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There are many risk factors for the recurrence of colorectal adenoma (CRA). The purpose of this study was to explore the predictive performance of fibrinogen-to-lymphocyte ratio (FLR) and neutrophil-to-lymphocyte ratio (NLR) on the recurrence of CRA and to construct a predictive model.This study analyzed the clinicopathological features of 421 CRA patients who underwent colonoscopy and adenectomy, and evaluated the recurrence of polyps under colonoscopy. Among them, 301 were training cohort and 120 were validation cohort. Multivariate logistic regression was used to identify independent risk factors associated with CRA recurrence. Established a nomogram model to predict the risk of recurrence in CRA patients using independent risk factors. The receiver operating characteristic (ROC) curves were used to verify the nomogram model discrimination. Calibration curves were used to verify the model calibration degree. The decision curve analysis (DCA) curves were used to verify the clinical efficacy of the nomogram model.Totally, six independent predictors, including smoking, diabetes, adenoma number, adenoma size, NLR, and FLR, were enrolled in the nomogram. In the training cohort and validation cohort, the area under the curve (AUC) of the nomogram for predicting the risk of CRA recurrence was 0.846 and 0.841, respectively. The calibration curves displayed a good agreement. DCA curves showed that this model had a high net clinical benefit.Smoking, diabetes, adenoma number, adenoma size, NLR, and FLR were influencing factors for CRA recurrence.

Crop growth period responses to climate change directly affect yield and quality; these changes have been investigated, but few studies have researched the quantitative effects of the sowing date (SD), cultivar shift and extreme temperatures on the vegetative growth period (VGP) and reproductive growth period (RGP) of crops. Based on the observed growth periods and weather data from 30 agro-meteorological stations in Northeast China (NEC), the middle and lower reaches of the Yangtze River (MLYR), the Sichuan Basin (SB) and on the Yunnan-Guizhou Plateau (YGP) during 1981–2010, we found that (1) advancing the SD resulted in the extension of the VGP but had no significant effect on the RGP. (2) Cultivar shift mainly prolonged the RGP, and its mean contribution to the trend in the RGP (68.4%) was greater than that of climate change (31.6%). (3) Increases in growing degree days (GDD) tended to lengthen the VGP and RGP, and their mean relative contribution to the VGP (65.9%) was higher than that of the RGP (58.4%). (4) Increases in killing degree days (KDD) and decreases in cold degree days (CDD) tended to shorten the VGP and RGP, and the mean relative contribution of KDD to the VGP (− 18.8%) was lower than that of the RGP (− 29.8%), while the mean relative contribution of CDD to the VGP (− 15.2%) was higher than that of the RGP (− 10.9%). The findings highlight the adverse effects of KDD and CDD on the growth periods of single-cropping rice and show how a reasonable SD scientifically matched with suitable cultivar types can make full use of climate resources and mitigate the adverse effects of extreme temperatures.

BACKGROUND: Accurate assessment of lymph node status in gastric cancer (GC) patients can help to select appropriate treatment strategies for GC, but the diagnostic accuracy of conventional methods needs to be improved. The aim of this study was to investigate the predictive value of preoperative hemoglobin and albumin levels and lymphocyte and platelet counts (HALP) on lymph node status in GC patients and to construct a risk prediction model. METHODS: This study retrospectively analyzed the clinicopathological characteristics of 349 patients with GC who underwent radical gastrectomy, among which 250 patients were recruited in the training cohort and 99 patients in the independent validation cohort. Significant risk factors in univariate analysis were further identified as independent variables in multivariate logistic regression analysis, which were then incorporated and presented in a nomogram. Receiver operating characteristic (ROC) curves, Calibration curve and decision curve analysis (DCA) curves were used to evaluate the discrimination, prediction accuracy and clinical effectiveness of the model RESULTS: Multifactorial logistic regression analysis showed that alcohol use (OR =2.203, P=0.036), Depth of invasion (OR =7.756, P

