Search Results (19)

An advanced gasification module (AGM) for green hydrogen production involves a small-scale biomass gasification process owing to the low energy density of biomass. Therefore, significant heat loss and the endothermic nature of gasification system require additional fossil fuel heat, increasing CO₂ emissions. This study focuses on bioenergy conversion with carbon capture and utilization (BECCU), where carbon-neutral CO₂ from biomass gasification is captured and reused as a gasifying agent to reduce the greenhouse gas intensity of green hydrogen. BECCU is expected to achieve negative emissions and enhance gasification efficiency by promoting conversion of char and tar through CO₂ gasification. To evaluate the effectiveness of BECCU in the AGM, we conducted a sensitivity analysis of the reformer temperature and S/C ratio using process simulation combined with life cycle assessment. In both sensitivity analyses, the GWP for CO₂ capture was lower compared with conventional conditions, considering recovered CO₂ from purification and the additional steam generated through heat recovery. This suggests improved hydrogen yields from enhanced char and tar conversion. Consequently, the GWP was reduced by more than 50%, demonstrating BECCU’s effectiveness in the AGM. This represents a step toward operating biomass gasification systems with lower environmental impact and contributing to sustainable energy production. Full article

Quantitative greenhouse gas (GHG) budgets for Mediterranean pepper cultivation are still missing, limiting evidence-based nitrogen management. Furthermore, mitigation value of fertigation respect to granular fertilization in vegetable systems remains uncertain. This study therefore compared the GHG footprint and productivity of ‘papaccella’ pepper under two nitrogen fertilization methods: granular fertilization versus low-frequency fertigation with urea, each supplying about 63 kg N ha⁻¹. Eight automated static chambers coupled to a cavity ring-down spectrometer monitored soil CO₂ and N₂O fluxes throughout the season. Cumulative emissions did not differ between treatments (CO₂: 811 ± 6 g m⁻² vs. 881 ± 4 g m⁻²; N₂O: 0.038 ± 0.008 g m⁻² vs. 0.041 ± 0.015 g m⁻², fertigation vs. granular), and marketable yield remained at ~11 t ha⁻¹, leaving product-scaled global warming potential (GWP) unchanged. Although representing less than 2% of measured fluxes, “hot moments,” burst emissions exceeding four standard deviations (SD) from the mean, accounted for up to 4% of seasonal CO₂ and 19% of N₂O. Fertigation doubled the frequency of these events but reduced their peak magnitude, whereas granular application produced fewer but more extreme bursts (>11 SD). Results showed that fertigation did not mitigate GHGs emission nor improve productivity for Mediterranean pepper, mainly due to the low application frequency and the use of a urea fertilizer. Moreover, we can highlight that in horticultural systems, omitting ‘hot moments’ leads to systematic underestimation of emissions. Full article

This study explores biochar’s impact on soil fertility, greenhouse gas (GHG) emissions, grain yield, carbon footprint (CF), and net ecosystem carbon budget (NECB) in northwest China’s arid regions. A two-year field experiment tested three biochar rates (15, 30, and 45 t ha⁻¹) against a control. The results showed that biochar significantly reduced overall soil GHG emissions, though the highest rate increased methane emissions. The 30 t ha⁻¹ rate yielded the highest average grain production (13.9 t ha⁻¹), boosted soil organic carbon storage by 76 kg ha⁻¹, and decreased global warming potential (GWP) by 87.8 kg CO₂ ha⁻¹ and GHG emission intensity by 6.74 kg t⁻¹. Biochar also lowered the CF and enhanced the NECB, primarily through increased net primary production and improved soil fertility and crop yields. CO₂ emissions and fertilizer use were major CF contributors, but biochar reduced both the biomass-scaled and yield-scaled CFs. Overall, biochar improved crop yields, NECB, and soil carbon storage while reducing GWP, GHGI, and CF. This study recommends 30 t ha⁻¹ biochar to optimize crop production, enhance carbon balance, and mitigate climate change impacts, highlighting biochar’s potential as a sustainable soil amendment in arid ecosystems. Full article

