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With more and more wind turbines coming into operation, inspecting wind farms has become a challenging task. Currently, the inspection robot has been applied to inspect some essential parts of the wind turbine nacelle. The detection of multiple objects in the wind turbine nacelle is a prerequisite for the condition monitoring of some essential parts of the nacelle by the inspection robot. In this paper, we improve the original YOLOX-Nano model base on the short monitoring time of the inspected object by the inspection robot and the slow inference speed of the original YOLOX-Nano. The accuracy and inference speed of the improved YOLOX-Nano model are enhanced, and especially, the inference speed of the model is improved by 72.8%, and it performs better than other lightweight network models on embedded devices. The improved YOLOX-Nano greatly satisfies the need for a high-precision, low-latency algorithm for multi-object detection in wind turbine nacelle. [ABSTRACT FROM AUTHOR]

For patients exhibiting non-small-cell lung cancer (NSCLC) with activating epidermal growth factor receptor (EGFR) mutations, epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) are a first-line treatment. However, most patients who initially responded to EGFR-TKIs eventually developed acquired resistance, limiting the effectiveness of therapy. It has long been known that epithelial–mesenchymal transition (EMT) leads to acquired resistance to EGFR-TKIs in NSCLC. However, the mechanisms underlying the resistance dependent on EMT are unknown. This research aimed to reveal the effects of LMNA in the regulation of acquired resistance to erlotinib by EMT in NSCLC. The acquired erlotinib-resistant cells (HCC827/ER) were induced by gradual increase of concentrations of erlotinib in erlotinib-sensitive HCC827 cells. RNA sequencing and bioinformatics analysis were performed to uncover the involvement of LMNA in the EMT process that induced acquired resistance to erlotinib. The effect of LMNA on cell proliferation and migration was measured by clone-formation, wound-healing, and transwell assays, respectively. The EMT-related protein, nuclear shape and volume, and cytoskeleton changes were examined by immunofluorescence. Western blot was used to identify the underlying molecular mechanism of LMNA regulation of EMT. HCC827/ER cells with acquired resistance to erlotinib underwent EMT and exhibited lower LMNA expression compared to parental sensitive cells. LMNA negatively regulated the expression of EMT markers; HCC827/ER cells showed a significant up-regulation of mesenchymal markers, such as CDH2, SNAI2, VIM, ZEB1, and TWIST1. The overexpression of LMNA in HCC827/ER cells significantly inhibited EMT and cell proliferation, and this inhibitory effect of LMNA was enhanced in the presence of 2.5 μM erlotinib. Furthermore, a decrease in LMNA expression resulted in a higher nuclear deformability and cytoskeletal changes. In HCC827/ER cells, AKT, FGFR, ERK1/2, and c-fos phosphorylation levels were higher than those in HCC827 cells; Furthermore, overexpression of LMNA in HCC827/ER cells reduced the phosphorylation of AKT, ERK1/2, c-fos, and FGFR. In conclusion, our findings first demonstrated that downregulation of LMNA promotes acquired EGFR-TKI resistance in NSCLC with EGFR mutations by EMT. LMNA inhibits cell proliferation and migration of erlotinib-resistant cells via inhibition of the FGFR/MAPK/c-fos signaling pathway. These findings indicated LMNA as a driver of acquired resistance to erlotinib and provided important information about the development of resistance to erlotinib treatment in NSCLC patients with EGFR mutations. [ABSTRACT FROM AUTHOR]

In this study, we describe the discovery of the 4H‐thieno[3,2‐b]pyrrole derivatives as an useful scaffold to obtain potent lead compounds for the treatment of colon cancer. We first started with the 4H‐thieno[3,2‐b]pyrrole derivatives which come from compound libraries screening, and then optimized their structures based on the cellular activities and pharmacophore models. The inhibition rate of cell growth assay demonstrated that this series compounds showed better inhibitory activities against colon cancer cells than other tested tumor cells. Moreover, the target of the most active compound 8i was explored by target fishing strategy and validated by molecular docking and biological activity analysis. The results of apoptosis and flow cytometry demonstrated that compound 8i induces cell apoptosis probably by inhibiting activity of methionine aminopeptidase 2, therefore compound 8i may be a potent inhibitor to methionine aminopeptidase 2. [ABSTRACT FROM AUTHOR]

The Quaternary red clay (QRC) is one of the typical terrestrial sediments in southern China which contains abundant palaeoclimatic information. A natural QRC outcrop, named the Jingxian red clay section (JRCS), was developed in Jingxian City on the northern piedmont of Mt. Huangshan, offering a valuable archive for long-term palaeoclimatic study from a southern China perspective. The objective of this study is to reveal palaeoclimatic information of regional precipitation from the JRCS and its correlation with the East Asian summer monsoon (EASM) intensity, using grain-size measurements combined with dating via Electron Spin Resonance (ESR) and palaeomagnetism. The results indicate that: (1) Ten palaeoclimatic wetter periods (PWPs) designated as PWP I to PWP X from top to bottom were detected from the grain-size analysis results of the upper 9.4 m JRCS. These PWPs span a period from approximately 840 ka ago to present; (2) three PWPs (PWP VIII to PWP X) were basically determined to approximately 612–690, 720–762 and 792–822 ka ago, basically corresponding to China loess layers of L6, L7 and L8 and deep-sea isotope stages of MIS16, MIS18 and MIS20, respectively. Data suggests that the PWPs in the study area were observed mainly during glaciations; (3) regional precipitation in the study area should be negatively related to the EASM intensity since approximately 840 ka ago as a result of variations in North Hemisphere solar insolation and uplifts of the Tibetan Plateau; (4) the modern anti-phase of monsoonal rainfall at glacial-interglacial timescales seemed to have existed between northern China and southern China since the late Early Pleistocene (approximately 840 ka ago). • We studied precipitation information recorded in the Jingxian red clay in southern China. • Regional rainfall was negatively related to the East Asian summer monsoon intensity since 840 ka ago. • Anti-phase of monsoonal rainfall at longer timescales existed between northern China and southern China since 840 ka ago. [ABSTRACT FROM AUTHOR]

Global warming has profound effects on the distribution of water and heat in soil. This study aimed to examine the effects of warming on water storage, thermal properties, and heat flux changes at different depth (5-10, 10-20, and 20-40 cm) in a winter wheat (Triticum aestivum L.) field. The experiment with simulated warming, manipulated with infrared heaters, and its control combined with a nitrogen fertilization treatment was conducted in the North China Plain. The results showed that warming of around 2°C at 5 cm soil depth reduced soil water storage by 3.2%-11.1% before the jointing stage. However, the difference in soil water storage between warming and non-warming conditions behaved inversely before and after mid-April. Experimental warming significantly reduced soil volumetric heat capacity and thermal conductivity. In the winter, the warming depressed the upward heat flux by 42.4%-50.1% at the 5-10 cm layer, whereas the warming increased the downward heat flux by 5.5%-12.3% in the spring. Our observation indicates that the effects of warming on the exchange process of mass and energy between soil and the atmosphere should be further studied in agro-ecosystem regions. [ABSTRACT FROM AUTHOR]

This paper focuses on climatic and tectonic controls to determine their relative importance to the Quaternary fluvial incision by the Qingyijiang River, eastern China. The Qingyijiang, which is one of longest tributaries of the lower Yangtze River, drains the northern piedmont of Mt. Huangshan. A field survey focused on three natural sections of the Qingyijiang in the Jingxian basin, where a well-preserved sequence of one alluvial platform (P) and three fluvial terraces (T3, T2, and T1) is presented. The heights of the platform and the terraces above river level are ~ 65, ~ 40, ~ 20, and ~ 7 m respectively. In this study, electron spin resonance (ESR), optical stimulated luminescence (OSL), and palaeomagnetic dating were applied to reconstruct the fluvial incision history of the Qingyijiang and evaluate the possible influence of tectonic uplift and/or climate change on the fluvial incision. The main results show that (1) the ages of P, T3, T2, and T1 were determined to be ∼ 1300, ∼ 900, ∼ 600, and ∼ 1.5 ka respectively, corresponding to four incision events in the Qingyijiang; (2) the East Asian summer monsoon (EASM) experienced four significant weakening events at ~ 1300, ~ 900, ~ 600, and ∼ 1.5 ka, according to previous research. Correspondingly, we propose that four significant increased periods of regional precipitation occurred at ~ 1300, ~ 900, ~ 600, and ∼ 1.5 ka in the study area because of the negative correlation between the intensity of the EASM and regional precipitation from 1960 to 2012; and (3) fluvial incision by the Qingyijiang arose as a result of the weakening of the EASM in combination with tectonic uplift, determined by matching fluvial incision history of the Qingyijiang with tectonic movement and EASM change. In addition, the weakening of the EASM climatically triggered fluvial incision by the Qingyijiang. This study supports the conclusion that major fluvial incision has been climatically triggered; however, it also suggests that the mechanism of river incision may be regionally distinctive in different climatic zones. [ABSTRACT FROM AUTHOR]

