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The environmental consequences of residue removal practices to support cellulosic biofuel production remain poorly understood. In the U.S. Midwest, corn (Zea mays L.) stover removal combined with no‐till practices may increase or decrease soil N2O emissions by influencing soil moisture, temperature, and nutrient dynamics, yet empirical evidence fro...
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... However, the effect of conservation tillage on the contributions of major microbial processes to N 2 O emissions is still controversial (Preza-Fontes et al., 2022). Some studies have shown that no-tillage and straw mulching measures promote denitrification by enhancing organic C and water content, thereby reducing N 2 O emissions due to further reduction of N 2 O to N 2 ( van Kessel et al., 2013;Yuan et al., 2018;Wang et al., 2019). On the other hand, some researchers have argued that soil compaction under no-tillage practices leads to an increase in soil bulk and WFPS, resulting in higher N 2 O emissions compared to traditional tillage (Badagliacca et al., 2018;Li et al., 2022;Pulido-Moncada et al., 2022). ...
... The cumulative N 2 O emissions were decreased by 339.07% in NT compared to that in CT as a N 2 O sink (Fig. 3c), as observed by the findings of Wang et al. (2019b). Meanwhile, the reduction of N 2 O emissions under NT was also observed in the study of Yuan et al. (2018). The lower N 2 O emissions in NT were attributed to the decreased nitrification resulted from the lower topsoil pH . ...
To mitigate greenhouse gas (GHG) emissions of intensified agriculture, conservation practices are gradually being implemented in Chinese wheat–maize cropping systems. However, the effects of different tillage practices on agricultural field GHG emissions and subsequent global warming potential (GWP) are poorly documented. In this study, a three-year field experiment was conducted from 2019 to 2021 to assess the effects of tillage on the emissions of carbon dioxide (CO 2 ), methane (CH 4 ), nitrous oxide (N 2 O), and eventually GWP. Compared to conventional tillage (CT), no-tillage (NT) significantly decreased CO 2 , CH 4 , and N 2 O emissions by 35.43%, 67.33%, 339.07%, respectively, which resulted in a decrease of 37.25% in GWP during three annual cycles. Based on the results of this study, soil could potentially act as a net source of CO 2 and CH 4 under both CT and NT, and a net sink of N 2 O under NT. Annually, non-growing season contributed 16.9%, 15.6%, and 13.8% soil CO 2 , CH 4 , and N 2 O fluxes, and 16.6% GWP under CT and 17.3%, 16.4%, 21.6%, and 17.3% under NT, respectively. Compared to CT, NT improved the aboveground biomass and grain yields of wheat by 21.3% and 13.3% from averaged results, respectively; no significant differences were found for maize yields. Although principal component analysis showed that soil temperature had higher correlations with CO 2 emissions and GWP as compared to soil moisture, soil moisture affected GHG emissions more than soil temperature as demonstrated by the structural equation model. The modeling analysis found that NT increased soil moisture, pH, and bulk density, thus increasing soil organic carbon and decreasing total nitrogen content, eventually inhibiting GHG emissions. This research demonstrated that NT had the potential to mitigate GHG emissions, yet stability needed further investigation on long-term scales.∙
Graphical Abstract
... 4.2.3 | Availability of labile C and N Labile C sources and NO − 3 availability are also known to be important factors in controlling denitrification (Weier et al., 1993). In bulk soil, total content and distribution of these two substrates for denitrification can vary substantially between perennial or no-till systems and intensively managed annual cropping systems (Neugschwandtner et al., 2014;Palm et al., 2014;Yuan et al., 2018). Untilled soil from perennial systems commonly has a gradient in the content of these substrates that decreases with soil depth. ...