As the main contributor to greenhouse gas (GHG) in paddy soil, information on methane (CH₄) emission characteristics under different tillage and cultivation practices are limited. A five-year field trial was conducted from 2019 in a single-cropping rice system in Taihu Lake region, east of China. The experiment had a completely randomized block design, and the treatments included rotary tillage plus rice dry direct seeding (RD), rotary tillage plus rice mechanical transplanting (RT), and plowing tillage plus rice mechanical transplanting (PT). We determined the rice yield, GHG emission, soil traits, and methanogens and methanotrophs in 2022 and 2023. The results revealed that PT and RT significantly increased rice yield compared to RD, whereas PT simultaneously increased CH₄ emissions. The year-averaged cumulative CH₄ emissions in PT were increased by 38.5% and 61.4% higher than RT and RD, respectively. Meanwhile, yield-scaled global warming potentials (GWPs) in RT and RD were lower than those in PT. Tillage and cultivation practices shifted mcrA and pmoA abundances, and PT significantly decreased pmoA abundance. The community structure and diversity of the methanogens and methanotrophs were not significantly affected. Structural equation model analyses illustrated that CH₄ emissions were regulated by mcrA and pmoA directly, which in turn, regulated by soil carbon and nitrogen. Overall, rotary tillage plus mechanism transplanting was a feasible agronomic technology in a single-cropping rice system in Taihu Lake region, exhibiting higher and more stable rice productivity, accompanied with lower CH₄ emissions and yield-scaled GWP. Full article

The ratoon rice cropping pattern is an alternative to the double-season rice cropping pattern in central China due to its comparable annual yield and relatively lower cost and labor requirements. However, the impact of the ratoon rice cropping pattern on greenhouse gas (GHG) emissions and yields in the double-season rice region requires further investigation. Here, we compared two cropping patterns, fallow-double season rice (DR) and fallow-ratoon rice (RR), by using two early-season rice varieties (ZJZ17, LY287) and two late-season rice varieties (WY103, TY390) for DR, and two ratoon rice varieties (YLY911, LY6326) for RR. The six varieties constituted four treatments, including DR1 (ZJZ17 + WY103), DR2 (LY287 + TY390), RR1 (YLY911), and RR2 (LY6326). The experimental results showed that conversion from DR to RR cropping pattern significantly altered the GHG emissions, global warming potential (GWP), and GWP per unit yield (yield-scaled GWP). Compared with DR, the RR cropping pattern significantly increased cumulative methane (CH₄), nitrous oxide (N₂O), and carbon dioxide (CO₂) emissions by 65.73%, 30.56%, and 47.13%, respectively, in the first cropping season. Conversely, in the second cropping season, the RR cropping pattern effectively reduced cumulative CH₄, N₂O, and CO₂ emissions by 79.86%, 27.18%, and 30.31%, respectively. RR led to significantly lower annual cumulative CH₄ emissions, but no significant difference in cumulative annual N₂O and CO₂ emissions compared with DR. In total, the RR cropping pattern reduced the annual GWP by 7.38% and the annual yield-scaled GWP by 2.48% when compared to the DR cropping pattern. Rice variety also showed certain effects on the yields and GHG emissions in different RR cropping patterns. Compared with RR1, RR2 significantly increased annual yield while decreasing annual GWP and annual yield-scaled GWP. In conclusion, the LY6326 RR cropping pattern may be a highly promising strategy to simultaneously reduce GWP and maintain high grain yield in double-season rice regions in central China. Full article