The Qingyijiang River, which originates from the northern fringe of Mt. Huangshan, is an important tributary of the lower Yangtze River. A field investigation focused on the natural outcrops of the Qingyijiang in the Jingxian Basin, where a well-preserved sequence of three gravel beds of fluvial terraces is present. Based on gravel fabric analysis and ESR dating, this paper discusses the genesis of the Qingyijiang on the northern fringe of Mt. Huangshan. The main results show that (1) the diameter of the gravels is mainly medium and coarse, showing that the hydrodynamic conditions were strong in the formation periods of the terrace gravel beds, especially for the T3 terrace gravel bed; (2) the gravel orientations in the gravels of the T3 and T2 terraces are 191° and 250°, which are to the SSW and SWW, respectively, and are similar to the present flow, which is from southwest to northeast; (3) the roundness of the gravels is mainly subrounded or rounded, implying that these gravels were transported significant distances from their provenances; (4) the terrace gravels contain mainly quartz sandstone, sandstone, vein quartz and quartzite, which account for 90% of the rudaceous clasts in each terrace gravel, which shows that there was no significant provenance change; (5) the gravels of the T2 and T1 terraces are typical fluvial sediments, whereas that of the T3 terrace is a product of superimposition of debris flow and fluvial deposits; and (6) the Qingyijiang originated from a braided river on an alluvial (or pluvial) fan, and the timing of the Qingyijiang can be traced back at least to 905.4 ± 272.4 kyr ago when the Yangtze cut through the Three Gorges. [ABSTRACT FROM AUTHOR]

Evapotranspiration (ET) and water use efficiency (WUE) are critical indexes in water flux cycles of croplands, being affected by climate change. However, field studies addressing influence of experimental warming on ET and WUE in semi-arid cropland are highly deficient. A two-factor experiment, including soil temperature [ambient (C) and increased average 1.5 °C (T) at 5 cm soil depth] and nitrogen fertilizer (N) [without (N0) and with 315 kg N ha input (N1)], was conducted from 2010 to 2014 in North China Plain to measure ET and WUE of wheat-soybean/fallow rotation. In the N1 treatment, warming increased ET by 3 %, 22 %, 34 % and 16 % in wheat growing seasons of 2011, 2012, 2013 and 2014, respectively, compared with ambient temperature. N addition increased ET by 9 %, 22 %, 11 % and 27 % under ambient temperature, and by 14 %, 60 %, 45 % and 50 % under warming during the four wheat growing seasons. Warming reduced WUE by 15 %-45 % under N1. N addition increased WUE by 68 % under ambient temperature during 2010 to 2012, decreased WUE by 45 % under warming during 2011 to 2013. Warming did not alter ET and WUE in the N0 treatment during whole years. Under N1 treatment, the reduction in WUE with increasing soil temperature is likely due to the increased vapour pressure deficit (VPD). The study highlights the interactions between climate warming and N addition on hydrological cycles during wheat growth, contributing the understanding of how fertilized semi-arid cropland respond to climate change. [ABSTRACT FROM AUTHOR]

Inflammatory pain and neuropathic pain are major clinical health issues that represent considerable social and economic burden worldwide. In the present study, we investigated the anti-nociceptive efficacy of delivery of human proenkephalin gene by a plasmid DNA vector (pVAX1-PENK) on complete Freund’s adjuvant (CFA) induced inflammatory pain and spared nerve injury (SNI) induced neuropathic pain in mice. Mice were intramuscularly or intrathecally administered pVAX1 or pVAX1-PENK, respectively. Pain thresholds in the pVAX1-PENK treated mice were significantly higher at day 3, then reached a peak at day 7 and lasted until day 28 after gene transfer, and the analgesic effect of pVAX1-PENK was blocked with naloxone hydrochloride. In contrast, pVAX1 treated mice did not significantly improve pain thresholds. These results indicate that peripheral or spinal delivery of a plasmid encoding human proenkephalin gene provides a potential therapeutic strategy for inflammatory pain and neuropathic pain. [ABSTRACT FROM AUTHOR]

The demand of a plasmid encoding human hepatocyte growth factor gene (pUDK-HGF) in large quantities at high purity and concentration has increased for gene therapy of critical limb ischemia (CLI) in clinical trials. In this article, we produced pUDK-HGF in compliance with current good manufacturing practices at gram scale. The process included a 50-L batch fermentation, continuous alkaline lysis, and integrated three-step chromatography on Sepharose 6 Fast Flow, PlasmidSelect Xtra, and Source 15Q. The production process has been scaled up to yield 4.24 ± 0.41 g of pharmaceutical pUDK-HGF from 1.0 kg bacterial cell paste and the overall yield reached range from 58.37 to 66.70%. The final pUDK-HGF product exhibited high purity with supercoiled percentage of > 95.8% and undetectable residual RNA, contaminated protein, and bacterial endotoxin. The phase I clinical study indicates that intramuscular injection of pUDK-HGF is safe, well tolerated, and may provide symptomatic relief to CLI patients. These results show that our manufacturing process of pUDK-HGF is efficient in producing pharmaceutical-grade plasmid DNA and is safe for clinical applications. [ABSTRACT FROM AUTHOR]

We investigated the antinociceptive effect of local intramuscular injection of a plasmid encoding human proenkephalin (pVAX1-hPPE) on postoperative pain in rats. Male Sprague-Dawley rats with incision-induced pain were intramuscularly injected into injured plantaris muscle with empty vector (pVAX1) or pVAX1-hPPE, respectively. Paw mechanical threshold and thermal latency in the 200 μg pVAX1-hPPE treated rats were significantly higher at 6 h and on 1 day, and lasted until day 7 after intramuscular administration, respectively. The analgesic effects were reversed by methylnaltrexone, suggesting that the antinociceptive effect of pVAX1-hPPE was mediated through peripheral opioid receptor pathway. In contrast, incisional or pVAX1-treated rats did not significantly affect pain thresholds. These results demonstrated that single intramuscular injection of pVAX1-hPPE attenuated incision-induced pain in rats, and it is worthy of further study as a potential gene therapy for postoperative pain. [ABSTRACT FROM AUTHOR]

Based on daily precipitation data from 24 stations over the Yangtze River Delta (YRD) region, the long-term trends of daily precipitation are analyzed during the period 1960-2012 using 12 precipitation indices. The results indicate that the following. (1) For the regional average trends of precipitation, nine indices [i.e., RR, SDII, PCI(day), R25mm, R50mm, R25mmT, R50mmT, R25mmTOT, and R50mmTOT] show the increasing trends, while three indices [i.e., RX1day, RR1 and PCI(month)] display the decreasing trends. Furthermore, the annual total precipitation (RR) is correlated strongly with most of the other precipitation indices, especially indices represent the heavy precipitation which is responsible for more than 90 % of the total increase of precipitation. (2) The central and southern parts of the study area become more humid than the northern parts, although the daily precipitation undergo a consistent concentrated trend over almost all of the study area. Moreover, the frequency and contribution of the heavy precipitation also arise dramatically in almost the entire study area, and the precipitation events show the significant trend of extremeness. (3) The abrupt changes for RR, RX1day, SDII, R50mm, R50mmT, and R50mmTOT are detected in 1984, 1988, 1987, 1984, 1988, and 1988, respectively, which indicate the abrupt change of precipitation occurred consistently in the mid-1980s. Three major cycles of precipitation detected are 5-6-year cycle, 13-year cycle, and 20-year cycle, with a nonsignificant 2-year cycle coexisted. In addition, a significant change of cycles occurred in the 1980s, when the short cycle was set to overtake the long cycle, resulting in high-frequency and instability of precipitation changes over the YRD region in recent decades. (4) There are three factors (the global warming, the East Asian summer monsoon change, and the urbanization development) might potentially impact on the frequency and volume of precipitation. The variation of East Asian summer monsoon is the key factor that influences the increase of precipitation, while the global warming and the urbanization development perform the background factor and the local factor, respectively. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N 2 O) emissions from agricultural soils play an important role in the global greenhouse gas budget. However, the response of N 2 O emissions from nitrogen fertilized agricultural soils to climate warming is not yet well understood. A field experiment with simulated warming ( T ) using infrared heaters and its control (C) combined with a nitrogen (N1) fertilization treatment (315 kg N ha −1 y −1 ) and no nitrogen treatment (N0) was conducted over five years at an agricultural research station in the North China Plain in a winter wheat–soybean double cropping system. N 2 O fluxes were measured using static chambers about once every week during July 2009–June 2014. In the N1 treatment, warming decreased the soil moisture and N 2 O emissions in spring, autumn and winter and the annual cumulative emissions. Across all years, N 2 O fluxes were positively correlated with soil temperature and soil moisture. The effect of lower soil moisture on N 2 O fluxes exceeded that of higher temperature, leading to less N 2 O being released by the drier soils under warming. Nitrogen fertilizer increased N 2 O emissions without warming, but did not routinely increase N 2 O emissions under warming treatment. In the N0 treatment, warming neither decreased soil water content nor N 2 O emissions. Temperature and nitrogen input had significant direct and antagonistic effects on cumulative N 2 O flux in the N1 treatment. The decrease in N 2 O emissions from N1 T was due to the significant decrease of soil water content, soil total nitrogen and organic matter, which consequently accelerated N cycle dynamics and advanced wheat growth. [ABSTRACT FROM AUTHOR]

