Soil Carbon Dioxide Emissions Research Articles

How Tillage System Affects the Soil Carbon Dioxide Emission and Wheat Plants Physiological State

How Tillage System Affects the Soil Carbon Dioxide Emission and Wheat Plants Physiological State

МОНИТОРИНГ ПОТОКОВ ДИОКСИДА УГЛЕРОДА НА РАЗНОВОЗРАСТНЫХ ЗАЛЕЖАХ В РАЗЛИЧНЫХ ПРИРОДНО-КЛИМАТИЧЕСКИХ ЗОНАХ ЮГА ЗАПАДНОЙ СИБИРИ

The paper reflects the spatial and temporal variability of CO2 fluxes on fallow lands. The aim was to determine the soil CO2 emissions from fallow lands of different ages, taking into account the natural and climatic zones of the south of Western Siberia. The research was carried out in three natural and climatic zones of the Omsk region: steppe, forest-steppe, subtaiga; in each zone, three sites with different age fallow lands were identified: 5-10, 10-20 and older than 20 years. The soil CO2 emission was measured using exposure chambers with determination on a gas chromatograph. When comparing the intensity of CO2 emissions from fallow lands, depending on the natural and climatic zone, it can be noted that in the warm season the maximum level was in the subtaiga zone (on average for May-September 54.1 g of CO2 ∙ m-2 ∙ day-1), followed by the magnitude of flows in the forest-steppe zone (29.4), the minimum It was observed in the steppe zone (25.0). At the same time, the maximum value of the flows was observed in the subtaiga zone in July, in the forest–steppe and steppe zone in June. Younger deposits are characterized by a large amount of soil carbon dioxide emissions compared with older ones: in the subtaiga zone, the average seasonal emission of deposits 5-10 years old is 1.30 times higher than deposits older than 20 years, in the forest–steppe zone, respectively, 1.51, steppe – 1.63 times. The daily dynamics of soil CO2 fluxes has an increased level in the morning and afternoon hours, decreased in the evening and night hours, regardless of the zone.

Impact of Plant Community Diversity on Greenhouse Gas Emissions in Riparian Zones.

Plant community succession can impact greenhouse gas (GHG) emissions from the soil by altering the soil carbon and nitrogen cycles. However, the effects of community landscape diversity on soil GHG emissions have rarely been fully understood. Therefore, this study investigated how plant landscape diversity, structure type, and species composition, affect soil GHG emissions in a riparian zone. Soil GHG emissions were assessed by measuring the air samples collected from four study sites, which have different plant community structure types and species compositions (natural sites with complex plants, landscaped sites with fruit trees and grasses, untended sites with ruderals, and farmland sites), using the static chamber method. Significant differences were observed in soil carbon dioxide (CO2; p < 0.001), nitrous oxide (N2O; p < 0.001), and methane (CH4; p = 0.005) emissions. The untended site with ruderals exhibited the highest CO2 emissions, while N2O emissions increased as plant community diversity decreased. All sites acted as sinks for CH4 emissions, with decreased CH4 uptake efficiency in more diverse plant communities. The Mantel test and variance partitioning analysis revealed soil microbial biomass as an indirect influencer of GHG emissions. This study could help predict soil GHG emissions and their global warming potential under future changes in the island riparian zones.

Soil Carbon Dioxide Emissions and Carbon Sequestration with Implementation of Alley Cropping in a Mediterranean Citrus Orchard.

Agroecological ecosystems produce significant carbon dioxide fluxes; however, the equilibrium of their carbon sequestration, as well as emission rates, faces considerable uncertainties. Therefore, sustainable cropping practices represent a unique opportunity for carbon sequestration, compensating greenhouse gas emissions. In this research, we evaluated the short-term effect of different management practices in alleys (tillage, no tillage, alley cropping with Rosmarinus officinalis and Thymus hyemalis on soil properties, carbon sequestration, and CO2 emissions in a grapefruit orchard under semiarid climate). For two years every four months, soil sampling campaigns were performed, soil CO2 emissions were measured, and rhizosphere soils were sampled at the end of the experimental period. The results show that alley cropping with Thymus and Rosmarinus contributed to improve soil fertility, increasing soil organic carbon (SOC), total nitrogen, cation exchange capacity, and nutrients. The CO2 emission rates followed the soil temperature/moisture pattern. Tillage did not contribute to higher overall CO2 emissions, and there were no decreased SOC contents. In contrast, alley crops increased CO2 emission rates, especially Rosmarinus; however, the bigger root system and biomass of Rosmarinus contributed to soil carbon sequestration at a greater rate than Thymus. Therefore, Rosmarinus is positioned as a better option than Thymus to be used as an alley crop, although long-term monitoring is required to evaluate if the reported short-term benefits are maintained over time.

