The objective of this study was to clarify the changes of soil organic carbon (SOC) content, the saturation capacity of soil carbon sequestration and its cooperation with carbon input (crop source and organic fertilizer source carbon) under long-term (1982-2012) different fertilization in red paddy soil. The results showed that fertilization could increase SOC content. The SOC content of all the fertilization treatments demonstrated a trend of stabilization after applying fertilizer for 30 years. The SOC content in the treatments applying organic manure with mineral fertilizers was between 21.02 and 21.24 g · kg(-1), and the increase rate ranged from 0.41 to 0.59 g · kg(-1) · a(-1). The SOC content in the treatments applying mineral fertilizers only was 15.48 g · kg(-1). The average soil carbon sequestration in the treatments that applied organic manure with mineral fertilizers ranged from 43.61 to 48.43 t C · hm(-2), and the average SOC storage over the years in these treatments was significantly greater than those applying mineral fertilizers only. There was an exponentially positive correlation between C sequestration efficiency and annual average organic C input. It must input exogenous organic carbon at least at 0. 12 t C · hm(-2) · a(-1) to maintain the balance of soil organic carbon under the experimental conditions.
Microplastics (MPs) are a new environmental pollutant that has attracted widespread attention because of their negative effects on organisms and the environment. However, studies on the impact of co-contamination of MPs and heavy metals on vegetables are limited. To explore the effects of polystyrene nanoplastics (PSNPs), lead (Pb), and their co-contamination on seed germination and seedling growth of spinach, we investigated the germination rate, germination vigor and germination index of seeds; root length, shoot length, superoxide dismutase (SOD) and peroxidase (POD) activities, and soluble protein content of seedlings of spinach (Spinacia oleracea), which were exposed to the control, PSNPs (200, 400, 800, and 1600 mg·L−1) and Pb (5, 25, 50, and 100 mg·L−1) and their combination (Pb 5 mg·L−1 + PSNPs 200 mg·L−1, Pb 5 mg·L−1 + PSNPs 800 mg·L−1, Pb 50 mg·L−1 + PSNPs 200 mg·L−1, and Pb 50 mg·L−1 + PSNPs 800 mg·L−1). Single effects of PSNPs (≥400 mg·L−1) significantly decreased the germination rate, vigor, and index; however, there was no significant difference between 200 mg·L−1 PSNPs and the control for those indicators. PSNPs at low concentrations (200 mg·L−1) promoted the length of roots and shoots, but other PSNPs concentrations (≥400 mg·L−1) had no significant impacts on roots and shoots. SOD activity was inhibited at a high concentration (≥800 mg·L−1) of PSNPs, and the POD activity was induced when PSNPs ≤800 mg·L−1, whereas POD was inhibited at the high PSNPs concentration (1600 mg·L−1). The soluble protein content in spinach seedlings under different concentrations of PSNPs increased, but the content was significantly higher than the control at 800 mg·L−1 PSNPs. Under Pb exposure alone, germination rate, vigor, and index decreased. Further, treatments with low Pb concentration (5 mg·L−1) increased root and shoot length, whereas high concentrations (≥25 mg·L−1) reduced them. Moreover, SOD inhibition and POD induction were observed following Pb treatment. With increased Pb concentration, the soluble protein content of spinach seedlings decreased firstly at low concentration (5 mg·L−1) and then increased. Compared with single Pb treatment, combined effects of PSNPs and Pb were generally antagonistic to seed germination. For example, PSNPs weakened the promotion effects of low Pb concentration (5 mg∙L−1), inhibited the growth of root and shoot of spinach seedlings, and alleviated the inhibitory effects of high Pb concentrations (50 mg∙L−1) on seedling root and shoot growth. Low concentration (200 mg·L−1) of PSNPs and Pb showed synergistic effects in spinach seedlings, such as enhanced induction effects of Pb on POD activity. The co-contamination of PSNPs at high concentrations (800 mg·L−1) and Pb caused greater damage to seedlings, and the activities of SOD and POD decreased significantly. These results showed that PSNPs alleviated the inhibitory effects of Pb on spinach seed germination. Low concentrations of PSNPs (200 mg∙L−1) and Pb mainly showed synergistic effects, whereas high concentrations of PSNPs (800 mg∙L−1) and Pb mainly showed antagonistic effects. This study demonstrates that co-contamination of PSNPs and Pb has significant toxicity on seed germination and seedling growth, affecting the antioxidant system and soluble proteins of spinach. In conclusion, coexisting PSNPs can alter the bioavailability of Pb and plant performance. Our findings can help evaluate the individual and comprehensive toxicity of microplastics and heavy metals in vegetable crops.
