Search Results (184)

Understanding the dynamic changes in the quality of the ecological environment and its potential driving forces is essential for protecting regional ecosystems and promoting sustainable development. In this study, we developed an improved remote sensing ecological index (IRSEI) by integrating the kernel normalized difference vegetation index (kNDVI) with an abundance index (AI) and conducted a comprehensive analysis of the spatiotemporal evolution of the quality of the ecological environment in the North China Plain (NCP) from 2000 to 2020. A multistep driving analysis framework was established to identify key climatic factors via the XGBoost algorithm and to quantify the effects of climate change and human activities through partial correlation analysis and a multiple regression residual model. The results indicate the following: (1) From 2000 to 2020, the ecological quality of the NCP significantly improved, with the average IRSEI increasing from 0.41 to 0.45. The proportion of areas with “good” or “excellent” ecological quality increased, revealing a south–north gradient, with higher values in the southern part and lower values in the northern part of the NCP. (2) Among the key climatic variables, surface temperature was significantly negatively correlated with the IRSEI, whereas atmospheric pressure and evapotranspiration were significantly positively correlated. (3) Approximately 51.97% of the ecological quality changes were jointly driven by climate change and human activities, with the contribution of human activities (28.80%) exceeding that of climate change (19.23%). These findings provide a scientific basis for understanding the driving mechanisms behind ecological environment changes and support ecological restoration and coordinated human–environment development in the context of climate change. Full article

Maize, as a critical crop for China’s food security, is constantly challenged by weed infestations and environmental risks associated with herbicide overuse. Improving herbicide utilization efficiency through equipment optimization and intelligent control during spraying has become an essential strategy for weed management in Chinese maize fields. However, most current sprayers fail to achieve coordinated control of spray volume and nozzle parameters, and their performance is typically evaluated using single indices, such as the coefficient of variation (CV) for spray uniformity and deposition density. In this study, a split-split-plot experiment was conducted in 2022–2023 to assess the feasibility of herbicide reduction using intelligent variable-rate boom sprayers in summer maize fields on the North China Plain (NCP). The key variables included spray volume (225 vs. 180 L/ha), nozzle type (AI11003VS/LECHLER11003 in 2022; TTI11004/LECHLER11004 in 2023), and herbicide dose (recommended, −15%, and −30% reduction). Results showed that the coefficients of variation for droplet coverage and density remained below 12% for all treatments (n = 4), indicating stable spray performance. A higher spray volume (225 L/ha) significantly improved deposition uniformity (p < 0.01). In 2022, herbicide input could be reduced by 15–30% while maintaining efficacy above 90% when applied at the 3–4 leaf stage of dominant weeds. However, in 2023, efficacy dropped to 72.67% when the herbicide was applied at a 30% reduced dose with 180 L/ha and when dominant weeds had reached the 5–6 leaf stage or higher, indicating an agronomic risk. Reduced herbicide input decreased maize injury by 47–53%. Only the 30% reduced-dose treatment significantly increased maize yield by 3.05% in 2022 and 2.62% in 2023 compared to the control (both p < 0.05). Spray volume significantly influenced droplet deposition and weed control efficacy; thus, caution is warranted regarding herbicide reduction for later weed growth stages. This study demonstrates that real-time variable-rate boom sprayers, optimized for spray volume and nozzle type, can reduce herbicide use without compromising weed control efficacy or maize yield, providing both theoretical support and practical guidance for sustainable herbicide management in summer maize fields on the NCP. Full article