Effective nitrogen management practices by using two cultivation techniques can improve corn productivity and soil carbon components such as soil carbon storage, microbial biomass carbon (MBC), carbon management index (CMI), and water-soluble carbon (WSC). It is essential to ensure the long-term protection of dry-land agricultural systems. However, excessive application of nitrogen fertilizer reduces the efficiency of nitrogen use and also leads to increased greenhouse gas emissions from farming soil and several other ecological problems. Therefore, we conducted field trials under two planting methods during 2019–2020: P: plastic mulching ridges; F: traditional flat planting with nitrogen management practices, i.e., 0: no nitrogen fertilizer; FN: a common nitrogen fertilizer rate for farmers of 290 kg ha⁻¹; ON: optimal nitrogen application rate of 230 kg ha⁻¹; _ON75%+DCD: 25% reduction in optimal nitrogen fertilizer rate + dicyandiamide; _ON75%+NC: 25% reduction in optimal nitrogen rate + nano-carbon. The results showed that compared to other treatments, the _PON75%+DCD treatment significantly increased soil water storage, water use efficiency (WUE), and nitrogen use efficiency (NUE) because total evapotranspiration (ET) and GHG were reduced. Under the P_ON75%+DCD or P_ON75%+NC, the soil carbon storage significantly (50% or 47%) increased. The P_ON75%+DCD treatment is more effective in improving MBC, CMI, and WSC, although it increases gaseous carbon emissions more than all other treatments. Compared with FFN, under the P_ON75%+DCD treatment, the overall CH₄, N₂O, and CO₂ emissions are all reduced. Under the P_ON75%+DCD treatment, the area scale GWP (52.7%), yield scale GWP (90.3%), biomass yield (22.7%), WUE (42.6%), NUE (80.0%), and grain yield (32.1%) significantly increased compared with F_FN, which might offset the negative ecological impacts connected with climate change. The P_ON75%+DCD treatment can have obvious benefits in terms of increasing yield and reducing emissions. It can be recommended to ensure future food security and optimal planting and nitrogen management practices in response to climate change. Full article

This study focuses on the development of more cropping systems in response to global warming and food security concerns. A two-year field experiment (2017–2018) was conducted to investigate the effects of greenhouse gases (GHGs), soil environmental factors and yield on traditional double-cropping rice (DR), maize rice (MR) and ratooning rice (Rr). The results showed a significant annual effect of temperature and rainfall on GHG emissions under different cropping systems. Annual CH₄ emissions under MR and Rr were significantly lower than under DR. Compared to DR, the highest cumulative N₂O emissions were observed in MR (14.9 kg·ha⁻¹) with a reduction of 23.7% in Rr. In addition, the upland crops significantly reduced CH₄ emissions for late rice, while N₂O emissions increased by 20.6%. Compared with DR and Rr, global warming potential (GWP) and greenhouse gas intensity (GHGI) were significantly lower for MR (p < 0.05). Meanwhile, the annual yield of MR (16.40 t·ha⁻¹) was 8.1% and 2.4% higher than that of DR and Rr, respectively. This study further found that soil temperature and NH₄⁺-N content were positively correlated with CH₄ and N₂O emissions, and soil moisture was positively correlated with N₂O emission. Thus, we concluded that MR has the greatest potential to improve crop yield and mitigate GHG emissions in central China. Full article

Freshwater aquaculture is an important source of greenhouse gas (GHG) emissions. GHG emissions are expected to lead to global warming and climate change. A reduction in GHG emissions is urgently required for the sustainable development of freshwater aquaculture. In this study, a laboratory-scale experiment was conducted to analyze the effects of a vegetable–fish co-culture on CH₄ and N₂O emissions from a freshwater aquaculture pond. The results show that the co-culturing of yellow catfish with pak choi (PC-F) or water spinach (WS-F) significantly reduced the N₂O emission from the aquaculture pond by 60.20% and 67.71%, respectively, as compared with a yellow catfish monoculture (F). However, the co-culture of these two vegetables did not affect the level of CH₄ emissions. The reduction in N₂O emissions was primarily attributed to the decrease in the concentration of N₂O and NO₃⁻ in the water. The overall global warming potential (GWP) of CH₄ and N₂O was significantly reduced by 19.1% with PC-F compared to F, but it did not significantly differ between WS-F and F. PC and WS cultivation improved the food yield by 1555.52% and 419.95% compared to F, respectively. Consequently, the GHG emissions intensity (GHGI) under PC-F and WS-F decreased by 96.15% and 80.77% compared to F, respectively. Altogether, the results highlight that a vegetable–fish co-culture is likely an efficient system for mitigating GWP per unit of food yield in freshwater aquaculture ponds. These results can provide a reference for the mitigation of GHG emissions from freshwater aquaculture. Full article

