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Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Climate change had widespread and profound impacts on both natural and social ecological systems. Agricultural soil carbon storage, an important component of the terrestrial carbon pool, played a critical role in global climate change, sustainable agricultural development, and global food security. This study conducted a comprehensive literature review to investigate the multi-dimensional effects of climate change on agricultural soil carbon storage and evaluated the advantages, disadvantages, and applicability of various assessment methods for agricultural soil carbon storage. The results showed that the multi-dimensional effects of climate change included both single-factor effects and the combined effects of multiple climatic factors. Single-factor effects included rising temperatures, changes in precipitation patterns, increasing carbon dioxide concentrations, atmospheric nitrogen deposition, and various extreme weather events. These factors individually affected the input, output, and transformation processes of soil carbon in agricultural systems. For example, rising temperatures accelerated the decomposition of soil organic matter, leading to soil carbon loss, while elevated carbon dioxide concentrations enhanced plant photosynthesis, increasing carbon inputs from plant residues to the soil. The combined effects of multiple climatic factors, such as temperature-precipitation, temperature-precipitation-carbon dioxide, and carbon dioxide-nitrogen deposition-ozone, added complexity to understanding the effects of climate change on agricultural soil carbon storage. These interactions could have synergistic or antagonistic effects on soil carbon dynamics, highlighting the need for a comprehensive approach to studying the response of agricultural soil carbon to climate change. Three main categories of methods were identified to assess agricultural soil carbon storage under climate change: statistical analysis models, process-based simulation models, and hybrid models. Statistical analysis models, including linear regression and machine learning models, established relationships between environmental factors and soil carbon storage, revealing the influence of environmental variables on soil carbon. Process-based simulation models could be divided into process-oriented and microbial-oriented models, depending on whether the decomposition of microorganisms was explicitly represented. These models quantitatively described the interactions among climate, vegetation, soil, and other factors and predicted dynamic changes in agricultural soil carbon storage under future climate change scenarios. Hybrid models took advantage of each method to achieve greater simulation accuracy, reliability, and interpretability by combining two or more different types of models. Some common hybrid models included regression kriging model, process-oriented machine learning model, and so on. Finally, four key areas for future research were suggested. First, the soil carbon storage mechanisms driven by microorganisms should be studied in more detail, as they played an important role in soil carbon cycling. Second, the interactive effects of multiple climate change factors should be emphasized to capture the complexity of future climate change scenarios. Third, the development of hybrid models that integrated statistical analysis and process-based simulation was crucial to improve the accuracy and applicability of soil carbon storage assessments. Fourth, uncertainty analysis in model parameters, input data, and scaling methods should be improved to enhance the reliability of model predictions. In conclusion, this study presented a comprehensive climate-crop-soil research framework through systematic integration and analysis, contributing to the scientific understanding of the impact mechanisms of climate change on agricultural soil carbon storage. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Soil & Water Conservation (1009-2242) is the property of Institute of Soil & Water Conservation and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Change in soil water content is not only an indicator of water stresses used for irrigation management but also controls biogeochemical processes in soil. In this paper, we study the feasibility of using thermal infrared imaging to estimate soil moisture dynamics. [Method] The experiment was conducted in July-August 2023 in a walnut orchard in Xinjiang. Thermal infrared images of the walnut canopy were measured continuously using a thermal infrared camera. Based on the HSV color space of the images, an improved K-means segmentation algorithm was proposed to analyze the change in canopy temperature. We also measured air temperature and humidity, illuminance, wind speed, atmospheric CO2, and soil water content in the 0-80 cm soil layer, from which we proposed an inversion model to estimate soil water dynamics. [Result] The improved K-means algorithm increased the accuracy from 82.34% to 94.55%, and the errors between the canopy temperature acquired from the images and the measured canopy temperature were in the range of 0 to 1.0. The infrared imaging method was most accurate between 14:00 pm to 16:00 pm. Our results showed that the walnut roots were most active in taking up water from the 40-60 cm soil layer 50-60 cm away horizons from the tree truck. Canopy temperature, air temperature and relative humidity, and atmospheric CO2 concentration were correlated with soil water content at significant levels; they can thus be used to estimate soil water dynamics, with a coefficient of determination of R2=0.86 and p<0.01. [Conclusion] The temperature acquired from the infrared images of the walnut canopy can be used with other metrological data and atmospheric CO2 concentration to estimate soil water dynamics in the root zone of the walnut. It provides a new method for improving soil water management in walnut orchards in Xinjiang. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Guangdong University of Technology is the property of Journal of Guangdong University of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In humid karst area, the change of soil moisture in winter is an important part of hydrological process, which affects vegetation restoration and ecological reconstruction. Taking secondary forest land as the research sample plot, the HOBO H21_USB automatic soil moisture monitoring system was used to continuously monitor soil moisture in different soil layers (0-20 cm). the dynamic changes of soil moisture in different soil layers before and after rainfall and the response of soil moisture to rainfall were analyzed. The results show that: (1) The rainfall of 0.3 mm has almost no effect on the soil moisture. The rainfall of 4 mm only affects the soil moisture of the 0-5 cm soil layer. The rainfall of 7 mm and 10 mm has an effect on the soil moisture of the soil layer above 10 cm. The rainfall of 12 mm mainly affects the soil moisture of the soil layer above 20 cm, and the rainfall of 25 mm mainly affects the soil moisture of the soil layer above 15 cm. (2) The fastest response time of soil moisture in each soil layer of forest land to rainfall in winter is 0.1 h. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Harbin Institute of Technology. Social Sciences Edition / Haerbin Gongye Daxue Xuebao. Shehui Kexue Ban is the property of Harbin Institute of Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

