefore, the EMsurf from Chernozems of different land use during the growing season might be predicted on the basis of BR measurements (0–10 cm).В черноземе под степной растительностью, лесом (дубрава), в чистом пару (территория заповедника) и в урбаноземе города Курск (Курская область) изучали взаимосвязь эмиссии СО2 из почвы и ее микробиологических показателей. Измерения эмиссии СО2 с поверхности почвы (ЭМпов) и из двух нижележащих слоев почвы (глубина 10 и 20 см, ЭМ10, ЭМ20) проводили ежемесячно (май–октябрь), одновременно регистрировали температуру и влажность почвы. В отобранных образцах почвы слоев 0–10, 10–20, 20–30 см (всего 360) измеряли микробиологические показатели (углерод микробной биомассы (Смик), базальное дыхание). Химические свойства почвы (содержание Сорг общего С, N, Р, К, Са; рН) определяли в образцах, отобранных в июле. Показано, что ЭМпов степи составила в среднем 24 г СО2/(м2 сут), леса, города и пара – в 1.6, 1.5 и 6 раза меньше соответственно. ЭМ10 и ЭМ20 леса оказалась в среднем в 2 раза больше таковой с поверхности, пара и города – примерно одинаковой, а степи – на 34% меньше. Эмиссия СО2 из почвы изученных экосистем за наблюдаемый период слабо зависела от ее температуры и влажности. Смик и базальное дыхание почвы (0–10 см) ненарушенных экосистем (степи, леса) в среднем в 3–5 и 2–4 раза, соответственно, превышали таковые нарушенных (пара, города). Показана положительная корреляция ЭМпов изученных экосистем с Смик и базальным дыханием (0–10 см, r = 0.56 и 0.74 соответственно). ЭМпов чернозема разного землепользования за вегетационный период на 78% была обусловлена их базальным дыханием (линейная регрессия). Следовательно, ЭМпов чернозема разного землепользования за вегетационный период можно в определенной степени прогнозировать на основе экспериментальных данных о базальном дыхании его верхнего слоя (0–10 см)

Soil CO2 Emission, Microbial Biomass, and Basal Respiration of Chernozems under Different Land Uses

Abstract—: The relationships between the soil CO2 emission and microbial properties have been studied in Haplic Chernozem of steppe, forest (oak), bare fallow of the reserve area and in Urbic Technosols of Kursk city. The CO2 emission was monthly measured (May–October) from the soil surface (EMsurf) and two subsoil layers at the depths of 10 and 20 cm (EM10, EM20), and the soil temperature and water content were simultaneously recorded. Overall, 360 soil samples have been taken from the layers 0–10, 10–20, and 20–30 cm for determining the microbial properties (microbial biomass carbon, Cmic; basal respiration, BR). Soil chemical properties (the organic C content, total C, N, P, K, and Ca; and pH) have been measured in the samples taken in July. The EMsurf of steppe averaged 24 g СО2/(m2 day), which was 1.6, 1.5 and 6 times higher than that of forest, urban, and fallow soils, respectively. In the forest, EM10 and EM20 were two times higher than reference EMsurf; they were similar in the fallow and urban soils; and they were by 34% lower in the steppe soil. The soil CO2 emission of studied ecosystems depended weakly on soil temperature and water content during the growing season. The Cmic and BR (0–10 cm) of undisturbed ecosystems (steppe, forest) were higher by, on average, 3–5 and 2–4 times, respectively, than those of disturbed (fallow, urban) ecosystems. The positive correlations between EMsurf and Cmic, BR (0–10 cm) were found (r = 0.56 and 0.74, respectively). The seasonal average EMsurf for different land uses was controlled mainly (78%) by soil BR (linear regression). Therefore, the EMsurf from Chernozems of different land uses during the growing season might be predicted on the basis of BR measurements (0–10 cm). © 2019, Pleiades Publishing, Ltd

Fungi-to-bacteria ratio in soils of European Russia

The selective inhibition technique by specific antibiotics (streptomycin, cycloheximide) applied to substrate-induced respiration (SIR) measurement was used to test the relative contribution of fungi to bacteria (F/B ratio) to the overall microflora-induced activity in soils of European Russia. Investigated soils covered a wide climatic transect and different ecosystem types including managed vs. natural ecosystems. Before direct comparison among sites, the antibiotic inhibition technique was optimized for soil characteristics. Once the optimal concentration was set, the combined effect of the two antibiotics resulted in average 60% inhibition of SIR. The analyzed sites (in total 47) including various biomes (tundra, middle taiga, southern taiga, subtaiga, dark coniferous forests outside the boreal region, steppe, mountain forests and arable sites), were characterized by a wide range of soil pHw (3.95–7.95), soil organic carbon (0.69–24.08%), soil microbial biomass carbon (149–5028 µg C g−1 soil) and soil basal respiration (0.24–8.28 µg CO2-C g−1 soil h−1). In all the analyzed sites, a predominance of fungal over bacteria activity was observed with F/B ratios always higher than one (4.9 on average). Natural sites were characterized by higher F/B ratios (on average 5.6) compared to agricultural ones (on average 3.5)

Biomass and respiration activity of soil microorganisms in anthropogenically transformed ecosystems (Moscow region)