Sustainability of biogas production is strongly dependent on soil‐borne greenhouse gas (GHG) emissions during feedstock cultivation. Maize (Zea mays) is the most common feedstock for biogas production in Europe. Since it is an annual crop requiring high fertilizer input, maize cropping can cause high GHG emissions on sites that, due to their hydrology, have high N2O emission potential. On such sites, cultivation of cup plant (Silphium perfoliatum) as a perennial crop could be a more environmentally‐friendly alternative offering versatile ecosystem services. To evaluate the possible benefits of perennial cup‐plant cropping on GHG emissions and nitrogen losses, an incubation study was conducted with intact soil cores from a maize field and a cup plant field. The 15N gas flux method was used to quantify N source‐specific N2 and N2O fluxes. Cumulated N2O emissions and N2+N2O emissions did not differ significantly between maize and cup plant soils, but tended to be higher in maize soil. Soils from both systems exhibited relatively high and similar N2O/(N2+N2O) ratios (N2Oi). N2O emissions originating from sources other than the 15N‐labelled NO3 pool were low, but were the only fluxes exhibiting a significant difference between the maize and cup plant soils. Missing differences in fluxes derived from the 15N‐pool indicate that under the experimental conditions with high moisture and NO3‐ level, and without plants, the cropping system had little effect on N fluxes related to denitrification. Lower soil pH and higher bulk density in the cup plant soil are likely to have reduced the mitigation potential of perennial biomass cropping.
... Applying crop residues to the soil generally increases N 2 O production mainly because the increased available organic C can be used in the N mineralization processes [108,136,137]. In addition, crop residues decomposition requires aerobic conditions, following which the drawdown of soil oxygen activates denitrification [44]. ...
... In SWAT, nitrification occurs only when the soil temperature exceeds 5 • C and the correlation is linear, which is different to DAYCENT and DNDC ( Figure 4B). The SWAT model calculates the impact of soil water on nitrification not by using the WFPS, but rather by using the soil water content of each soil layer, the wilting point water content, and the field capacity water content (Equations (S46) and (S47)), which vary with soil texture, climate and crop type [137]. SWAT does not take into account the changes of soil pH and therefore does not consider the impact of soil pH on nitrification. ...
Nitrous oxide (N2O) is a long-lived greenhouse gas that contributes to global warming. Emissions of N2O mainly stem from agricultural soils. This review highlights the principal factors from peer-reviewed literature affecting N2O emissions from agricultural soils, by grouping the factors into three categories: environmental, management and measurement. Within these categories, each impact factor is explained in detail and its influence on N2O emissions from the soil is summarized. It is also shown how each impact factor influences other impact factors. Process-based simulation models used for estimating N2O emissions are reviewed regarding their ability to consider the impact factors in simulating N2O. The model strengths and weaknesses in simulating N2O emissions from managed soils are summarized. Finally, three selected process-based simulation models (Daily Century (DAYCENT), DeNitrification-DeComposition (DNDC), and Soil and Water Assessment Tool (SWAT)) are discussed that are widely used to simulate N2O emissions from cropping systems. Their ability to simulate N2O emissions is evaluated by describing the model components that are relevant to N2O processes and their representation in the model.
... Possibly, SOM from residue retention and less aeration from no-till increased net ammonia (NH 3 ) mineralization, which increased AOB abundance while the unused NH 3 protonated into NH 4 + (Hirsch and Mauchline, 2015;Osterholz et al., 2017). Moreover, research on the same experimental site by Yuan et al. (2018) reported reduced nitrous oxide (N 2 O) emissions under no-till management compared to that of chisel tillage, regardless of residue management. As no-till plots had more AOB, which also harbors the hao genes responsible for completing the ammonia oxidation, no-till plots could have had a higher rate of completed nitrification and less spontaneous decomposition of hydroxylamine into N 2 O (Hirsch and Mauchline, 2015). ...