Invasive plants pose a serious threat to plant diversity in rural areas, weaken their ecosystem service functions, and have become a prominent issue that urgently needs to be addressed in rural revitalization and beautiful rural construction. In this study, based on survey data from 127 sampling sites, we aimed to explore the degree of invasion and influencing factors of the invasive plant Solidago canadensis in a leisure-tourism village located in south of the Yangtze River. The height of S. canadensis showed a normal distribution, whereas its coverage showed a significantly positively skewed distribution. In rural areas, it displayed a multipoint scattered distribution pattern, forming a single optimal community locally and exhibiting a trend of further potential dispersal. We also found that the height and coverage of S. canadensis were significantly affected by various factors in rural environments. Specifically, the height of S. canadensis was negatively correlated with the species number and coverage of native plant species in the community, in which the number of native plant species played a more important role. In contrast, the coverage of S. canadensis showed a decreasing trend with increasing distance from the farmland, and the species number and coverage of native plant species. The interaction between the number of native plant species and coverage significantly suppressed the coverage of S. canadensis, and the inhibitory effect of native plant coverage on the coverage of S. canadensis increased with the increase in the number of native plant species in the rural community. In conclusion, leisure-tourism villages have been severely affected by the invasion and spread of S. canadensis. This study also identified the fundamental role of multiple community attributes of native plant species in resisting the invasiveness of single alien plant species and broadened our current understanding of the invasion mechanism of single invasive plants in rural landscapes. These findings emphasize the urgent need to incorporate the monitoring and prevention of invasive plant species into rural ecological landscape planning for the development of leisure tourism in the future, thus providing a solid scientific basis for the comprehensive prevention and control of invasive plants in different rural areas and the maintenance of rural biodiversity during the construction of beautiful rural areas.
Under the carbon emission pattern of “carbon peak and carbon neutral”, agricultural carbon emissions, as one of the main sources of greenhouse gases, have become a key area for emission reduction. High-standard farmland construction is an important measure for promoting green, low-carbon, and high-quality agricultural development. An in-depth investigation of the effects and mechanisms of high-standard farmland construction policies on agricultural carbon emissions can provide an empirical basis for optimizing policy formulation and reducing agricultural carbon emissions. This is of great significance in promoting the development of low-carbon agriculture. Based on the theories of scale economy and division of labor, this study constructed a theoretical model of “high-standard farmland construction-agrochemical input intensity/socialized service-agricultural carbon emission”. Based on panel data from 30 provinces in China from 2007 to 2017, this study analyzed the effect and mechanism of the high-standard farmland construction policy on agricultural carbon emissions using a continuous differences-in-differences approach (DID) and mediation effect model. By measuring the agricultural carbon emissions of each province, this study found that national agricultural carbon emissions showed an inverted U-shaped trend, rising at the beginning, then declining, and peaking in 2015. Regions such as Henan, Shandong, Hebei, Jiangsu, and Anhui are at the forefront of agricultural carbon emissions nationwide, whereas regions such as Beijing, Shanghai, Tianjin, Hebei, and Shandong have higher rates of agricultural carbon emission reduction. The dynamic estimation results showed that the carbon reduction of the high-standard farmland construction policy had a lag effect, and the carbon reduction effect appeared in 2013 and continued to increase gradually. The results of the benchmark regression showed that a high-standard farmland construction policy significantly suppressed agricultural carbon emissions. On average, when all other conditions remained unchanged, implementing a high-standard farmland construction policy reduced agricultural carbon emissions significantly, i.e., by 10.1%. Robustness tests were conducted using the approach of substituting variables and considering the interference of other relevant policies. The results confirmed the positive effect of the high-standard farmland construction policy on reducing agricultural carbon emissions. The results of the mechanism analysis showed that agricultural chemical input intensity and agricultural socialized services played mediating roles in reducing agricultural carbon emissions through the construction of high-standard farmland. The construction of high-standard farmlands suppressed agricultural carbon emissions, mainly by reducing agricultural chemical input intensity and improving agricultural socialized services. Heterogeneity analysis revealed that the carbon reduction effect of the high-standard farmland construction policy mainly occurred in provinces with a high degree of land transfer and in non-food-producing areas. In contrast, it did not have a corresponding carbon reduction effect in provinces with a low degree of land transfer and in food-producing areas. Therefore, the government should strengthen the construction of high-standard farmlands and differentiate the implementation of high-standard farmland construction policies according to local conditions and classifications to give full play to the emission reduction effect. In addition, the government should pay great attention to the role of agricultural chemicalization and socialized agricultural services in carbon reduction effects.