Soil respiration and CH 4 emissions play a significant role in the global carbon balance. However, in situ studies in agricultural soils on responses of soil respiration and CH 4 fluxes to climate warming are still sparse, especially from long-term studies with year-round heating. A warming experiment was conducted at Luancheng research station in the North China Plain from 2008 to 2013. Two levels of temperature ( T : increase on average 1.5 °C at 5 cm soil depth by infrared heaters, C : ambient temperature) were combined with two levels of nitrogen (N) treatments (N1: with 315 kg N ha −1 y −1 , N0: no nitrogen input) in the farmland. Soil was found to be a sink for CH 4 with no marked seasonal variations. In the wheat-growing season, warming and N input both decreased cumulative CH 4 uptake, probably because warming-induced soil drying in N1 treatment reduced (or limited) methanotroph activity by affecting soil NH 4 concentration. Across years, CH 4 emissions were negatively correlated with soil temperature in N1 treatment. Soil respiration showed clear seasonal fluctuations, with the largest emissions during summer and smallest in winter. Warming and nitrogen fertilization had no significant effects on total cumulative soil CO 2 fluxes. Soil respiration was positively correlated with microbial biomass C, and microbial biomass C was not affected significantly by warming or nitrogen addition. The lack of significant effects of warming on soil respiration may have resulted from: (1) warming-induced soil drying offsetting the effects of soil temperature; or (2) adaption of soil respiration to increased temperature. [ABSTRACT FROM AUTHOR]

The production and consumption of the greenhouse gases (GHGs) methane (CH4), carbon dioxide (CO2) and nitrous oxide (N2O) in soil profile are poorly understood. This work sought to quantify the GHG production and consumption at seven depths (0–30, 30–60, 60–90, 90–150, 150–200, 200–250 and 250–300 cm) in a long-term field experiment with a winter wheat-summer maize rotation system, and four N application rates (0; 200; 400 and 600 kg N ha−1 year−1) in the North China Plain. The gas samples were taken twice a week and analyzed by gas chromatography. GHG production and consumption in soil layers were inferred using Fick’s law. Results showed nitrogen application significantly increased N2O fluxes in soil down to 90 cm but did not affect CH4 and CO2 fluxes. Soil moisture played an important role in soil profile GHG fluxes; both CH4 consumption and CO2 fluxes in and from soil tended to decrease with increasing soil water filled pore space (WFPS). The top 0–60 cm of soil was a sink of atmospheric CH4, and a source of both CO2 and N2O, more than 90% of the annual cumulative GHG fluxes originated at depths shallower than 90 cm; the subsoil (>90 cm) was not a major source or sink of GHG, rather it acted as a ‘reservoir’. This study provides quantitative evidence for the production and consumption of CH4, CO2 and N2O in the soil profile. [ABSTRACT FROM AUTHOR]

Highlights: [•] Wheat grain yield was decreased under warming treatment in 3 out of 4 years. [•] Warming limited yield gain from nitrogen fertilization under normal winter weather. [•] Wheat yield was increased by warming following an unusual cold and snowy winter. [•] Warming improved nitrogen utilization in a year with unusual cold and wet winter. [•] Early growth phases were shortened whereas later ones were extended under warming. [ABSTRACT FROM AUTHOR]

Differentiating intracellular from extracellular enzyme activity is important in soil enzymology, but not easy. Here, we report on an adjusted sonication method for the separation of intracellular from extracellular phosphatase activity in soil. Under optimal sonication conditions [soil:water ratio  =  1/8 (w/v) and power density  =  15 watt ml-1], the activity of alkaline phosphomonoesterase (phosphatase) in a Haplic Cambisol soil increased with sonication time in two distinct steps. A first plateau of enzyme activity was reached between 60 and 100 s, and a second higher plateau after 300 s. We also found that sonication for 100 s under optimal conditions activated most (about 80%) of the alkaline phosphatase that was added to an autoclaved soil, while total bacteria number was not affected. Sonication for 300 s reduced the total bacteria number by three orders of magnitude but had no further effects on enzyme activity. Our results indicate that the first plateau of alkaline phosphatase activity was derived from extracellular enzymes attached to soil particles, and the second plateau to the combination of extracellular and intracellular enzymes after cell lysis. We conclude that our adjusted sonication method may be an alternative to the currently used physiological and chloroform-fumigation methods for differentiating intracellular from extracellular phosphatase activity in soil. Further testing is needed to find out whether this holds for other soil types. [ABSTRACT FROM AUTHOR]

Abstract: The acetylene inhibition technique (AIT) is commonly used for the determination of soil denitrification potential (SDP). However, the results obtained with this technique have intrinsic uncertainties. This study aimed at quantifying these uncertainties. A silt loam topsoil from an experimental station was incubated under standard conditions for SDP measurements, with and without acetylene additions. Changes in the concentrations of N2O and N2 in the headspace of incubation vials were monitored during the incubation, using a robotized sampling and analyzing system. Our results showed that the AIT did not completely inhibit the reduction of N2O to N2. As much as 11.7% of the produced N2O was reduced into N2 in the presence of acetylene. We conclude that SDP has to be corrected when determined by the AIT. The procedures used in this study will allow the estimation of correction factors, possibly as function of soil type and environmental conditions. [Copyright &y& Elsevier]

Abstract: The majority of soil urease activity measurements have been based on the rate of ammonium production under optimal conditions. However, such procedures do not exclude ammonium consumption by the nitrification process. The purpose of this study was to determine the percentage of soil urease activity that is underestimated due to soil nitrification. Six soils with diverse properties were incubated using a standard procedure for measuring soil urease activity. The dynamics of nitrite and nitrate were observed during the incubation. Our results showed that the percentage of underestimation ranged from 7.38% to 15.97%, depending on soil types and whether or not a buffer was used. We recommend that nitrification be taken into account when soil urease activity is assayed by the ammonium production rate method. [ABSTRACT FROM AUTHOR]

Abstract: Micro-scale investigation is helpful for better understanding of the relationships between organic matter, microorganisms and nutrients in soil, and for better interpretation of modifications induced by soil management. The soil particle-size fractions (2000–200, 200–63, 63–2, and 2–0.1μm), contents of soil organic carbon (SOC), total N (STN), available P (SAP), dissolved organic C (DOC), light fraction organic C (LOC), microbial biomass N (MBN), basal respiration (SBR), and relevant enzyme activities of C, N and P transformations, such as β-glucosidase (β-G), N-acetyl-β-glucosaminidase (N-G), protease, urease and alkaline phosphomonoesterase (APH) were analyzed to study the effects of 8-year-period conservational (no-till with residue retention) (CAM) versus traditional agricultural management (moldboard plowing without residue retention) (TAM) to a Haplic Cambisol soil in the North China Plain (NCP). Our results showed that CAM significantly enlarged the stocks of SOC, DOC, LOC, STN and SAP in the 0–10cm layer, increased the contents of SOC, STN and SAP in the sand fractions, and promoted all of the enzyme activities in the bulk soil and all of the four particle-size fractions. Our results suggested that CAM increased the nutrient contents in the sand fractions by both enlarging the content of particulate organic matter and enhancing the activities of enzymes involved in nutrient cycling in these fractions. On the contrary, the contents of SOC and nutrients in the silt and clay fractions were relatively resistant to the conversion from CAM to TAM, indicating the limitation of CAM for stable SOC sequestration. [Copyright &y& Elsevier]