No-till in continuous corn (Zea mays L.) production helps to keep an important volume of residues on the soil surface, creating management challenges that could be alleviated by residue removal for bioenergy or animal use. Crop residues, however, are essential to stimulate microbial nutrient cycling in agroecosystems. Thus, both residue removal and tillage options need to be fully evaluated for their impacts on ecosystem services related to soil health, including microbial N cycling. We explored the main steps of the microbial N cycle in relation to soil properties by using targeted gene abundance as a proxy following over a decade of residue removal in continuous corn systems either under no-till or chisel tillage. We used real-time quantitative polymerase chain reaction (qPCR) for the quantification of phylogenetic groups and functional gene screening of the soil microbial communities, including genes encoding critical enzymes of the microbial N cycle: nifH (N2 fixation), amoA (nitrification – ammonia oxidation), nirK and nirS (denitrification – nitrite reduction), and nosZ (denitrification – nitrous oxide reduction). Our results showed that long-term residue removal and tillage decreased soil organic matter (SOM), water aggregate stability (WAS), and the relative abundance (RA) of ammonia-oxidizing bacteria (AOB) carrying nitrifying amoA genes. Denitrifiers carrying nirS genes decreased under no-till as crop residue was removed. In addition, our results evidenced strong correlations among soil properties and phylogenetic groups of bacteria, archaea, and fungi. Overall, this study demonstrated limited but definite impacts of residue management and tillage on the soil environment, which could be exacerbated under less resilient conditions.
... Кроме того, no-till неэффективно использовать для переувлажненных территорий и полей со сложным рельефом (Anderson, 2008;Trusov, 2012;Kiryushin, 2013;Sheehy et al., 2015;Liang et al., 2020). Нулевая обработка почв из-за недостаточного рыхления приводит также и к снижению аэрации, что усиливает денитрификацию и приводит к потерям азота из почвы (Yuan et al., 2018). В умеренном климатическом поясе обилие растительной мульчи на полях с no-till приводит к замедлению прогревания почвы, как следствие, растягиванию во времени периода всходов возделываемой культуры, а также к трудностям с внесением удобрений (Sheehy et al., 2015;Zhelezova et al., 2017). ...
... Incorporation of crop residues resulted in mixed effects on N 2 O emissions, and responses are mostly strongly influenced by soil texture, feedstock quality and climate variability (Yuan et al., 2018). Gentile et al. (2008) measured a reduction of fertilizer-derived N 2 O emissions when urea (120 kg N/ha) was applied with a low-quality corn feedstock (42% C, 1.3% N, C:N ratio of 31, 3.1% lignin, 1.1% polyphenols) at ~9.5 Mg/ha in two coarse textured soils in Zimbabwe, likely explained by an increased in the N immobilization from the fertilizer. ...
Biofuel production from crop residues is widely recognized as an essential component of developing a bioeconomy, but the removal of crop residues still raises many questions about the sustainability of the cropping system. Therefore, this study reviews the sustainability effects of crop residues removal for biofuel production in terms of crop production, soil health and greenhouse gas emissions. Most studies found little evidence that residue management had long-term impacts on grain yield unless the available water is limited. In years when water was not limiting, corn and wheat removal rates ≥ 90% produced similar or greater grain yield than no removal in most studies. Conversely, when water was limiting, corn grain yield decreased up to 21% with stover removal ≥ 90% in some studies. Changes in soil organic fractions and nutrients depended largely on the amount of residue returned, soil depth and texture, slope and tillage. Reductions in organic fractions occurred primarily with complete stover removal, in the top 15 to 30-cm in fine-textured-soils. Soil erosion, water runoff and leaching of nutrients such as total nitrogen (N) and extractable soil potassium decreased when no more than 30% of crop residues were removed. Stover management effects on soil bulk density varied considerably depending on soil layer, and residue and tillage management, with removal rates of less than 50% helping to maintain the soil aggregate stability. Reductions in CO 2 and N 2 O fluxes typically occurred following complete residue removal. The use of wheat straw typically increased CH 4 emissions, and above or equal to 8 Mg ha-1 wheat straw led to the largest CO 2 and N 2 O emissions, regardless of N rates. Before using crop residues for biofuel production, it should therefore always be checked whether neutral to positive sustainability effects can be maintained under the site-specific conditions.