As an important equipment in soil dynamics experiment teaching and scientific research, the resonant column is mainly used to test the dynamic parameters of soil. At present, there are some problems in equipment calibration and sample installation of resonant column test (RCT), resulting in unreliable test results. Based on the torsional excitation mode, the Stoke fixed-free RCT equipment is calibrated by deducing the principle of the RCT, and repeated calibration tests of different calibration rods and additional blocks are carried out to obtain the mass inertia moment of the drive system with irregular shape in this paper. The shear modulus of soft clay is measured by RCT and compared with the test results of dynamic triaxial and bending element. It is found that the shear modulus of RCT and dynamic triaxial is the same in the range of strain coincidence, and the shear modulus in the small strain range is close to the test results of bending element. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Railway Investigation & Surveying is the property of Railway Investigation & Surveying Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Wheat model algorithms integration platform (WMAIP) has been integrated various algorithms from the different modules, including CERES-Wheat, APSIM-Wheat, WOFOST, SWAT, AquaCrop, and WheatSM, in order to simulate the soil water stress and winter wheat growth and development indices. The WMAIP can be potential to the prospects of application in the wheat model algorithm comparison and improvement, integrated simulation, and climate change impact assessment. The WMAIP verification and algorithm comparison have been carried out to focus mainly on a single site so far. The platform can be expected to guide the water management of local winter wheat. However, the current WMAIP cannot evaluate in the regional multi-point production of winter wheat. Therefore, it is a high demand to evaluate the adaptability of WMAIP in North China Plain (NCP). In this study, two algorithms were selected from the different modules in WMAIP. The phenology algorithm included the clock model of WheatSM module and the thermal time of APSIM-Wheat module, whereas, the biomass algorithm contained the carbon assimilation of WOFOST and canopy photosynthesis of WheatSM model, and the water stress algorithm consisted of the actual to potential transpiration ratio of CERES-Wheat model and the water supply to demand ratio of APSIM-Wheat model. 16 combined models were formed to combine the different algorithms from different modules using WMAIP. These models were verified using experimental data from four typical NCP experimental stations for several years. The optimal model was selected using the normalized root mean squared error (NRMSE). Finally, the adaptability of WMAIP integrated model in the NCP was evaluated to simulate the soil water dynamics, as well as the growth and development indicators of winter wheat. The results showed that all 16 models using the WMAIP platform were effectively simulated these parameters, with a simulation error of the development period below 4.2% and the soil water storage in the 2 m soil layer below 7.0%. The simulation errors of biomass and yield were ranged from 17.3% to 23.7% and 10.8% to 20.8%, respectively. However, the simulation performance of a single model was unstable, and there were differences between the calibration and validation for the optimal model. Nevertheless, the model integration was significantly reduced the simulation error of winter wheat yield in the NCP. Meanwhile, the simulation errors were similar to the field experiments using the integration of six models. Overall, the WMAIP ensemble model was able to simulate the response of winter wheat yield to the sowing date and irrigation treatment in the NCP. Among them, the NRMSE of biomass and yield values were 18.7% and 11.8%, respectively. The multi-year experimental data was effectively evaluated the WMAIP simulation on the winter wheat growth and development in different years, sowing dates, and irrigation treatments in the North China Plain. The excellent adaptability was achieved in the NCP for the wheat production management and climate change impact assessment. [ABSTRACT FROM AUTHOR]

Copyright of China Rural Water & Hydropower is the property of China Rural Water & Hydropower Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