LiFePO 4 batteries generally face a challenge of inaccurate state of charge (SoC) estimation due to the plateaus existing in the middle range of the open circuit voltage (OCV)-SoC curve. Generally, conventional SoC estimation methods are not capable of accurately estimating the SoC in this range. In this paper, a deep neural network (DNN) is constructed to estimate the SoC in the charging process. Battery data collected from five state-of-the-art charging protocols at 10 °C, 25 °C and 40 °C are used to train the DNN. The developed DNN can be used for online SoC estimation subsequently. This estimated SoC can serve as the initial SoC of the ampere-hour counting method to calculate the SoC of the discharging process. The overall maximum error and the root mean square error of the SoC estimation over charging process are within 2.5% and 0.8%, respectively. In addition, the input depth of time from 10 s to 100 s with a 10 s interval is investigated. The maximum error is less than 5% in the case of the depth time within 100 s and the error fall to 2% when the depth of time reaches 90 s. • Accurate estimation results can be obtained with only data sampled in 90 s. •A deep neural network is developed to accurately estimate the SOC of LiFePO 4 batteries. • Five state-of-the-art charging protocols are employed for validation. • Accurate SOC estimation can be ensured even in a flat voltage range. • The proposed method has robust performance at different temperatures. [ABSTRACT FROM AUTHOR]

Abstract: The Northern China Plain (NCP) produces over 20% of the national grain production. Best management practices (BMP) for intensive irrigated cropping systems of the NCP are based on large nitrogen (N) applications without accounting for N budgets. There are concerns that non-scientific based BMPs may be impacting underground water resources. We conducted the first study in this region, located at the Luancheng Experimental Research Station that measured the effects of N fertilizer rates on nitrate-nitrogen (NO3-N) leaching losses. From October 1, 2001 to September 30, 2004, we used a water balance approach with a neutron probe, weighing lysimeter, and suction cups located at 1.8m depths on a winter wheat (Triticum aestivum L.)–corn (Zea mays L.) rotation to monitor NO3-N leaching. Residual soil NO3-N, yields, and N uptake by aboveground biomass were also measured. Corn received two surface broadcast applications every year of 50, 100, 150 and 200kg urea-Nha−1 for the N200, N400, N600, and N800 treatments, respectively. The first broadcast application was at seeding and the second at tassel. Similarly, winter wheat received two surface broadcast applications, initially as a pre-plant and a second application at the jointing stage of growth in spring. We monitored NO3-N leaching losses for the N200, N400, and N800 treatments. Average NO3-N leaching losses during wheat–corn season were 6, 58, and 149kg NO3-Nha−1 year−1 for the 200, 400, and 800kgNha−1 year−1 treatments, respectively. The NO3-N leaching increased with N applications (P <0.05) and were in agreement with the NO3-N concentrations of 12, 74, and 223mg NO3-NL−1 for soil water at 1.8m depths for the 200, 400, and 800kgNha−1 year−1 treatments, respectively. Higher than needed N fertilizer applications increased the NO3-N leaching losses and reduced the N use efficiency (NUE) without yield increases. We propose that there is a need for a new scientifically based BMP approach for the NCP based on N budgets that credits soil NO3-N before planting, N mineralization from soil organic matter, and other potential N sources as a key mitigation alternative to increase NUE and reduce NO3-N leaching in this region. [Copyright &y& Elsevier]

Incorporating crop residues into the soil is an effective method for improving soil carbon sequestration, fertility, and crop productivity. Such potential benefits, however, may be offset if residue addition leads to a substantial increase in soil greenhouse gas (GHG) emissions. This study aimed to quantify the effect of different crop residues with varying C/N ratios and different nitrogen (N) fertilizers on GHG emissions, yield, and yield-scaled emissions (GHGI) in winter wheat. The field experiment was conducted during the 2018–2019 winter wheat season, comprising of four residue treatments (no residue, maize residue, soybean residue, and maize-soybean mixed residue) and four fertilizer treatments (control, urea, manure, and manure + urea). The experiment followed a randomized split-plot design, with N treatments as the main plot factor and crop residue treatments as the sub-plot factor. Except for the control, all N treatments received 150 kg N ha−1 season−1. The results showed that soils from all treatments acted as a net source of N2O and CO2 fluxes but as a net sink of CH4 fluxes. Soybean residue significantly increased soil N2O emissions, while mixed residue had the lowest N2O emissions among the three residues. However, all residue amendments significantly increased soil CO2 emissions. Furthermore, soybean and mixed residues significantly increased grain yield by 24% and 21%, respectively, compared to no residue amendment. Both soybean and mixed residues reduced GHGI by 25% compared to maize residue. Additionally, the urea and manure + urea treatments exhibited higher N2O emissions among the N treatments, but they contributed to significantly higher grain yields and resulted in lower GHGI. Moreover, crop residue incorporation significantly altered soil N dynamics. In soybean residue-amended soil, both NH4+ and NO3− concentrations were significantly higher (p < 0.05). Conversely, soil NO3− content was notably lower in the maize-soybean mixed residue amendment. Overall, our findings contribute to a comprehensive understanding of how different residue additions from different cropping systems influence soil N dynamics and GHG emissions, offering valuable insights into effective agroecosystems management for long-term food security and soil sustainability while mitigating GHG emissions. [ABSTRACT FROM AUTHOR]

Vertical profiles of N2O production and consumption within soils have not been carefully quantified and mechanism for N2O consumption also not clear. The objective of this study was to quantify the depth-dependent contributions of N2O fluxes in the soil profile to soil surface gas exchange in field and confirm the aerobic pathways for N2O consumption with incubation method.We found that unfertilized maize-based farmland acted as N2O sinks for 2 years. N2O consumption originated from the 0–15 cm soil horizons. Specifically, we revealed that the N2O consumption at 0–5 and 5–15 cm depths accounted for 80.4 and 6.6% of the surface exchange, respectively. N2O were very weak below 40 and 15 cm depths, respectively. In conclusion, our results highlight that the topsoil (0–40 cm) plays a critical role in N2O consumption in an unfertilized maize-based farmland in Taihang mountain areas of northern China. For confirm the mechanism of N2O consumption, we extracted micro-biota from three typical upland soils with variable properties and incubated them under aerobic and anaerobic conditions, with nitrate, to investigate whether N2 production occurred via aerobic pathways and the relative importance of it when compared with the N2 production via anaerobic pathways. Our results showed that the N2 produced via aerobic pathways equated to 29–51% of that produced via anaerobic pathways. Thus N2 production via aerobic pathways may play a significant role in soil nitrogen (N) cycling, which may be the pathway for soil N2O sink. [ABSTRACT FROM AUTHOR]

Nitrogen (N) fertilizer and crop residue amendments are important agricultural practices that could increase soil health, fertility, and crop yield. Such practices may also change soil denitrification processes where contradictory observations have been reported on soil N2O emissions with fewer studies on N2 emissions due to its large atmospheric background concentrations limiting its soil-borne measurement. This study aims to investigate N2O production and reduction of N2 emissions under a conducive denitrifying environment (like anaerobic microsites, 80% WFPS, available N and C) after rice straw amendment and KNO3 application to three different soil types (fluvo-aquic, black, and paddy soils). In this regard, three treatments for three different soil types were set consisting of (a) a non-amended treatment (control), (b) a KNO3 treatment (KNO3, 20 mM KNO3), and (c) a straw plus KNO3 treatment (2.5 g rice straw kg−1 dry soil and 20 mM KNO3), which were incubated under 80% WFPS. Moreover, direct N2O and N2 fluxes were measured over 17 days in the current incubation experiment with a robotized incubation system using a helium atmosphere. Results showed that rice straw amendment combined with N fertilizer increased both N2O and N2 fluxes compared with control or KNO3 treatments in all three soil types. Overall, compared with the black and paddy soils, the N2O and N2 fluxes were higher in the fluvo-aquic soil, with a maximum of 234.2 ± 6.3 and 590.1 ± 27.3 g N ha−1 from F_SK treatment, respectively, during the incubation period. The general trends in three soil types of both N2O and N2 emissions were control < KNO3 < rice straw plus KNO3 treatments. Straw amendment in combination with KNO3 can stimulate a high denitrification rate (less N2O and higher N2), whereas their effect on stoichiometric ratios of N2O/(N2O + N2) highly depends on soil nitrate concentration, oxygen level, soil moisture content, and labile C. The current study underscores that the rice straw amendment in combination with N fertilizer can trigger denitrification with less increment on soil N2O but higher N2 emissions under conditions favoring denitrification. [ABSTRACT FROM AUTHOR]

