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• Plant N/P may regulate the response of plant and bacterial richness to different treatments. • Manure application (M), and poa annua, elymus dahuricus , and puccinellia distans mixed with non-tillage reseeding (R), and the interaction (MR) did not significantly change the correlation between plant and bacterial communities, and plant abundance was closely related to bacterial abundance. • N limitation may be a key factor in determining the effectiveness of close-to-nature restoration measures. As important terrestrial ecosystems on the Qinghai‒Tibet Plateau with important ecological and economic value, alpine meadows in some regions are in a degraded state due to climate change and unsustainable grazing. Due to the fragile ecological environment, exploring sustainable restoration models of degraded alpine meadows using close-to-nature restoration measures is the direction of ongoing efforts. Thus, in this study, three close-to-nature restoration measures, namely, manure application (M), Poa annua, Elymus dahuricus , and Puccinellia distans mixed with non-tillage reseeding (R), and the combined treatments (MR), were used to restore degraded alpine meadows from 2019 to 2021. The results showed that the M and MR treatments significantly enhanced plant biomass and reduced forbs dominance, thus improving community structure. Moreover, the M and MR treatments significantly affected plant and bacterial alpha diversity. However, the three restoration measures did not alter the correlation between the plant and bacterial communities. Furthermore, these three measures resulted in a significant increase in the plant carbon:nitrogen ratio and a significant decrease in the nitrogen:phosphorus ratio, while neither the plant carbon:phosphorus ratio nor the soil stoichiometric ratio changed significantly, indicating that nitrogen limitation was an important factor that limited the recovery process of the alpine meadows. The structural equation model indicated that the plant nitrogen:phosphorus ratio may regulate the response of plant and bacterial diversity to different restoration measures in alpine meadows. Our findings emphasize that the management of degraded alpine meadows using close-to-nature restoration measures should be a long-term effort, with more attention given to changes in the nitrogen content of meadow ecosystems. [ABSTRACT FROM AUTHOR]

Nitrogen (N) deposition is a vital process of N cycling and is consequently important for the evaluation of N budgets. However, the character and quantity of N deposition inside the horticultural greenhouse remain unknown, impeding a deep understanding of N cycling among soil, vegetable and atmosphere. Here, we measured the dry and wet N deposition, and disentangled the relative percentages of ammonia (NH 3) and nitrogen oxides (NO X) gases deposition based on the greenhouse vegetable cultivation experiment. Results found the annual N deposition, was 7.2–17.5 kg N·ha−1 under different chemical/organic N fertilizer managements, consisting of 77.0%–85.5% by dry deposition and 14.5–23% by wet deposition. The proportions of N deposition from NH 3 and NO X emissions ranged within 37.5–83.0% under different N managements. The NH 3 emission was the dominant driving factor of dry N deposition, while soil moisture was the dominant driving factor of wet N deposition. Controlled-release fertilizer combined with organic fertilizer resulted in the lowest N deposition (10.2 kg N·ha−1) and NH 3 and NO X emissions (12.5 kg N·ha−1), which could be recommended as the mitigation strategy in greenhouse cultivation. This study investigated the dry and wet N deposition characteristics and their influencing factors, as well as the proportion of N deposition attributed to NH 3 and NO X emissions, which provides preliminary understanding of N deposition and the reactive N gas diffusion from greenhouse into the atmosphere. [Display omitted] • The characteristics of dry and wet N deposition inside greenhouse were investigated. • Annual N deposition varied from 7.2 to 17.5 kg N·ha−1 with different N managements. • N deposition accounted for 37.5–83.0% of NH 3 and NO X emissions. • Dry N deposition has taken up of 77.0%–85.5% of annual N deposition. • NH 3 emission and soil moisture were key to regulating N deposition inside greenhouse. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) data submitted in April 2014 on land use, land use change and forestry (LULUCF), energy, industrial processes, solvents and other product use, agriculture, and waste for 37 developed countries was analyzed to estimate the relative contributions of different sectors to GHG emission reductions. This GHG data from the first commitment period of the Kyoto Protocol included 35 parties to Annex B of the Kyoto Protocol, the United States and Canada. Results show that the contribution of each sector was, in order: energy (36.9%), industrial processes (12.4%), agriculture (9.9%), LULUCF (7.7%), waste (3.4%), and solvents and other product use (0.1%). The average proportion of base year emissions reduced in each sector by countries in Annex B was, in order: energy (7.4%), agriculture (2.7%), LULUCF (1.9%), industrial processes (1.2%), waste (0.5%), and solvents and other product use (0.1%). Overall, the energy sector contributed the highest GHG emission reductions, while the agriculture and LULUCF sectors also made contributions. Most countries achieved limited absolute GHG reductions from their chosen LULUCF activities, but the relative contribution of GHG emission reductions from LULUCF was significant but small. This suggests that, unless there are substantial changes to accounting rules, future emission reductions will mainly result from mitigation actions targeting fossil fuel consumption, while the agriculture and LULUCF sectors will continue to play auxiliary roles. [ABSTRACT FROM AUTHOR]