[Objective] Water flow and solute transport in soil is important not only for plant acquisition of resources from soil but also for soil and water environment. In terrestrial ecosystems, they are impacted by numerous factors. The objective of this paper is to investigate the effects of drip irrigation amount on spatiotemporal change in water and nitrogen in Hetao Irrigation District, Inner Mongolia. [Method] A field experiment was conducted to measure the movement of water, nitrate and ammonium in soils, with the irrigation amount controlled at 6 mm (D1) or 60 mm (D2). The measured data was used to calibrate the HYDRUS-2D model, and the calibrated model was then used to elucidate how increasing the irrigation amount to 120 mm would affect water and nitrogen movement. [Result] Irrigation increased soil water content in all growth stages. Following irrigation and fertilization, ammonium and nitrate contents both increased rapidly and then decreased. On average, ammonium and nitrate in the 0~10 cm soil layer decreased by 60.0%~62.0% and 40.0%~46.7%, respectively, after the D1 and D2 irrigations, with the decreasing rate varying with growing stage. Compared to D2, D1 increased soil water content at jointing, heading and filling stage by 5.9%, 8.0% and 6.7%, respectively. Soil ammonium and nitrate both decreased along the soil depth. Nitrate accumulation decreased gradually when the crop grew from jointing stage to filling stage. The simulated soil water content and nitrogen agreed well with the measured data. [Conclusion] Experimental data and simulated results showed that irrigating the maize by 120 mm of water can effectively reduce accumulation of nitrate in the 0~60 cm soil layer, and that increasing irrigation frequencies can further curtail nitration accumulation in the 60~100 cm soil layer. These results provide guidance for improving irrigation and fertigation for maize production in Hetao Irrigation District. [ABSTRACT FROM AUTHOR]

[Objective] Soil salinization is a dynamic process, affected by numerous factors. Understanding its spatiotemporal variation in a region and catchment is important for management. In this paper, we present the soil salinity dynamics and its determinants in Songnen Plain of Heilongjiang province. [Method] The calculation was based on remote sensing imagery of the region acquired from 2000-2020. We used correlation analysis and relative contribution rate analysis to map the spatiotemporal distribution of soil salinity in this region. [Result] On average, areas affected by salt in the region had decreased from 2000 to 2020, at a rate of 2.73 km²/a. But this is mainly due to the reduced soil salinization in some regions, as other regions actually had seen an increase in soil salinization. In particular, soil salinization in Qiqihar had increased because of the increase in cropped lands and GDP. Suihua also saw soil salinity rising due to increased plant areas and population. In contrast, soil salinity in Daqing and Harbin had decreased, due to the increase in surface water resources and decrease in evaporation for Daqing, and the change in cropped land and livestock industry for Harbin. [Conclusion] Change in soil salinization from 2000 to 2020 in Songnen Plain varied, with some areas seeing an increase and others witnessing a decline. In addition to climate change, other reasons underlying such variations in soil salinization include economic development, change in cropping systems and livestock industry. To ameliorate soil salinization and improve land quality, this region should consider improving irrigation and drainage facilities and controlling the groundwater depth not exceeding a critical level. [ABSTRACT FROM AUTHOR]

In order to approach the seasonal dynamics of rhizosphere soil microbial biomass carbon (MBC) and nitrogen (MBN) of dominant tree species in tropical cloud forests in Limushan National Nature Reserve in Hainan, it measured MBC and MBN in rhizosphere and non-rhizosphere soil collected using shaking off method in three dominated tree species (Cyclobalanopsis championii, Castanopsis fabri, Eurya loquaiana) in tropical cloud forests during dry and rainy season from February to December 2019. Meanwhile, the relationships between the seasonal dynamics of soil microbial biomass and the soil nutrient, and soil water were also analyzed. Our results showed that the changes of variations of MBC and MBN in rhizosphere soil of the different species varied significantly with dry and rainy season. The contents of MBC and MBN in rhizosphere soil were 188.68-322.75 mg·kg-1, and 104.02-184.44 mg·kg-1, respectively. The ration of MBC/MBN in rhizosphere soil ranged from 1.60 to 2.01, which was showed that "N" shape seasonal change. While the ration of MBC/MBN in non-rhizosphere soil ranged from 1.63 to 2.10, which was showed that "V" shape seasonal change. Additionally, the rhizosphere effects of MBC and MBN were positive effects in different tree species, and the rhizosphere effect in E. loquaiana was higher than other tree species. The content of MBC and MBN had a significant positive correlation with soil organic carbon (SOC), total nitrogen (TN), which suggested that SOC, TN were important factors affecting soil microbial biomass. The content of MBC and MBN in rhizosphere soil was significantly higher than those in non-rhizosphere soil in three dominant tree species in tropical cloud forests during the dry and rainy season, which indicated that the rhizosphere effect was significant. The rhizosphere enrichment of E. loquaiana was stronger than those of the other tree species, which was the most benefit to the accumulation of nutrients. [ABSTRACT FROM AUTHOR]