As a typical grain base with a dense population and high-level urbanization, the North China Plain (NCP) faces a serious threat to its sustainable development due to water shortage. Surface water area (SWA) is a key indicator for continuously measuring the trends of regional water resources and assessing their current status. Therefore, a deep understanding of its changing patterns and driving forces is essential for achieving the sustainable management of water resources. In this study, we examined the interannual variability and trends of SWA in the NCP from 1990 to 2023 using annual 30 m water body maps generated from all available Landsat imagery, a robust water mapping algorithm, and the cloud computing platform Google Earth Engine (GEE). The results showed that the SWA in the NCP has significantly increased over the past three decades. The continuous emergence of artificial reservoirs and urban lakes, along with the booming aquaculture industry, are the main factors driving the growth of SWA. Consequently, the expansion of artificial water bodies resulted in a significant increase in water evaporation (0.16 km³/yr). Moreover, the proportion of water evaporation to regional evapotranspiration (ET) gradually increased (0–0.7%/yr), indicating that the contribution of water evaporation from artificial water bodies to ET is becoming increasingly prominent. Therefore, it can be concluded that the ever-expanding artificial water bodies have become a new hidden danger affecting the water security of the NCP through evaporative loss and deserve close attention. This study not only provides us with a new perspective for deeply understanding the current status of water resources security in the NCP but also provides a typical case with great reference value for the analysis of water resources changes in other similar regions. Full article

This study aimed to systematically evaluate the effects of different nitrogen application rates and irrigation practices on water-saving and yield enhancement in winter wheat production in the North China Plain (NCP) using a meta-analysis. By quantifying the impacts on crop yield, nitrogen use efficiency (NUE), and water use efficiency (WUE), the research provides a scientific basis for optimizing management practices in winter wheat production in this region. A comprehensive literature search was conducted across multiple databases, resulting in the inclusion of 94 eligible studies from 2018 to 2023. A random-effects model was employed to calculate the combined effect sizes, followed by subgroup and sensitivity analyses to further investigate the influence of nitrogen application rates, irrigation methods, and study regions on winter wheat production efficiency. The findings reveal that increasing nitrogen application rates and adopting deficit irrigation practices significantly improved winter wheat yield (combined effect size: 4.53 t·ha⁻¹), NUE (43.29%), and WUE (0.013 t·ha⁻¹·mm⁻¹). The subgroup analysis further elucidated the critical roles of nitrogen application ratios, irrigation methods, and study regions in determining winter wheat production efficiency, while the sensitivity analysis confirmed the robustness of these findings, as the pooled effect sizes decreased by merely 0.69% and increased by 0.61% after excluding small-sample or highly biased studies, respectively. The above meta-analysis did not incorporate long-term field trials; hence, two-year field experiments with designed irrigation and organic–inorganic fertilizer treatments were conducted, which provided further validation for the meta-analysis. Under short-term conditions (excluding CO₂ effects), we observed that chemical fertilizer exhibited a measurable inhibitory effect on crop water uptake and optimal water–fertilizer management was achieved with a 7:3 inorganic–organic fertilizer ratio combined with 450 m³·ha⁻¹ irrigation. This study demonstrates the effectiveness of optimizing nitrogen fertilization and irrigation management in enhancing winter wheat yield and resource utilization efficiency. The findings offer actionable insights for sustainable agricultural practices in the NCP and similar regions, contributing to improved crop productivity and resource conservation. Full article

Combined air pollution of ozone and PM_2.5 often occurs in coal-based cities of China such as Taiyuan City. In this study, the Weather Research and Forecasting/Chemistry (WRF-Chem) model was employed to simulate a combined high air pollution event of ozone and PM_2.5 in Taiyuan City from 20 May to 29 May 2015,with the maximum daily 8-hour average (MDA8) for ozone exceeding 140 ppbv and PM_2.5 concentrations surpassing $200\mu \mathrm{g}{\mathrm{m}}^{-3}$. We further investigated the drivers of the combined air pollution in Taiyuan during the polluted period. The simulation results showed that the model can well simulate the combined pollution event in Taiyuan, with assessment parameters within reasonable ranges. Moreover, by analyzing the observational data and simulations, the major factors causing the PM_2.5 pollution in Taiyuan during this time period were suggested to be local emissions and pollutant transport from the North China Plain (NCP) located to the east of Taiyuan. In addition, unfavorable meteorological and geographical conditions in Taiyuan also play important roles in forming severe PM_2.5 pollution. Regarding the ozone pollution in Taiyuan, we suggest that the mechanism dominating the pollution event is that of ozone-rich air being transported to Taiyuan at high altitudes and then mixed downwards, resulting in an increase of the ground-level ozone in Taiyuan. Furthermore, we found local emissions and emissions from Taiyuan Basin and Henan Province, which are located to the south of Taiyuan, contributing significantly to the ozone pollution in Taiyuan City during this time. Full article