Microbial residue nitrogen can indicate soil quality and is crucial for soil nitrogen retention and supply. However, it is still unclear how the dynamic changes in soil microbial residue nitrogen affect crop nitrogen uptake in agricultural practice. Based on a long-term wheat-maize rotation experiment with different nitrogen application rates (150 kg N ha−1, 200 kg N ha−1, and 300 kg N ha−1), 15N-labeled nitrogen fertilizer was applied during the wheat season to track the dynamics of soil microbial residue nitrogen and its mediated fertilizer nitrogen. The results showed that nitrogen addition was beneficial to the accumulation of microbial residue nitrogen (mainly fungal microbial residue nitrogen). Its contribution rate to soil total nitrogen is 54.87–56.55%, and the fertilizer nitrogen allocated to it accounts for 27.10–47.50% of the remaining fertilizer nitrogen in the soil. Ultimately, 6.77–10.24% of the nitrogen fertilizer applied remained in the soil as microbial residue nitrogen. In addition, microbial residue nitrogen is mainly mineralized during the jointing and filling stages of wheat. In a word, the accumulation and mineralization of soil microbial residue nitrogen during the application of 200 kg N ha−1 better guaranteed the uptake of nitrogen by wheat, which provided a reliable basis for guiding farmland fertility improvement and nitrogen fertilizer reduction in the North China Plain. [ABSTRACT FROM AUTHOR]

Lack of dissolved organic carbon (DOC) is generally one of the key factors limiting denitrification in subsoil beneath the root zone. Despite a number of laboratory DOC amendment studies, the effects of in situ DOC infiltration on subsoil denitrification, and on subsequent end product composition, are less understood. Here, we report on the effects of in situ infiltration of a DOC-rich liquid, derived from decomposing straw, on potential denitrification rate (PDR), N 2 O/(N 2 O + N 2 ) product ratio, and nitrate stock in a 0–2 m soil profile. The results showed that in situ infiltration with a DOC-rich liquid (100 mm, 2 ton DOC ha −1 ) significantly increased the DOC concentration and PDR, and significantly decreased the N 2 O/(N 2 O + N 2 ) product ratio in the soil profile. Up to 70% of the nitrate accumulated in the 0–2 m soil profile disappeared within three weeks following the infiltration of the DOC-rich liquid. The majority of the nitrate removed could be accounted for by denitrification. The predominant end product of denitrification was N 2 . The mass ratio between the consumed DOC and nitrate-N was about 5. Our results demonstrate the significant potential for removing subsoil nitrate by in situ introduction of DOC generated from the above-ground crop biomass. [ABSTRACT FROM AUTHOR]

Compound 6d, a spiroindoline compound, exhibits antiproliferative capability against cancer cell lines. However, the exact underlying mechanism of this compound-mediated inhibitory capability remains unclear. Here, we showed that compound 6d is an inhibitor of Bcl-2, which suppresses CRC growth by inducing caspase 3-mediated intrinsic apoptosis of mitochondria. Regarding the underlying mechanism, we identified HDAC6 as a direct substrate for caspase 3, and caspase 3 activation induced by compound 6d directly cleaves HDAC6 into two fragments. Moreover, the cleavage site was located at D1088 in the DMAD-S motif HDAC6. Apoptosis stimulated by compound 6d promoted autophagy initiation by inhibiting interaction between Bcl-2 and Beclin 1, while it led to the accumulation of ubiquitinated proteins and the reduction of autophagic flux. Collectively, our findings reveal that the Bcl-2-caspase 3-HDAC6 cascade is a crucial regulatory pathway of autophagy and identify compound 6d as a novel lead compound for disrupting the balance between apoptosis and autophagy. [ABSTRACT FROM AUTHOR]

Background: Lung adenocarcinoma (LUAD) is one of the most common cancers with high morbidity and mortality and remains a crucial factor endangering human health.Objective: This study aimed to elucidate the potential treatment target and prognostic biomarker in patients with LUAD through a comprehensive bioinformatics analysis.Methods: The three public microarray datasets of GSE118370, GSE116959, and GSE43767 were obtained from the GEO data resource. The DEGs were explored between LUAD and non-malignant samples using GEO2R online tool in GEO data resource. GO along with KEGG analysis of DEGs were examined using WebGestalt tool. The STRING web resource was employed to develop the PPI network of DEGs, whereas Cytoscape software was employed to perform module analysis. Finally, the mRNA, protein expression along with survival analysis of hub genes were explored via GEPIA, HPA along with Kaplan-Meier plotter web resource, respectively.Results: Only 82 upregulated and 105 downregulated DEGs were found among the three datasets. Further, GO analysis illustrated that 187 DEGs were primary enriched in extracellular structure organization, tube development along with cell adhesion. The KEGG enrichments showed that these DEGs were primary linked to leukocyte transendothelial migration, vascular smooth muscle contraction along with ECM-receptor interaction. Among the 187 DEGs, the 10 hub genes (P4HB, SPP1, CP, GOLM1, COL1A1, MMP9, COL10A1, APOA1, COL4A6, and TIMP1) were identified. The mRNA along with protein levels of hub genes in LUAD tissues were further verified by Oncomine, UCSC Xena, GEPIA and HPA databases. Additionally, overall survival curves illustrated that LUAD patients with the higher levels of P4HB, SPP1, COL1A1, and MMP9 were dramatically linked to shorter overall survival.Conclusions: The current study identified DEGs candidate genes (P4HB, SPP1, COL1A1, and MMP9) and pathways in LUAD using bioinformatics analysis, which could enhance our understanding of pathogenesis along with underlying molecular events in LUAD, and these hub genes and pathways may help provide candidate treatment targets for LUAD. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is one of the most common causes of cancer-related death worldwide, and more therapies are needed to treat CRC. To discover novel CRC chemotherapeutic molecules, we used a series of previously synthesized novel imidazolidin-4-one derivatives to study their anticancer role in several cancer cell lines. Among these compounds, compound 9r exhibited the best anticancer activity in CRC cell lines HCT116 and SW620. We further investigated the anticancer molecular mechanism of compound 9r. We found that compound 9r induced mitochondrial pathway apoptosis in HCT116 and SW620 cells by inducing reactive oxygen species (ROS) production. Moreover, the elevated ROS generation activated the c-Jun N-terminal kinase (JNK) pathway, which further accelerated apoptosis. N-acetylcysteine (NAC), an antioxidant reagent, suppressed compound 9r-induced ROS production, JNK pathway activation, and apoptosis. Collectively, this research synthesized a series of imidazolidin-4-one derivatives, evaluated their anticancer activity, and explored the molecular mechanism of compound 9r-induced apoptosis in CRC cells. The present results suggest that compound 9r has a potential therapeutic role in CRC. Hence, it deserves further exploration as a lead compound for CRC treatment. [ABSTRACT FROM AUTHOR]

Enhancing dissimilatory nitrate reduction to ammonium (DNRA) is environmentally and agronomically beneficial due to DNRA improving nitrogen (N) retention in soil. However, the rate of DNRA is generally considerably lower than that of denitrification because DNRA requires more electron donors than denitrification. Biochar has been increasingly reported to act as an "electron shuttle" to facilitate electron transfer and to promote redox reactions in soil. Thus, this study aimed to investigate whether and how biochar could enhance the DNRA process in a paddy soil. The results showed that, compared with the no-biochar control, the application of rice straw biochar increased the DNRA rate from 0.2 to 0.7 mg NH 4 +-N kg−1 dry soil d−1. As well, biochar simultaneously, increased the relative abundance of DNRA functional microbes (nrfA -type microbes) and functional gene (nrfA) expression levels. Biochar's enhancement of DNRA was positively correlated with the biochar properties relevant to electron shuttling (e.g., specific capacitance). In contrast, the application of electron shuttle-weakened biochar (oxidized by H 2 O 2) did not increase, or even decreased, the DNRA rate in the paddy soil. These results demonstrate that biochar can act as an electron shuttle to enhance electron availability for DNRA functional microorganisms and consequently promote the DNRA process in paddy soil. Our results indicate that amendment of paddy soil with biochar containing a high-capacity electron shuttle function is beneficial for preserving N by transforming the mobile nitrate anion into the less mobile ammonium cation in paddy soils. [Display omitted] • Biochar promoted the DNRA rate and DNRA functional gene expression in paddy soil. • The promotion of DNRA resulted from the electron shuttle function of the biochar. • Biochar's role as an electron shuttle increases N retention in paddy soils. [ABSTRACT FROM AUTHOR]

