Livestock manure emits considerable amounts of greenhouse gases (GHGs) and ammonia (NH3), inducing climate change and air pollution. However, there remains a lack of knowledge in the literature ...related to GHGs and NH3 emissions from the manure of various livestock species. This study reports on a field observation we conducted to analyze GHGs and NH3 emissions of solid stored manure from dairy cattle and swine, which represent the two main livestock species raised in China. Results showed that although dairy cattle manure emitted 521.9% more methane (CH4) than swine manure, they separately emitted 50.8% and 40.9% less nitrous oxide (N2O) and carbon dioxide (CO2) emissions, respectively. With respect to their global warming potential, the GHGs emission from dairy cattle manure was similar to that from swine manure. NH3 emissions from swine manure were significantly higher, namely, greater by a factor of 2.4 compared to dairy cattle manure. Differences in gas emissions between dairy cattle and swine manure can be explained by differences in the physicochemical characteristics of their manure and their associated microbiological, chemical, and physical processes that produce gas during storage periods. Based on our results, this study highlights the necessity for prospective mitigation strategies to simultaneously decrease GHGs and NH3 emissions from livestock manure. Our findings provide useful implications for understanding GHGs and NH3 emissions, which can be used to develop corresponding mitigation strategies for livestock manure management in China.
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•Quantifying GHGs and NH3 emissions of solid stored manure from dairy cattle and swine•Dairy cattle manure emits similar amounts of GHGs but lower NH3 compared to swine manure.•Physicochemical characteristics of manure significantly influence gases emissions.
Substituting organic manure for compound fertilizer may play an important role in regulating the nitrogen (N) cycle and consequently affecting crop yield in agroecosystems. However, how substituting ...different organic manures for compound fertilizer affects crop yield and ammonia (NH
) and nitrous oxide (N
O) emissions in the vegetable system during the life-cycle production (including storage and field application) remains poorly elucidated. Thus, we conducted a greenhouse experiment to investigate the effects of substituting organic manure species, i.e., stored swine manure fertilizer (SS), swine manure covered by straw (CS), stored swine fertilizer mixed with biochar (BS), and stored swine manure fertilizer with void expansion (OS) for compound fertilizer (FC) on rapeseed yield and NH
and N
O emissions in a rapeseed-cropping system in China. The results showed that the total gaseous N losses (NH
and N
O) were 1.6, 1.4 and 1.1 times higher in SS, CS and OS than FC, respectively. However, total gaseous N losses in BS was 0.9 times less than FC. Compared with FC, rapeseed yield and N uptake in SS and CS were decreased by 17.2-20.2% and 16.0%-28.1%, respectively, but which were increased by 7.3% and 54.1% in BS, respectively. In addition, OS decreased rapeseed yield by 17.2%, but increased N uptake by 8.5%. Therefore, the effects of substituting organic manure for compound fertilizer on rapeseed yield, N uptake, NH
and N
O varied regarding different organic manure species. Adopting stored swine fertilizer mixed with biochar might be a sound management practice to reduce gaseous N losses and enhance N uptake and yield in intensive vegetable production systems.
Increased nitrogen (N) losses from linear agri-food systems result in severe environmental issues. These problems can be mitigated by circular N use. Yet, circularity is a scale-specific problem, and ...the feasibility of pathways towards N circularity at different scales is unclear.
This study aimed to 1) evaluate N circularity of a complete agri-food system, including household compartment, at both the village and county scale; and 2) assess potential pathways towards N circularity.
We used the county of Quzhou (China) with 342 villages as a case study and applied the modified version of a nutrient flow model (NUFER) to calculate N flows, using national statistical data and own survey data collected from farms and households. To evaluate N circularity, we selected four key performance indicators: N import, N loss, N use efficiency and N recycling rate.
Our analysis showed significant variation at the village scale, depending on local production and consumption patterns. At county level, total N import was 546 kg ha−1 yr−1, of which 54% was lost to the environment. The N use efficiency of the agri-food system and N recycling rate of excreta were both <30%. We investigated scenarios to increase N circularity, including application of good management practices in crop and animal production; household dietary change to more plant protein; recycling of organic waste; growing legumes instead of cotton; and reducing livestock breeding. All measures combined increased the system's N use efficiency by 172% and N recycling rate by 87%, while reducing N import by 68% and N loss by 77%. Recycling of organic waste was the most effective and most feasible strategy to promote circularity.
Our study bridges the gap between village and county level N cycles, illustrates possibilities to transition towards circular N use, and can help policymakers worldwide to achieve more sustainable agri-food systems.