Partial organic substitution increases soil quality and crop yields but promotes global warming potential in a wheat-maize rotation system in China

Excessive application of synthetic fertilizer has resulted in serious soil degradation and significant greenhouse gases (GHGs) fluxes in farmlands. Partial organic substitution for synthetic fertilizer was considered as a possible strategy for sustainable agricultural development, but its potential effects on soil quality, GHGs emissions, and crop productivity remain unclear. A field experiment across 3-year was conducted to evaluate the responses of soil quality, nitrous oxide (N2O), carbon dioxide (CO2), and methane (CH4) emissions, and crop yields to different ratios of organic fertilizer (OF) to synthetic fertilizer (SF). Six treatments were included: non-fertilization (CK); total SF; total OF; 15 %, 30 %, and 45 % organic substitution (LO, MO, and HO). Soil cumulative N2O emission was decreased with increasing organic substitution ratios, mainly attributing to the reducing soil NH4+ content. However, organic substitution increased soil CO2 and CH4 emissions due to the high manure-driven C input, consequently promoting global warming potential (GWP). Meanwhile, soil organic C, total N, P, available P, K, and C-acquisition enzyme activities were increased with organic substitution, resulting the higher soil quality index (SQI) under HO and OF. HO enhanced the annual yield of wheat and maize by 7.2 % and 13.0 % compared with SF and OF, respectively. The positive relationship between crop yield and SQI indicated that the yield-enhancing effect with partial organic substitution was mainly attributed to the improved synchronization in nutrient supply and soil fertility. Overall, partial organic substitution, especially 45 % organic substitution represents a viable strategy to improve soil quality and crop productivity while mitigating N2O emission in wheat-maize rotation systems. However, organic substitution promoted the GWP through stimulating soil CO2 and CH4 emissions. Further investigations of optimize fertilization managements are still needed to reduce manure-induced CO2 and CH4 emissions to achieve higher climate change mitigation.

The Effects of Cultivation Practices and Fertilizer Use on the Mitigation of Greenhouse Gas Emissions from Kentucky Bluegrass Athletic Fields

Greenhouse gas (GHG) emissions are known to contribute to global climate change. A two-year field study on Kentucky bluegrass (Poa pratensis L.) evaluated cultivation practices and fertilizer use on GHGs. The presence of urea and hollow-tine aerification resulted in the highest soil carbon dioxide (CO2) emissions. No significant differences between soil methane (CH4) flux were observed based on fertilizer; however, in 2014 the verticutting cultivation treatment fluxed significantly more soil CH4 than the uncultivated control. Results showed no significant differences in soil nitrous oxide (N2O) in 2013; however, in 2014, both fertilizer and cultivation practices showed significant differences between treatments, with the urea and the hollow-tine treatments fluxing significantly more soil N2O. The hollow-tined plots produced the greenest turf in 2013, followed by the uncultivated control and the verticutted treatment. In 2014, both the hollow-tine and the uncultivated control produced the greenest turf, followed by the verticutted treatment. The hollow-tined and uncultivated control treatments had significantly higher turfgrass quality than the verticutted treatment. The verticutted urea treatment was above acceptable levels (&gt;6.0) for turfgrass quality following all cultivation events. The results show cultivation practices can be identified that reduce GHG emissions while maintaining turfgrass quality and color.

Effects of Wildfire on Soil CO2 Emission and Bacterial Community in Plantations.