Autumn phenology, determined mainly by temperature and photoperiod, is essential for ecosystem carbon sequestration. Usually, the variations in the maximum rate of Rubisco (Vcmax) and the maximum rate of ribulose-bisphosphate regeneration (Jmax) are taken as the mechanism regulating the seasonal pattern of photosynthetic rates and autumn phenology. In this study, we used Quercus mongolicus seedlings as an example to examine the photosynthetically physiological mechanism of leaf coloration onset (LCO) responding to different warming and photoperiod treatments based on experimental data acquired from large artificial climate simulation chambers. The results indicated that: (1) LCO and the net CO2 assimilation rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), Vcmax, and Jmax of Quercus mongolicus seedlings were significantly affected by the changes of photoperiod. (2) LCO was significantly correlated only with the Pn approach, supporting the view that leaf senescence is the result of a trade-off between nutrient resorption and reserves. (3) The major variation in stomatal conductance (Gs) is the mechanism by which photoperiod regulates the seasonal pattern of photosynthetic rates, implying that both limitations of stomatal and photosynthetical capacity (Vcmax and Jmax, non-stomatal limitation) are able to modulate LCO. Our study riches the knowledge of phenology and provides a reference for phenological modelling and ecosystem carbon estimation.

Fluxes of carbon and water along a vertical profile within a canopy, particularly the associations between canopy and ecosystem levels, are not well studied. In this study, gas exchange along the vertical profile in a maize canopy was examined. The relationships between leaf- and ecosystem-level carbon and water fluxes were compared. The results from research conducted over two growing seasons showed that during vegetative growth, the top and middle leaf layers in the canopy contribute most to the carbon and water fluxes of the entire canopy. During the grain-filling stage, gas exchange processes were performed mostly in the middle leaves with and near the ears. Significant relationships were observed between the net ecosystem CO2 exchange rate (NEE) plus soil respiration and the assumed canopy levels (Acanopy) and between evapotranspiration rates at the ecosystem (ET) and assumed canopy levels (Ecanopy). This highlights the close associations between these parameters by integrating the leaf gas exchange rates measured in a conventional leaf cuvette and those at the ecosystem level via the eddy covariance technique. These results improve our understanding of how carbon assimilation varies vertically within a canopy, highlighting the critical role of ear leaves.

Lactic acid, a metabolic by-product of host and intestinal microbiota, has been recovered as an active signal molecule in the immune system. In this study, a lactic acid biosynthesis pathway that directly produces lactic acid from glucose rather than ethanol with high production was reconstructed in Saccharomyces cerevisiae. The engineered S. cerevisiae showed anti-inflammatory activity in dextran sulfate sodium (DSS)-induced mice with improved histological damage, increased mucosal barrier, and decreased intestinal immune response. Lactic acid regulated the macrophage polarization state and inhibited the expression of pro-inflammatory cytokines in vivo and in vitro. Increasing the macrophage monocarboxylic acid transporter-mediated active lactic acid uptake suppressed the excessive activation of the NLRP3 inflammasome and the downstream caspase-1 pathway in macrophages. Moreover, lactic acid promoted histone H3K9 acetylation and histone H3K18 lactylation. Meanwhile, the engineered S. cerevisiae altered the diversity and composition of the intestinal microbiota and changed the abundance of metabolic products in mice with colitis. In conclusion, this study shows that the application of engineered S. cerevisiae attenuated DSS-induced colitis in mice via suppressing macrophage pyroptosis and modulating the intestinal microbiota, which is an effective and safe treatment strategy for ulcerative colitis.

Scope: Gut microbiome-derived metabolites are the major mediators of diet-induced host-microbial interactions. Aryl hydrocarbon receptor (AHR) plays a crucial role in glucose, lipid, and cholesterol metabolism in the liver. In this study, we aimed to investigate the role of indole-3-acetic acid (IAA) and AHR in sulforaphane (SFN) alleviates hepatic steatosis in mice fed on a high-fat diet (HFD).Methods and Results: The HFD-fed male C57BL/6 mice were intervened with SFN for 6 weeks. HFD-mice showed classical pathophysiological characteristics of hepatic steatosis. The results showed that SFN significantly reduced body weight, liver inflammation and hepatic steatosis in HFD-fed mice. SFN reduced hepatic lipogenesis by activating AHR/SREBP-1C pathway, which was confirmed in HepG2 cell experiments. Moreover, SFN increased hepatic antioxidant activity by modulating Nrf-2/NQO1 expression. SFN increased serum and liver IAA level in HFD mice. Notably, SFN manipulated the gut microbiota, resulting in reducing Deferribacteres and proportions of the phylum Firmicutes/Bacteroidetes and increasing the abundance of specific bacteria that produce IAA. Furthermore, SFN upregulated Ahr expression and decreased the expression of inflammatory cytokines in Raw264.7 cells.Conclusions: SFN ameliorated hepatic steatosis not only by modulating lipid metabolism via AHR/SREBP-1C pathway but regulating IAA and gut microbiota in HFD-induced NAFLD mice.