In the forest, meadow, arable, and urban ecosystems (recreational, residential, and industrial zones) of Sergiev Posad, Shatura, Serpukhov, and Serebryanye Prudy districts of Moscow region, spatially separated sites (3-5 points per site) have been randomly selected and soil samples have been taken from the 0-10 (plant litter excluded) and 10- to 150-cm layers (a total of 201 samples have been taken). In the samples, the microbial biomass carbon (Cmic), the rate of the basal (microbial) respiration (BR), and the physical parameters (the particle size distribution (PSD), organic carbon (Corg), pH, heavy metals, and nutrients (NPK)) have been determined. High spatial variability has been revealed for Cmic and BR in all the ecosystems and the functional zones of the studied districts, and a clear tendency of a decrease in these parameters has been shown in the arable soils (by 1.4-3.2 times) and the industrial zone (by 1.7-3.3 times) compared to the natural analogues and other corresponding functional zones. It has been shown that the spatial distribution of the microbiological parameters is significantly (p ≤ 0.05) affected by the physicochemical properties of the soil (Cmic by the PSD and PSD × Corg; BR by the pH and pH × NPK; contributions of 40 and 63%, respectively), as well as by the type of ecosystem and the region of study (the contribution of the sum of these factors to the Cmic and BR was 56 and 67%, respectively). A tendency toward the deterioration of the functioning of the microbial community under the anthropogenic transformation of the soil has been shown. The contribution of the urban soils as a potential source of CO2 emission to the atmosphere has been calculated and discussed. © 2014 Pleiades Publishing, Ltd

Biomass and respiration activity of soil microorganisms in anthropogenically transformed ecosystems (Moscow region)

In the forest, meadow, arable, and urban ecosystems (recreational, residential, and industrial zones) of Sergiev Posad, Shatura, Serpukhov, and Serebryanye Prudy districts of Moscow region, spatially separated sites (3-5 points per site) have been randomly selected and soil samples have been taken from the 0-10 (plant litter excluded) and 10- to 150-cm layers (a total of 201 samples have been taken). In the samples, the microbial biomass carbon (Cmic), the rate of the basal (microbial) respiration (BR), and the physical parameters (the particle size distribution (PSD), organic carbon (Corg), pH, heavy metals, and nutrients (NPK)) have been determined. High spatial variability has been revealed for Cmic and BR in all the ecosystems and the functional zones of the studied districts, and a clear tendency of a decrease in these parameters has been shown in the arable soils (by 1.4-3.2 times) and the industrial zone (by 1.7-3.3 times) compared to the natural analogues and other corresponding functional zones. It has been shown that the spatial distribution of the microbiological parameters is significantly (p ≤ 0.05) affected by the physicochemical properties of the soil (Cmic by the PSD and PSD × Corg; BR by the pH and pH × NPK; contributions of 40 and 63%, respectively), as well as by the type of ecosystem and the region of study (the contribution of the sum of these factors to the Cmic and BR was 56 and 67%, respectively). A tendency toward the deterioration of the functioning of the microbial community under the anthropogenic transformation of the soil has been shown. The contribution of the urban soils as a potential source of CO2 emission to the atmosphere has been calculated and discussed. © 2014 Pleiades Publishing, Ltd

Changes in physical properties and carbon stocks of gray forest soils in the southern part of Moscow region during postagrogenic evolution

Changes in carbon stocks and physical properties of gray forest soils during their postagrogenic evolution have been studied in the succession chronosequence comprising an arable, lands abandoned 6, 15, and 30 years ago; and a secondary deciduous forest (Experimental Field Station of the Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Moscow region). It is found that carbon stocks in the upper 60-cm soil layer gain with increasing period of abandonment, from 6.17 kg C/m2 on the arable land to 8.81 kg C/m2 in the forest soil, which represents the final stage of postagrogenic succession. The most intensive carbon accumulation occurs in the upper layer of the former plow (0- to 10-cm) horizon. It is shown that the self-restoration of gray forest soils is accompanied by a reliable decrease of bulk density in the upper 10-cm layer from 1.31 ± 0.01 g/cm3 on the arable to 0.97 ± 0.02 g/cm3 in the forest. In the former plow horizon of the arable–abandoned land–forest succession series, the portion of macroaggregates increases from 73.6 to 88.5%; the mean weighted diameter of aggregates, by 1.6 times; and the coefficient of aggregation, by 3.8 times. Thus, the removal of lands from agricultural use results in a gradual restoration of their natural structure, improvement of soil agronomical properties, and carbon sequestration in the upper part of the soil profile. © 2017, Pleiades Publishing, Ltd

Changes in physical properties and carbon stocks of gray forest soils in the southern part of Moscow region during postagrogenic evolution

Changes in carbon stocks and physical properties of gray forest soils during their postagrogenic evolution have been studied in the succession chronosequence comprising an arable, lands abandoned 6, 15, and 30 years ago; and a secondary deciduous forest (Experimental Field Station of the Institute of Physicochemical and Biological Problems of Soil Science, Russian Academy of Sciences, Pushchino, Moscow region). It is found that carbon stocks in the upper 60-cm soil layer gain with increasing period of abandonment, from 6.17 kg C/m2 on the arable land to 8.81 kg C/m2 in the forest soil, which represents the final stage of postagrogenic succession. The most intensive carbon accumulation occurs in the upper layer of the former plow (0- to 10-cm) horizon. It is shown that the self-restoration of gray forest soils is accompanied by a reliable decrease of bulk density in the upper 10-cm layer from 1.31 ± 0.01 g/cm3 on the arable to 0.97 ± 0.02 g/cm3 in the forest. In the former plow horizon of the arable–abandoned land–forest succession series, the portion of macroaggregates increases from 73.6 to 88.5%; the mean weighted diameter of aggregates, by 1.6 times; and the coefficient of aggregation, by 3.8 times. Thus, the removal of lands from agricultural use results in a gradual restoration of their natural structure, improvement of soil agronomical properties, and carbon sequestration in the upper part of the soil profile. © 2017, Pleiades Publishing, Ltd