In order to study the effects of wildfires on soil carbon dioxide (CO2) emissions and microbial communities in planted forests, Pinus massoniana Lamb. and Cunninghamia lanceolata (Lamb.) Hook. forests were selected as the research subjects. Through a culture test with 60 days of indoor constant temperature, the soil physical and chemical properties, organic carbon mineralization, organic carbon components, enzyme activity, and microbial community structure changes of the two plantations after fire were analyzed. The results showed that wildfires significantly reduced soil CO2 emissions from the Pinus massoniana forests and Cunninghamia lanceolata forests by 270.67 mg·kg-1 and 470.40 mg·kg-1, respectively, with Cunninghamia lanceolata forests exhibiting the greatest reduction in soil CO2 emissions compared to unburned soils. Bioinformatics analysis revealed that the abundance of soil Proteobacteria in the Pinus massoniana and Cunninghamia lanceolata forests decreased by 6.00% and 4.55%, respectively, after wildfires. Additionally, redundancy analysis indicated a significant positive correlation between Proteobacteria and soil CO2 emissions, suggesting that the decrease in Proteobacteria may inhibit soil CO2 emissions. The Cunninghamia lanceolata forests exhibited a significant increase in soil available nutrients and inhibition of enzyme activities after the wildfire. Additionally, soil CO2 emissions decreased more, indicating a stronger adaptive capacity to environmental changes following the wildfire. In summary, wildfire in the Cunninghamia lanceolata forests led to the most pronounced reduction in soil CO2 emissions, thereby mitigating soil carbon emissions in the region.

Microbially Driven Iron Cycling Facilitates Organic Carbon Accrual in Decadal Biochar-Amended Soil.

Soil organic carbon (SOC) is pivotal for both agricultural activities and climate change mitigation, and biochar stands as a promising tool for bolstering SOC and curtailing soil carbon dioxide (CO2) emissions. However, the involvement of biochar in SOC dynamics and the underlying interactions among biochar, soil microbes, iron minerals, and fresh organic matter (FOM, such as plant debris) remain largely unknown, especially in agricultural soils after long-term biochar amendment. We therefore introduced FOM to soils with and without a decade-long history of biochar amendment, performed soil microcosm incubations, and evaluated carbon and iron dynamics as well as microbial properties. Biochar amendment resulted in 2-fold SOC accrual over a decade and attenuated FOM-induced CO2 emissions by approximately 11% during a 56-day incubation through diverse pathways. Notably, biochar facilitated microbially driven iron reduction and subsequent Fenton-like reactions, potentially having enhanced microbial extracellular electron transfer and the carbon use efficiency in the long run. Throughout iron cycling processes, physical protection by minerals could contribute to both microbial carbon accumulation and plant debris preservation, alongside direct adsorption and occlusion of SOC by biochar particles. Furthermore, soil slurry experiments, with sterilization and ferrous iron stimulation controls, confirmed the role of microbes in hydroxyl radical generation and biotic carbon sequestration in biochar-amended soils. Overall, our study sheds light on the intricate biotic and abiotic mechanisms governing carbon dynamics in long-term biochar-amended upland soils.

Greenhouse gas mitigation and soil carbon stabilization potential of forest biochar varied with biochar type and characteristics

Biochar is increasingly used in climate-smart agriculture, yet its impact on greenhouse gas (GHG) emissions and soil carbon (C) sequestration remains poorly understood. This study examined biochar-mediated changes in soil properties and their contribution to C stabilization and GHG mitigation by evaluating four types of biochar. Soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions, soil chemical and biological properties, and soil organic carbon (SOC) mineralization kinetics were monitored using greenhouse, laboratory, and modeling experiments. Three pine wood biochars pyrolyzed at 460 °C (PB-460), 500 °C (PB-500), 700 °C (PB-700), and one pine bark biochar from gasification at 760 °C (GB-760) were added into soil at 1 % w/w basis. Soils amended with biochar were used to cultivate sorghum for three months in a greenhouse, followed by three months of laboratory incubation. Data obtained from laboratory incubation was modeled using various statistical approaches. The PB-500 and PB-700 reduced cumulative N2O-N emissions by 68.5 % and 73.9 % and CO2 equivalent C emissions by 66.9 % and 72.4 %, respectively, compared to unamended control. The N2O emissions were positively associated with soil nitrate N, available P, and biochar ash content while negatively associated with SOC. The CO2 emission was negatively related to biochar C:N ratio and volatile matter content. Biochar amended soils had 49.2 % (PB-500) to 87.7 % (PB-700) greater SOC and 22.9 % (PB-700) to 48.1 % (GB-760) greater sorghum yield than the control. While PB-700 had more saprophytes than the control, the GB-760 yielded a greater yield than biochars prepared by pyrolysis. Microbial biomass C was 7.23 to 23.3 % greater in biochar amended soils than in control. The double exponential decay model best explained the dynamics of C mineralization, which was associated with initial soil nitrate N and available P positively and total fungi and protozoa biomass negatively. Biochar amendment could be a climate smart agricultural strategy. Pyrolysis pine wood biochar showed the greatest potential to reduce GHG emissions and enhance SOC storage and stability, and gasification biochar contributed more to SOC storage and increased crop yield.