Climate change, characterized by warming and precipitation variability, restricted the growth of plants in arid and semiarid areas, and various functional traits are impacted differently. Comparing responses of functional traits to warming and precipitation variability and determining critical water threshold of dominate steppe grasses from Inner Mongolia facilitates the identification and monitoring of water stress effects. A combination of warming (ambient temperature, +1.5°C and +2.0°C) and varying precipitation (−30%, −15%, ambient, +15%, and +30%) manipulation experiments were performed on four Stipa species (S. baicalensis, S. bungeana, S. grandis, and S. breviflora) from Inner Mongolia steppe. The results showed that the functional traits of the four grasses differed in their responses to precipitation, but they shared common sensitive traits (root/shoot ratio, R/S, and specific leaf area; SLA) under ambient temperature condition. Warming increased the response of the four grasses to changing precipitation, and these differences in functional traits resulted in changes to their total biomass, with leaf area, SLA, and R/S making the largest contributions. Critical water thresholds of the four grasses were identified, and warming led to their higher optimum precipitation requirements. The four steppe grasses were able to adapt better to mild drought (summer precipitation decreased by 12%–28%) when warming 1.5°C rather than 2.0°C. These results indicated that if the Paris Agreement to limit global warming to 1.5°C will be accomplished, this will increase the probability for sustained viability of the Stipa steppes in the next 50–100 years.

Evaluating climatic suitability of crop cultivation lays a foundation for agriculture coping with climate change scientifically. Herein, we analyse changes in the climatically suitable distribution of summer maize cultivation in China at 1.5 °C (GW1.5) and 2.0 °C (GW2.0) global warming in the future according to the temperature control targets set by the Paris Agreement. Compared with the reference period (1971–2000), the summer maize cultivation climatically suitable region (CSR) in China mainly shifts eastwards, and its acreage significantly decreases at both GW1.5 and GW2.0. Despite no dramatic changes in the CSR spatial pattern, there are considerable decreases in the acreages of optimum and suitable regions (the core of the main producing region), indicating that half-a-degree more global warming is unfavourable for summer maize production in China’s main producing region. When the global warming threshold increases from GW1.5 to GW2.0, the centres-of-gravity of optimum areas shift northeastward under RCP4.5 and RCP8.5, the centres-of-gravity of both suitable and less suitable areas shift northwestward, though the northward trend is more prominent for the less suitable areas, and the centre-of-gravity of unsuitable areas shifts southeastward. Generally, half-a-degree more global warming drives the cultivable areas of summer maize to shift northward in China, while the west region shows a certain potential for expansion of summer maize cultivation.

Objective: Endoscopy is the main method to treat gastrointestinal neuroendocrine tumors (GI-NETs), but the specific indications are still controversial. We aim to investigate the clinical outcomes ...

