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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]

Increasing crop biodiversity often increases agro-ecosystem services, however, the effects of crop biodiversity on crop yield and environmental benefits are still unclear. Thus, we conducted a 4-yr field experiment in northeastern China including continuous maize (CM), continuous soybean (CS), maize and soybean rotation (M-S), and maize and soybean intercropping (M/S) to evaluate the crop productivity, economic returns, carbon footprint (CF) and carbon sustainability index (CSI) among the cropping system regimes. Compared with CM treatment, M-S and M/S achieved lower energy yield (EY) and maize equivalent economic yield (MEEY), but higher economic returns. The mean annual net revenue of M-S treatment was 7.2% higher, and the mean annual benefit: cost ratio of M-S and M/S treatments were 12.0% and 8.8% higher than those of CM treatment. Based on the life cycle assessment (LCA), lower CFs were observed in the M-S and M/S systems. The CF per unit of area (CF A) of M-S and M/S treatments was 21.4% and 51.3% lower than that of the CM treatment, respectively. The CF per kg of energy yield (CF EY) of M/S treatment was 35.4% lower, compared with that of the CM treatment. The CF per kg of maize equivalent economic yield (CF MEEY) under M/S treatment was 44.0% lower, than that of the CM treatment. Moreover, CF per unit of economic output (CF E) of M/S treatment was 45.0% lower than that of the CM treatment. The highest CSI was observed in M-S treatment, and it was 61.4% higher than that of CM treatment. Our findings indicate that diversified crop practice (e.g. maize-soybean intercropping and rotation systems) could achieve lesser carbon footprint and higher profitability, however, might compromise grain or energy yield. [Display omitted] • The productivity, profitability, and environmental costs of different cropping systems were evaluated. • Diversified crop practice had lesser carbon footprint and higher profitability. • Maize-soybean intercropping systems is an alternative to the traditional maize monoculture system in northeastern China. [ABSTRACT FROM AUTHOR]