... Combining a high crop residue input with no-till (NT) not only increases the soluble organic C and N substrates but may simultaneously increase soil moisture and reduce aeration, which contribute to higher denitrification rates and greater N 2 O emissions (Mei et al. 2018). Alternately, greater residue input and no-till can also create drier, cooler soil conditions due to greater water infiltration and less heat retention, which reduces N 2 O emissions (Yuan et al. 2018). Laboratory-based incubations are a suitable way to eliminate many of the confounding biophysical factors and focus on how soluble organic C and NO 3 -N influence denitrification activity. ...
Conservation tillage and crop residues should increase the soluble organic carbon and nitrate concentration in agricultural soil, which increases the denitrification potential. Basal denitrification (72 h laboratory incubation) was 2.1–2.7 times higher in a sandy loam soil under 15 yr of conservation tillage than conventional tillage, and 1.8–2.0 times higher with high residue (additional input 8.6–9.4 Mg dry matter ha-1 yr-1) than low residue inputs. Adding glucose and nitrate increased the soil denitrification potential 3- to 14- fold. Denitrification was limited by carbon availability, even in soil with 15 yr of conservation tillage and high residue inputs.
... In an Iowa residue removal study, N 2 O emissions were greater with CT than NT at the 0 and 50% removal rates, but they were similar at the 100% removal rates (Guzman et al., 2015). Yuan, Greer, Nafziger, Villamil, and Pittelkow (2018) reported lower N 2 O emissions under NT compared with CT in 2 out of 3 yr in a recent corn study. Elevated N 2 O emissions under CT were observed in a study on the same soil type under a winter wheat-corn-soybean rotation, whereby 3-yr N 2 O emissions with CT were on average 4.19 kg N ha −1 compared with 3.50 kg N ha −1 under NT (Drury et al., 2012). ...
Harvesting corn (Zea mays L.) stover for production of biofuels, industrial sugars, bioproducts, and livestock bedding is increasing rapidly, but little is known of the impacts of stover removal on soil‐borne greenhouse gas (GHG) emissions. This study evaluated the impacts of removing surface corn stover (0, 25, 50, 75, 100 wt. % removal) on carbon dioxide (CO2) and nitrous oxide (N2O) emissions from a sandy loam soil cropped to monoculture corn using conventional moldboard plow tillage (CT) and no‐tillage (NT). Stover removal systematically decreased CO2 emissions from CT, whereas stover removal had little effect on CO2 emissions from NT. In particular, the CT 0% stover removal treatment produced 47% greater CO2 emissions (5.75 Mg CO2–C ha⁻¹) than the CT 100% removal (3.91 Mg CO2–C ha⁻¹) treatment. Stover removal increased N2O emissions from both tillage treatments, producing up to a 75% increase under CT (2.79 kg N ha⁻¹ at 0% removal; 4.87 kg N ha⁻¹ at 100% removal) and up to a 95% increase under NT (1.75 kg N ha⁻¹ at 0% removal; 3.41 kg N ha⁻¹ at 100% removal). Cumulative nitrate exposure increased in comparable patterns to N2O emissions when stover residues were removed. There was a trade‐off in GHG emissions resulting from stover removal under CT, whereby increasing stover removal reduced CO2 emissions but increased N2O emissions. In contrast, stover removal did not affect CO2 emissions under NT but it increased N2O emissions especially at the 100% removal rates.
... In addition, NT can reduce total energy input (such as cost of machinery and fuel consumption), leading to less indirect greenhouse gas (GHG) emissions compared with the conventional tillage (CT) (Šarauskis et al., 2014;Keshavarz-Afshar et al., 2015). However, the impacts of NT on soil N 2 O emission are still uncertain because of differences in site conditions and soil characteristics (van Kessel et al., 2013;Yuan et al., 2018). For example, Six et al. (2004) and Yuan et al. (2018) reported that compared with the CT, NT mitigated N 2 O emissions by 50% in a spring barley cultivated loamy sand soil (with 8.1% clay and 20.3 g C kg -1 ) and by 37% during the maize growing season over 3 years, respectively. ...