Biodiversity in rural landscapes plays a critical role in the vitalization and sustainable development of rural regions. We explored a set of methods for identifying biodiversity at different scales and uncovered the mechanisms that drive biodiversity in rural landscapes. We also formulated technical specifications for the maintenance of biodiversity from genes to ecosystems in rural landscapes. In addition, we developed a framework for biodiversity monitoring and warning systems in rural landscapes based on the Driving Force-Pressure-State-Impact-Response (DPSIR) conceptual mode. We developed a multiscale full-chain technology for biodiversity identification, maintenance, and warning in rural ecological landscapes. This study yielded powerful insights into the biodiversity maintenance mechanism in rural landscapes by integrating multidisciplinary research methods, such as literature research, field survey, and laboratory analysis, and filled the gap in biodiversity maintenance technology in rural ecological landscape construction. Our study plays a theoretical and practical foundation for the development of rural ecological construction models, planting design and configuration, and species selection for the construction of beautiful villages in China. Furthermore, this multiscale and full-chain technology developed for biodiversity identification, maintenance, and warning in rural ecological landscapes provides key technical support for the dynamic management of rural ecological resources and plays a fundamental role in rural revitalization and the construction of a beautiful China.
Plant diversity plays a fundamental role in rural ecological revitalization and sustainable development. Studying the characteristics and influencing factors of rural plant diversity has important theoretical and practical implications for maintaining and enhancing rural biodiversity. In this study, we identified the composition and community types of plant species and explored the effects of natural and human activities in Changkou Village, an ecologically protected village in western Fujian Province. We identified 578 plant species belonging to 130 families and 378 genera, including 396 wild plant species and 53 cultivated agricultural species, exhibiting high plant diversity. Seventeen species of invasive plants have not yet posed a threat to rural biodiversity. The seed plant flora in this rural area was complex, with 14 types of genera, including 188 tropical genera, and showed transitional features from tropical to temperate zones. There were 106 plant vegetation alliances, including 52 natural and semi-natural vegetation, 25 agricultural vegetation, and 29 green space vegetation alliances, which were representative of this region. Natural and semi-natural vegetation were mainly composed of different natural and semi-natural forests, such as the Castanopsis fargesii Forest Alliance and Pinus massoniana + Castanopsis fargesii Forest Alliance, whereas agricultural and green space vegetation areas were very small. Green space vegetation was mainly composed of Cinnamomum camphora and Osmanthus fragrans, and green space tree species predominated in subtropical rural areas. Furthermore, there was a significant positive correlation between the differences in species composition in different rural areas and differences in comprehensive environmental factors. Specifically, the plant species composition of natural and semi-natural vegetation was mainly driven by natural factors, whereas the differences of plant species composition of green space vegetation significantly increased with the increasing distance to roads and residential areas. Overall, these results indicate that ecologically protected rural areas are important reserves for plant diversity and have important maintenance value. The composition of plant species and vegetation alliances completely differs between different vegetation categories in rural areas, and altitude plays a key role. We highlight the necessity of incorporating ecological conservation-oriented rural areas into biodiversity conservation management, and emphasize various maintenance and improvement strategies, such as zoning management of rural plant diversity and building habitat networks. This study could provide useful references for promoting plant diversity in the process of rural revitalization in other regions of China.
