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The Songnen typical black soil belt is distributed with black soil resources with high organic matter and high fertility. Long-term overloaded farming has led to a significant reduction in soil organic matter content. Therefore, it is of great significance to study the reserve of soil nutrient elements for the protection of black soil resources and national food security. The Songnen typical black soil belt was took as the research area, based on 1 057 field soil sample measured data, using geostatistical analysis and other methods, the spatial distribution characteristics and influencing factors of TC (total carbon), TN (total nitrogen) and TP (total phosphorus) soil in the 0 ~20 cm tillage layer were studied. The results show these as follows. The contents of soil TC, TN and TP in the Songnen typical black soil belt were 19. 25, 1. 88 and 1. 28 g/ kg, respectively, which were higher than the national level. The high-density calorific value area and high aggregation areas of soil TC, TN and TP are mainly distributed in the northern part of the Songnen typical black soil belt, and TC, TN and TP showed a trend from north to south decrease. The spatial aggregation of C∶ N, C∶ P and N∶ P is higher in the northern part of this region. The soil silt content was more than 30%, and the contents of TC, TN and TP were high, ranging from 6. 86 to 74. 74 g/ kg, 0. 94 to 5. 93 g/ kg and 0. 66 to 3. 76 g/ kg, respectively. The content of soil TC, TN and TP are greatly affected by soil pH, average annual temperature, average annual precipitation and topography and other factors. The research results can provide a scientific basis for the protection of black soil resources and sustainable agricultural development. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Agricultural Big Data is the property of Journal of Agricultural Big Data 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 Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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】 The experiment was conducted to study the effect of different planting patterns arrangements of maize and soybean intercropping on spatial distribution of soil total nitrogen and organic matter contents, in order to provide reference for optimal management and fertilizer utilization and better crop yield at lower fertilizer cost.【Method】 The soil samples of continuous maize/soybean relay strip intercropping (MS1), maize/soybean relay strip intercropping in rotations (MS2), Traditional maize/soybean intercropping (MS3), sole maize (M), sole soybean (S), and fallow land (FL) were used as tests from 2018 to 2020 to analyze the differences of soil organic matter and total nitrogen contents under different planting patterns.【Result】 The highest content of soil organic matter (29.19 g/kg) and total nitrogen (10.19 g/kg) were detected under MS2. The minimum content of organic matter (1.69 g/kg) and total nitrogen (0.64 g/kg) were under FL. Soil total nitrogen in soybean row was higher than that in maize row, and organic matter content was significantly different under different planting patterns (P<0.05). Compared with other planting patterns, soil organic matter changed greatly under MS2 planting patterns, and the spatial distribution was the most dense. The variation coefficient of soil organic matter content was used to classify the soil. It was found that the variation of MS1, MS2, MS3, M and S was moderate, the variation of FL was weak, and the variation of MS2 was the largest. The spatial distribution density of total nitrogen in maize row was lower than that in soybean row, but the maximum and minimum values of total nitrogen and organic matter had the same distribution pattern. The moderate variation of soil total nitrogen was MS1, MS2, MS3, M, and S, the weak variation was FL, and the maximum variation was MS2. At the same time, the correlation analysis of soil nitrogen and organic mass variability showed that there was a high correlation between soil organic matter and soil total nitrogen, indicating that the change rule of total nitrogen and organic matter was consistent, and soil organic matter and total nitrogen content showed a significant positive correlation under different planting patterns. 【Conclusion】 There were significant variations for soil organic matter and total nitrogen under different planting patterns of maize and soybean in intercropping. MS2 was a better planting pattern for strip relay intercropping, it could increase spatial distribution of soil organic matter and total nitrogen unit content, and improve the soil fertility and carbon to nitogen ratio. [ABSTRACT FROM AUTHOR]

Copyright of Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica 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 Acta Prataculturae Sinica is the property of Acta Prataculturae Sinica 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 Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment 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 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 Journal of Ecology & Rural Environment is the property of Journal of Ecology & Rural Environment 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 Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department 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.)