Sustainable production of paddy rice is essential in supplying staple food worldwide. In the present study, we determined annual yield, greenhouse gas emissions (GHGs) and carbon footprint of double cropping paddy rice (Oryza sativa L.) as impacted by organic and inorganic amendments in a 38-year study from central China. A balanced synthetic fertilizer of nitrogen (N), phosphorus (P) and potassium (K) combined with rice straw application (NPK_RS) consistently produced higher annual grain yield by 5%, 11% and 64%, respectively, compared with NPK, anaerobically digested manure (NKM) and NK. Average GHGs associated with both early- and late-season rice production were 47,300 kg CO 2 eq ha-1 yr-1 for the NPK_RS, 24,100 kg CO 2 eq ha-1 yr-1 for the NPK, 27,700 kg CO 2 eq ha-1 yr-1 for the NKM, 24,300 kg CO 2 eq ha-1 yr-1 for the NK, and 20,400 kg CO 2 eq ha-1 yr-1 for the non-fertilized control (CK). Of the total GHGs, approximately from 80% to 95% of the emissions resulted from methane fluxes, and from 3% to 7% emitted as soil nitrous oxide while only from 2% to 15% of the total emissions derived from other sources such as fertilizer, herbicide and pesticide production and field operation. As a result, carbon footprint of paddy rice varied from 2.1 to 3.9 kg CO 2 eq kg-1 grain. Straw addition with the NPK improved rice yield only marginally, but increased methane emissions and carbon footprint significantly, compared with the NPK. On the other hand, the NKM increased rice yield by 48% and GHGs by 10% and lowered carbon footprint by 23%, compared with the NK. Timing of straw application and manure amendments are critical for improving yield of paddy rice, reducing GHGs, and lowering carbon footprint. [Display omitted] • Manure application effectively eliminates soil phosphorus deficiency. • Balanced chemical fertilizers sustain high yield of double cropping paddies. • Manure and straw addition increase methane emissions. • Straw addition improves rice yield marginally and increases carbon footprint. [ABSTRACT FROM AUTHOR]

Scaling up of farming operations by land use rights transfers has been a growing trend in China in recent years. However, little is known about the implications of this trend for greenhouse gas (GHG) emissions and soil organic carbon (SOC) stock changes. Using farm survey data from Shandong Province, a typical grain production region in China, we used a life cycle assessment (LCA) method to evaluate the impact of different farm scales on input use efficiency, grain production, SOC stock changes and GHG emissions. Large-scale farming operations (LSFO) enhanced input use efficiency by reducing fertilizer and pesticide consumption rates and energy use for irrigation. Compared with small household farming operations (SHFO), LSFO attained higher grain yield in wheat-maize and wheat-rice cropping systems. Compared with small farms, carbon footprints per unit area of large-scale farms were lower for wheat (17%) and maize (28%) in the wheat-maize cropping system and for wheat (14%) and rice (8%) in the wheat-rice cropping system. Moreover, LSFO reduced GHG emissions (7–21%) and enhanced SOC stocks (6–9%), compared with SHFO. This study highlights that in China, land use rights transfers to promote large-scale farming can help achieve cleaner grain production with less negative impact on the environment. [ABSTRACT FROM AUTHOR]