The incorporation of rural landscape plants plays a pivotal role in the development and establishment of ecotourism. By studying the genetic diversity of plants in rural landscapes, the richness of genetic variation and the stability of the genetic structure within a population can be revealed. This serves as an important theoretical foundation for the construction of rural ecological landscapes and biodiversity maintenance and is of great significance for the construction of beautiful villages. In this study, eight native landscape species were selected from two ecotourism villages (Changkou Village, Sanming City, Fujian Province; and Paifang Community, Nanjing City, Jiangsu Province). Native rural landscape plant samples were collected from the whole village area. Phenotypic characteristics were measured, and ISSR-PCR experiments were performed. Through analysis of phenotypic features and detection of molecular markers, the Shannon index and Nei’s genetic diversity indexes were calculated to elucidate the levels of genetic diversity of native landscape plant species in different areas. Cluster analysis using phenotypic features identified five types of Liquidambar formosana, six types of Cyclobalanopsis chungii, four types of Quercus glauca, sixteen types of Zelkova serrata, seven types of Toona sinensis, ten types of Aster indicus, five types of Chrysanthemum indicum, and six types of Rubus hirsutus. The phenotypic coefficient variation and Shannon index of the eight native landscape plant species ranged from 0.23 to 0.58, and from 1.51 to 6.74, respectively. In the total area, artificial area and natural area, the Nei’s genetic diversity indexes of the eight native landscape plant species ranged from 0.240 to 0.536, 0.244 to 0.540, and 0.193 to 0.367, respectively. For the eight native landscape plant species, the percentage of polymorphic loci varied from 45.00% to 100.00%, the number of alleles varied from 1.45 to 2.00, and the number of effective alleles varied from 1.30 to 1.64. The results revealed that the phenotypic (Shannon index) and molecular (Nei’s genetic diversity index) genetic diversity levels of the eight native landscape plant species were higher than the average diversity level in numerous other landscape plant species. Additionally, the rural landscape plant species exhibited abundant genetic variation. The genetic diversity of certain rural landscape plant species exhibited a notable degree of variability; however, there were significant differences in the levels of genetic diversity observed between natural and artificial areas. In the context of rural landscape construction, it is important to prioritize the assessment of genetic diversity in rural landscape plant populations. Appropriate measures should be implemented to enhance the even distribution of genetic polymorphisms within the population and preserve the genetic diversity of native landscape plant species. This approach is essential to ensure the long-term stability of rural ecological landscapes.
Continuously promoting scientific fertilization is a powerful support for achieving a stable food supply and constructing an ecological civilization. To explore the effective strategies to promote scientific fertilization by Chinese farmers in the context of digital village construction, this study uses the Heckman two-stage model based on the data from 1256 surveys of farmers in the rice producing areas of Hubei Province to explore the influence of informatization of agricultural extension services on the adoption decision of scientific fertilization technology by farmers in terms of “adoption behavior” and “the degree of adoption”. Additionally, we analyzed the mechanism of informatization of agricultural extension services on scientific fertilization technology adoption decision by farmers using the stepwise regression method. The results are presented as follows: 1) The informatization of agricultural extension services had a significant positive effect on adoption behavior of farmers and the degree of adoption of scientific fertilization technologies. 2) There are differences in the effects of informatization of agricultural extension services on different types of scientific fertilization technologies. The informatization of agricultural extension services had a more significant effect on the adoption of efficient fertilization technologies by farmers than the application of new fertilizers. 3) The informatization of agricultural extension services promoted adoption behavior of farmers by improving benefit perception; it also promoted the adoption behavior of farmers and the degree of their adoption by reducing risk perception. Consequently, this study proposes policy recommendations to continuously enrich the forms and service contents of information-based agricultural extension services, improve the cooperative extension mechanism, and enhance the effectiveness of agricultural extension services through personalization and precision.