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•Current nitrogen flows in agri-food systems are generally linear.•Key performance indicators are used to evaluate N circularity.•Characterization of village-level systems to quantify nitrogen flows at county level.•Turning organic waste into a resource contributes most to N circularity.•Circular N use to double nitrogen use efficiency and halve nitrogen losses.
China is facing the dual challenge of achieving food security and agricultural carbon neutrality. Developing spatially explicit crop emission profiles can help inform policy to mitigate agricultural ...greenhouse gases (GHGs), but previous life-cycle studies were conducted mostly at national and provincial levels. Here, we estimate county-level carbon footprint of China’s wheat and maize production based on a nationwide survey and determine the contribution of different strategies to closing regional emission gaps. Results show that crop carbon footprint varies widely between regions, from 0.07 to 3.00 kg CO2e kg–1 for wheat and from 0.09 to 2.30 kg CO2e kg–1 for maize, with inter-county variation generally much higher than interprovince variation. Hotspots are mainly concentrated in Xinjiang and Gansu provinces, owing to intensive irrigation and high plastic mulch and fertilizer inputs. Closing the regional emission gaps would benefit mostly from increasing crop yields and nitrogen use efficiency, but increasing manure use (e.g., in Northeast, East, and Central China) and energy use efficiency (e.g., in North and Northwest China) can also make important contributions. Our county-level carbon footprint estimates improve upon previous broad-scale results and will be valuable for detailed spatial analysis and the design of localized GHG mitigation strategies in China.
Livestock production, an important source for non-CO2 greenhouse gases (GHGs) including methane (CH4) and nitrous oxide (N2O) in China, has changed remarkably over the past decades due to economic ...development and demand for livestock product. However, the variation of non-CO2 GHGs from China's livestock have not received sufficient attention in existing literature. Here, we examine the spatiotemporal patterns of emissions of CH4 and N2O from main livestock in China as well as their long-term trends during the period 2000–2015. Results suggest that the livestock sourced emissions of non-CO2 GHGs in China experienced three phases: a rapid increase from 2000 to 2006, followed by a sharp drop in 2007 and then a slow increase at a lower level from 2008 to 2015. The 2007 drop reflects the impact of macro-control policies on livestock development and extensive measures taken on livestock to control the flu outbreak that year, and the slower increase from 2008 to 2015 with respect to the period 2000–2006 reflects the changes in livestock categories and a general improvement in production efficiency. Spatiotemporal patterns demonstrate that traditional livestock provinces including Henan, Sichuan, Inner Mongolia, Shandong, Yunnan and Hunan stood out as top six provinces in emission of non-CO2 GHGs in 2015. On the other hand, provinces like Jiangxi, Hubei, Hunan, Yunnan, Inner Mongolia, Liaoning and Xinjiang, identified as the emerging provinces, demonstrate the highest growth rates over the last decades. We find that different livestock categories dominated the difference in pattern of non-CO2 GHG emissions in both provinces with high emissions and those with high growth rates. Mitigation measures and policies suggestions should not only focus on high non-CO2 GHG emissions provinces, but also pay attention to the emerging new sources.
•Spatiotemporal patterns are examined for livestock non-CO2 GHG emissions in China.•Featured livestock categories differentiate non-CO2 GHG emissions across provinces.•Mitigation policies should focus on high emission provinces and emerging sources.
Substituting organic manure for compound fertilizer may play an important role in regulating the nitrogen (N) cycle and consequently affecting crop yield in agroecosystems. However, how substituting ...different organic manures for compound fertilizer affects crop yield and ammonia (NH3) and nitrous oxide (N2O) emissions in the vegetable system during the life-cycle production (including storage and field application) remains poorly elucidated. Thus, we conducted a greenhouse experiment to investigate the effects of substituting organic manure species, i.e., stored swine manure fertilizer (SS), swine manure covered by straw (CS), stored swine fertilizer mixed with biochar (BS), and stored swine manure fertilizer with void expansion (OS) for compound fertilizer (FC) on rapeseed yield and NH3 and N2O emissions in a rapeseed-cropping system in China. The results showed that the total gaseous N losses (NH3 and N2O) were 1.6, 1.4 and 1.1 times higher in SS, CS and OS than FC, respectively. However, total gaseous N losses in BS was 0.9 times less than FC. Compared with FC, rapeseed yield and N uptake in SS and CS were decreased by 17.2–20.2% and 16.0%–28.1%, respectively, but which were increased by 7.3% and 54.1% in BS, respectively. In addition, OS decreased rapeseed yield by 17.2%, but increased N uptake by 8.5%. Therefore, the effects of substituting organic manure for compound fertilizer on rapeseed yield, N uptake, NH3 and N2O varied regarding different organic manure species. Adopting stored swine fertilizer mixed with biochar might be a sound management practice to reduce gaseous N losses and enhance N uptake and yield in intensive vegetable production systems.