Drought stress has adverse effects on crop growth and yield, and its identification and monitoring play vital roles in precision crop water management. Accurately evaluating the effect of drought stress on crop photosynthetic capacity can provide a basis for decisions related to crop drought stress identification and monitoring as well as drought stress resistance and avoidance. In this study, the effects of different degrees of persistent drought in different growth stages (3rd leaf stage, 7th leaf stage and jointing stage) on the maximum carboxylation rate at a reference temperature of 25 °C (Vcmax25) of the first fully expanded leaf and its relationship to the leaf water content (LWC) were studied in a field experiment from 2013 to 2015. The results indicated that the LWC decreased continuously as drought stress continued and that the LWC decreased faster in the treatment with more irrigation. Vcmax25 showed a decreasing trend as the drought progressed but had no clear relationship to the growth stage in which the persistent drought occurred. Vcmax25 showed a significantly parabolic relationship (R2 = 0.701, p &lt, 0.001) with the LWC, but the different degrees of persistent drought stress occurring in different growth stages had no distinct effect on the LWC values when Vcmax25 reached its maximum value or zero. The findings of this study also suggested that the LWC was 82.5 ± 0.5% when Vcmax25 reached its maximum value (42.6 ± 3.6 μmol m−2 s−1) and 67.6 ± 1.2% (extreme drought) when Vcmax25 reached zero. These findings will help to improve crop drought management and will be an important reference for crop drought identification, classification and monitoring as well as for the development of drought monitoring and early warning systems for other crops or maize varieties.

Leaves play an important role in plant growth and development through photosynthesis and transpiration. Many studies have explored the effects of short-term drought stress on leaf water status; however, few studies have focused on the leaf water content capacity as an indicator of soil–plant water status during prolonged droughts. The results of a field experiment with various irrigation regimes that was conducted during two consecutive maize growing seasons from 2013 to 2014, indicated that the water content of the first fully expanded leaf (LWCtop1) was representative of the soil–plant water status with the development of drought. LWCtop1 was closely linked to the water condition of other leaves and different plant parts in response to progressive water stress. LWCtop1 shared a quadratic relationship with the photosynthetic rate (Pn), and Pn peaked when LWCtop1 approached 84.11% and decreased to zero when LWCtop1 dropped to 68.26%. Moreover, three stages (slow-fast-slow) were observed as leaf water content responded to soil drying, and two important threshold values (minimum: 70.86 ± 0.80%, maximum: 84.58 ± 1.10%) of the leaf water content were determined. The results of this study may provide a physiological and ecological basis for the identification and monitoring of crop drought.

Apoptosis of gastric mucosa epithelial cells caused by the abuse of alcohol produces injury to the gastric mucosa and acute or chronic gastritis. In recent years, it has been demonstrated that endoplasmic reticulum stress (ERS) is involved in mediating apoptosis, and that autophagy has a protective effect on survival of cells. Rebamipide is a gastric mucosal protectant used to treat gastritis and stomach ulcers. In this study, ethanol was used to overstimulate gastric mucosal epithelial cells and gavage mice. It was found that 400 mmol/L ethanol overstimulation could activate ERS and induce apoptosis (control vs ethanol treatment: 15.24 ± 1.10% vs 33.80 ± 1.47%, P 0.001); but could not activate the autophagy pathway. Rebamipide intervention can reduce apoptosis rate (20.78 ± 1.63%), and significantly inhibit the activation of ERS and the active ERS-related downstream NF-κB signaling pathway. Additionally, rebamipide can activate the expression of autophagy-related pathway proteins and increase the expression of p-ERK and p-p38. In addition, rebamipide relieved oxidative stress after an ethanol insult. In the present study, molecular evidence of rebamipide inhibition of ERS and regulation of the protein expression of autophagy pathway components were produced using an acute alcoholic gastric mucosal injury model. This model provides a new approach for investigating the effects of rebamipide treatment on alcohol-induced gastric mucosal damage.

Abnormally altered precipitation patterns induced by climate change have profound global effects on crop production. However, the plant functional responses to various precipitation regimes remain unclear. Here, greenhouse and field experiments were conducted to determine how maize plant functional traits respond to drought, flooding and rewatering. Drought and flooding hampered photosynthetic capacity, particularly when severe and/or prolonged. Most photosynthetic traits recovered after rewatering, with few compensatory responses. Rewatering often elicited high photosynthetic resilience in plants exposed to severe drought at the end of plant development, with the response strongly depending on the drought severity/duration. The associations of chlorophyll concentrations with photosynthetically functional activities were stronger during post-tasseling than pre-tasseling, implying an involvement of leaf age/senescence in responses to episodic drought and subsequent rewatering. Coordinated changes in chlorophyll content, gas exchange, fluorescence parameters (PSII quantum efficiency and photochemical/non-photochemical radiative energy dissipation) possibly contributed to the enhanced drought resistance and resilience and suggested a possible regulative trade-off. These findings provide fundamental insights into how plants regulate their functional traits to deal with sporadic alterations in precipitation. Breeding and management of plants with high resistance and resilience traits could help crop production under future climate change.