Optimizing farmers’ crop production management is an effective strategy to synergize yields, resource utilization, and environmental conservation. However, the mechanisms by which agronomic management in the North China Plain (NCP) determines the wheat yield, water use efficiency (WUE), and physiological performance remain largely unexplored. To address this knowledge gap, a field experiment was conducted from 2022 to 2024 to investigate the effects of conventional farmer practices (CK) and a Integrated High-Yield and Efficiency Cultivation Management (HHL) strategy incorporating pre-sowing soil moisture creation, optimized tillage, fertilization, and irrigation on the yield, water consumption characteristics, leaf photosynthetic physiology, and root traits. The results demonstrated that HHL significantly enhanced the root morphology in winter wheat compared to CK. Specifically, HHL increased the net photosynthetic rate (Pn), chlorophyll content, and leaf area index (LAI) at the flowering stage by 20.5%, 8.8%, and 11.1%, respectively, thereby boosting dry matter accumulation by 40.3% and yields by 10.9%. Furthermore, HHL reduced soil water evaporation by 12.1% and the total water consumption by 112.1 mm, while improving the WUE by 25.4% and nitrogen fertilizer partial productivity by 38.7%, alongside a 12.5% increase in economic benefits. Through rigorous field experimentation, this study elucidates the potential of HHL in water conservation, yield enhancement, and comprehensive benefit improvement, offering an effective cultivation paradigm for the wheat production systems in the NCP. The findings indicate that this management strategy exhibits superior water-saving and yield-enhancing effects, with promising prospects for widespread adoption and application. Full article

Mulberry (Morus spp.) is resilient to water deficit conditions, and the high protein content of its leaves means they can be used as forage. Therefore, it could be a valuable resource for alleviating the animal feed crisis, but it is crucial that its high productivity and stable traits are sustained to achieve this. We conducted a 2-year field experiment in the North China Plain (NCP), which investigated different irrigation levels (W1 = 15 mm, W2 = 30 mm) and genotypes (Feng Yuan No. 1, Feng Chi). This study demonstrates that using water-saving irrigation coupled with selected genotypes can increase the leaf yield and protein content. We measured various physiological and ecological indicators of mulberry, including the leaf area, fresh leaf weight, dry leaf weight, net photosynthetic rate, leaf water use efficiency (WUE_L) under limited irrigation, protein content, and yield. The results from both years indicate that, under deficit irrigation conditions, Feng Yuan No. 1 exhibited drought resistance while maintaining relatively high and stable growth traits. When the irrigation amount was increased (W2 = 30 mm), the net photosynthetic rate and leaf water use efficiency of Feng Yuan No. 1 were significantly better than those of Feng Chi. Additionally, Feng Yuan No. 1 combined with the W2 irrigation treatment led to a higher protein content of leaves (19.98 g/100 g and 21.19 g/100 g) and greater yield of leaves and branches (9.79 t·ha⁻¹ and 11.19 t·ha⁻¹) in the two years. Furthermore, under deficit irrigation conditions, Feng Yuan No. 1 effectively compensated for yield losses caused by water scarcity. Full article