To quantitatively analyze the impact of foliar Se application on grain yield, quality, and Se accumulation in winter wheat in China, 41 published studies (36 in Chinese and 5 in English) with a total of 379 pairs of samples were collected. A Meta-analysis was used to comprehensively analyze the effects of foliar Se application on the yield, grain protein, and Se content of winter wheat, and a subgroup analysis was used to evaluate the effects of different factors on response of winter wheat to foliar Se application, with no Se application as the control group and foliar Se application as the experimental group. The results showed that compared with no Se application, the yield, grain protein, and Se contents of winter wheat were increased by foliar Se application, with incremental rates of 3.80%, 2.44%, and 764.56%, respectively. In terms of the different regions, the effect of foliar Se application on yield and quality improvement was greater in the east and south than in the west and north, respectively. Overall, the effect of grain Se enrichment gradually decreased from west to east. In terms of foliar Se application management factors, it was most worthwhile to apply 15−60 g·hm−2 once at the early filling stage or twice at the boot stage and early filling stage, which would meet the standard of Se enrichment and human needs. Soil fertility was an important factor influencing the effect of foliar Se application on the yield and quality of winter wheat. Soil contents of Se and total N had a significant effect on yield-increasing effect of foliar Se application. The effect of foliar Se application on yield improvement was the highest when the Se content of soil was between 0.2–0.4 mg·kg−1. The effect of foliar Se application on winter wheat yield decreased with increasing total soil N. Soil Se, total N, available P, and available K contents significantly affected the effects of foliar Se application on protein content. The effect of foliar Se application on grain protein was higher when the soil Se content was between 0.2−0.4 mg·kg−1, total N>1.5 g·kg−1, available P>20 mg·kg−1, and available K=100−200 mg·kg−1. Soil fertility (soil Se content, organic matter content, and available K content) was the main factor affecting Se accumulation in grain when Se fertilizer was applied to the foliar. When the soil organic matter and available K contents were enhanced, foliar Se application had significantly increased the Se accumulation; however, the effect of Se accumulation caused by foliar Se application was high in Se-poor soil (<0.2 mg·kg−1). Therefore, foliar Se application measures and soil conditions for optimization in different regions not only synergistically achieve the goals of high yields, good quality, and Se accumulation standards of wheat, but also reduce environmental contamination, which provides support for sustainable wheat production management with Se enrichment.
Global warming is becoming increasingly serious, and the complicated climate change situation has led to obvious changes in global snow cover patterns. Therefore, we explored the effects of future climate warming on the physical and chemical properties of black soil in Northeast China. This study adopted the method of artificial snow depth control from November 2020 to May 2022 and divided the plots in the test area into three treatment groups: snow increase (TS), snow removal (TR), and control (C). Soil environmental factors, available carbon and nitrogen contents, microbial biomass, urease activity, and sucrase activity were determined. The seasonal dynamic change process of each index was analyzed. Long-term field experiments showed that snow removal significantly reduced soil temperature and humidity. In addition, lower soil temperature and humidity accelerated the release of soil nutrients, and significantly increased the contents of soil nitrate nitrogen and ammonium nitrogen in early winter, while the opposite was true with snow increase treatment. However, from the beginning of the deep snow period, the snow removal treatment caused a loss of soil inorganic nitrogen to a certain extent while increased contents of soluble organic carbon and nitrogen. The snow removal treatment maintained soil microbial activity at a high level for most of the winter. However, at the end of winter, owing to the rapid release of soluble organic matter under snow treatment, soil microorganisms under snow treatment absorbed a large amount of nutrients and exist in a more suitable soil environment, which significantly increases the soil microbial activity under the snow treatment. However, owing to the loss of heat insulation from snow cover, a large number of microorganisms decomposed and died at this time, which significantly reduced soil microbial activity. Before and after the test period, snow treatment significantly increased the soil microbial activity by 23.07 mg∙kg−1, and snow removal treatment significantly increased the soil microbial activity by 11.92 mg∙kg−1, with a difference of 93.5%. The decrease in snow cover significantly decreased the activities of soil urease and sucrase during most of the winter, and the activities of soil urease and sucrase were significantly increased by snow treatment. These results show that the activities of these two enzymes increased significantly by more than 10.5%. In summary, this study demonstrated that changes in snow cover in the future will lead to changes in the dynamic change characteristics of soil available carbon and nitrogen and microbial activity, and the influence of snow cover change on soil enzyme activity will also indirectly affect the soil nutrient cycling process and physical and chemical properties of soil. The results of this study provide a theoretical foundation and scientific basis for further research on the material cycle of terrestrial ecosystems in the black soil region of northeast China in the context of climate warming.