Biochar (BC), nitrification inhibitors (methyl 3-(4-hydroxyphenyl) propionate, MHPP), and urease inhibitors (n-butyl phosphorothioate triamine, NBPT) have emerged as effective soil greenhouse gas (GHG) mitigation strategies in agroecosystems. However, the combined use of BC and inhibitors in karst areas has no available data. Therefore, the combined effects of BC, MHPP, and NBPT on GHG emissions, global warming potential (GWP) and nitrogen use efficiency (NUE) in roasted tobacco cropping systems were studied to improve the understanding in climate mitigation. CO₂, CH₄, and N₂O emissions from soils were measured using static chamber-gas chromatography. Results showed that the combined use of BC and inhibitors significantly increased soil total nitrogen, available potassium, electric conductivity, pH, and soil organic matter compared to the control. The combined use of BC and MHPP or NBPT significantly increased cumulative soil CO₂ emissions by 33.95% and 34.25%, respectively. The exponential–exponential function of soil CO₂ fluxes with soil moisture and temperature demonstrated good fit (R²: 0.506–0.836). The combination of BC and NBPT increased the cumulative soil CH₄ emissions by 14.28% but not significantly compared to the fertiliser treatment. However, the combination of BC and MHPP resulted in a significant reduction in cumulative soil CH₄ emissions by 80.26%. In addition, the combined use of BC and MHPP or NBPT significantly reduced the cumulative soil N₂O emissions by 26.55% and 40.67%, respectively. The inhibition effect of NBPT was better than MHPP. Overall, the combined use of BC and inhibitors significantly reduced the yield-scaled GWP, markedly increased crop yield and NUE, and mitigated climate change in the southwest karst region. Full article

Straw input is a helpful approach that potentially improves soil fertility and crop yield to ensure food security and protect the ecological environment. Nevertheless, unreasonable straw input results in massive greenhouse gas (GHG) emissions, leading to climate change and global warming. To explore the optimum combination of straw input and management practices for achieving green agricultural production, a worldwide data set was created using 3452 comparisons from 323 publications using the meta-analysis method. Overall, straw input increased soil carbon and nitrogen components as compared with no straw input. Additionally, straw input significantly boosted crop yield and nitrogen use efficiency (NUE) by 8.86% and 22.72%, respectively, with low nitrogen fertilizer rate benefiting the most. The cumulative of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) emissions increased by 24.81%, 79.30%, and 28.31%, respectively, when straw was added. Global warming potential (GWP) and greenhouse emission intensity (GHGI) increased with the application of straw, whereas net global warming potential (NGWP) decreased owing to soil carbon sequestration. Low straw input rate, straw mulching, application of straw with C/N ratio > 30, long-term straw input, and no-tillage combined with straw input all result in lower GHG emissions. The GWP and GHGI were strongly related to area-scaled CH₄ emissions, but the relationship with N₂O emissions was weak. Straw application during the non-rice season is the most important measure for reducing CH₄ emissions in paddy–upland fields. An optimum straw management strategy coupled with local conditions can help in climate change mitigation while also promoting sustainable agricultural production. Full article