High nitrogen (N) input to soil can cause higher nitrous oxide (N2O) emissions, that is, a higher N2O/(N2O+N2) ratio, through an inhibition of N2O reductase activity and/or a decrease in soil pH. We assumed that there were two mechanisms for the effects of N input on N2O emissions, immediate and long-term effect. The immediate effect (field applied fertilizer N) can be eliminated by decreasing the N input, but not the long-term effect (soil accumulated N caused by long–term fertilization). Therefore, it is important to separate these effects to mitigate N2O emissions. To this end, soil samples along a 0‒5.2 m profile were collected from a long-term N fertilization experiment field with two N application rates, that is, 600 kg N ha-1 year-1 (N600) and no fertilizer N input (N0). External N addition was conducted for each subsample in the laboratory incubation study to produce two additional treatments, which were denoted as N600+N and N0+N treatments. The results showed that the combined immediate and long-term effects led to an increase in the N2O/(N2O+N2) ratio by 6.8%. Approximately 32.6% and 67.4% of increase could be explained by the immediate and long-term effects of N input, respectively. Meanwhile, the long-term effects were significantly positively correlated to soil organic carbon (SOC). These results indicate that excessive N fertilizer input to the soil can lead to increased N2O emissions if the soil has a high SOC content. The long-term effect of N input on the N2O/(N2O+N2) ratio should be considered when predicting soil N2O emissions under global environmental change scenarios. [ABSTRACT FROM AUTHOR]

Oxygen (O2) is the most crucial substrate for numerous biochemical processes in plants. Its deprivation is a critical factor that affects plant growth and may lead to death if it lasts for a long time. However, various biotic and abiotic factors cause O2 deprivation, leading to hypoxia and anoxia in plant tissues. To survive under hypoxia and/or anoxia, plants deploy various mechanisms such as fermentation paths, reactive oxygen species (ROS), reactive nitrogen species (RNS), antioxidant enzymes, aerenchyma, and adventitious root formation, while nitrate (NO3−), nitrite (NO2−), and nitric oxide (NO) have shown numerous beneficial roles through modulating these mechanisms. Therefore, in this review, we highlight the role of reductive pathways of NO formation which lessen the deleterious effects of oxidative damages and increase the adaptation capacity of plants during hypoxia and anoxia. Meanwhile, the overproduction of NO through reductive pathways during hypoxia and anoxia leads to cellular dysfunction and cell death. Thus, its scavenging or inhibition is equally important for plant survival. As plants are also reported to produce a potent greenhouse gas nitrous oxide (N2O) when supplied with NO3− and NO2−, resembling bacterial denitrification, its role during hypoxia and anoxia tolerance is discussed here. We point out that NO reduction to N2O along with the phytoglobin-NO cycle could be the most important NO-scavenging mechanism that would reduce nitro-oxidative stress, thus enhancing plants' survival during O2-limited conditions. Hence, understanding the molecular mechanisms involved in reducing NO toxicity would not only provide insight into its role in plant physiology, but also address the uncertainties seen in the global N2O budget. [ABSTRACT FROM AUTHOR]

Aims: The priming effect (PE) on native soil organic matter induced by exogenous carbon addition influences soil carbon and nutrient cycling across the soil depths. Therefore, this study aimed to explore the effects of exogenous glucose-induced PE on native soil organic carbon (SOC) influenced by soil properties across soil depths, weather factors in different ecosystems and experimental variables. Methods: We conducted a meta-analysis of 1231 experimental comparisons from 41 publications to explore the responses of native SOC to stable or radioactive carbon isotope (glucose) addition in laboratory incubation experiments representing various ecosystems and soil depths on the global scale. Results: Overall, glucose addition had 110% positive PE on native SOC. The PE was higher in deep soil (197%) and lowest in topsoil (99%). Deep soil contains significantly lower SOC, dissolved organic carbon and microbial biomass carbon and a higher soil carbon/nitrogen ratio than topsoil. The PE positively correlated with soil carbon/nitrogen ratio and glucose addition rate but negatively correlated with microbial biomass carbon, dissolved organic carbon, SOC and incubation duration. Furthermore, PE positively related to mean annual temperature and precipitation in cropland while negatively correlated with mean annual precipitation in grassland ecosystem. Conclusions: Low soil nutrients and high carbon/nitrogen ratio is the reason for higher PE in deep soil than topsoil. Furthermore, the experimental variables and weather factors provide a framework for understanding the magnitude and direction of PE on native SOC induced by glucose addition and highlight the need for future integrated approaches of studies on PE. [ABSTRACT FROM AUTHOR]

Abstract: Emissions of nitrous oxide (N2O) from agricultural soils contribute to global warming and stratospheric ozone depletion. Applications of fertilizer nitrogen (N) increase N2O emission, but also increase agricultural production. Here, we report on the responses of crop yield, N2O emission and yield-scaled N2O emission (N2O emission per unit N uptake by grain and aboveground biomass) to different N fertilizer rates in a winter wheat–summer corn double-cropping system in the North China Plain. Soil N2O emission measurements were carried out for two years in a long-term field experiment, under semi-arid conditions with four flood irrigations events per year. Our results indicated that N2O emissions were linear functions and yield-scaled N2O emissions were cubic functions of N fertilizer application rate. Yield-scaled N2O emissions were lowest at application rates of 136 kg N ha−1 yr−1. Using a quadratic-plateau model, it was found that maximal crop yields were achieved at an application rate of 317 kg N ha−1 yr−1, which is 20% less than current practice. This level is suggested to be a compromise between achieving food security and mitigation N2O emissions. [Copyright &y& Elsevier]

Abstract: This study compared the responses of soil chemical and microbial indicators to the conservational tillage (CT) versus traditional tillage (TT) in a Haplic Cambisol in the North China Plain (NCP). These indicators included soil organic C (SOC), soil total N (STN), soil available P (SAP), cation exchange capacity (CEC), exchangeable Ca2+ and Mg2+, microbial biomass C (MBC), microbial biomass N (MBN), alkaline phosphomonoesterase (AP), β-glucosidase, N-acetyl-β-glucosaminidase (NAG), nitrate reductase (NR), protease, urease and the geometric mean of the assayed enzymes (GMea). Our results showed that almost all investigated parameters, except the contents of CEC, Ca2+, Mg2+ and the ratios of GMea/MBN and C/N, were significantly higher under the CT (no-till, NT and reduced-till, RT) than those under the TT, whilst the crop yield was not significantly affected by tillage treatments. Principle component analysis (PCA) showed that the first and second component explained 67.2% and 16.6% of the total variation, respectively. The first component was significantly correlated with GMea, MBC, MBN and β-glucosidase, and effectively discriminated soils under the NT or RT from those under the TT. Our results indicated that the 6-year CT improved the quality of the Haplic Cambisol by enhancing its chemical and microbial properties, whilst GMea, MBC, MBN and β-glucosidase were among the most effective indicators for monitoring these improvements. [Copyright &y& Elsevier]

Little information is available about their influences of conservation tillage on the distribution and storage of soil organic C (SOC) and total N in soil profiles in the North China Plain. We investigated the changes in SOC and total N as related to the shift from conventional to conservation tillage using a long-term held experiment with a winter wheat (Triticum aestivum L.)-com (Zea mays L.) double cropping system. The experiment included four tillage treatments for winter wheat: moldboard plow without corn residue return (MP-R), moldboard plow with corn residue return (MP+R), rotary tillage (RT), and no-till (NT). Compared with the MP-R treatment, returning crop residue to the soil (MP+R, RT, and NT) increased SOC and total N in the 0- to 30-cm soil layer, but no distinct changes in SOC and total N concentration were observed among the four treatments at soil depths >30 cm. Compared with the MP+R treatment, the RT and NT treatments increased SOC and total N concentration significantly in the 0- to 10-cm layer but decreased SOC and total N concentration in the 10- to 20-cm layers. As a consequence, soil profile SOC and total N storage did not vary among the MP+R, RT, and NT treatments. Thus under the experimental conditions, conservation tillagc (RT and NT) increased SOC and total N contents in the upper soil layers, but did not increase SOC and total N storage over conventional tillage (MP+R) in the soil profile. [ABSTRACT FROM AUTHOR]