The net primary productivity (NPP) of vegetation—a critical component of ecosystem carbon cycling and a key indicator of the quality and functionality of ecosystems—is jointly influenced by natural and anthropogenic factors. As NPP is a vital agricultural and ecological region in China, understanding the spatiotemporal dynamics and driving mechanisms of vegetation NPP in the North China Plain (NCP) has significant implications for regional sustainable development. Utilizing MODIS NPP, temperature, precipitation, and human activity data from 2003 to 2023, this study employs univariate linear regression, ArcGIS spatial analysis, and the Hurst index to investigate the spatiotemporal characteristics, driving factors, and future trends in vegetation NPP. The results indicate that vegetation NPP exhibited a fluctuating upward trend over the 21-year period, with an annual increase of 2.60 g C/m². Spatially, NPP displayed a “high in the south, low in the north” pattern. There is significant spatial heterogeneity between temperature, precipitation, and vegetation NPP in the study area, with natural factors generally exerting a greater influence than human activities; however, the coupling of human activities with other factors significantly amplify their impact. The Hurst index (mean: 0.43) revealed an anti-persistent future trend in vegetation NPP, suggesting substantial uncertainties regarding its long-term dynamics. These findings enhance our understanding of the responses of vegetation to global change and provide a scientific basis for balancing food security and ecological conservation in the NCP. Full article

The ozone levels over eastern China show a distinct two-stage process, with an inter-seasonal low (ISL) between May and September, unlike other polluted northern low-to-mid-latitude regions. The timing and progression of this low from southern to northern China align with the East Asian summer monsoon (EASM). The EASM leads to a decrease (ΔISL1) during the first stage and an increase (ΔISL2) during the second stage. The response varies by region, with the ΔISL1 (25 to 60 ppbv) greater than the ΔISL2 (20 to 30 ppbv) in the North China Plain (NCP), and the ΔISL1 (20 to 35 ppbv) less than the ΔISL2 (35 to 55 ppbv) in the Pearl River Delta (PRD). The ozone levels are inversely related to the monsoon index (MI) during stage 1 (r = −0.69, p < 0.05), while during stage 2, the ozone levels are anticorrelated with the maximum MI in the NCP and PRD (r = −0.73 and −0.80, p < 0.05). And the average ozone levels are anticorrelated with the MI during stage 2 in the Yangtze River Delta (YRD) (r = −0.71, p < 0.05). The simulations using CMIP6 suggest that intensified EASM caused by greenhouse emissions may help reduce summertime ozone pollution. The results show that different regions require different pollution control policies during pre- and post-monsoon seasons. Full article

The agricultural water–soil matching coefficient is a key factor for reflecting regional grain production status, which can be used to evaluate the reasonableness of water–soil allocation in certain areas. Taking the North China Plain (NCP) as the study area, in this study, we constructed a framework from a “physical water–water footprint” standpoint. The binary matching characteristics of “water–soil–grain” were then analyzed, and the water–soil matching coefficient method was employed to evaluate the pattern of water–soil matching for the years 1984, 1998, 2003, and 2022. Through the perspective of physical water–water footprint coupling, field trials of grain were utilized to calculate the range of water–soil matching coefficients under high yields. The results showed the following: ① From 1949 to 2022, the grain yield and planting areas increased. Wheat, the dominant crop, required substantial irrigation. Precipitation, cultivated land, and irrigation water exhibited spatial mismatches over the last ten years. ② The total water footprint showed an increasing trend, and the blue water footprint accounted for 19.47%. The spatial distribution of the water and land footprints of grain crops largely overlapped, and their values were higher in the central and southern regions, and lower in the north. ③ The current water–soil matching coefficient was in the range of [0.28, 1.75], which fell outside the optimal range of [0.534, 0.724]. The soil–water matching coefficients of wheat and rice were overall higher than those of other crops. We found higher values in the southwestern region and lower values in the northern areas, which aligns with the boundary of the groundwater funnel area. To address the identified challenges, we recommend implementing a tiered regulatory zone system based on the matching coefficient. The government should encourage a reduction in water-intensive crops like wheat and rice in high-value regions by providing subsidies. Additionally, a monitoring mechanism for water and soil compatibility should be established, considering the specific growth requirements of various crops. Full article