Straw incorporation has a variety of impacts on greenhouse gas (GHG) emissions. However, few studies have focused on the effects of multi-year straw incorporation. In this study, a field experiment was established to study the effects of straw incorporation and water-saving irrigation on GHG emissions in the cold region of Northeast China. The following four treatments were included: (i) controlled irrigation (CI) with 1-year straw incorporation (C1), (ii) controlled irrigation with 5-year straw incorporation (C5), (iii) flooded irrigation (FI) with 1-year straw incorporation (F1), and (iv) flooded irrigation with 5-year straw incorporation (F5). The fluxes of N₂O, CO₂, and CH₄ were measured by the static chamber–gas chromatography method, and their global warming potential (GWP) and greenhouse gas intensity (GHGI) in units of CO₂-equivalent at the 100-year scale were calculated. The results showed that the 5-year straw incorporation reduced N₂O emissions but increased CH₄ emissions. Compared with C1 and F1, C5 and F5 reduced N₂O emissions by 73.1% and 44.9%, respectively, while increasing the CH₄ emissions by 101.7 and 195.8%, respectively. Under different irrigation regimes, CI reduced CH₄ emissions by 50.4–79.7% while increasing CO₂ emissions by 8.2–44.9% compared with FI. The contribution of N₂O and CO₂ emissions were relatively high at the mature and milk stages, respectively, with a range of 16–54% and 41–52% for the treatments. In contrast, CH₄ emissions were mainly manifested at the tillering stage, with a contribution of 36–58% for the treatments. Affected by higher CH₄ emissions in FI, the GWP of CI was 1.4–47.6% lower than FI. In addition, the yield of CI was 10.0–11.5% higher than FI, which resulted in a GHGI of 11.5–52.4% lower than FI, with C5 being the lowest. The irrigation regime of CI combined with 5-year straw incorporation was an effective agronomic measure to increase yield and reduce GHG emissions from paddy fields in the cold region of Northeast China. Full article

Achieving an economically feasible and environmentally robust model in agriculture while satisfying the expanding population’s food demands is a global challenge. Hence, a three-year (2014–2017) study was conducted at Punjab Agricultural University, Ludhiana to design environmentally clean, energy-efficient, and profitable cropping systems. Twelve cropping systems viz., rice-wheat (CS₁), basmati rice-hayola (transplanted)-mung bean (CS₂), basmati rice-radish-maize (CS₃), maize-potato-maize (CS₄), maize + turmeric-barley + linseed (CS₅), maize + turmeric-wheat + linseed (CS₆), maize + radish-wheat + linseed-mung bean (CS₇), groundnut + pigeon pea (5:1)-wheat + sarson (9:1) (CS₈), maize + black gram-pea (bed) + celery (furrows) (CS₉),_: maize + pigeon pea-chickpea (bed) + gobhi sarson (furrows) (CS₁₀), maize (green cobs) + vegetable cowpea + dhaincha (Sesbania spp.)-chickpea + gobhi sarson (CS₁₁) and sorghum + cowpea (fodder)-wheat + gobhi sarson (9:1) (CS₁₂) were tested in a four-times-replicated randomized block design. CS₁₁ had the maximum system productivity (28.57 Mg ha⁻¹), production efficiency (78.27 Kg Day⁻¹ ha⁻¹), irrigation water use efficiency (2.38 kg m⁻³), system net returns (4413.3 US$ ha⁻¹), and benefit to cost (B:C) ratio (2.83) over others. In comparison to the CS₁ system, this cropping system required ~78% less irrigation water for a unit economic production. However, the cultivation of CS₁₂ registered the highest energy use efficiency (49.06%), net energy returns (6.46 × 10³ MJ ha⁻¹), and global warming potential (GWP) (Mg CO₂ e ha⁻¹) at spatial scale. Among all the intensified systems, CS₁₁ had the lowest GHGI (0.29 kg CO₂ e kg⁻¹). Furthermore, cultivation of CS₆ resulted in the maximum bacterial and actinomycetes population in the soil, while CS₅ yielded the highest fungal count (23.8 × 10³ cfu g⁻¹ dry soil) in soil. Our study suggests that the cultivation of CS₁₁ is a resource-efficient, economically viable, and environmentally clean production system and could be a potential alternative to rice-wheat systems for developing a green economy policy for agricultural development in the Indo-Gangetic Plains (IGP) of India. Full article