Responses of plant biomass and yield components to warming are species-specific and are shifted as increased warming magnitude rises; this finding improves the results of IPCC AR5. The responses of crop yields to climatic warming have been extensively reported from experimental results, historical yield collections, and modeling research. However, an integrative report on the responses of plant biomass and yield components of three major crops to experimental warming is lacking. Here, a meta-analysis based on the most recent warming experiments was conducted to quantify the climatic warming responses of the biomass, grain yield (GY), and yield components of three staple crops. The results showed that the wheat total aboveground biomass (TAGB) increased by 6.0% with general warming, while the wheat GY did not significantly respond to warming; however, the responses shifted with increases in the mean growing season temperature (MGST). Negative effects on wheat TAGB and GY appeared when the MGSTs were above 15 °C and 13 °C, respectively. The wheat GY and the number of grains per panicle decreased by 8.4% and 7.5%, respectively, per degree Celsius increase. Increases in temperature significantly reduced the rice TAGB and GY by 4.3% and 16.6%, respectively, but rice straw biomass increased with increasing temperature. However, the rice grain weight and the number of panicles decreased with continuous increasing temperature (ΔTa). The maize biomass, GY, and yield components all generally decreased with climatic warming. Finally, the crop responses to climatic warming were significantly influenced by warming time, warming treatment facility, and methods. Our findings can improve the assessment of crop responses to climatic warming and are useful for ensuring food security while combating future global climate change.

In this work, we developed a simple and sensitive colorimetric detection platform for specific DNA sequences by using peroxidase mimetics of platinum nanoparticles supported on reduced graphene oxide. This nanocomposite possessed the combined advantages of platinum nanoparticles (superior peroxidase-like activity) and reduced graphene oxide (π-stacking interaction with single-stranded but not double-stranded DNA). The catalytic activity was strongly dependent on the chloroplatinic acid-to-graphene oxide mass ratio during the synthesis step, with an optimum ratio of 7 : 1. Unlike natural peroxidase, the nanocomposite had excellent stability over wide ranges of temperature (4-90 °C) and pH (1-13). For DNA detection, the nanocomposite had higher affinity for the single-stranded probe (in the absence of target) than the probe-target duplex. The probe-bound nanocomposite was stabilized against salt-induced aggregation and thus upon the addition of 3,3',5,5'-tetramethylbenzidine and hydrogen peroxide to the supernatant, an intense blue color was generated. The linear range and limit of detection of this assay platform were 0.5-10 nM and 0.4 nM, respectively. Moreover, this platform featured high specificity that 3-base-mismatched sequence could be distinguished with the naked eye and 1-base-mismatched sequence with absorbance measurement. Furthermore, the applicability for real sample detection was demonstrated by polymerase chain reaction product analysis. Taken together, this new platform is well suited for point-of-care and on-site nucleic acid testing.

The main characteristics of global climate change include significant temperature increases and uneven precipitation distributions, which are both limiting factors for the sustainable development of dryland agriculture in semiarid regions. Inner Mongolia, which occupies the largest area of the semiarid region in China, is a good representation of the region’s climate and dryland agricultural conditions. Spring wheat is widely grown in this region, but the negative impacts of climate change have seriously threatened spring wheat production in recent years. To adapt to these changes, it is imperative to study the influence of climate change on spring wheat production. We employed a vulnerability assessment method to quantitatively evaluate the impacts of climate change on spring wheat production in Inner Mongolia and recommended specific countermeasures based on the results. The average temperature and precipitation during the spring wheat growing season was 16.5 °C and 224 mm, respectively, from 1961 to 2012. Northeastern Inner Mongolia was characterized by lower temperature and higher precipitation; the eastern region had both higher temperature and precipitation; and the southwestern area had higher temperature and lower precipitation. The climate in this region showed a warming and drying trend from 1961 to 2012, with average temperature during the spring wheat growing season increasing with an average rate 0.3 °C/10a and average precipitation decreasing with an average rate 4.3 mm/10a. Over the study period (from 1996 to 2012), the vulnerability of spring wheat in the eastern, central, and southwestern areas of Inner Mongolia was high, whereas that in the northeast was relatively low. Assuming the adaptive capacity of spring wheat is stable, the comprehensive unit vulnerability of spring wheat production is expected to significantly increase under the investigated climate change scenarios (based on historical climate trends and RCP4.5, RCP8.5 scenarios) relative to average values over the study period. Exposure and regional vulnerability could be reduced by decreasing the proportion of spring wheat grown in vulnerable areas, such as the central and southwestern areas of Inner Mongolia.