Field studies were conducted in the North China Plain (NCP) during the 2023–2024 season to investigate the vertical microclimate, yield, and yield-related characteristics of winter wheat during the grain-filling stage under no-till direct seeding and conventional tillage. The aim was to compare the differences in microclimate between the two tillage methods in wheat fields and the impact of microclimate on yield. The results indicated that, compared to conventional tillage, no-till direct seeding reduced the air temperature and increased the relative humidity of the air at 20 cm and 100 cm above the ground during the wheat grain-filling period. The soil moisture content at 20 cm below the ground under no-till direct seeding was higher than under conventional tillage during the early grain-filling stage. Seven days before the wheat harvest, the dry weight per plant and the dry weight per spike were significantly greater under no-till direct seeding than under conventional tillage. Consequently, the thousand-grain weight of no-till direct seeding was significantly higher than that of conventional tillage, with an increase of 7.9%. The number of wheat sterile spikelets under no-till direct seeding was significantly lower than that under conventional tillage. Furthermore, the number of grains per spike was higher than that of conventional tillage. Although the number of harvested spikes under no-till direct seeding was 10.8% lower than under conventional tillage, the increase in thousand-grain weight and the number of grains per spike compensated for the reduced number of harvested spikes. As a result, the grain yield of winter wheat under no-till direct seeding was higher than that of conventional tillage, increasing by 2.7%. Therefore, adopting no-till direct seeding in the NCP is conducive to increasing winter wheat production and efficiency, as well as supporting sustainable agricultural development. Full article

The wheat–maize rotation system in the North China Plain (NCP) has a large amount of crop straw. However, improper crop straw management and blind fertilization lead to nutrient imbalance and accelerated nutrient loss from the soil, ultimately leading to nutrient deficiency affecting the wheat–maize rotation system. In order to explore the effects of nutrient deficiency on the yield and nutrient use efficiency of wheat and maize, the experiment was conducted in a randomized complete block design consisting of five treatments with three replicates for each treatment: (1) a potassium fertilizer deficiency and appropriate nitrogen and phosphate fertilizer treatment (NP); (2) a phosphate fertilizer deficiency and appropriate nitrogen and potassium fertilizer treatment (NK); (3) a nitrogen fertilizer deficiency and appropriate phosphate and potassium fertilizer treatment (PK); (4) an adequate nitrogen, phosphorus, and potassium fertilizer treatment (NPK); and (5) a no-fertilizer treatment (CK). The results showed that, compared with CK, the yields of wheat and maize treated with NPK were increased by 21.5% and 27.5%, respectively, and the accumulation of the dry matter of the wheat and maize was increased by 42.5% and 57.3%. In all the deficiency treatments, the NK treatment performed better in terms of yield compared to the NP and PK treatments, while the NP treatment demonstrated a greater increase in dry matter accumulation. The NPK treatment significantly improved the nitrogen use efficiency (NUE) and nitrogen harvest index (NHI) of the wheat and maize, which resulted in higher nitrogen accumulation in the NPK treatment, and the NP treatment was the best among the other nutrient deficiency treatments. The inorganic nitrogen content showed a similar trend. In conclusion, nutrient deficiency can severely restrict crop growth. Nitrogen deficiency can significantly reduce crop yields. Phosphorus deficiency had a greater impact than potassium deficiency in terms of nutrient absorption and accumulation. Therefore, nitrogen fertilizer application should be emphasized in crop rotation systems, with moderate increases in phosphorus fertilizer application. This practice can effectively improve the nutrient deficiency under the wheat and maize rotation system in the NCP and complete a rational fertilization system. Full article