Long-term addition of manure increases soil organic carbon (SOC), provides nutrient supply, enhances soil quality and crop yield (CY), but may also increase global warming potential (GWP). In this study, a long-term experiment was conducted to investigate impacts of organic dairy manure and inorganic fertilizer on the spatial distribution of soil quality indicators in field scale. The experiment was initiated in 2008 (seven years), and includes three manure and two inorganic fertilizer treatments along with a control (no manure or no inorganic fertilizer addition). The study was set into a randomized complete block design with six treatments and four replications in a total of 24 plots with an equal size each of 6 × 18 m (108 m²). Soil physical, chemical and biological properties (total 26 properties) were considered as the total data set and principal component analysis (PCA) was used to determine long-term organic and inorganic fertilizer-induced changes in soil quality. Ordinary kriging interpolation methods were used to predict the spatial distributions of soil quality index (SQI) and mean soil quality values were compared with fertilization treatments by using Duncan’s test. Results showed that most measured soil quality index parameters showed significant differences (p < 0.05). The long-term dairy manure applications had positive impacts on soil quality index parameters where overall SQI scores were higher under high manure (HM) compared to medium manure (MM), low manure (LM), medium fertilizer (MF), high fertilizer (HF), control (CK) by 25%, 27%, 47%, 55% and 92%. A similar trend was observed for CY and GWP. This indicates that long-term dairy manure can be an option to increase SQI values and provide higher CY, however, this may lead to greater GWP. Full article

The olive oil industry produces high amounts of waste, which need to be valorized in a more sustainable way as an alternative to its traditional use as an energy source, with high associated CO₂ emissions. Rice (Oryza sativa L.) is one of the most important crops for global food security; however, the traditional cropping systems under flooding lead to an important decrease of soil quality, as well as relevant emissions of greenhouse gases (GHG). The aim of this study was to assess the GHG emission from rice fields amended with composted two-phase olive mill waste (C-TPOW), in Mediterranean conditions. A field experiment was carried in rice cultivated by the traditional system, either unamended (Control) or amended with C-TPOW (Compost). GHG emissions were measured over three years following a single C-TPOW application (80 Mg ha⁻¹ only in the first year of study), so that the results found in the first and third years correspond to its direct and residual effects, respectively. Compost decreased CO₂ emissions relative to Control by 13% and 20% in the first and third year after C-TPOW application, respectively. However, in the case of CH₄ and N₂O, increases in the total cumulative emission were recorded in Compost relative to Control throughout the study, in agreement with the highest β-glucosidase and urease activity observed in the amended soil. The values of global warming potential (GWP) and yield-scaled GWP increased by 14% and 11%, respectively, in Compost relative to Control in the first year, but no significant differences between treatments were observed three years after application for GWP and yield-scaled GWP. Therefore, the use of C-TPOW as soil amendment in rice fields could be a good option since its impact on GHG emissions seems to decrease over time, while the benefit for soil remained clear even after 3 years. Full article

We quantified the soil carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) fluxes of five soil fertility management practices (inorganic fertilizer (Mf), maize residue + inorganic fertilizer (RMf), maize residue + inorganic fertilizer + goat manure (RMfM), maize residue + tithonia diversifolia + goat manure (RTiM), and a control (CtC)) in Kenya’s central highlands using a static chamber method from March 2019 to March 2020. The cumulative annual soil CH₄ uptake ranged from −1.07 to −0.64 kg CH₄-C ha⁻¹ yr⁻¹, CO₂ emissions from 4.59 to 9.01 Mg CO₂-C ha⁻¹ yr⁻¹, and N₂O fluxes from 104 to 279 g N₂O-N ha⁻¹ yr⁻¹. The RTiM produced the highest CO₂ emissions (9.01 Mg CO₂-C ha⁻¹ yr⁻¹), carbon sequestration (3.99 Mg CO₂-eq ha⁻¹), yield-scaled N₂O emissions (YSE) (0.043 g N₂O-N kg⁻¹ grain yield), the lowest net global warming potential (net GWP) (−14.7 Mg CO₂-eq ha⁻¹) and greenhouse gas intensities (GHGI) (−2.81 Kg CO₂-eq kg⁻¹ grain yield). We observed average maize grain yields of 7.98 Mg ha⁻¹ yr⁻¹ under RMfM treatment. Integrating inorganic fertilizer and maize residue retention resulted in low emissions, increased soil organic carbon sequestration, and high maize yields. Full article