Activated Carbon Application Simultaneously Alleviates Paddy Soil Arsenic Mobilization and Carbon Emission by Decreasing Porewater Dissolved Organic Matter.

Flooding of paddy fields during the rice growing season enhances arsenic (As) mobilization and greenhouse gas (e.g., methane) emissions. In this study, an adsorbent for dissolved organic matter (DOM), namely, activated carbon (AC), was applied to an arsenic-contaminated paddy soil. The capacity for simultaneously alleviating soil carbon emissions and As accumulation in rice grains was explored. Soil microcosm incubations and 2-year pot experimental results indicated that AC amendment significantly decreased porewater DOM, Fe(III) reduction/Fe2+ release, and As release. More importantly, soil carbon dioxide and methane emissions were mitigated in anoxic microcosm incubations. Porewater DOM of pot experiments mainly consisted of humic-like fluorophores with a molecular structure of lignins and tannins, which could mediate microbial reduction of Fe(III) (oxyhydr)oxides. Soil microcosm incubation experiments cospiking with a carbon source and AC further consolidated that DOM electron shuttling and microbial carbon source functions were crucial for soil Fe(III) reduction, thus driving paddy soil As release and carbon emission. Additionally, the application of AC alleviated rice grain dimethylarsenate accumulation over 2 years. Our results highlight the importance of microbial extracellular electron transfer in driving paddy soil anaerobic respiration and decreasing porewater DOM in simultaneously remediating As contamination and mitigating methane emission in paddy fields.

The impact of household wealth on soil organic carbon and nitrogen stocks in enset (Ensete ventricosum (welw.) cheesman) based farming systems in southern Ethiopia

Enset [Ensete ventricosum (welw.) cheesman] is a multi-purpose perennial crop that is an important keystone species for home garden agroforestry systems in Ethiopia and has great potential to increase resilience to climate change, sequester carbon and reduce net greenhouse gas emissions. Therefore, it could be an important crop to be grown more widely in the future. Carbon sequestration is in part due to application of large amounts of organic matter to enset. However, availability of organic matter for use in enset-based farming systems is likely to be related to wealth status of farmers. Because evidence on the influence of wealth on soil carbon is limited, this study assessed influence of household wealth on soil organic carbon, nitrogen and carbon dioxide emissions from enset-based farming systems in southern Ethiopia. Farmlands managed by resource rich farmers had significantly higher organic carbon in 0–20 cm soil depth (4.6 % and 5.8 %) than those managed by resource-poor farmers (3.7 % and 4.3 %). Total nitrogen followed similar trends. Results suggest that wealth status influences soil properties by determining organic inputs, highlighting the importance of livestock. Resource-poor farmers who do not own livestock should therefore take measures to obtain inputs from other sources, such as compost or vermi-compost.

The responses of CO2 emission to nitrogen application and earthworm addition in the soybean cropland.

The effects of nitrogen application or earthworms on soil respiration in the Huang-Huai-Hai Plain of China have received increasing attention. However, the response of soil carbon dioxide (CO2) emission to nitrogen application and earthworm addition is still unclear. A field experiment with nitrogen application frequency and earthworm addition was conducted in the Huang-Huai-Hai Plain. Results showed nitrogen application frequency had a significant effect on soil respiration, but neither earthworms nor their interaction with nitrogen application frequency were significant. Low-frequency nitrogen application (NL) significantly increased soil respiration by 25%, while high-frequency nitrogen application (NH), earthworm addition (E), earthworm and high-frequency nitrogen application (E*NH), and earthworm and low-frequency nitrogen application (E*NL) also increased soil respiration by 21%, 21%, 12%, and 11%, respectively. The main reason for the rise in soil respiration was alterations in the bacterial richness and keystone taxa (Myxococcales). The NH resulted in higher soil nitrogen levels compared to NL, but NL had the highest bacterial richness. The abundance of Corynebacteriales and Gammaproteobacteria were positively connected with the CO2 emissions, while Myxococcales, Thermoleophilia, and Verrucomicrobia were negatively correlated. Our findings indicate the ecological importance of bacterial communities in regulating the carbon cycle in the Huang-Huai-Hai Plain.

