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As one of the most representative Paleoproterozoic orogenic belts in the North China Craton, the Jiao-Liao-Ji Belt is of great significance to explore the Paleoproterozoic tectonic evolution of the North China Craton, as well as the convergence process of the Columbia Supercontinent. In this study, we present new geochronological and geochemical data of Paleoproterozoic meta-mafic rocks in the Southern Jilin Province, NE China. Our primary objective is to further constraint the formation and evolution of the Jiao-Liao-Ji Belt. The zircon U–Pb dating reveals that the meta-mafic rocks crystallized at 2.2–2.0 Ga, followed by a metamorphism occurring at ~ 1.9 Ga. Additionally, most of the mafic rocks display moderate fractionation in both light rare earth elements (LREEs) and heavy rare earth elements (HREEs), suggesting their association with an arc setting. Furthermore, the rocks also display an enrichment in large ion lithophile elements (LILEs) such as Cs, Rb, Ba, and Pb, and depletion in high field strength elements (HSFEs) including Nb, Ta, Zr, and Ti. These geochemical characteristics suggest a back-arc setting, indicating that the meta-mafic rocks originated from asthenospheric mantle that was metasomatized by fluids or melts derived from the subducting slab. Notably, a shoshonitic metabasalt exhibits trace element and REEs patterns that resemble those of ocean–island basalts. This suggests that the shoshonitic metabasalt was formed in an oceanic island environment, likely generated from the asthenospheric mantle. Combining these findings with previous studies, we can conclude that the Jiao-Liao-Ji Belt is associated with arc–continental collision, indicating the presence of a modern-type plate tectonic regime in the northeastern North China Craton during the Paleoproterozoic period. [ABSTRACT FROM AUTHOR]

Soil acidification has become a major global issue, and it is important to study the causes and mechanisms of soil pH changes. This study detected soil pH changes in data collected from 1162 papers published during 1996–2000 and 2016–2020 in China, and it discussed the influencing factors on soil pH changes using Geodetector. The results showed that 58.4% of the collected data pairs were significantly acidified. Alfisols, desert soils, primarosols, semi-aqueous soils and aqueous soils were significantly acidified, while other types of soil did not change significantly. Soil pH on construction land decreased in units of 0.39 and on cultivated land decreased by 0.12, but soil pH changes in forest land and grassland were not significant. Nitrogen deposition, the amount of precipitation, sulphur deposition, temperature and vegetation planted in the soil had a great effect on soil acidification. This study provided a scientific reference for clarifying soil pH changes and made suggestions for subsequent soil remediation. [ABSTRACT FROM AUTHOR]

Long-term frequent tillage would cause black soil degradation and serious soil erosion as soil microbial communities and soil structure are extremely sensitive to tillage process. However, there is no unified conclusion on the relationship between the distribution of soil water-stable aggregates (WSAs), and microbial community construction and diversity under long-term tillage in black soil during different seasons. In this study, we used wet-sieving method to evaluate the composition and stability of soil WSAs and employed Illumina MiSeq high-throughput sequencing technology to study the diversity, taxonomic composition and co-occurrence network properties of microbial community, comparing outcomes between uncultivated soil and long-term cultivated soil for 60 years in Keshan farm of Heilongjiang Province. The results showed that after long-term tillage, the proportion of larger than 1 mm WSAs reduced by 34.17–51.37%, and the stability of WSAs, soil pH, organic matter (OM), total nitrogen (TN) contents decreased significantly in all seasons (P < 0.05), while soil available phosphorus (AP) and available potassium (AK) contents increased remarkably (P < 0.05). The diversity of bacteria increased, while that of fungi decreased. Soil fungal communities were more susceptible to long-term tillage than bacterial and archaeal communities. Actinobacteria mainly exist in large WSAs (˃1 mm), and when their relative abundance is high, it is beneficial to improve the water-stability of black soil; while Proteobacteria and Gemmatimonadetes may exist in small WSAs (˂1 mm), whose high relative abundance will weaken the water-stability of black soil. The experimental results provide a scientific theoretical basis for sustainable utilization of black soil. [ABSTRACT FROM AUTHOR]

It is significant to investigate the coupling and coordination between agricultural carbon emission efficiency (ACEE) and food security and to achieve peak carbon dioxide emissions and carbon neutrality in agriculture as early as possible while ensuring national food security. The Super-SBM (slack-based model) and the comprehensive index method were used to measure the ACEE and food security level in Henan province from 2010 to 2020. The coupling coordination degree (CCD) and the relative state of ACEE and food security were analyzed using the coupling coordination degree model (CCDM) and the relative development degree model (RDDM). In addition, the interaction between ACEE and food security and the spatial-temporal heterogeneity were analyzed by combining with the geographically and temporally weighted regression (GTWR) model. The results showed that: Firstly, the overall level of ACEE was high, and the spatial heterogeneity of ACEE was significant. The spatial pattern of food security is relatively stable, with high levels in the south and low levels in the north. Secondly, The CCD between ACEE and food security in Henan province generally shows a decreasing trend. In the spatial dimension, the CCD between ACEE and food security in Henan province exhibits a spatial divergence characteristic of low in the center and high in the north and south, with significant regional variations. Finally, there is spatial and temporal heterogeneity between ACEE and food security. The regression coefficients differ significantly among different cities, the regression coefficients do not show a consistent positive or negative correlation, and the regression coefficients are distributed both positively and negatively. This study serves as a guide for achieving the goal of double carbon in agriculture and ensuring food security., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Soil aggregates not only store carbon (C) and nitrogen (N) but hold a critical role in determining the nutrients supply, crop productivity, and climate change mitigation. However, the impact of cropping system and N fertilization on aggregate-associated C and N in both topsoil and subsoil remains unclear. Here, we assessed the effect of cropping systems (wheat-soybean vs. wheat-maize cropping systems) and N fertilization rates (0 N; medium N, 120 kg N ha -1 ; high N, 240 kg N ha -1 ) on soil water-stable aggregates distribution, as well as aggregate-associated C and N based on a field study in North China Plain. Our study suggests that the variations of soil organic carbon (SOC) and total nitrogen (TN) stocks were more affected by N fertilization than short-term cropping systems. In the wheat-soybean system, medium N increased the SOC stock by 19.18% and 15.73% as compared to high N in the topsoil and subsoil, respectively. Additionally, medium N resulted in 6.59-18.11% higher TN stock in the topsoil for both wheat-soybean and wheat-maize cropping systems as compared to 0 N and high N. Notably, the water-stable macroaggregates (> 0.25 mm) in the topsoil occupied more than 70% of the soil, which increased under medium N in the wheat-soybean cropping system. In conclusion, medium N fertilization combined with a legume-based cropping could be used to improve SOC stock, promote soil aggregation, and enhance aggregate-associated C., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)