【Objective】The study of the effect of apomictic litter on soil respiration in forest ecosystems can provide a scientific basis for accurate assessment of forest CO2 under the context of climate change.【Method】The dominant tree species of Ningxia Helan Mountain National Nature Reserve, including Pinus tabuliformis forest, Picea crassifolia forest and mixed forest of P.tabuliformis-Populus davidiana forest were selected as the objects of the study. Three treatments were set up in each stand, namely, no litter（NL）, control（CK） and double litter（DL）, and soil respiration and soil temperature and humidity were measured using LI-8100A.【Result】The daily dynamics of soil temperature in the three stands during the measurement period showed an obvious single-peaked curve, while the variation pattern of soil moisture was different and was influenced by precipitation.Soil temperature and moisture in the three stands under different treatments of apomictic litter reached highly significant differences among different months（P＜0.01）.Under different apomictic litter treatments, the daily dynamics of soil respiration in the three stands showed a multi-peaked curve on different measurement dates, and the maximum values appeared at different times; while the monthly dynamics of soil respiration showed an obvious single-peaked curve. Moreover, under different apomictic litter treatments, the peaks of P.tabuliformis and oleander stands were both in August, while the mixed stands were in July, and soil respiration showed litter doubling ＞ control ＞ litter removal.It indicated that the addition of litter enhanced soil respiration, while the removal of litter diminished soil respiration.Soil respiration was significantly correlated（P＜0.05） with soil temperature(T10) in all three stands under different treatments of apomictic litter, and T10 explained 51.9%-66.7%, 72.8%-76.7%, and 72.8% of the monthly variation of NL,CK and DL in P.tabuliformis, P.crassifolia and mixed forests, respectively. Meanwhile, soil temperature sensitivity(Q10) showed that P.crassifolia forest ＞ mixed forest ＞ P.tabuliformis forest, while soil moisture(W10) had no significant effect on soil respiration rate（P＞0.05）, but the interaction of soil temperature and moisture had a greater effect on soil respiration than individual factors.【Conclusion】The study suggests that apomictic litter is one of the important factors affecting soil respiration in Helan Mountain forest ecosystem. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

(Objective) Bioavailable water and nutrients to crops depend not only on root architecture but also on how water and nitrogen fertilizer are applied. In this paper, we investigated the effects of irrigation and fertilization on water and nitrogen dynamics in soil of a winter wheat field under border irrigation.(Method) The experiment was conducted in a wheat field in Henan province, where changes in water and nitrogen in soil under border irrigation were measured. These data were used to validate the HYDRUS-1D model, and the validated model was then used to elucidate how a change in irrigation and fertilization modulates water and nitrogen dynamics in the root zone of wheat under border irrigation. (Result) The HYDRUS-1D model simulated water and nitrogen dynamics in the root zone well. The coefficient of determination (R2) between the simulated and measured data was greater than 0.84, with its associated RMSE and MAE less than 0.807 and 0.695, respectively. Increasing the low critical soil water content for resuming irrigation moved nitrate in the top 0~20 cm soil layer to 20~100 cm soil layer 1~2 days after the irrigation, but it did not show significant effects on ammonium dynamics in the soil. Increasing nitrogen fertilization increased nitrate and ammonium nitrogen in the 0~60 cm soil layer significantly, especially in the 0~40 cm soil, but reduced water content in the 0~40 cm soil layer. (Conclusion) The HYDRUS-1D model is able to simulate water and nitrogen movement in soil under border irrigation, and the simulated results can help to improve irrigation and fertilization management for wheat production in the studied and similar areas. [ABSTRACT FROM AUTHOR]

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Bulletin of Soil & Water Conservation is the property of Bulletin of Soil & Water Conservation Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Natural Gas Industry is the property of Natural Gas Industry Journal Agency and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Experimental Technology & Management is the property of Experimental Technology & Management Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Agricultural Science & Technology (1008-0864) is the property of Journal of Agricultural Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Ground Improvement is the property of Journal of Ground Improvement Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Soil water content is one of the essential indicators for crop growth. The main source of soil water is then the rainfall in the rainfed agricultural region. Among them, tillage management is one of the important factors for the distribution of rainfall above and below ground, which is closely related to the dynamics of soil water content. However, it is still unclear in the response of soil water content to rainfall events under different tillage management. The objective of this study is to determine the effect of tillage management on the response characteristics of soil water content to rainfall events on Mollisol. The long-standing tillage experiment was carried out in the spring of 2011 at the Lishu Experiment Station of China Agricultural University (43°16′ N, 124°26′ E), located in Lishu, Jilin Province, China. The time-domain reflectometer (TDR) probes were installed in the soil depths of 2.5, 5, 10, 20, 30, 40, and 50 cm under No-Tillage (NT), and Conventional Tillage (CT) treatments, in order to monitor the dynamics of soil water content. Some parameters were used to quantify the dynamic response of soil water content under NT and CT to rainfall events, including the Accumulated Soil Water Content Increment (ASWI), the ratio of accumulated soil water content increment between adjacent soil layers (RSWI), the maximum (Smax) and mean (Smean) rate or the slope of a soil water content curve under rainfall events, the difference of the soil water content response time between two adjacent soil layers (DRTlayer), the difference of the soil water content response time and rainfall onset time (DRTrainfall), and the duration of soil water response to rainfall events (DUR). According to the rainfall duration and intensity, 24 rainfall events were divided into three categories with the K-means clustering: the rainfall events with the large Ⅰ rainfall (25.53±6.52 mm) and long rainfall duration (15.92 h), the rainfall events with the small rainfall (5.42 Ⅱ ±2.58 mm) and long rainfall duration (2.00 h), and the rainfall events with the large rainfall (19.22 Ⅲ ±6.49 mm), short rainfall duration (4.92±3.42 h) and heavy rainfall intensity (0.29±0.17 mm/min). The results indicated that: 1) The ASWI of NT was significantly lower than that of CT under 0-2.5, 2.5-5, and 5-10 cm soil layer, due to the lower soil water content of CT in the surface layer. 2) The ASWI of CT decreased with the increase of soil depth, while remaining stable under the NT. 3) The RSWI of NT was over 100% under the most rainfall conditions, whereas less than 100% under the CT. The values of Smax and Smean of NT were generally higher than those of CT. Moreover, there was a high frequency of negative abnormal values and average values of DRTlayer under the NT management at the high rainfall intensity. It infers that the activities of preferential flow were greater under the NT management. Therefore, the soil water content under the NT presented a stronger response to extreme rainfall. Furthermore, there was no significant influence of soil bulk density on the soil water infiltration, due to the well-developed biological pores network. Therefore, the rainfall can be percolated into the soil, as the extreme rainfall continued, which was beneficial to reduce surface runoff and soil erosion. [ABSTRACT FROM AUTHOR]