Abstract: It is unclear how inhibition of nitrous oxide (N2O) emissions by nitrification inhibitor (NI) is regulated through the ammonia oxidizing bacteria (AOB) or archaea (AOA) in arable soils. In this study, we investigated effects of 2-chloro-6-(trichloromethyl)-pyridine (Nitrapyrin, NP) on N2O emissions, and characterized the ammonia oxidizing microbial community in three arable soils typical of northern China. In alluvial, black, and paddy soils, average N2O emission rates were increased by addition of urea by 3.5, 0.7 and 2.1 pM N2O g−1 soil h−1, respectively, but were reduced by 2.9, 0.4 and 2.2 pM N2O g−1 soil h−1 when urea was applied with NP. The stimulation and suppression of N2O emission by urea and NP occurred alongside fluctuation in the growth of AOB in alluvial and paddy soils (P < 0.01). Weak stimulation and suppression of N2O emissions by urea and NP corresponded with weak effects on AOB abundances in the black soil. Changes in N2O emissions were not significantly correlated with AOA abundances in any of the three soils. The results showed that differential responses of N2O emission to urea and NP application in arable soils can be mainly explained by differences in growth of ammonia oxidizing bacteria. [Copyright &y& Elsevier]

Highlights: [•] The cost-effectiveness of water-saving irrigation based climate change mitigation was researched. [•] The cost-effectiveness of water-saving irrigation based climate change adaptation was researched. [•] The mitigation and adaptation potential in the coming decade was researched. [•] Development proposal of water-saving irrigation was made according to cost-effectiveness analysis. [ABSTRACT FROM AUTHOR]

Abstract: Although sensitivity analysis (SA) was conducted on the DeNitrification–DeComposition (DNDC) model, a global SA over a long period of time is lacking. We used a method of Bayesian analysis of computer code outputs (BACCO) with the Gaussian emulation machine for sensitivity analysis software (GEM-SA) to conduct a long-term SA of DNDC for predicting the annual change of soil organic carbon (dSOC), nitrous oxide emission (N2O) and grain yield of spring wheat. Twenty seven non-weather input parameters with wide ranges were selected for SA using weather data recorded from Three Hills, Alberta over 86 years (1921–2006). The SA had two steps: 1) a preliminary BACCO GEM-SA was conducted to identify a more accurate emulator sampling method and to screen out parameters with insignificant influence on model outcomes; and 2) final BACCO GEM-SA was conducted with optimal input design set for emulator training runs varying only the significant input parameters. Results indicated that the Maximin Latin Hypercube sampling method outperformed the LP-τ method with higher emulator accuracy. Most of the 27 input parameters contributed little to the three outputs by the first step BACCO GEM-SA. In the second step of BACCO GEM-SA there were only three (in the case of dSOC) and six (in the cases of N2O and yield) input parameters whose influence contributed to more than 10% of the total output variances by their total effects. Among the selected parameters, initial soil organic carbon and clay content are very important and were important in determining results for all three outputs. Sensitivities of some parameters, such as clay content and urea fertilizer amount changed dramatically over the years. This indicates that a single year SA may overestimate or underestimate a long-term parameter effect on the model prediction. The two-step procedure with the BACCO GEM-SA method improved the accuracy of SA and provided important information for model validation and parameterization. [Copyright &y& Elsevier]

