作者机构：
[Li, Zhuofan] Xinyang Normal Univ, Coll Tourism, Xinyang 464000, Peoples R China.;[Li, Zhuofan] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan 430079, Peoples R China.
关键词：
rural regional system;rural restructuring;rural transformation;Jianghan Plain in China
摘要：
The rural decline accompanying industrialization and urbanization is a lingering puzzle in human society, while promoting rural restructuring and transformation is considered the primary task of contemporary rural development. It is the historical mission of rural geography research in the new era to scientifically understand the characteristics of contemporary rural development and accurately explain the patterns of rural reconstructing and transformation. In this paper, the Jianghan Plain in China is selected for the case study. Characteristic indexes are selected based on the "structure-function" correlation to interpret rural restructuring. Measurement benchmarks are unified through functional value marketization to interpret rural transformation. Multiple statistical analysis is adopted to identify the action paths and decipher the correlation mechanisms. The case study yields the following findings. (1) The rural restructuring on Jianghan Plain has spatial and temporal differences. Rural restructuring has roughly gone through the social restructuring-led, economic restructuring-led, and spatial restructuring-led evolution stages, showing spatially divergent patterns with high rural comprehensive restructuring index (RRC) areas concentrated around the main traffic arteries and linear low RRC areas along the Yangtze River banks. (2) Rural restructuring and transformation on Jianghan Plain show significant correlation effects. During the study period, the rural transformation magnitude (RTM) continues to increase and shows a spatial map similar to that of rural restructuring, with economic-spatial restructuring-led and economic-social restructuring-led as the main modes of rural transformation. (3) The correlation mechanism of rural restructuring and transformation on Jianghan Plain has characteristics typical of less-developed agricultural areas. The economic restructuring led by agricultural land changes and the social restructuring led by rural population outward migration remain the main paths of rural transformation, and the agricultural function still plays an important role in some rural areas. The quantitative measurement of rural region functions in this study need further optimization, and the refinement and accuracy of regional function accounting needs further exploration. The research results are expected to provide a scientific basis for stimulating rural development and promoting sustainable rural development in contemporary developing countries.
摘要：
Inorganic fertilizers are widely used to provide crops with significant amounts of nitrogen (N) and phosphorus (P), but can exacerbate soil carbon (C) limitation and acidification. Crop residues with distinct ecological stoichiometry from inorganic fertilizers can help balance soil ecological stoichiometry and thus increase soil organic matter accumulation. The combined use of inorganic fertilizers and crop residues is expected to alleviate the metabolic limitations of organisms and enhance soil C, N, and P sequestration, hence increasing grain yields. However, the effects of this practice on soil C, N, and P stocks and grain yield remain unclear. In this study, we conducted a meta-analysis of 806 paired data to investigate the impact of crop residue return combined with inorganic fertilizer on soil and grain yield across different land uses (paddy, upland, paddy-upland rotation) and soil profiles (0–60 cm). Our findings indicate that crop residue return significantly enhances soil C (8–13%) stocks across all soil layers, particularly in the topsoil (0–20 cm). Soil N (9%) and P (5%) stocks also increase significantly in the topsoil. In uplands, crop residue return can mitigate soil acidification and increase grain yield (by 7%). Moreover, the soil C and N stocks increase depending on the initial soil pH, C and N levels, and C:N ratio. In contrast, the soil P stock increase depends on rainfall, while the grain yield increase is closely linked to the soil texture and fertilizer rate. Our study highlights that crop residue return can increase topsoil C, N, and P stocks, which can benefit crop growth and environmental mitigation efforts. Furthermore, this practice can increase C stocks in deeper soil horizons (below 20 cm), providing a long-term solution to mitigate climate change.
摘要：
The global shipping industry faces increasingly complex safety challenges due to the rapid growth of international maritime trade. This study develops a novel framework that combines spatial density analysis and machine learning (i.e., extreme gradient boosting model) to investigate the evolutionary patterns of global maritime accidents during 2001-2020 from both spatial and temporal dimensions, and then identifies key environmental risk factors affecting maritime safety. The results show that the number of global maritime accidents exhibits fluctuations between 2001 and 2019, with a significant decrease observed in 2020. Furthermore, the distribution of global maritime accidents shows significant spatial variation over different time periods. Denmark's sea areas have high accident rates between 2001 and 2005, while concentrated accidents are observed in the seas around the United Kingdom, Denmark, and China between 2006 and 2010. From 2011 to 2015, Europe's accident-prone areas increase, but fewer accidents are reported along China's east coast. The Strait of Malacca is also an accident-prone area from 2016 to 2020. In addition, wave height, sea surface temperature, wind speed, water depth, and precipitation are identified as key environmental risk factors affecting maritime safety. These findings can inform strategies and mitigation plans to improve navigational safety in the global shipping industry.