Abstract: Visual observations of soil structure in the field offer the potential of semi-quantitative information for use in extension and monitoring. The aim of the study was to test the diagnostic value of different visual methods of soil structure assessment in relation to measurements of topsoil physical quality and yield of cereals. Visual methods that emphasized aggregate and pore characteristics were considered and included procedures of Peerlkamp [Peerlkamp, P.K., 1967. Visual estimation of soil structure. In: de Boodt, M., de Leenherr, D.E., Frese, H., Low, A.J., Peerlkamp, P.K. (Eds.), West European Methods for Soil Structure Determination, vol. 2, no. 11. State Faculty Agric. Sci., Ghent, Belgium, pp. 216–223], Diez and Weigelt [Diez, T., Weigelt, H., 1997. Bodenstruktur erkennen und beurteilen. Anleitung zur Bodenuntersuchung mit dem Spaten. Sonderdruck diz agrarmagazin. Bayer. Landesanstalt fuer Bodenkultur und Pflanzenbau, Freising-Muenchen., 2nd ed., 16 pp.], Shepherd [Shepherd, T.G., 2000. Visual Soil Assessment. Volume 1. Field Guide for Cropping and Pastoral Grazing on Flat to Rolling Country. Horizons.mw/Landcare Research, Palmerston North, 84 pp.], Werner and Thaemert [Werner, D., Thaemert, W., 1989. Zur Diagnose des physikalischen Bodenzustandes auf Produktionsflaechen. Arch. Acker-Pflanzenbau Bodenkd., Berlin 33, 729–739], FAO [FAO, 2006. Guidelines for soil description, 4th ed. FAO, Rome, 95 pp.] and the Peerlkamp method, modified by [Ball, B.C., Batey, T., Munkholm, L.J., 2007. Field assessment of soil structural quality—a development of the Peerlkamp test. Soil Use and Management 23, 329–337]. Measurements of soil quality included soil density (DBD), strength (penetrometer resistance, vane shear strength), permeability (initial infiltration rate) and biological activity (earthworm counts). The study was conducted on sites in Canada (Elora), China (Luancheng), and Germany (Dedelow). Soils were loamy and silty textured Haplic Luvisols (Elora, Dedelow) and Haplic Cambisols (Luancheng). Results showed that shape and size of aggregates were quickly recognizable diagnostic features of soil structure. Structure scores of most methods gave similar results after standardizing data. Measured soil physical qualities and crop yields correlated significantly with visual soil structure. Unfavourable visual structure was associated with increased dry bulk density, higher soil strength and lower infiltration rate but correlations were site-specific. Biological features like earthworm or root numbers were less reliable indicators of soil structure than aggregate characteristics. Visual soil structure assessment is a useful diagnostic tool and may indicate soil structure states clearly. Methods should be selected according to site conditions and should include a fast method of the Peerlkamp type. [Copyright &y& Elsevier]

Based on the aeolian loess sequence-stratigraphic division and paleomagnetic datings on terraces, we found that an undiscovered terrace with the age of 1.0 Ma BP lies between the Dunwashan terrace and Wuyishan terrace. This terrace recorded an intensive Yellow River incision event during that period. Results of paleomagnetic dating and optically stimulated luminescence (OSL) dating of the Wuyishan loess section and Zaoshugou loess section on the fourth Yellow River terrace (T4) show that the age of the fourth Yellow River terrace in Lanzhou area is 0.86 Ma BP rather than the previously believed 0.6 Ma BP. This result answers a long-term question in the geomorphology community of whether there exists a 0.8 Ma terrace in Lanzhou area. The discovery of the 1.0 Ma Yellow River terrace and redating of the age of 0.6 Ma terrace in Lanzhou area provide new insights into further research on the evolution of Yellow River. [ABSTRACT FROM AUTHOR]

In sub-Saharan Africa, agriculture can account for up to 66% of anthropogenic greenhouse gas (GHG) emissions. Unfortunately, due to the low number of studies in the region there is still much uncertainty on how management activities can affect these emissions. To help reduce this uncertainty, we measured GHG emissions from three maize (Zea mays) growing seasons in central Kenya. Treatments included: (1) a no N application control (C); (2) split (30% at planting and 70% 1 month after planting) mineral nitrogen (N) applications (Min—100 kg N ha−1); (3) split mineral N + irrigation (equivalent to 10 mm precipitation every three days—MI); (4) split mineral N + 40 kg N ha−1 added as manure (MM—total N = 140 kg ha−1); and (5) split mineral + intercropping with faba beans (Phaseolus vulgaris—MB). Soil CO2 fluxes were lower in season 1 compared to seasons 2 and 3 with fluxes highest in Min (p = 0.02) in season 2 and lowest in C (p = 0.02) in season 3. There was uptake of CH4 in these soils that decreased from season 1 to 3 as the mean soil moisture content increased. Cumulative N2O fluxes ranged from 0.25 to 2.45 kg N2O-N ha−1, with the highest fluxes from MI during season 3 (p = 0.01) and the lowest from C during season 1 (p = 0.03). The average fertilizer induced emission factor (0.36 ± 0.03%) was roughly one-third the default value of 1%. Soil moisture was a critical factor controlling GHG emissions in these central Kenya highlands. Under low soil moisture, the soils were CH4 sinks and minimal N2O sources. [ABSTRACT FROM AUTHOR]

The enzymatic activities and ratios are critical indicators for organic matter decomposition and provide potentially positive feedback to carbon (C) loss under global warming. For agricultural soils under climate change, the effect of long-term warming on the activities of oxidases and hydrolases targeting C, nitrogen (N) and phosphorus (P) and their ratios is unclear, as well as whether and to what extend the response is modulated by long-term fertilization. A 9-year field experiment in the North China Plain, including an untreated control, warming, N fertilization, and combined (WN) treatment plots, compared the factorial effect of warming and fertilization. Long-term warming interacted with fertilization to stimulate the highest activities of C, N, and P hydrolases. Activities of C and P hydrolase increased from 8 to 69% by N fertilization, 9 to 53% by warming, and 28 to 130% by WN treatment compared to control, whereas the activities of oxidase increased from 4 to 16% in the WN soils. Both the warming and the WN treatments significantly increased the enzymatic C:N ratio from 0.06 to 0.16 and the vector length from 0.04 to 0.12 compared to the control soil, indicating higher energy and resource limitation for the soil microorganisms. Compared to WN, the warming induced similar ratio of oxidase to C hydrolase, showing a comparable ability of different microbial communities to utilize lignin substrates. The relationship analyses showed mineralization of organic N to mediate the decomposition of lignin and enzyme ratio in the long-term warming soil, while N and P hydrolases cooperatively benefited to induce more oxidase productions in the soil subject to both warming and N fertilization. We conclude that coupled resource limitations induced microbial acclimation to long-term warming in the agricultural soils experiencing high N fertilizer inputs. [ABSTRACT FROM AUTHOR]

Straw retention has been widely implemented to increase soil organic carbon (SOC) sequestration and greenhouse gas (GHG) mitigation for global agriculture. However, the combined effects of long-term straw retention on crop production, SOC sequestration and GHG emissions response to climate change remain unknown. Two nearby wheat–maize rotation field experiments in the North China Plain, combined with local weather, soil and agronomic measurements, were used to evaluate the applicability of the SPACSYS model. The model was then applied to assess the response of crop yield, SOC storage and nitrous oxide (N 2 O) emissions to three nitrogen fertilizer application levels (100, 200, 400 kg N ha−1) and three representative concentration pathway scenarios (RCP2.6, RCP4.5 and RCP8.5) under straw retention for the wheat–maize rotation systems during 2021–2100. In general, the model was reasonably accurate with R 2 and model efficiency (EF) ranging from 0.25 to 0.96 and 0.32–0.94, respectively. Climate change decreased wheat yield by 4–39%, while maize showed a slight increase (3%) under RCP2.6 and a decrease of 1–15% under RCP4.5 and RCP8.5. The SOC storage in the 0–20 cm soil increased at a rate of 73–195 kg C ha−1 yr−1 but decreased within the upper 1 m soil at 280–390 kg C ha−1 yr−1. Climate change reduced the positive effect of SOC sequestration except in RCP2.6 and stimulated substantial N 2 O emissions ranging from 1–7.5 to 2.9–23.2 kg N ha−1 yr−1, consequently, the global warming potential increased from –79–2555 to 548–9357 kg CO 2 -eq ha−1 yr−1 under various N fertilizer application levels. This study reveals that the negative feedback under climate change with modelling approach, and extensive efforts are needed to make adaptations to ensure food production and reduce GHG emissions in the future. [Display omitted] • Climate warming led to the decline of wheat and maize yield except under RCP2.6. • Negative feedback on SOC storage was found under RCP4.5 and RCP8.5. • The SOC storage within 0–1 m soil depth declined under climate warming. • The N 2 O emissions were strongly intensified by climate warming. [ABSTRACT FROM AUTHOR]