Rapid urbanization processes alter the regional underlying surface, leading to changes in the hydrological cycle. Such changes have made it difficult to explain the traditional water yielding and runoff routing mechanism, which necessitates our new exploration. In this paper, taking the Yangtze River Delta region as an example, we have conducted the experimental observations in basins with the different urbanization levels and different space scales. Via the collected first- hand hydrologic data, namely, rainfall, soil moisture, and streamflow with high resolutions (5 min time intervals), we adopted data-driven flood feature analysis to reveal the responses of the flood characteristics, such as flood lag time and peak discharge. Then, we discussed the response mechanism of rainstorm and flood in rapid urbanization areas. The main conclusions are as follows: ① Compared with other land use / cover types, the response of soil moisture for urban land are more intense under different rainstorm events ( usually increasing more than 4% for the surface layer) . The change of underlying surface in urbanized area affects the processes of surface runoff by influencing the dynamics of soil moisture. The soil moisture content of urban land and wasteland with low vegetation coverage showed steep rise and fall with the beginning and end of rainfall, while that of land use with higher coverage showed slow rise and decline trends. ② Flood peak lag time and peak discharge are mainly controlled by watershed scale. There have power law relationships between flood lag time and peak flow with watershed scale, and factors such as impervious surface and topography also have some influences on flood characteristics. ③ Rainstorm is a direct driving factor of flood in the Yangtze River Delta region. Rainfall characteristics are strongly correlated with the peak discharge, peak discharge per unit area, and runoff depth, with correlation coefficients above 0. 49, 0. 41 and 0. 78, respectively. In general, the natural geographical characteristics and rainfall are the main factors affecting the flood characteristics, but the impact of the urban underlying surface on the flood characteristics cannot be ignored. The processes of rainstorm floods have been directed affected by the modification of soil moisture dynamics due to urbanization. Under the dual role of urbanization and climate change, the regional flood risk would be intensified in the future. [ABSTRACT FROM AUTHOR]

Methane (CH4) is the second most important greenhouse gas, after Carbon Dioxide (CO2). The concentration of CH4 in the atmosphere is still rising more rapidly than ever before. Among them, most CH4 sinks are widely distributed in water-unsaturated lands. It is a high demand to clarify the CH4 uptake characteristics in the different types of soils in response to certain environmental factors. The soil CH4 uptake potential can then be improved to mitigate global warming. In this study, a soil laboratory incubation experiment was conducted to investigate the CH4 uptake rates of the salt-affected soil at the different moisture (50%, 75%, and 100% of Field Capacity (FC)), and Salinity Levels (LS1: 0.3 dS/m, LS2: 1.0 dS/m, LS3: 2.0 dS/m, LS4: 3.2 dS/m, and LS5: 4.9 dS/m, and LS6: 6.2 dS/m). A field plot experiment was also carried out to verify the reproducibility of the laboratory incubation under natural conditions. The soil CH4 uptake was characterized by three soil salinity levels (PS1: 0.3 dS/m, PS2: 1.0 dS/m, and PS3: 5.0 dS/m), and their responses to the soil moisture dynamics. The soil laboratory incubation results showed that the cumulative CH4 uptake of soils (including all six salinity levels) under 100%FC was 1.08-1.39 times those of the 75%FC, and 1.27-1.72 times those of the 50%FC, respectively. It infers that the capacity of soil CH4 uptake increased with the increase of soil moisture within the range of field water-holding capacity. By contrast, the cumulative soil CH4 uptake decreased under all three soil moisture levels, as the soil salinity increased from 0.3 to 6.2 dS/m. Specifically, the cumulative CH4 uptake of the highest salinity LS6 was significantly reduced by 42.6%, 52.3%, and 55.1% under three soil moisture levels, respectively, compared with the non-saline soil of LS1. The soil moisture with the 100%FC aggravated the soil CH4 uptake capacity along the salinity gradient from 0.3 to 6.2 dS/m, compared with the 50%FC. There was a significant interaction between the soil moisture and salinity on the soil CH4 uptake. The laboratory incubation was validated by the field plot experiment under natural environments. The soil CH4 uptake rates were significantly positively correlated with the soil moisture for all three soil salinity levels (P<0.01). Compared with soil PS1, both PS2 and PS3 salinity levels led to a significant decrease in the cumulative CH4 uptake, indicating that the high salinity significantly inhibited the soil CH4 uptake. The laboratory incubation and field experiments indicated that the salt-affected soil was a CH4 sink, where the CH4 uptake capacity depended mainly on the soil moisture and salinity. Consequently, a sub-goal of the water-salt regulation can be formulated to improve the CH4 sink capacity for the high agricultural productivity in salt-affected soils. [ABSTRACT FROM AUTHOR]