摘要：
Semantic change detection (SCD) holds a critical place in remote sensing image interpretation, as it aims to locate changing regions and identify their associated land cover classes. Presently, post-classification techniques stand as the predominant strategy for SCD due to their simplicity and efficacy. However, these methods often overlook the intricate relationships between alterations in land cover. In this paper, we argue that comprehending the interplay of changes within land cover maps holds the key to enhancing SCD's performance. With this insight, a Temporal-Transform Module (TTM) is designed to capture change relationships across temporal dimensions. TTM selectively aggregates features across all temporal images, enhancing the unique features of each temporal image at distinct pixels. Moreover, we build a Temporal-Transform Network (TTNet) for SCD, comprising two semantic segmentation branches and a binary change detection branch. TTM is embedded into the decoder of each semantic segmentation branch, thus enabling TTNet to obtain better land cover classification results. Experimental results on the SECOND dataset show that TTNet achieves enhanced performance when compared to other benchmark methods in the SCD task. In particular, TTNet elevates mIoU accuracy by a minimum of 1.5% in the SCD task and 3.1% in the semantic segmentation task.
通讯机构：
[Yi, J.] H;Hubei Province Key Laboratory for Geographical Process Analysis and Simulation, China
关键词：
nitrogen balance;nitrogen leaching;nitrogen uptake;nitrogen use efficiency;paddy yield
摘要：
Nitrogen loss from paddy fields contributes to most of the nitrogen pollution load in the Ningxia Yellow River irrigation area, threatening the water quality of the Yellow River. Consequently, optimizing the nitrogen management practices in this area is essential, which can maintain paddy grain productivity and reduce nitrogen loss simultaneously. Five treatments with different nitrogen application rates and nitrogen fertilizer types were set in this study, including conventional urea application with zero nitrogen application rate (CK, 0 kg hm(-2)), nitrogen expert-based fertilization application strategy (NE, 210 kg hm(-2)), optimized nitrogen fertilizer application strategy recommended by local government (OPT, 240 kg hm(-2)), and farmer's experience-based nitrogen fertilizer application strategy (FP, 300 kg hm(-2)), and controlled-release urea application (CRU, 180 kg hm(-2)). The data from one growth season field experiment in 2021 revealed the dynamics of nitrogen concentration, paddy yield and its nitrogen uptake characteristic, and nitrogen balance in the paddy field under different nitrogen application practices. Most nitrogen leaching was observed during the seedling and tillering stages in the form of nitrate nitrogen (NO3-N). Compared with the FP, the CRU and OPT significantly reduced the nitrogen concentrations of total nitrogen (TN), ammonium nitrogen (NH4+-N), and NO3-N in the surface and soil water and reduced the nitrogen leaching at 100 cm soil depth. Meanwhile, the paddy grain yield in CRU (7737 kg hm(-2)) and OPT (7379 kg hm(-2)) was not significantly decreased compared with FP (7918 kg hm(-2)), even though the nitrogen uptake by grain and straw was higher in FP (135 kg hm(-2)) than in other treatments (52.10 similar to 126.40 kg hm(-2)). However, the grain yield in NE (6972 kg hm(-2)) was decreased compared with the FP. The differences in grain yield among these treatments were mainly attributed to the ear number and grain number changes. Also, the highest nitrogen use efficiency (40.14%), apparent nitrogen efficiency (19.53 kg kg(-1)), and nitrogen partial productivity (43.98 kg kg(-1)) were identified in CRU than in other treatments. Considering increased grain yield and reducing nitrogen loss in the paddy field simultaneously, the treatments of CRU (i.e., 180 kg hm(-2) nitrogen application rate with controlled-release urea) and OPT (i.e., 240 kg hm(-2) nitrogen application rate with conventional urea) were recommended for nitrogen fertilizer application in the study area.
作者机构：
[Zhu, Yuanyuan; Ao, Rongjun; Shen, Xue; Zhou, Xiaoqi; Chen, Jing; Aihemaitijiang, Yierfanjiang] Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan, Hubei, Peoples R China.;[Zhu, Yuanyuan; Ao, Rongjun; Shen, Xue; Zhou, Xiaoqi; Chen, Jing; Aihemaitijiang, Yierfanjiang] Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan, Hubei, Peoples R China.
通讯机构：
[Ao, RJ ] C;Cent China Normal Univ, Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan, Hubei, Peoples R China.;Cent China Normal Univ, Coll Urban & Environm Sci, Wuhan, Hubei, Peoples R China.