In view of the potential threats to biodiversity in the process of rural revitalization and the needs of conservation and management, this study organically combined the theories and methods of biodiversity with society, economy, population, etc., and built the early warning index system of biodiversity in rural ecological landscape based on the DPSIR (Driving Force-Pressure-State-Impact-Response) model. Based on the principles of scientificity, relevance, practicality and comparability, the index system reflects the impact of human interference, global change, major disasters, measures and inputs taken by human to maintain the biodiversity of rural ecological landscape, and other factors on rural biodiversity, including 12 factors and 25 indicators of the driving force, pressure, state, impact and response of biodiversity. The mean square deviation method was used to determine the weight value of each index, divide the evaluation level. And the comprehensive index method was used to warn the biodiversity of the rural ecological landscape. The rural biodiversity in this study comprehensively considered the “Ecology, Production, Living” functions of the countryside. Therefore, the species of wild animals and plants, crop species, and rural green plants were all included in the calculation of the biodiversity index. This research method has been applied in the Paifang Community of Nanjing to give early warning to the high risk area. This study provides a new idea and method for biodiversity protection and evaluation in the revitalization and planning of green livable countryside, and it is of great significance to build a beautiful countryside with green harmony.
Agricultural intensification has simplified agricultural landscapes through the expansion of agricultural land, enlargement of field size, and removal of non-crop habitats. Rural vegetation is a key component of agricultural landscapes as it produces food, fiber and fuel, and performs ecosystem services, such as recycling of nutrients, regulation of microclimate, and local hydrological processes. Vegetation classification is the basis for surveying, monitoring, and managing rural vegetation. However, to date, green space vegetation, a cultivated vegetation type, has not been listed in the vegetation classification system of China, and little is known about its functional role in the production and regulation of rural landscapes. Here, we reviewed the literatures on different vegetation classifications in China and developed a renewal framework for rural vegetation classification systems. The system includes nine classification units. First, rural vegetation is classified into three vegetation categories: natural and semi-natural vegetation, agricultural vegetation, and green space vegetation (level 0, the highest-level unit). Then, each of the highest-level units is classified into three upper level units (levels 1–3, including the vegetation formation group, vegetation formation, and vegetation subformation), three middle level units (levels 4–6, including the alliance group, alliance, and suballiance), and two lower level units (levels 7–8, including the association group and association). We clarified the division basis and nomenclature for each classification level unit with examples and proposed a reference scheme for the classification and nomenclature of rural vegetation. Following the common classification principle of “plant community ecology”, which is widely used in China, we revised the classification principles and nomenclature based on the functions of the three vegetation categories. Natural and semi-natural vegetation focus on comprehensive ecological conditions and community appearance; agricultural vegetation highlights the functional use, cultivation conditions, and farming system of crops; and green space vegetation focuses on landscape appearance and community assembly. Based on this scheme, rural vegetation in China is classified into three vegetation categories, 23 vegetation formation groups, 66 vegetation formations, and 142 vegetation subformations. Natural and semi-natural vegetation includes 6 vegetation formation groups (Forest, Shrubland, Herbaceous Vegetation, Desert, Alpine Tundra and Sparse Vegetation, and Swamp and Aquatic Vegetation), 30 vegetation formations, and 81 vegetation subformations. Agricultural vegetation includes 13 vegetation formation groups (Food Crop, Vegetable Crop, Fruit Crop, Flower Crop, Oilseed Crop, Fiber Crop, Sugar Crop, Medicine Crop, Beverage Crop, Forage Crop, Tobacco Crop, Spice Crop, and Other Crops), 23 vegetation formations, and 40 vegetation subformations. Green space vegetation includes 4 vegetation formation groups (Arbor Green Space, Shrub Green Space, Herb Green Space, and Wetland Green Space), 13 vegetation formations, and 21 vegetation subformations. This study clarified the definition boundaries of different classification units and illustrated the nomenclature of various types of vegetation in current vegetation classification research. Thus, this study modified some shortcomings in the classification and nomenclature of agricultural vegetation and renewed the vegetation classification system of China by including green space vegetation. The results of this study are beneficial for the protection, management, and spatial planning of rural landscapes.