As the global climate changes, different degrees of variation in climatic factors will have various impacts on agricultural production, leading to appropriate or stressed conditions. The impact threshold of climate change (ITCC) for agriculture refers to the value of a climatic factor at which the agricultural status mutates. Due to the urgency of addressing the negative impacts of climate change on agriculture, research on the ITCC of agriculture is crucial. Here, we built models to reflect the relationship between agricultural climate yield and climatic factors based on climate change characteristics and objective agricultural status. Using the models, we obtained the appropriate and stressed thresholds of different climatic factors. We calculated the ITCC of spring wheat in Wuchuan County as an example and identified warming and drying trends in Wuchuan County from 1961 to 2013, especially during the period from 1991 to 2013 (i.e., the period after mutation or the change period). Over the past 53 years, spring wheat yield increased with an average rate of 81.3 kg ha−1 dec−1. Over the change period, however, yield decreased with an average rate of 13.8 kg ha−1 dec−1 and the fluctuation range increased. The appropriate threshold for average temperature during the growth period of spring wheat was 11.4 °C, and the stressed thresholds were 8.2 and 14.6 °C. The appropriate threshold for precipitation during the growth period was 391.1 mm, and the stressed thresholds were 247.4 and 534.9 mm. During the period before mutation (i.e., the basic period), the average temperature was below the upper temperature threshold, and precipitation was 26.9 mm above the lower precipitation threshold. During the change period, the average temperature was 0.3 °C above the upper temperature threshold, and precipitation was 9.8 mm above the lower precipitation threshold.

Global warming and dimming/brightening have significant implications for crop systems and exhibit regional variations. It is important to clarify the changes in regional thermal and solar radiation resources and estimate the impacts on potential crop production spatially and temporally. Based on daily observation data during 1961&ndash, 2015 in the North China Plain (NCP), the impacts of climate change associated with climate warming and global dimming/brightening on potential light&ndash, temperature productivity (PTP) of summer maize were assessed in this study. Results show that the NCP experienced a continuous warming and dimming trend in maize growing season during the past 55 years, and both ATT10 and solar radiation had an abrupt change in the mid-1990s. The period of 2000&ndash, 2015 was warmer and dimmer than any other previous decade. Assuming the maize growing season remains unchanged, climate warming would increase PTP of summer maize by 4.6% over the period of 1961&ndash, 2015, which mainly occurred in the start grain filling&ndash, maturity stage. On the other hand, as negative contribution value of solar radiation to the PTP was found in each stage, dimming would offset the increase of PTP due to warming climate, and lead to a 15.6% reduction in PTP in the past 55 years. This study reveals that the changes in thermal and solar radiation have reduced the PTP of summer maize in the NCP. However, the actual maize yield could benefit more from climate warming because solar radiation is not a limiting factor for the current low production level.