Mechanical termination of a perennial grain crop minimally impacts soil structure, carbon and carbon dioxide emissions

AbstractIntroductionMechanical termination of crops can negatively affect soil biological, chemical, and structural characteristics. Perennial crops do not require annual termination and can improve these same soil characteristics, which has catalysed interest in the development of new perennial crops. Advanced lines of the perennial grass intermediate wheatgrass (Thinopyrum intermedium [Host] Barkworth and Dewey; IWG) have been bred for increased seed size and marketed as Kernza® perennial grain, but little is known about how this new crop can be terminated for subsequent annual crop production in rotations that enhance agricultural productivity and environmental sustainability.Materials and MethodsFive methods of terminating IWG were tested in Minnesota, USA. Treatments included mechanical tillage using a chisel plow (CHI), undercutter (UND), and disc (DSC), along with no‐till treatments of glyphosate (GLY) and a repeated‐mowing control (CTRL). Treatment effects on IWG mortality, soil carbon dioxide (CO2) emissions, bulk density, aggregate stability, soil carbon stocks and soybean yield were measured.ResultsDaily CO2 fluxes differed by treatment (p &lt; 0.05) on only one of 19 sample dates, and cumulative soil CO2 emissions over the course of the growing season did not differ across treatments. Bulk density decreased relative to baseline in all treatments except CTRL. Aggregate stability remained unchanged in all treatments except CTRL, which increased from the baseline. Soil carbon stocks did not change in any treatment. Soybean yield was highest in GLY but was not significantly different from CHI or UND.ConclusionsSoil structure, soil carbon stocks and soil CO2 emissions were unaffected by tillage and no‐till IWG termination treatments. However, tillage followed by preplanting harrowing proved ineffective at terminating IWG and required subsequent summer herbicide applications. Therefore, additional tillage events may be required to fully terminate IWG when herbicide use is prohibited.

The global‐scale impacts of metallic nanoparticles on soil carbon dioxide emissions

AbstractTerrestrial ecosystems are increasingly being exposed to metallic nanoparticles (MNPs). However, the global‐scale impact of MNPs on soil carbon dioxide (CO2) emission remains unknown, limiting our understanding of the role of MNPs in global carbon cycle. We compiled a dataset comprising 1764 pairs of experimental observations to investigate the effects of MNPs exposure on soil respiration parameters, including respiration rates, related enzyme activities, and microbial variables. We found that MNPs could stimulate or suppress soil basal respiration rates across global environments, depending largely on the type of MNPs. We further showed that, although the inhibition of MNPs on most enzyme activities peaked in short‐term exposure (≤28 days), prolonged exposure to MNPs still inhibited soil organic carbon degradation. Finally, we determined that environmental conditions (e.g., soil pH and presence/absence of plants) were also important regulators of the influence of MNPs on soil respiration parameters. Our findings underline that the effects of MNPs on soil CO2 emission depended on MNPs type, exposure design, and environmental factors, which is critical for predicting the role of MNPs in influencing the global carbon cycle and climate change.

Long term response and adaptation of farmland water, carbon and nitrogen balances to climate change in arid to semi-arid regions