Although the expansion of agricultural land and intensive production have contributed to increased food production, the resulting high-intensity human disturbances and excessive use of agrochemicals have caused significant environmental damage. This has led to the loss of biodiversity and degradation of ecosystem services, ultimately posing threats to both sustainable food production and human health. Therefore, it is crucial to develop sustainable production management strategies. Organic production at the field scale and the establishment of flowering boundaries are considered efficient measures for biodiversity and ecosystem services. However, few studies have investigated whether organic practices and flowering boundaries can effectively increase the natural enemies of arthropods and improve the control of pests in cultivated fields, particularly in paddy planting systems. In this study, we aimed to fill this knowledge gap by investigating the distribution and diversity of natural enemies and pests of arthropods in paddy fields and their field margins, and how vegetation on the field margin affect diversities of natural enemies and pests of arthropods in paddy fields. The following three treatments were established: conventional paddy fields with traditional field margins (Con), organic paddy fields with traditional field margins (Org), and organic paddy fields with flowering boundaries (OrgF). Arthropods were sampled at the field margins and in paddy fields 5 and 20 m away from the margin using a suction sampler. Vegetation coverage and diversity in the field margins were also investigated. The results are as follows: 1) a total of 9531 arthropods belonging to 50 families were caught, with 2653 individuals identified as natural enemies from 28 families (including 2253 individual spiders belonging to 14 families and 41 species), and a total of 3971 individual pests representing 18 families (dominated by Cicadellidae, accounting for 84.01% of the total pests). 2) The richness of the natural enemies in Org was greater than that in Con. The richness of natural enemies in OrgF was higher than that in Con and Org, and the abundance of natural enemies in OrgF was higher than that in Con. 3) In OrgF, the abundance and richness of natural enemies at different distances between the boundary of the paddy field and the interior of the paddy field were significantly different, with a greater richness of natural enemies in the paddy field 5 m away from the field margin than at 20 m. Furthermore, the abundance of natural enemies was significantly lower at the field margins than in paddy fields 5 m away from the boundary. 4) The richness and abundance of natural enemies and pests in paddy fields and their boundaries were positively correlated with vegetation coverage at the paddy field boundary. 5) The ratio of enemies to pests was the highest in the conventional paddy fields (Con), as most pests might be killed by broad-spectrum insecticides, followed by Org and OrgF, which had a large number of pests with only targeted bio-pesticides being used. In conclusion, organic practices in the fields and the flowering boundaries can effectively help to maintain arthropod diversity and increase the diversity of natural enemies in paddy fields. However, to effectively control pests and improve biological control services, an in-depth understanding of the plant-arthropod relationship and careful selection of the “correct” plant diversity are required.
Analyzing rural plant diversity in relation to landscape spatial morphology is necessary to improve rural living environments and maintaining stable rural ecosystems and biodiversity. Fourteen villages in Jiangning District, Nanjing City, Jiangsu Province were selected as experimental areas, and models such as stepwise regression and NMDS-Envfit were used to explore the impact of rural landscape spatial indicators on the α diversity and β diversity of rural plants in the Yangtze River Delta region. Landscape indicators included two-dimensional plane forms, three-dimensional surface features, and four-dimensional historical dynamics. The research conclusions can be summarized as follows: 1) Landscape spatial morphological indicators, such as the percentage of the landscape area covered with semi-natural patches, landscape cohesion index, surface roughness, and patch Euclidean nearest neighbor distance, had relatively significant impact on plant diversity. The patch Euclidean nearest-neighbor distance and patch area significantly and negatively affected the diversity of the arborous layer. Patch fragmentation, higher road density, and higher comprehensive dynamic degree of land use had a negative impact on the α diversity of shrub layer, while the distance from the road obviously affected the α diversity of herbaceous layer. 2) Rural landscape spatial morphological indicators had an impact on plant β diversity. Specifically, in the arborous layer, surface roughness and percentage of landscape area covered with semi-natural patches were the most important influencing factors. In the shrub layer, surface roughness and Shannon diversity index were the most important influencing factors. In the herbaceous layer, patch area and rural road density were the most important influencing factors. 3) Considering the significance of landscape indicators, landscape ecological indicators and three-dimensional surface characteristics had the most significant impact on plant diversity. The main manifestations were the positive correlation between the proportion of semi-natural patch area, patch area, cohesion degree, surface roughness, and plant diversity. The historical dynamics of the four-dimensional landscape had a weak impact on plant diversity, mainly manifesting as a positive correlation with the dynamic degree of semi-natural patches. Two-dimensional landscape indicators based on urban spatial morphology had the weakest impact on plant diversity, mainly manifesting as the negative effects of rural spatial accessibility and road density on plant diversity. Based on the above results, landscape response strategies are proposed to provide guidance for the rural landscape construction process, such as effectively increasing the proportion of semi-natural habitat areas and landscape heterogeneity, comprehensively improving rural landscape cohesion, scientifically maintaining rural high-value woodland landscapes, and fully focusing on rural historical land use. This study provides a reference for the maintenance of biodiversity during rural landscape construction and useful quantitative guidance for rural spatial planning in the Yangtze River Delta region.
