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Maize production is facing multiple challenges toward increasing crop productivity, enhancing resource utilization, and mitigating climate change nowadays. Climate-smart agriculture (CSA) is an emerging concept, which pursues the synthesis of higher crop productivity, lower carbon emissions, and improved soil resilience to the climate change. However, few studies have been done to evaluate the productivity and environmental consequences following the CSA of maize production. Herein, the effects of CSA practice on maize yield, nitrogen use efficiency (partial factor productivity, PFP N), soil organic carbon (SOC) sequestration, and carbon footprint (CF) were evaluated based on a nine-year in-situ field experiment in northeastern China. The experiment followed a randomized block design with three treatments including in traditional farmers' practices (FM), optimized agronomic practices (OPT, aiming to high grain yield and PFP N), and climate-smart agriculture practices (CSA, aiming to higher grain yield, PFP N , SOC stock, while lower CF). Compared with FM, OPT and CSA practices significantly increased grain yield and PFP N by 25.0%− 30.1% and 92.2%− 100.2% on average of experimental duration, respectively. CSA practice had significant higher global warming potential (GWP) but equivalent global warming potential intensity (GWPI) than these of FM and OPT practices during 2016 and 2017. Meanwhile, CSA practice also achieved the highest SOC sequestration in 0–40 cm soil depth compared to other treatments. Consequently, CF per hectare (CF a) of CSA significantly decreased by 41.4% on average than that of FM mainly due to higher SOC sequestration. Concerning the profit of cropping system, CSA had the highest net ecosystem economic budget (NEEB) of 2090.62 $ ha−1 among the treatments. Overall, CSA practice showed advantages in promoting maize yield while reducing carbon footprint by integrated agronomic management (e.g. dense planting, subsoiling tillage, manure amendments, nitrogen fertilizer optimization, and so on), which could be regarded as a promising practice towards food security and carbon emission mitigation. [Display omitted] • An integrated agronomic practice was setup aiming to climate-smart agriculture (CSA). • CSA practice increased maize yield and nitrogen use efficiency compared to business as usual management. • CSA practice reduced carbon footprint by enhancing soil organic carbon stock and reducing indirect greenhouse gas emission. • It was demonstrated that CSA practice achieves the synergy of sustainable maize productivity and lower environmental costs. [ABSTRACT FROM AUTHOR]

Great efforts have been made on the assessment of the effects of straw managements or tillage practices on rice yield and greenhouse gas (GHG) emissions. However, their interactive effects were not well documented. Based on a seven-year field experiment under a double rice system, we tested the effects of rotary tillage (RT) vs. plough tillage (PT) on rice yield, methane (CH 4 ) and nitrous oxide (N 2 O) emissions with or without straw incorporation. As compared to straw removal, straw incorporation increased rice yield by 12.7% and 1.3% under the PT and the RT, respectively. Straw incorporation significantly stimulated CH 4 emissions under both tillage regimes in the late rice season, while no significant effect occurred in the early rice season. Compared to the RT, PT significantly decreased DOC concentrations and methanogen abundances, resulting in a reduction in CH 4 emission. The PT decreased yield-scaled global warming potential (GWP) with or without straw incorporation by 31.0% and 15.5%, respectively, as compared to the RT. Together, our results indicate that straw incorporation with plough tillage benefits rice production for higher-yield with less GHG emissions in double rice cropping areas. [ABSTRACT FROM AUTHOR]

Significant efforts have been made to assess the impact of tillage regimes on crop yields and/or greenhouse gas (GHG) emissions across single crop growing season. However, few studies have quantified the impact across a whole rotation cycle in multiple cropping systems. Utilizing on a long-term tillage experiment with the rice–wheat rotation system in East China, we examined the GHG emissions under different tillage practices with or without crop straw incorporation. Results showed that compared to the no-straw control, straw incorporation increased wheat yield by 28.3% ( P < 0.05), irrespective of tillage practices, but had no significant effect on rice yield. Although straw incorporation did not significantly affect CH 4 emissions during the wheat season and N 2 O emissions during the whole rice–wheat cycle, it significantly stimulated CH 4 emissions by 98.8% ( P < 0.01) during the rice season. Also, there were no significant differences in CH 4 and N 2 O emissions between tillage practices during the wheat season. Compared to plowing, rotary tillage increased CH 4 emissions significantly by an average of 38.8% ( P < 0.01) but had no significant impacts on N 2 O emissions during the rice season. Across the rotation cycle, annual yield-scaled global warming potential of CH 4 and N 2 O emissions under no-tillage plus rotary tillage was 26.8% ( P < 0.01) greater than that of rotary tillage plus plowing with or without straw incorporation. Significant interactions between soil tillage and straw management practices were found on annual GHG emissions, but not on crop yields. Together, these results indicate that plowing in the rice season plus rotary tillage in the wheat season may reduce GHG emissions while increasing crop yield in rice–wheat cropping areas. [ABSTRACT FROM AUTHOR]