... However, the impacts of NT on soil N 2 O emission are still uncertain because of differences in site conditions and soil characteristics (van Kessel et al., 2013;Yuan et al., 2018). For example, Six et al. (2004) and Yuan et al. (2018) reported that compared with the CT, NT mitigated N 2 O emissions by 50% in a spring barley cultivated loamy sand soil (with 8.1% clay and 20.3 g C kg -1 ) and by 37% during the maize growing season over 3 years, respectively. The lower emissions in NT soil were attributed to reduced nitrification rate resulted from the lower topsoil pH , and increased anaerobic zones and more complete denitrification to dinitrogen (Mutegi et al., 2010). ...
... Wan et al., 2009). A significantly higher SOC content in the 0-5 cm layer under NT could not only stimulate N 2 O emission from denitrification process through formation of more oxygen-limited microsites in soil (Yuan et al., 2018), but also directly provide more labile C substrates for denitrifiers . Increased SOC content in the surface layer under NT accelerated aggregation by increasing the mass proportion of macroaggregates compared with the CT (Dai et al., 2010), which in turn increased the proportion of pores with a neck diameter < 4 μm and as a result, reduced the effective oxygen diffusion coefficient, and shifted microbial community structure and abundance towards anaerobic microorganisms (Yu et al., 2012;Zhang et al., 2014). ...
Although numerous studies have been conducted on the effects of no-tillage on carbon (C) sequestration in agricultural systems, there is still no consensus on the balance between the potential of C sequestration and nitrous oxide (N 2 O) or nitric oxide (NO) emissions. A no-tillage field experiment in the North China Plain was established in 2006 and the influence of no-tillage on N 2 O and NO emissions was monitored under an annual wheat-maize cropping system. The study included four treatments: no-tillage (NT) and conventional tillage (CT) soils amended with N fertilizer at a rate of 225 kg N ha-1 for wheat and 195 kg N ha-1 for maize (NTN and CTN) and without N fertilizer (NT0 and CT0). Three years of no-tillage significantly (p < 0.05) increased soil organic C (SOC) content by 12.2% in the 0-5 cm soil layer, possibly due to the surface aggregation of organic C derived from crop roots and exudates, but did not alter SOC pool in the 0-30 cm profile. Annual N 2 O emissions in the NT0 and CT0 treatments were 0.53 and 0.57 kg N 2 ON ha-1 , respectively, and were significantly (p < 0.05) increased to 0.96 kg N 2 ON ha-1 in CTN and to 1.23 kg N 2 ON ha-1 in NTN. Remarkable differences in N 2 O emissions between CTN and NTN were observed during the maize growing season. In contrast, NO emissions were not affected by the tillage regimes regardless of N fertilization. The mean ratios of NO/N 2 O fluxes in N-unfertilized plots were 0.26-0.29 and 1.79-2.11 for the maize and wheat season, respectively, indicating that both NO and N 2 O were primarily derived from denitrification during the maize growing season and from ni-trification under wheat cultivation. Under N-fertilized plots, the ratios increased to 1.44-2.02 and 5.00-6.03 for the maize and wheat season, respectively, with significantly (p < 0.05) lower values in NTN plots than in CTN plots. The N 2 O emission factors for N applied in the wheat-maize rotation system were 0.16% and 0.09% for NTN and CTN, respectively, which was far lower than the IPCC Tier 1 default value (1.0%), primarily due to the absence of irrigation after fertilization in maize season and low temperature in wheat season. The results suggest that the 3-year no-tillage regime with residue removal did not substantially increase C storage in the 0-30 cm profile, but stimulated N 2 O emissions primarily by increasing denitrification.