Amorphous iron (Fe) oxides are commonly deposited on rice roots, forming a distinctive Fe plaque, which has been observed as a notable hotspot for increased nitrous oxide (N 2 O) emission from paddy fields. However, the precise mechanisms underlying this phenomenon have remained uncertain. We hypothesized that the interaction between Fe plaque and rice root radial oxygen losses (ROL) leads to the generation of hydroxyl radical (•OH), thereby inhibiting N 2 O reduction and increasing N 2 O emission. To test this hypothesis, we transplanted rice seedlings with induced Fe plaque coating alongside those without Fe plaque coating into the same paddy soil. The results showed that paddy soil with Fe plaque-coated rice seedlings exhibited significantly higher concentrations of •OH and increased N 2 O emission rates, but a reduced abundance of the microbial N 2 O reduction gene (nosZ), compared to paddy soil with Fe plaque-free rice seedlings. These observed differences in N 2 O emission disappeared when we introduced an •OH scavenger into the paddy soil or shaded the rice leaves to reduce ROL. Furthermore, the supplementation of Fe (II) into the paddy soil with Fe plaque-free rice seedlings markedly increased •OH concentrations and N 2 O emissions. Our results demonstrate that Fe plaque, in conjunction with rice root ROL, facilitates •OH generation through the Fenton reaction. This •OH production effectively inhibits microbial N 2 O reduction, ultimately leading to increased N 2 O emissions from paddy soils. Our study uncovers a new mechanism whereby Fe plaque enhances N 2 O emissions from paddy soil. Minimizing Fenton reactions on Fe plaque may offer a promising strategy for reducing N 2 O emissions from paddy fields. [Display omitted] • Interaction of Fe plaque with rice root radial oxygen loss induces.•OH generation. • Rice root Fe plaque-induced.•OH generation is mediated by light exposure on rice leaves. • Fe plaque-induced.•OH enhances paddy soil N 2 O emissions by inhibiting N 2 O reduction. [ABSTRACT FROM AUTHOR]

Excessive nitrogen (N) fertilization in agricultural ecosystems strongly affects microbial N-cycling processes in soil. However, a comprehensive understanding of how microorganisms involved in each N transformation process respond to long-term N input is lacking. Here, using metagenomic sequencing combined with the direct assembly of N-cycling genes, we found that long-term N fertilization elevated the abundance of the microorganisms involved in most N-transforming processes but decreased that of N-fixing assemblages. The composition of the microbial groups involved in each N-transforming process was altered by fertilization, even though the abundance of several functional genes was not significantly changed. The relative abundance of microbial genera participating in the same step of N-cycling processes correlated with different soil properties, suggesting niche separation of these N-cycling taxa. Our results also indicated that the different responses to N fertilization exhibited by the taxa within the same functional group may be important for sustaining microbial nitrogen cycling in complex and dynamic environments. • Urea fertilization increased the abundance of most N-cycling genes but decreased that of nifH. • N-cycling microbial community structure was highly sensitive to urea fertilization. • Microbial genera carrying the same functional gene could occupy different niches. [ABSTRACT FROM AUTHOR]

• Regional simulation of nitrate leaching from NCP croplands was done using NLEAP-GIS. • Spatial-temporal variation of nitrate leaching in North China Plain was quantified. • Water input, fertilizer and soil jointly affect N leaching spatial-temporal pattern. • Optimal fertilizer N rates were recommended for winter wheat-summer maize rotation. • Spatial distribution of potential groundwater nitrate pollution risk was implied. Identifying the regional characteristics of nitrate leaching from croplands is of great importance when attempting to assess the groundwater contamination risk due to nitrate leaching from croplands. The regional scale model in the Nitrogen Loss and Environmental Assessment Package with GIS Capabilities (NLEAP-GIS), which takes spatial variations in soil profile properties, meteorological data, and farm practices into account, was adopted in this study to simulate the occurrence dynamics and spatial pattern of nitrate leaching downwards through the crop root zone (0–100 cm) in winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) rotation croplands during 2011 and 2012 across the Jing-Jin-Ji region on the North China Plain (NCP). The results showed that the monthly nitrate leaching occurrences were driven by rainfall, irrigation, and fertilizer application. The simulated large spatial variation in cumulative nitrate leaching was positively correlated with both rainfall and fertilizer N application rates, whereas it was negatively correlated with N use efficiency. The cumulative nitrate leaching was mostly lower than 10 kg N ha–1 during the winter wheat growing season, whereas nitrate leaching during the summer maize growing season was much higher and mostly ranged from 20 to 100 kg N ha–1. The average cumulative nitrate leaching in the winter wheat-summer maize rotation system was 55.7 ± 33.5 kg N ha–1, accounting for 17.2 ± 10.2 % of the fertilizer N applied (average 176.3 ± 86.2 kg N ha–1 during each crop season). Fertilizer N application rates of 100–200 kg N ha–1 are recommended during each winter wheat and summer maize season to simultaneously achieve higher grain yields, greater N use efficiency, and a lower groundwater nitrate pollution risk on the NCP. The simulated spatial variation in nitrate leaching implied that there was a potential nitrate groundwater contaminant source and the results contributed to the spatial distribution assessment of groundwater nitrate contamination risk caused by fertilizer N inputs. [ABSTRACT FROM AUTHOR]

The conversion of natural grassland to semi-natural or artificial ecosystems is a large-scale land-use change (LUC) commonly occurring to saline–alkaline land. Conversion of natural to artificial ecosystems, with addition of anthropogenic nitrogen (N) fertilizer, influences N availability in the soil that may result in higher N2O emission along with depletion of 15N, while converting from natural to semi-natural the influence may be small. So, this study assesses the impact of LUC on N2O emission and 15N in N2O emitted from naturally occurring saline–alkaline soil when changing from natural grassland (Phragmites australis) to semi-natural [Tamarix chinensis (Tamarix)] and to cropland (Gossypium spp.). The grassland and Tamarix ecosystems were not subject to any management practice, while the cropland received fertilizer and irrigation. Overall, median N2O flux was significantly different among the ecosystems with the highest from the cropland (25.3 N2O-N µg m−2 h−1), intermediate (8.2 N2O-N µg m−2 h−1) from the Tamarix and the lowest (4.0 N2O-N µg m−2 h−1) from the grassland ecosystem. The 15N isotopic signatures in N2O emitted from the soil were also significantly affected by the LUC with more depleted from cropland (− 25.3 ‰) and less depleted from grassland (− 0.18 ‰). Our results suggested that the conversion of native saline–alkaline grassland with low N to Tamarix or cropland is likely to result in increased soil N2O emission and also contributes significantly to the depletion of the 15N in atmospheric N2O, and the contribution of anthropogenic N addition was found more significant than any other processes. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) is a critical greenhouse gas and an ozone-depleting substance, with a global warming potential 298–310 times greater than that of CO2. Mitigating N2O emissions from soils has environmental benefits. Recent research indicates that biochar can serve as an “electron shuttle” to reduce N2O emissions from soils. Electron shuttle is defined as organic molecules capable of reversibly receiving and donating electrons. Thus, biochar is expected to facilitate stepwise reduction of denitrification products, reducing N2O to environmentally harmless N2. However, it remains uncertain whether biochar’s capacity to mitigate N2O can be enlarged by augmenting its function as an electron shuttle. Thus, this study prepared a biochar with enhanced electron shuttle potential by loading redox-active (Fe) onto biochar. The effectiveness of this biochar in mitigating soil N2O emissions was investigated by incorporating it into the soil. The results showed that Fe-loaded biochar significantly augmented its function as an electron shuttle and dramatically reduced soil N2O emissions by 92% compared to the original biochar. The degree of decrease in N2O emissions was strongly associated with both the electron shuttle capacity and the concentration of redox-active Fe in the biochar. Additionally, Fe-loaded biochar significantly decreased the N2O/(N2O + N2) emission ratio and increased the expression of the nosZ-II gene. Our findings suggest that redox-active Fe loading in biochar is an effective strategy to enhance its electron shuttle function. The augmented electron shuttle function of biochar can successfully facilitate N2O mitigation emission by promoting complete denitrification. [ABSTRACT FROM AUTHOR]

Iron (Fe) plaque is a concentrated form of microbially available Fe oxide that coats rice plant root surfaces, representing a high density of Fe oxide and which potentially mediates paddy soil CH 4 emissions. Using a combination of methods including Fe plaque induction, isotopic labeling, pure microbial strains, and Fe oxide addition experiments, we investigated the impact of Fe plaque on methane (CH 4) emissions from paddy soils and explored the associated mechanisms underlying the influence of Fe plaque on CH 4 emissions. A 13C–CH 4 isotopic labeling experiment showed that Fe plaque did not significantly affect CH 4 oxidation and associated gene expression, whereas Fe plaque significantly enriched methanogenic archaea and their expression of genes associated with methanogenesis. Pure microbial strain and Fe oxide addition experiments showed that the enhancement of CH 4 production in the presence of Fe plaque was caused by the (semi) conductive minerals within the Fe plaque, specifically, hematite, which promoted the extracellular electron transfer between the methanogenic archaea and their syntrophic bacteria, resulting in enhancement of methanogenesis. Our results imply that the presence of Fe plaque will accelerate CH 4 emissions from paddy soils and suppressing Fe plaque has the potential to mitigate CH 4 emissions. [Display omitted] • Fe plaque increased CH 4 emissions by facilitating extracellular electron transfer. • Fe oxide promoted direct interspecies electron transfer for methanogenesis. • Limiting Fe plaque could reduce paddy soil CH 4 emissions. [ABSTRACT FROM AUTHOR]