Copyright of Arid Zone Research / Ganhanqu Yanjiu is the property of Arid Zone Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BACKGROUND: Identifying the occurrence form of iodine in soil and the law of iodine migration and transformation in soil is of great significance for evaluating the biogeochemical behavior of iodine and preventing human iodine deficiency diseases. OBJECTIVES: To review the source, content, speciation, transportation, and transformation of iodine in soils; and briefly summarize the transportation of iodine between soil and plants. METHODS: The source, content, speciation, transportation, and transformation characteristics of iodine in soils were reviewed. The influences of soil types, environmental factors, organic matter, microbial activity, pH, and Eh on iodine dynamics were summarized. Great emphasis was laid on the main factors affecting the sorption of iodine in soil, which is the key process regulating soil iodine mobility and bioavailability. RESULTS: The dry and wet deposition of the atmosphere, the weathering of the soil parent rock, and the absorption and release of plants are the main sources of iodine in soil. Iodine contents in soil typically range from 1 to 5 mg/kg. Organic iodine is the dominant form of iodine in soil due to the close association of iodine with organic matter, which is the critical factor affecting soil iodine dynamics. Sorption is the key process regulating soil iodine mobility and bioavailability. Under acidic conditions, hydroxyl groups on soil mineral surface are protonated, and thus facilitating iodine sorption via electrostatic interaction. CONCLUSIONS: Due to the complex composition of soil, establishing a complete soil iodine database is the basis for exploring soil iodine related aspects. It is necessary to further seek better soil iodine analysis methods. Studying the adsorption mechanism of soil iodine and the effect of organic matter and microorganisms on iodine in soil are also an important direction for future research. [ABSTRACT FROM AUTHOR]

【Objective】The study aimed to clarify the degradation behavior and residual risk of fluazinam on Pamax notoginseng,and to provide a theoretical busis for the sate use of fluazinam.【Method】In 2018, controlled field application of fluazinam on P. notoginsengwere carried out inexperimental sites in Zhanyi, Shilin, Mile and Qiubei of Yunnan province. To detect and quantify fluazinamin P. notoginseng, an ultra-performance liquid chromatography-tandem mass spectrometry（UPLC-MS/MS） method was established.【Result】The recovery efficiency of fluazinam in P. notoginseng and soil ranged from 82% to 103% with relative standard deviations（RSDs） of 1%-13% and limits of quantification（LOQ） of 0.01-0.02 mg/kg. The results of dissipation dynamic experiments indicated that the half-lifeof fluazinam in P. notoginseng plants were 6.5-7.4 days, and the half-lifein soils were 20.0-30.1 days, but the degradation of fluazinam in rhizosphere soils and roots of P. notoginseng were not consistent with the first-order kinetic model. The ultimate residue experiments showed that 50% fluazinam suspension applied at doses of 250 g/hm²and 375 g/hm² for 3-4 times with an interval of 7 days, at 7, 14, and 21 days after the last application the residues of fluazinam were below 1 mg/kg and 2 mg/kg in rhizome and root hair, respectively. The results of the dietary intake risk assessment revealed that the national estimated daily intake（NEDI） of fluazinam was 0.45 mg, with a risk quotient（RQ） of 71.4%, will be a posean unacceptable risk to the health of the general population. 【Conclusion】Fluazinam is easy to be degraded in crops and environment. At present, the Maximum Residue Level（MRL values） of fluazinam isset at 1 and 2 mg/kg in rhizome and root hair of P. notoginseng in China, respectively. When using 50% fluazinam suspension to control P. notoginseng diseases, it is recommended to apply at the most effective dose of 250 g/hm² and up to 3 times, and the safe pre-harvest interval is 7 days. [ABSTRACT FROM AUTHOR]