Studies on greenhouse gas (GHG) emissions from paddy field have primarily focused on the post-transplanting period, however, recent researches raise new concerns about GHGs emission from rice nursery. In this study, CH 4 and N 2 O fluxes were determined from different nurseries under major rice cropping systems in China. The tested nurseries included flooded nursery (FN), moist nursery (MN) and dry nursery (DN). Methane emissions from FN were significantly higher than those from MN and DN under all the rice cropping systems. When comparing with FN, MN decreased total CH 4 emissions by 74.2%, 72.1% and 49.6% under the rice–upland rotation cropping system (RUR), and the double rice cropping system for the early rice (EDR) and the late rice (LDR), respectively. DN decreased CH 4 emissions by 99.2%, 92.0%, 99.0% and 78.6% compared to FN under the single rice cropping system (SR), RUR, EDR and LDR, respectively. When comparing with FN, MN and DN increased N 2 O emissions by 58.1–134.1% and 28.2–332.7%, respectively. Ultimately, compared with FN across the cropping systems, MN and DN decreased net global warming potentials (GWPs) of CH 4 and N 2 O by 33–68% and 43–86%, respectively. The mitigating effect of MN and DN on total GWPs varied greatly across the systems, ranging from 30.8% in the LDR to 86.5% in the SR. Chinese actual emission from rice nurseries was reduced to 956.66 × 10 3 t CO 2 eq from the theoretical estimate of 2242.59 × 10 3 t CO 2 eq if under the flooded nursery scenario in 2012. Taking into account the large rice nursery area (2032.52 × 10 3 ha) in China, the results of this study clearly indicate the importance to estimate and mitigate GHGs emission from flooded rice nursery. Being effective to reduce GHG emissions and increase rice yield, dry nursery technique is a promising candidate for climate smart rice cropping. [ABSTRACT FROM AUTHOR]

A better understanding of wheat cultivar impact on field N 2 O emissions could provide important information for cultivar improvement and selection to meet food security and greenhouse gas (GHG) mitigation. A 2-year field experiment was carried out from 2015 to 2017 on 12 leading cultivars released in the major winter wheat cropping regions of China since the 1940s. Field N 2 O emissions, wheat growth, and plant nitrogen uptake were determined. The results showed that both the cumulative and yield-scaled N 2 O emissions differed significantly among cultivars, varying on average from 1.64 to 2.10 kg N 2 O–N ha−1 and 232.65–529.37 mg N 2 O–N kg−1, respectively. As the wheat cultivar renewal progressed, the cumulative and yield-scaled N 2 O emissions declined significantly at the relative decrease rates of 0.2% yr−1 and 0.9% yr−1, respectively. In addition to wheat grain yield and biomass, amount of plant N uptake has been enhanced significantly over the past sixty years. The spike number per unit area, leaf dry matter, net photosynthesis rate, and transpiration rate also all increased, whereas wheat plant height decreased over the decades. Our findings demonstrate that lower N 2 O emissions can primarily be attributed to the greater N uptake of the newly high-yielding wheat cultivars, suggesting a great chance of ensuring food security and GHG mitigation simultaneously through cultivar selection and improvement. [Display omitted] • Both the cumulative and yield-scaled N 2 O emissions were lower with new wheat cultivars compared to old ones. • The reduction effects of yield-scaled N 2 O emissions with the cultivar improvement overperformed the cumulative N 2 O emissions. • Wheat yield and N uptake increased significantly along with the cultivar improvement. • Lower N 2 O emissions with new cultivars was associated with higher productivity and N uptake, and lower soil N availability. [ABSTRACT FROM AUTHOR]