Crop photosynthesis is closely related to leaf water content (LWC), and clarifying the LWC conditions at critical points in crop photosynthesis has great theoretical and practical value for accurately monitoring drought and providing early drought warnings. This experiment was conducted to study the response of LWC to drought and rewatering and to determine the LWC at which maize photosynthesis reaches a maximum and minimum and thus changes from a state of stomatal limitation (SL) to non-stomatal limitation (NSL). The effects of rehydration were different after different levels of drought stress intensity at different growth stages, and the maize LWC recovered after rewatering following different drought stresses at the jointing stage, however, the maize LWC recovered more slowly after rewatering following 43 days and 36 days of drought stress at the tasselling and silking stages, respectively. The LWC when maize photosynthesis changed from SL to NSL was 75.4% ± 0.38%, implying that the maize became rehydrated under physiologically impaired conditions. The LWCs at which the maize Vcmax25 reached maximum values and zero differed between the drought and rewatering periods. After exposure to drought stress, the maize exhibited enhanced drought stress tolerance, an obviously reduced suitable water range, and significantly weakened photosynthetic capacity. These results provide profound insight into the turning points in maize photosynthesis and their responses to drought and rewatering. They may also help to improve crop water management, which will be useful in coping with the increased frequency of drought and extreme weather events expected under global climate change.

To meet the food demands of a growing population, the maize production systems deployed by smallholders in China have tended towards extremely intensive planting and excessive use of fertilizers, which have caused serious environmental impacts. This study investigated the balance between the maize yield and nitrogen (N) input in the North China Plain (NCP), which is one of the most important grain-producing region in China. Our study compared yield simulations generated by the DSSAT-CERES-Maize model with actual data from a number of multi-site field experiments and an extensive household surveys encompassing 1671 farmers. The smallholders' maize cultivars, plant population, and amount of N input on the crop yield and how these affects the economic benefits were analyzed. The results showed that the average traditional farming methods' yield was 72% of the attainable yield, which means that farmers have ample room to improve their yields. We also found that the maize yields varied widely between farmers, and that most of them applied excessive amounts of N but failing to achieve an optimal yield due to poor fertilization management techniques. The study found that the economic benefits achieved by the farmers were low, but after deploying high-yield (HY) methods, the yield was increased by 34.9% and the economic benefits by 14.4%. The greenhouse gas (GHG) emissions associated with the traditional farming methods were high and could potentially be reduced by 48.6%. All in all, farmers should be given guidance on how to appropriately increase the plant population, reduce the input of N fertilizer, and optimize farmland management measures, so that China can achieve intensive but sustainable agricultural production at a lower environmental cost. It was concluded that there are still numerous biological and abiotic factors that restrict production increases by smallholders. These factors vary from region to region and require further investigation.

Maize is one of the three major grain crops in China; it is widely planted in Northeastern China (NEC), Northern China (NC) and Northwestern China (NWC). However, large regional variations in maize yield using the same cultivar and management measures occur due to climate diversity. It is important to clarify the differences in regional maize production and climate resources in order to improve resource utilization efficiency. Long-term field experiments with the same maize cultivar (i.e., Zhengdan 958) and management measures were carried out at 26 sites from 2007 to 2015 in the main corn-producing areas of China. Based on the field experiment data, we analyzed the regional differences in maize production according to yield, growth period, grain number per spike and 1000-grain weight. The climate resources and utilization efficiency in NEC, NC and NWC were then determined by combining daily temperature and solar radiation data. The results show that NWC had significantly greater maize yield compared to NEC and NC, by 49.5 % and 38.7 %, respectively. A non-significant difference in maize yield was found between NC and NEC, and similar results were also found for the 1000-grain weight. NWC experienced significantly greater solar radiation during the maize growth period; the value was 14.0 % and 19.6 % higher than in NEC and NC, respectively. In addition, thermal time was 5.1 % and 8.9 % higher than in NEC and NC, respectively. The radiation utilization efficiency (RUE) in the NWC was the highest, 14.5 % and 27.2 % higher than those in NC and NEC, respectively. Similar to RUE, the heat utilization efficiency (HUE) value in NWC was 27.4 % and 46.5 % higher than in NC and NEC, respectively. The yield of maize was positively correlated with the total radiation and thermal time during the growth period; however, regional radiation had a greater impact on maize production than thermal time. Overall, NWC showed higher maize yield, higher radiation and higher thermal time during the maize growth period as well as higher RUE and HUE compared to NC and NEC. Improving resource utilization efficiency using the theory and technology of quantitative matching of maize yield formation and resources in NC and NEC may be a way to reduce the regional yield gap in China.