Climate change poses a challenge for resource utilization and environmental pollution issues caused by agricultural production, especially in arid to semi-arid regions. Farmland water, carbon and nitrogen balances are closely related to these resource and environmental issues. Thus, the Agro-Hydrological & chemical and Crop systems simulator was used to assess the response of water, carbon and nitrogen balances to climate change in a spring wheat farmland of arid to semi-arid Northwest China and to propose adaptation strategies. Five Global Climate Models from the Coupled Model Intercomparison Project 6 and two Shared Socioeconomic Pathways (SSP1–2.6 and SSP5–8.5) were used to establish scenarios with the Agro-Hydrological & chemical and Crop systems simulator to simulate farmland water, carbon and nitrogen balances for the 2025–2100 period. Various irrigation amounts and nitrogen fertilization rates were tested as compensation strategies. Results indicated that climate change could negatively affect farmland water, carbon and nitrogen balances, especially under the SSP5–8.5 scenario. Precipitation showed an increasing trend, thus percolation increased and soil water consumption decreased from 2025 to 2100. However, for the carbon budget, although the soil carbon dioxide emissions tend to decrease, the net primary production was also significantly reduced, which resulted in declining the net ecosystem carbon budget under future climatic conditions. In addition, higher temperature and increased precipitation enhanced soil inorganic nitrogen leaching and nitrous oxide emissions but reduced ammonia volatilization from 2025 to 2100. Overall, the soil total nitrogen loss was increased over time, whereas crop nitrogen uptake was significantly reduced. In relation to the SSP1–2.6 scenario, the SSP5–8.5 scenario accelerated the increase rates of soil water percolation and total nitrogen loss over time, as well as the decrease rates of crop nitrogen uptake and net primary production over time. The negative effects caused by climate change can be mitigated by reducing irrigation and increasing nitrogen fertilization. For the SSP1–2.6 scenario, 30% irrigation reduction and 30% nitrogen fertilization increase can effectively decrease soil water percolation and the related nitrogen losses while crop nitrogen uptake, net primary production and net ecosystem carbon budget increase in relation to the current management (irrigation = 240 mm and nitrogen fertilization = 200 kg ha–1). For SSP5–8.5 the strategy with 45% irrigation reduction and 45% nitrogen fertilization increase can also decrease nitrogen losses and increase crop nitrogen uptake, net primary production and net ecosystem carbon budget.

Post-fire soil carbon emission rates along boreal forest fire chronosequences in northwest Canada show significantly higher emission potentials from permafrost soils compared to non-permafrost soils

Boreal forests are one of the most important biomes storing carbon (C). Wildfires burn yearly on average more than 1% of the boreal forest, and it is expected that the fire return intervals will shorten due to climate change. Fire is one of the most influential factors affecting soil organic matter quantity and quality, soil C pools, and presumably also the time C resides in the soil (soil C turnover time in years). We compared the potential effects of forest fire through post-fire succession on soil carbon dioxide (CO2) emission rates and soil C turnover time in two fire chronosequences, one with underlying permafrost soil and the other without permafrost. We found that fire had a significant effect on potential soil C turnover times, but surprisingly there was no significant difference in soil C turnover times between the permafrost and non-permafrost areas, although the soil CO2 emissions rates in permafrost areas are approximately three times higher compared to non-permafrost areas. In recently burned areas the potential soil C turnover times were two times longer compared to control areas located in forests burned more than 100 years ago. The longest potential soil C turnover times were recorded in mineral soil layers (30 cm) of permafrost soils, and the shortest potential soil C turnover times were recorded in humus layers of non-permafrost areas.

Effects of microplastics on soil C and N cycling with or without interactions with soil amendments or soil fauna

AbstractMicroplastics (MPs) enter the global soil ecosystem in significant quantities, and in agricultural lands, interact with soil amendments (e.g, fertilisers, pesticides, biochar), pollutants (e.g., heavy metals and acid rain) and soil fauna (e.g., earthworms and microbial biomass) which impacts carbon (C) and nitrogen (N) cycling in soil in ways that are largely unexplored. Here, we analysed the difference in the responses of soil C and N contents, greenhouse gas emissions and soil enzyme activities in experiments where MPs alone or MPs in combination with other soil amendments or soil fauna had been explored, by conducting a global meta‐analysis of 2543 observational data extracted from 84 published studies. The results show that MPs alone are associated with significantly increased soil C storage and altered soil N pool composition, increased soil carbon dioxide (CO2) and nitrous oxide (N2O) emissions, reduced soil ammonia (NH3) emissions, increased activity of one of the five major enzymes related to C cycle, and increased activity of three of the four major enzymes related to N cycling in soil. Experiments that explored the combined effects of MPs combined with fertilisers on soil C and N contents and enzyme activities indicated greater effects than MPs alone. However, the effects of MPs combined with soil fauna, heavy metals, acid rain, glyphosate, and carbon nanotubes on soil C and N cycling differed from findings of studies that considered the effects of MPs alone. The results of this meta‐analysis provide a theoretical basis for further study of the effects of MPs on C and N cycling in fertilized agricultural soil, compound‐contaminated soil and acidified soil. We also show that, despite the global importance of MPs in soil, the number of studies of their effects on soil C and N cycling is relatively few, and further research on the mechanisms of interactions of MPs with multiple soil amendments in soil systems is urgently needed.