摘要：
This study introduces the principle of resilience into the study of human settlements. In this study, a comprehensive evaluation model of urban human settlements' resilience based on the provincial region of China was constructed using the Driver-Pressure-State-Impact-Response framework. The spatio-temporal evolution characteristics of urban human settlements' resilience was explored. The influencing factors were analysed by geographical detectors, and the driving mechanism was constructed. Results show that the following. (1) The resilience level of human settlements in China continued to increase, and the resilience level of each province and city changed significantly. The overall clustering effect showed a tendency to fluctuate and weaken. The distribution of cold spot areas became less and less, and the hot spots were moving from northeast China to southeast China. (2) Significant differences existed in the intensity of the impact of different indicators on the resilience system. The value of the impact factor showed an overall upward trend, and the number of key impact factors increased. (3) Improving the ability of scientific and technological innovation, accelerating the transformation and upgrading of the regional economy, increasing the training of talents and making financial inclination in scientific and technological development and industrial pollution control were all important ways for developing and maintaining the resilience of urban human settlements. This study not only introduces a new evaluation of urban human settlements from the perspective of resilience but also explores key impact indices and driving mechanisms, which provides new ideas for studying urban human settlements.
摘要：
With ongoing climate change, aridity is increasing worldwide, affecting biodiversity and ecosystem function in drylands. However, how the depth-profile microbial community structure and metabolic limitations change along aridity gradients are still poorly explored. Here, 16S rRNA and ITS amplicon sequencing and ecoenzymatic stoichiometry analysis were used to investigate both bacterial and fungal diversities and resource limitations in 1 m depth profiles across a wide aridity gradient (0.51-0.78) in a semiarid region. Results showed a sharp decrease in microbial diversity with soil depth, accompanied by an increase in microbial phosphorus (P) vs. N (nitrogen) limitation and a decrease in microbial carbon (C) vs. nutrient limitation. Aridity led to a strong shift in microbial community composition, but aridity has a threshold effect on microbial resource limitation through impacts on soil pH and C/P or N/P. When the aridity threshold (1-precipitation/evapotranspiration) exceeds 0.65, relationship between aridity and microbial resource demand was decoupled; but at aridity threshold = 0.65, microbial relative C limitation and C-acquiring enzyme activity dropped. These results suggest that aridity might have a stronger influence on microbial community composition, than on diversity, shaped by inherent soil biotic factors (i.e., MBC:MBP or MBN:MBP). These findings suggest that soil microbial diversity or enzymatic stoichiometry may be not necessary to mirror changes in water availability in the drylands, while aridity would be well explained by microbial community composition.
作者机构：
[Ma, Li; Ni, Yongxin; Wang, Jianwei; Lv, Xizhi; Zhang, Qiufen] Yellow River Inst Hydraul Res, Henan Key Lab Yellow Basin Ecol Protect & Restorat, Zhengzhou 450003, Peoples R China.;[Zhang, Xin; Qin, TL; Qin, Tianling] China Inst Water Resources & Hydropower Res, State Key Lab Simulat & Regulat Water Cycle River, Beijing 100038, Peoples R China.;[Ni, Yongxin] Hohai Univ, Coll Hydrol & Water Recourses, Nanjing 210098, Peoples R China.;[Nie, Hanjiang] Key Lab Geog Proc Anal & Simulat Hubei Prov, Wuhan 430079, Peoples R China.;[Nie, Hanjiang] Cent China Normal Univ, Sch Urban & Environm Sci, Wuhan 430079, Peoples R China.
通讯机构：
[Qin, TL ] C;China Inst Water Resources & Hydropower Res, State Key Lab Simulat & Regulat Water Cycle River, Beijing 100038, Peoples R China.
关键词：
distributed hydrological model;water and land resources;evapotranspiration;runoff coefficient;Sihe River Basin
摘要：
Conflicts between humans and land use in the process of using water and conflicts between humans and water resources in the process of using land have led to an imbalance between natural ecosystems and socio-economic systems. It is difficult to understand the impact of the processes of water production and consumption on land patches and their ecological effects. A grid-type, basin-distributed hydrological model was established in this study, which was based on land-use units and coupled with groundwater modules to simulate the water production and consumption processes in different units. By combining land use and net primary productivity, the runoff coefficient and the water use efficiency (NPP/ET) of different land units were used as indicators to characterize the interaction between water and land resources. The results showed that the average runoff coefficients of cultivated land, forest land and grassland were 0.7, 0.5 and 0.9, respectively. Moreover, the average runoff coefficients of hills, plains and basins were 0.7, 0.7 and 0.8, respectively. The NPP produced by the average unit, evapotranspiration, in cultivated land, forest land and grassland was 7 (gC/(m(2).a))/mm, 0.7 (gC/(m(2).a))/mm and 0.2 (gC/(m(2).a))/mm, respectively. These results provide quantitative scientific and technological support in favor of the comprehensive ecological management of river basins.