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•Gaseous N losses and yield varied with different fertilizer management practices.•Organic manure substitution decreased gaseous N losses and increased yield.•Reducing NH3 under organic manure substitution should be considered.
For lithium–sulfur batteries (LSBs), the dissolution of lithium polysulfide and the consequent “shuttle effect” remain major obstacles for their practical applications. In this study, we designed a ...new cathode material comprising MoSe2/graphene to selectively adsorb polysulfides on the selenium edges and thus to mitigate their dissolution. More specifically, few-layered MoSe2 was first grown on nitrogen-doped reduced graphene oxide (N-rGO) using the chemical vapor deposition method and then infiltrated with sulfur as the cathode for LSBs. An initial capacity of 1028 mA h g–1 was achieved for S/MoSe2/N-rGO at 0.2 C, higher than 981 and 405.1 mA h g–1 for pure graphene and sulfur, respectively, along with enhanced cycling durability and rate capability. Moreover, the density functional theory simulation, in addition to the experimental adsorption test, X-ray photoelectron spectroscopy analysis, and transmission electron microscopy technique, reveals the dual roles that MoSe2 plays in improving the performance of LSBs by functioning as the binding sites for lithium polysulfides and as the platform that enables fast Li-ion diffusion by reducing its diffusion barrier. The reported finding suggests that the transition-metal selenides could be an efficient alternative material as the cathode for LSBs.
Approximately seven million population in the Qinghai-Tibet Plateau of China, a global climate sensitive region, still rely primarily on yak dung for household cooking and heating. The treatment and ...combustion of yak dung result in a variety of negative impacts in terms of local alpine grassland degradation, indoor air pollution, public health risk, as well as global climate change. There is an urgent need to explore alternative pathway for affordable and clean energy as indicated in the United Nations’ Sustainable Development Goals for 2030. This perspective has analyzed the key challenges rooted in yak dung use on the Qinghai-Tibet Plateau region. Based on this, this perspective has further proposed a new complementary energy system to take advantage of locally available, clean and sustainable energy sources of wind and solar power, and have provided economic analyses. Meanwhile, this perspective has pointed out the potential barriers to promoting the new complementary energy system in the Qinghai-Tibet Plateau region due to traditional habits, economic factors and policies. Finally, strategies for transitioning from yak dung to the proposed alternative energy system is discussed at the end. Successful energy transition for the Qinghai-Tibet Plateau region offers an important option to achieving many other sustainable development goals related to climate change, economic development, and environment. The perspective is expected to shed light on the development of sustainable energy in other developing region or countries in the world to address multiple societal goals.
•Integrative analysis on negative impacts of dung combustion on ecological system, public health, and climate change.•Proposal of coupled wind-solar-storage system on the Qinghai-Tibet Plateau.•Solution toward sustainable energy transition on the Qinghai-Tibet Plateau.
How substituting compound fertilizer with organic manure affects crop productivity and reactive nitrogen (Nr) losses from vegetable production system during the cradle-to-gate life cycle is not well ...understood. We thus investigated the impact of substituting compound fertilizer with various organic manures (stored solid manure and composted manure) on spinach productivity, Nr losses (e.g. NH3, N2O, NOx, N-leaching) and yield-based Nr losses in Changsha, Hunan, China. We found that the application of stored solid manure and composted manure decreased the total Nr losses by 58.1% and 75.0%, respectively, compared with compound fertilizer, but the spinach productivity was also decreased by 27.9% and 16.4%. Overall, substituting compound fertilizer with organic manure decreased yield-based Nr loss by 41.9–70.1%. These results highlight that substituting compound fertilizer with organic manure, particularly composted manure, may be beneficial to the environment at the expense of vegetable productivity. Strategies should be developed to decrease Nr losses from N input without compromising productivity in intensive vegetable production system.
Substituting compound fertilizer with organic manure effectively reduced total reactive N losses and N footprint, which depends on the manure types (manure solid storage or composted manure). However, substituting compound fertilizer with organic manure decreased N uptake and spinach productivity. Moreover, extra attention should be given to the effect of substituting compound fertilizer with organic manure on vegetable productivity such as spinach. We thus should strengthen the research on how to promote both N uptake and productivity in spinach while further mitigating N emission in adopting optimized organic manure management. Display omitted
•LCA was used to assess reactive nitrogen loss and yield in spinach cropping System.•Substituting compound fertilizer with organic manure decreased yield-based Nr loss.•Composted manure practice decreased concurrently reactive nitrogen loss and yield.•Improving the yield under various organic manure practices should be considered.