Carbon dioxide emission estimation in different zones of the south of Western Siberia

The research was carried out in key areas of fallow land in three natural agricultural zones of the south of Western Siberia in the Omsk Oblast: steppe (Cherlaksky district, v. Preobrazhenka), forest-steppe (Kormilovsky district, v. Sosnovka), subtaiga (Tarsky district, Tara); in each zone there are three sites with fallow land of different ages: 5-10, 10-20 and 20-30 years. When comparing the intensity of carbon dioxide emission from fallow lands depending on the conditions of natural and climatic zones, it can be noted that its highest value was in the subtaiga zone (average for April-September 39.4 CO2/m2 per day), which is higher than the emission in the forest-steppe zone (14.7) and steppe zone (16.6). The maximum intensity of fluxes was observed in the subtaiga zone in August, and in the forest-steppe and steppe zones in July. One of the main reasons for this pattern was the air and soil temperature: the higher it is, the more intensive is the release of carbon dioxide. The influence of the age of fallow land on the level of soil carbon dioxide emission is observed. Younger fallows are characterized by a higher value of CO2 emission compared to older ones, so in the subtaiga zone the average seasonal emission of fallows of 5-10 years is 1.51 times higher than fallows of 20-30 years, in the forest-steppe zone - 1.46 times, steppe zone - 1.48 times.

Biyokömür Karıştırma Zonu Toprak Karbondioksit Emisyonu Üzerinde Etkilidir

Several factors are effective on soil carbon dioxide emissions caused by agricultural practices; soil organic matter contents, soil moisture and temperature, climatic changes, and tillage techniques are predominant. In recent years, as a CO2 sequestration agent, biochar incorporation becomes a promising approach. Many studies show that biochar reduces soil CO2 emissions; however, incorporation depth is not widely studied. A pot experiment was carried out to determine the effects of the incorporation zone of rose pulp biochar produced at 400 C on carbon dioxide emission. Treatments were Z as without biochar incorporation (control), A, B, and C are the incorporation zone of 0-7, 0-14, and 0-21 cm soil layer. The measurements in the experiment last for about 2 months. Results revealed that mean CO2 emissions for Z, A, B, and C treatments were 0.048, 0.052, 0.064, and 0.076 g m-2h-1, respectively. According to these results, it was determined that the biochar admixed in the C layer caused more soil CO2 emissions, and there was no significant difference between the other treatments (p&amp;gt;0.05). The highest plant biomass development was obtained in the B treatment (p&amp;lt;0.05).

Acidified manure and nitrogen-enriched biochar showed short-term agronomic benefits on cotton–wheat cropping systems under alkaline arid field conditions

Application of organic residues such as farm manure and biochar in various agricultural environments have shown positive effects on soil carbon sequestration. However, there is a lack of consensus regarding the agronomical benefits of a single and small dose of biochar and farm manure in arid alkaline soils. Therefore, a field experiment with the given treatments (1) control (no amendment), (2) acidified manure (AM) at 300 kg ha−1, (3) nitrogen (N) enriched biochar (NeB) at 3 Mg ha−1, and (4) an equal combination of AM + NeB (150 kg ha−1 AM + 1.5 Mg ha−1 NeB)) was conducted in a typical cotton–wheat cropping system. A parallel laboratory incubation study with the same amendments was carried out to account for soil carbon dioxide emission (CO2). The N enrichment of biochar and its co-application with acidified manure increased soil mineral N (NO3− and NH4+) in the topsoil (0–15 cm), and increased total N uptake (25.92% to 69.91%) in cotton over control, thus reducing N losses and increased uptake over control. Compared to the control, co-application of AM + NeB significantly improved soil N and P bioavailability, leading to increased plant biomass N, P, and K (32%, 40%, 6%, respectively) uptake over control. The plant's physiological and growth improvements [chlorophyll (+ 28.2%), height (+ 47%), leaf area (+ 17%), number of bolls (+ 7%), and average boll weight (+ 8%)] increased the agronomic yield in the first-season crop cotton by 25%. However, no positive response was observed in the second season wheat crop. This field study improved our understanding that co-application of acidified manure and N-enriched biochar in small dose can be a strategy to achieve short-term agronomic benefits and carbon sequestration in the long run.