Carbon and nitrogen are two key elements in the natural wetland soil. Changes of organic carbon contents in wetland soil significantly affect the structure and function of wetland ecosystems. Soil carbon and nitrogen contents in coastal salt marshes are closely related to hydrological connectivity patterns of coastal wetlands. To explore the spatio-temporal characteristics of soil carbon and nitrogen contents in different tidal creek systems of salt marsh, this research selected a typical, complete tidal creek system with major and minor tributaries in the estuary of the Yellow River. By collecting surface soil (0-5 cm) in the first-, second-, and third-level tidal creek regions, we attempted to explore the relationship between soil organic carbon, total nitrogen contents and soil moisture contents, salinity, bulk density, pH and other physical- chemical factors. Results illustrated that the soil organic carbon and total nitrogen contents presented great heterogeneity on both temporal and spatial scales. On the time scale, the soil organic carbon contents increased firstly and then decreased, the second tidal creek changed the most striking while the third tidal creek showed the least significant. The soil total nitrogen contents presented variability in different grades of tidal creeks. The total nitrogen contents were listed as August > September > July in the first-degree tidal creek, while the contents reached the peak in September of the second and third tidal creeks. The soil carbon and nitrogen ratio reached the peak in August. On the spatial scale, the average contents of the soil organic carbon and total nitrogen (2.9 g·kg- 1, 0.36 g·kg- 1) in the first tidal creek were greater than those of the second tidal creek (1.4 g·kg-1, 0.18 g·kg-1) and the third tidal creek (1.6 g·kg- 1, 0.21 g·kg- 1). The longer the lateral distance of the first tidal creek is, the higher the contents of the soil organic carbon and total nitrogen are. The soil organic carbon and total nitrogen contents in the third- degree tidal creek showed a slow downward trend in distance which was opposite to those of the first- degree tidal creek. Correlation analysis showed that there was a significantly positive correlation between soil organic carbon, total nitrogen contents and salinity (P<0.01), and a prominently negative correlation with soil bulk density (P<0.01). In summary, the soil carbon and nitrogen contents of the salt marsh wetland are affected by the soil water and salt conditions, and the tree structure of the tidal water system is crucial to the water and salt conditions of the surrounding soil. The influence of the structural characteristics of the tidal water system on the water and salt conditions is one of the important factors of spatial and temporal differences in soil carbon and nitrogen content. [ABSTRACT FROM AUTHOR]

Three ecosystem services (SE), including, soil organic carbon (SOC) concentration, total N (TN) concentration, and plant species diversity, were analyzed in the following three subtropical secondary forests:Pinus massoniana+Lithocarpus glaber mixed forest (PM), Choerospondias axillaris deciduous broadleaved forest (CA), and Cyclobalanopsis glauca+L. glaber evergreen broadleaved forest (CG). The trade-off and synergy between the SE and thecontributing factors of trade-offs were also analyzed. The results showed the following. (1) Plant species diversity in CA was significantly higher than that in PM and CG; the SOC and TN concentrations in CA were significantly higher than those in PM. (2) The SOC and TN concentrations exhibited a 1:1 synergy in the three secondary forests. The highest trade-offs were observed between SOC concentration-plant species diversity and TN concentration-plant species diversity; plant species diversity had relatively higher benefits in PM and CA. (3) During the early stages of succession, the proportion of evergreen broadleaved species and TN-plant species diversity trade-off were significantly negatively correlated, as were pH and SOC-TN trade-off. With succession, the terrain, soil, and species composition factors had negligible effects on the trade-off between the SE. [ABSTRACT FROM AUTHOR]

Soil nitrogen was a vital nutrient to enhance plant growth. According to the data of soil nitrogen content collected from 121 random grid and hierarchical sampling points in top soil in 2014, spatial distribution characteristics and their influential factors of soil nitrogen in West River Valley were analyzed using the software ArcGIS 10. 0 with geostatistics and spatial analysis. Results showed that the content of soil total nitrogen (TN) and available nitrogen (AN) were (1.18 ±0.40) g. kg-1 and (86. 52 ± 28. 71) mg . kg-1 , respectively, with moderate spatial variability. Interpolation by kriging indicated that TN was annular distributed, while AN was patchy or banded. They all reached the lowest regions ( <0. 95 g • kg-1 , <60 mg . kg-1 ) round the central Huaiyuan village, while the highest ( > 1. 80 g • kg-1 , > 120 mg . kg-1 ) in northern Jiezi-Sanlang mountainous and southern top hills on the whole. Analysis of influential factors showed that soil nitrogen in the plain was significantly higher than that of the mountains and hilly areas. Soil nitrogen content of purple-gray sediment and sec­ond-amassment yellow soil was significantly higher than that of sandshale slope sediment and purple sediment as well. Furthermore, the high­est levels of soil nitrogen content existed in the rice-wheat rotation. Within the 2. 5 km buffer range, it implied that both natural geological and human activity factors determined the heterogeneity of soil nitrogen, with natural geological factors playing greater roles. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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 Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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 Chinese Journal of Applied Ecology / Yingyong Shengtai Xuebao is the property of Chinese Journal of Applied Ecology 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.)