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Copyright of Journal of Agro-Environment Science is the property of Journal of Agro-Environment Science Editorial Board and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Irrigation & Drainage is the property of Journal of Irrigation & Drainage Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Root-knot nematode disease is a stubborn and easily recurring disease in yam production and severely restricts the high-quality development of the yam industry. To develop an accurate control technology, this study focused on Ruichang yam and established test sites in Ruichang and Nanchang of Jiangxi Province for the collection and identification of the different root-knot nematodes. Population dynamics of the 2nd instar larvae (J2) of root-knot nematode were observed in the soils and the dynamics of nematode infection on yam were monitored in the fields for the determination of the appropriate control periods and the development of effective spraying technology in the fields. The result indicated the nematode isolates in the soils were southern root-knot nematode (Meloidogyne incognita). The J2 populations showed a continuous increase during the whole growth period of yam in the soils. Yam root infections by root-knot nematode occurred mostly in late May (seedling stage) and sick yam tubers appeared in mid-to-late June, then, the severity of the sick yam tubers continued to increase significantly. The critical periods for root-knot nematode control were at the neatlygrown seedling stage and the following 60 days and one application for each. The control efficacy of 41.7% fluopyram suspension (active ingredient amount 1 426 g/hm² ) and 30% thiazophos microcapsule suspension (active ingredient amount 2 925 g/hm² ) were 81.56%-83.43% and 75.95%-77.16%, respectively. The application of 30% thiazophos microcapsule suspension (active ingredient amount 2925 g/hm² ) combined with 10 billion spores/gram of Bacillus firmus wettable powder (active ingredient amount 12 000 g/hm² ), and 41.7% fluopyram suspension (active ingredient amount 1 426 g/hm² ) with newly generated twice uniform root irrigation technology improved the control efficacy to more than 81%, which is significantly higher than the combination of drip irrigation at the early stage and root irrigation at the later stage, two drip irrigation and two conventional root irrigation. [ABSTRACT FROM AUTHOR]

Copyright of Railway Standard Design is the property of Railway Standard Design Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objective Nitrogen in paddy soil is modulated by both rainfall and drainage, and in this paper we present the results of an experimental studies on its response to controlled drainage and deep rainfall storage. Method The experiment was conducted in 2018 in field plots at the Feidong Irrigation Experimental Station. We compared two irrigation methods: alternate dry and wet irrigation (L1), and deep rainfall storage and controlled drainage irrigation (L2 and L3). Business as usual used by local farmers was taken as the control (CK). During the experiment we measured nitrogen changes in soil water and the drainage water at the depths from 50 cm to 150 cm, and analyzed the response of nitrogen dynamics to irrigation amount, drainage amount, as well as rice yield under different water managements. Result Compared with CK, L1, L2 and L3 reduced the irrigation water by 725 m3/hm2, 1 703 m3/hm2 and 2 304 m3/hm2, and increased the rainwater utilization by 11.8%, 19.0% and 25.9% respectively. In the meantime, they also reduced the irrigation times by 13. Soil nitrogen content decreased as the soil depth increased, regardless of treatments. Compared to CK, L2 and L3 reduced the maximum total nitrogen (TN) compared to CK, and L1, L2 and L3 reduced TN pollution load by 21.3%, 26.7%, 31.5%, while no significant difference in the yield was found between them. Conclusion Increasing the upper limit of the rainfall storage and extending the interval, coupled with deep rainfall storage and controlled drainage, can effectively reduce irrigation requirement and drainage times, thereby improving rainwater use efficiency. It also reduced nitrogen pollution and can thus be used as an improved agronomic practice for rice production in paddy field. [ABSTRACT FROM AUTHOR]

Objective: Nitrogen (N) is the most important plant nutrient but its leaching to surface and subsurface water bodies is a great environmental concern. The dynamics of N in soil is mediated by a multitude of biotic and abiotic processes, and the aim of this project is to investigate the effect of water-nitrogen coupling on it. Method: A two-year experiment involving winter wheat-summer maize rotation was conducted. It consisted of two sets of treatments. The first one kept N fertilization at 5kg with the irrigation amount varying from 10 m3 to 40 m3; the second one kept the irrigation amount at 30 m3 with N fertilization varying from 5 kg to 15 kg. Added to these are three initial soil water treatments: dry, moderate and wet. Water and nitrogen movement in each treatment was simulated using the Hydrus-1D model.Result: Soil water content in the proximity of the soil surface increased drastically in the first four days after the irrigation, and spatiotemporal change in N was dominated by its movement more than by its transformation. After that, soil water in the topsoil stabilized asymptotically and the N change was dominated by transformation. N transformation in the subsoil (70-500 cm) was weak. Increasing irrigation amount or reducing initial soil water content led to a decrease in root uptake of N. The accumulated leaching of NH4 +-N and NO3 --N from the top 100 cm of soil increased with the irrigation amount. Increasing irrigation amount boosted mineralization, nitrification and denitrification, with their associated rates varying in the range of 1-2.5 mg/cm2, 1-4 mg/cm2 and 0-0.6 mg/cm2, respectively. Root N uptake from the top 100 cm of soil increased with N fertilization. The cumulative leaching of NH4 +-N and NO3 --N remained almost the same under different irrigation amounts, though increasing greatly with N fertilization. Mineralization, nitrification and denitrification in the topsoil increased with fertilization, with their rates varying in the range of 1-2.5 mg/cm2, 1.5-16 mg/cm2 and 0.3-1.2 mg/cm2, respectively. In contrast, their reactions in soil deeper than 100 cm were comparatively slow. Conclusion A rational water- nitrogen coupling can improve root N uptake and utilization. When initial soil water content was dry, coupling 525-900 m3/hm2 of irrigation with 225 kg/hm2 of N fertilization was optimal for winter wheat-summer maize rotation in the areas we studied. [ABSTRACT FROM AUTHOR]