Our understanding on how soil organic carbon (SOC) storage, crop yield, and yield stability are influenced by climate is limited. To critically examine this, the impact of long-term (≥10 years) application of nutrient management practices on SOC storage, crop productivity, and yield stability were evaluated under different climatic conditions in China using a meta-analysis approach. The cropping area of China was divided into four distinct groups based on local climatic conditions (warm dry, DW; warm moist, WM; cool dry, CD; cool moist, CM). Results indicated that the impact of nutrient management practices on SOC storage, crop yield, and yield stability varies under different climatic zone in China. The use of unbalanced mineral fertilizer (UMF), and balanced mineral fertilizer (BMF) led to a loss in SOC storage by 6%, and 11% under CM climatic zone and gains in DW, WM, and CD climates. Organic fertilizers (OF), combined unbalanced mineral and organic fertilizers (UMOF), and combined balanced mineral and organic fertilizers (BMOF) were able to sustain and enhance SOC storage under all climatic conditions. However, the largest increase in SOC storage across all climates was seen for BMOF. Further, corresponding values of crop productivity and yield stability were also highest for BMOF among all the nutrient management treatments. A linear-plateau model indicated that maximal yield responsive SOC stock (C opt) levels ranged from 33.43 to 45.51 Mg C ha−1 for rice (Oryza sativa), maize (Zea mays), and wheat (Triticum aestivum) production. To enhance and sustain SOC storage, and crop productivity of croplands under different climates, BMOF appears to be the most appropriate nutrient management strategy. Our findings demonstrate that it is essential to optimize nutrient management strategies according to the local climate to protect soil from SOC losses, and for achieving sustainable crop production. • The impact of nutrient managements on SOC storage, crop yield, and yield stability varies under different climatic zones. • Unbalanced mineral, and balanced mineral fertilizer led to a loss in SOC storage by 6%, and 11% under cool moist climate. • Combined balanced mineral with organic inputs is crucial for maximal SOC storage and crop yields under different climates. • Maximal yield responsive SOC stock levels ranged from 33.43 to 45.51 Mg C ha−1 for rice, maize, and wheat production. [ABSTRACT FROM AUTHOR]

• Elevated [CO 2 ] and temperature jointly stimulated leaf A net before heading. • Air warming accelerated photosynthetic down-regulation under CO 2 enrichment after heading. • G s acclimated to warming and CO 2 enrichment in parallel with A net under no stress conditions. • Earlier leaf senescence, larger sink capacity or lower rice sterility might cause photosynthetic acclimation. • Co-elevation of [CO 2 ] and temperature increased dry matter productivity in Chinese double rice cultivation. Changes in atmospheric CO 2 concentration ([CO 2 ]) and temperature have impacts on leaf photosynthesis (A net) and stomatal conductance (G s) of rice, which strongly affect dry matter productivity. Understanding of the acclimation responses of A net and G s under elevated [CO 2 ] and/or temperature is limited. A field experiment of double rice (early rice-late rice rotation) was conducted using open-top chambers from 2013 to 2016 in Hubei Province, Central China, with two levels of [CO 2 ] (ambient, ambient + 60 μmol mol−1) and two levels of temperature (ambient, ambient + 2°C). Averaging across the four-year experiment, elevated [CO 2 ] and elevated temperature increased A net by 2.4 %–9.4 % and 2.4 %–10.7 %, respectively at pre-heading stages. A positive interaction was observed between elevated [CO 2 ] and temperature in early rice which further increased A net , while the interaction was not additive in late rice. Elevated [CO 2 ] caused lower G s and partly offset the stimulation of elevated temperature on G s at tillering and jointing. At post-heading stages, photosynthetic acclimation to elevated [CO 2 ] was observed as the stimulation of A net was not continued. Elevated temperature decreased A net by 1.7 %–16.6 % and further accelerated photosynthetic down-regulation by elevated [CO 2 ]. Warming reduced G s at milking and maturity in early rice because of high ambient temperature, which resulted in stomatal limitation to photosynthesis, but its effects on G s in late rice were positive because the ambient temperature was low. Generally, G s acclimated to warming and CO 2 enrichment in parallel with A net when there were no environmental constraints. Earlier leaf senescence, decreased leaf SPAD, lower seed-setting rate or larger sink capacity caused by elevated [CO 2 ] and/or temperature might directly or indirectly explain the down-regulation on photosynthesis after heading. Our results show that warming alters the acclimation of leaf photosynthesis and stomatal conductance to CO 2 enrichment and the combined effects differ between growth stages, and indicate that co-elevation of [CO 2 ] and temperature may increase dry matter productivity in the Chinese double rice cropping system. [ABSTRACT FROM AUTHOR]