We comprehensively quantified the influence of cover crops on soil carbon and nitrogen storage in Chinese orchards by a meta-analysis based on the literature published during 1990 to 2020. The factors influencing soil carbon and nitrogen storage were also analyzed. The results showed that compared with clean tillage, soil carbon and nitrogen storage under the cultivation of cover crops considerably increased by 31.1% and 22.8%, respectively. Intercropping legumes enhanced soil organic carbon storage by 4.0% and total nitrogen storage by 3.0% compared with non-legumes. The effect of mulching duration was most prominent at 5-10 years, with 58.5% and 32.8% increases in soil carbon and nitrogen storage, respectively. The largest increase in soil carbon and nitrogen storage (32.3% and 34.1%, respectively) occurred in areas with low initial organic carbon (<10 g·kg -1 ) and total nitrogen (<1.0 g·kg -1 ). In addition, suitable mean annual temperature (10-13 ℃) and precipitation (400-800 mm) markedly contributed to soil carbon and nitrogen storage in the middle and lower reaches of the Yellow River. The findings indicated that multiple factors influence the synergistic changes in soil carbon and nitrogen storage in orchards, while intercropping with cover crops is an effective strategy for enhancing soil carbon and nitrogen sequestration.

Taking three Pinus yunnanensis forests at different ages (19, 28 and 45 a) in Panxian County of Guizhou Province as test objects, we investigated vertical distributions and accumulation rates of soil organic carbon (SOC) and total nitrogen (TN), as well as their relationships with soil bulk density. For the three forests at different age stages, SOC and TN changed consistently along the soil profile, declining with the soil depth. Both SOC and TN storage increased with the forest age. The SOC and TN storage amounts were 96. 24, 121. 65 and 148. 13 t·hm-2, and 10. 76, 1296 and 13. 08 t·hm-2 for the forest stands with 19 a, 28 a and 45 a, respectively. SOC had a significant positive correlation with soil TN, while both of them had a significant negative relationship with the soil bulk density. The accumulation rates of both SOC and TN storage at different growth periods were different, and the rate in the period from age 19 to 28 was higher than in the period from age 28 to 45. [ABSTRACT FROM AUTHOR]

With the shady and sunny northern slopes of Qilian Mountains along an altitude gradient from 2600 m to 3600 m as test objectives, this paper studied t he vertical distribution patterns of surface soil (0-20 cm) organic carbon (SOC) and total nitrogen (TN), and their relations to the altitude, landform, and vegetation. The results indicated that SOC and TN contents were significantly higher on shady than on sunny slope, and all increased with increasing altitude. The SOC and TN contents under different vegetation types were in the order of alpine bush > Picea crassifolia forest > alpine meadow > Sabina przewalskii forest, and alpine bush > alpine meadow > P. crassifolia forest > S. przewalskii forest, respectively. SOC had significant positive correlations with altitude, annual precipitation, soil moisture, and soil TN, and significant negative correlations with soil pH and annual temperature. Soil C/N ratio along the gradient was within the range of 6.7-23.3, being favorable to the nutrient release during organic matter decomposition. Among the factors affecting SOC, the annual temperature, precipitation, and soil moisture content constituted the first principal component, and soil C/N ratio constituted the second principal component . These two principal components accounted for 71% of the variance of SOC content, suggesting that climate factors controlled the vertical distribution patterns of SOC and TN along the altitude gradient. [ABSTRACT FROM AUTHOR]

Pollinators provide important ecosystem services for crop production and food security. With the development of agricultural economy and the increasing intensity of land-use, a large number of natural or semi-natural habitats have been converted to croplands. Landscape homogenization and intensive management lead to the decline of wild bee diversity and threaten the sustainable agricultural production. In this study, we investigated the effects of landscape complexity (proportion of semi-natural habitats), local management practices (local flowering plant diversity and soil total nitrogen), and their interactions on diversity of bee pollinators in apple orchard in Changping District, Beijing. A total of 8642 bee individuals were captured, including 5125 honey bees and 3517 wild bees from 5 families, 14 genera, and 49 species. The optimal landscape scale for the response of bee diversity to landscape complexity and local management intensity was 500 m. Within 500 m radius of the site, the abundance of overall bees and wild bees significantly increased with increasing proportion of semi-natural habitats. The landscape complexity interacting with local flowering plant diversity significantly affected the richness of overall bee and wild bee. When the proportion of semi-natural habitats surrounding the apple orchards was low (≤29.9%), we found a positive effect of flowering plant diversity on the richness of overall bee and wild bee, whereas a reversed trend was found when the proportion of semi-natural habitats surrounding the apple orchards was high (>29.9%). In addition, the abundance of honey bees significantly increased with the increase of local flowering plant diversity and soil total nitrogen. The soil total nitrogen interacting with local flowering plant diversity significantly affected the honey bee abundance. At low levels of soil total nitrogen (≤1.9 g·kg -1 ), there was a positive effect of flowering plant diversity on honey bee abundance; whereas this trend was reversed at high levels of soil total nitrogen (>1.9 g·kg -1 ). Increasing the proportion of semi-natural habitats in agricultural landscape was beneficial to the increase of wild bee abundance, and flowering plant diversity could promote bee diversity but depending on landscape scale (proportion of semi-natural habitats) and local scale (nitrogen application). Therefore, multi-scale factors should be considered to develop conservation strategies to maintain the diversity of wild bees in agricultural landscape. Maintaining a higher proportion of cultivated land as much as possible is still a long-term requirement for production, while maintaining intermediate landscape complexity, increasing the diversity of flowering plants on the ground, and reducing the application of nitrogen fertilizer would be effective ways to promote the diversity of pollinating bees in apple orchards.