Brown carbon aerosols (BrC), a subfraction of organic aerosols, significantly influence the atmospheric environment, climate and human health. The North China Plain (NCP) is a hotspot for BrC research in China, yet our understanding of the optical properties of BrC in rural regions is still very limited. In this study, we characterize the chemical components and light absorption of BrC at a rural site during winter in the NCP. The average mass concentration of PM₁ is 135.1 ± 82.3 μg/m³; organics and nitrate are the main components of PM₁. The absorption coefficient of BrC (b_abs,BrC) is 53.6 ± 45.7 Mm⁻¹, accounting for 39.5 ± 10.2% of the total light absorption at 370 nm. Diurnal variations reveal that the b_abs,BrC and organics are lower in the afternoon, attributed to the evolution of planetary boundary layers. BrC is mainly emitted locally, and both the aqueous phase and the photooxidation reactions can increase b_abs,BrC. Notably, the b_abs,BrC is reduced when RH > 65%. During foggy conditions, reactions in the aqueous phase facilitate the formation of secondary components and contribute to the bleaching of BrC. This process ultimately causes a decrease in both the absorption Ångström exponent (AAE) and the mass absorption efficiency (MAE). In contrast, the b_abs,BrC, along with AAE and MAE, rise significantly due to substantial primary emissions. This study enhances our understanding of the light absorption of BrC in rural polluted regions of the NCP. Full article

Black carbon (BC) changes the radiative flux in the atmosphere by absorbing solar radiation, influencing photochemistry in the troposphere. To evaluate the seasonal direct radiative effects (DREs) of BC and its influence on surface atmospheric oxidants in China, the WRF-Chem model was utilized in this study. The simulation results suggested that the average annual mean values of the clear-sky DREs of BC at the top of the atmosphere, in the atmosphere and at the surface over China are +2.61, +6.27 and −3.66 W m⁻², respectively. Corresponding to the seasonal variations of BC concentrations, the relative changes of the mean surface photolysis rates (J[O1D], J[NO₂] and J[HCHO]) in the four seasons range between −3.47% and −6.18% after turning off the BC absorption, which further leads to relative changes from −4.27% to −6.82%, −2.14% to −4.40% and −0.47% to −2.73% in hydroxyl (OH) radicals, hydroperoxyl (HO₂) radicals and ozone (O₃), respectively. However, different from the relative changes, the absolute changes in OH and HO₂ radicals and O₃ after turning off BC absorption show discrepancies among the different seasons. In the North China Plain (NCP) region, O₃ concentration decreases by 1.79 ppb in the summer, which is higher than the magnitudes of 0.24–0.88 ppb in the other seasons. In southern China, the concentrations of OH and HO₂ radicals reach the maximum decreases in the spring and autumn, followed by those in the summer and winter, which is due to the enhancement of solar radiation and the summer monsoon. Thus, BC inhibits the formation of atmospheric oxidants, which further weakens the atmospheric oxidative capacity. Full article

The rapid formation of secondary nitrate (NO₃⁻) contributes significantly to the nocturnal increase of PM_2.5 and has been shown to be a critical factor for aerosol pollution in the North China Plain (NCP) region in summer. To explore the nocturnal NO₃⁻ formation pathways and the influence of ozone (O₃) on NO₃⁻ production, the WRF-CMAQ model was utilized to simulate O₃ and PM_2.5 co-pollution events in the NCP region. The simulation results demonstrated that heterogeneous hydrolysis of dinitrogen pentoxide (N₂O₅) accounts for 60% to 67% of NO₃⁻ production at night (22:00 to 05:00) and is the main source of nocturnal NO₃⁻. O₃ enhances the formation of NO₃ radicals, thereby further promoting nocturnal N₂O₅ production. In the evening (20:00 to 21:00), O₃ sustains the formation of hydroxyl (OH) radicals, resulting in the reaction between OH radicals and nitrogen dioxide (NO₂), which accounts for 48% to 64% of NO₃⁻ formation. Our results suggest that effective control of O₃ pollution in NCP can also reduce NO₃⁻ formation at night. Full article