Attention should be paid to the dynamic response of railway track in seasonally frozen environment under moving tram loads in order to ensure the safety of tram during operation period. The black clay in Zhangjiakou was selected as the typical frozen soil sample, and the hydraulic and mechanical properties of the sample were tested under the environment of temperature variation. The long lined track of the tram was assumed as an infinite homogeneous beam resting on a Pasternak foundation, and the analytical solution for long lined tracks subjected to moving traffic loads was obtained based on the beam-elastic foundation theory. Parametric analyses were performed to investigate the influence of the freeze-thaw behaviors of soil on the dynamic response of railway subgrade. Results showed that the dynamic response of subgrade was affected by the freeze-thaw behaviors of soil, and the dynamic stiffness of foundation would decrease with the increase of temperature, and thus contributed to the amplification of dynamic responses of the track. [ABSTRACT FROM AUTHOR]

In order to study the dynamic response rules of subgrade on improved soft ground soil, a tran-nonballasted track-lay¬ered soil coupling dynamic model was established, and Fourier transform and the dynamic stiffness matrix method were applied to solve the model. Then the influence of ram speed, rail irregularity, thickness and modulus of improved soil on dynamic response of subgrade was studied using the proposed model. Attenuation law of vertical dynamic stress n subgrade was analyzed for differ¬ent conditions. The results show that the improved so- effectively reduces vertical dynamic stress on surface of soft soil With n- creasing train speed, the stress reduction is more obvious. It is an effective approach off controlling dynamic response off subgrade on soft so- to property design thickness and modulus off the improved soil. [ABSTRACT FROM AUTHOR]

BACKGROUND: Available selenium is an important index to evaluate the supply capacity of selenium from the soil to plants. Unfortunately, there is no general method for the determination of available selenium in soil in China. Chemical extraction and soil solution methods are commonly used to evaluate bioavailability of selenium. Furthermore, there are problems such as the lack of universally applicable extractant types, incomplete extraction of target states, and dissolution of non-target states. The diffusive gradient in thin-films (DGT) technique is a method based on dissociation and diffusion kinetics which has been successfully used to assess the bioavailability of selenium. However, it is not clear whether the DGT technique can be used in natural selenium-rich soil. OBJECTIVES: To investigate the feasibility of the DGT technique to evaluate the bioavailability of selenium in natural selenium-rich soil. METHODS: Natural selenium-rich soils from Shangshu and Fenkou in Zhejiang Province were chosen as the research objects. Fe-oxide DGT, Zr-oxide DGT, chemical extraction, and soil solution methods were used to evaluate selenium bioavailability. RESULTS: (1) The average of available selenium measured by Fe-oxide DGT was 0.17±0.076μg/L, whereas the average of available selenium measured by Zr-oxide DGT was 0.20±0.13μg/L. Zr-oxide DGT cannot be used effectively to reflect the content of selenium in plants due to the specific adsorption characteristics to Se4+. Fe-oxide DGT was suitable for the bioavailability evaluation of selenium in soil rather than Zr-oxide DGT. (2) There was a significant positive correlation between the selenium content in plants (Cplant-Se) and the available selenium content determined by the three methods. The correlation between available Se by Fe-oxide DGT and Se concentration in plants (r=0.705) was greater than the chemical extraction method and soil solution method. (3) The Kd value and R value calculated from DGT and soil solution methods indicated that the soil of the Shangshu area had stronger selenium mobility than the Fenkou area, but the rate of Se supply from the soil solid phase to the soil solution was less than the Fenkou area. CONCLUSIONS: DGT is more suitable for evaluating selenium bioavailability compared with chemical extraction and soil solution methods because it has more advantages in testing performance and reflecting the information of soil dynamics process. [ABSTRACT FROM AUTHOR]

Copyright of Forest Research is the property of Forest Research Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)