The multi-environment media of water, surface soil and vadose zone soil samples were collected in the upstream of Miyun Reservoir, in the Luanping Basin of Chengde City, Hebei Province. The aim was to identify the pollution source, ratio, spatial distribution, migration, and transformation characteristics of nitrogen in groundwater. Hydrogeochemistry, soil total nitrogen, and dissolved nitrate nitrogen of vadose zone soil analysis and a multi isotope tracer technique of δ 15 N-NO 3 and δ 18 O-NO 3 , δ 34 S-SO 4 and δ 18 O-SO 4 , δ concentration, soil total nitrogen and surface soil dissolved nitrate nitrogen of vadose zone was affected by the combination of natural structural factors and anthropogenic factors. The source of groundwater nitrate was mainly from livestock manure and domestic sewage, followed by chemical fertilizer leaching. The nitrogen cycle in the aeration zone-groundwater-dominated nitrogen circulation in the groundwater runoff area of the piedmont basin was nitrification. These findings are highly significant for the prevention and remediation of groundwater pollution when viewing the basin system as an independent unit, and for studying the sources and fate of nitrate pollution in the water environment.14 C, combined with land-use type analysis and geostatistics, were used in the study. The results showed that nitrate was the main form of nitrogen in the groundwater of the Luanping Basin. The NO 3 - concentration of groundwater was significantly correlated with the land-use types of residential land and cultivated land where the nitrate pollution of shallow groundwater was mainly distributed. Of the groundwater samples, 13.79% exceeded the National Standard Ⅲ for Groundwater (GB/T 14848-2017) of NO 3 - concentration value, while the excess multiple was 1.04-3.86, and 37.93% of the groundwater samples exceeded the World Health Organization NO 3 - concentration standard value. The excess multiple was 1.08-6.83. The spatial variation of groundwater NO 3 - concentration, soil total nitrogen and surface soil dissolved nitrate nitrogen of vadose zone was affected by the combination of natural structural factors and anthropogenic factors. The source of groundwater nitrate was mainly from livestock manure and domestic sewage, followed by chemical fertilizer leaching. The nitrogen cycle in the aeration zone-groundwater-dominated nitrogen circulation in the groundwater runoff area of the piedmont basin was nitrification. These findings are highly significant for the prevention and remediation of groundwater pollution when viewing the basin system as an independent unit, and for studying the sources and fate of nitrate pollution in the water environment.

Five land use types of Longzihu wetland in Bengbu City, Anhui Province of China, including woodland, greenbelt, aquaculture land, cultivated land, shelter forest, were chosen as the research object. Through analyzing the content and allocation proportion of total organic carbon (TOC), total nitrogen (TN), particulate organic carbon (POC), particulate organic nitrogen (PON), as well as soil carbon nitrogen ratio (C/N) and soil particles component carbon nitrogen ratio (POC/TOC), soil carbon and nitrogen distribution characteristics were discussed under dif-ferent human disturbance intensities and modes. Results showed that TOC showed surface accumulation in woodland, aquaculture land and cultivated land, while it did not show significant variation in each soil layer of greenbelt and shelter forest. POC, TN and PON showed surface accumulation in all land utilization types. Greenbelt and shelter forest, being disturbed strongly by human activities, had higher POC allocation proportions, while aquaculture land and cultivated land, heavily interfered by human activities, had relatively lower POC allocation proportions which were commensurate with that of woodland. Woodland received less interference by human activities, so in addition to disturbance intensity, disturbance mode might be another important factor affecting POC allocation proportion. C/N decreased with the increase of soil depth in woodland, but C/N of greenbelt, cultivated land and shelter forest had no obvious changes along the soil profile. Soil depth had no significant impact on POC/TOC in the land use types except woodland and cultivated land.