The Taihang Mountain Region is the ecological barrier and water source of North China Plain. In recent decades, with the implementation of Taihang Mountains Greening Project and other projects, the vegetation coverage in Taihang Mountain Region is recovering continuously, but the runoff in the mountains is rapidly declining. The mechanism of how the vegetation restoration affects the water yield is not clear. The process of rainfall partitioning is an important part of hydrological cycle. It is of great significance for the formation process of regional water yield and water resources. Pinus tabulaeformis is the main afforestation tree species in Taihang Mountain Region, and it affects regional water resources. The rainfall partitioning of P. tabulaeformis forest in Taihang Mountain Region remains poorly understood. It is required to assess the applicability of the revised Gash model and revised Liu model. In this study, the rainfall partitioning in P. tabulaeformis forest is examined from July to November of 2022. The canopy interception was simulated by revised Gash model and revised Liu model. The results showed that 1) the rainfall amount was 450.8 mm during the study period, the average rainfall duration was 10.4 h, and the average rainfall intensity was 2.7 mm∙h−1. Furthermore, we found that the rainfall during the study period was mainly light rain. The canopy interception, throughfall and stemflow of P. tabulaeformis forest were 105.5, 338.2 and 7.1 mm, respectively, accounting for 23.4%, 75.0% and 1.6% of the rainfall amount. 2) Throughfall and stemflow began to occur when the rainfall amount reached 1.7 and 5.5 mm, respectively. Significant linear relationships were found between the rainfall amount and throughfall amount. However, the relationship between rainfall amount and interception followed a power function. The throughfall percentage increased quickly with increasing rainfall amount, but when rainfall amount reached 11 mm, the throughfall percentage increased slowly. The interception percentage firstly decreased and then stabilized with increasing rainfall amount. 3) Based on the revised Gash model, the canopy interception, throughfall, and stemflow were calculated to be 105.3, 340.7, and 4.6 mm, respectively. The relative errors between the measured and simulated values were 0.2%, 0.8%, and 34.7%. According to the revised Gash model simulation results, we found that the interception amount was dominated by canopy evaporation during rainfall, accounting for 55.0% of the interception simulation, followed by evaporation after cessation of rainfall, accounting for 27.8% of the interception simulation. The revised Liu model calculated the interception as 96.0 mm, with a relative error of 9.0% between the measured and simulated values. The revised Gash model had lower relative errors in the simulation than the Liu model. 4) Sensitivity of the revised Gash model parameters were mean evapotranspiration rate > mean rainfall intensity > canopy storage capacity > canopy cover > trunk storage capacity > stemflow coefficient. These results indicate that typical P. tabulaeformis forests in the Taihang Mountains can intercept 23.4% of rainfall, with 75.0% throughfall and 1.6% stemflow. The revised Gash model can be used to predict canopy interception in P. tabulaeformis forests and provides a theoretical basis for water resource assessment and water conservation capacity improvement in mountainous areas.
Farmland ecosystems are essential sources and sinks of antibiotic resistance genes (ARGs), and the application of livestock manure is a major contributor to ARGs in soil. The massive application of livestock manure to vegetable fields has intensified the pollution caused by ARGs in soil. Raw consumption of edible vegetables is one of the most direct ways to introduce ARGs from the soil–plant system to humans, which poses a potential threat to human health. However, few studies have investigated the effects of different fertilizer types on ARGs and bacterial communities in vegetable fields. In this study, 21 soil samples (0–20 cm) were collected from vegetable fields in Hebei Province using different fertilizer types (fresh fowl manure, fresh sheep manure, fresh cattle manure, commercial organic fertilizer, and chemical fertilizer). The distributions and characteristics of ARGs and bacterial communities in vegetable fields were investigated using real-time quantitative polymerase chain reaction (PCR) and high-throughput sequencing techniques. Eight tetracycline resistance genes (tetA, tetC, tetG, tetL, tetO, tetM, tetW, and tetQ), two sulfonamide resistance genes (sul1 and sul2), and one intI1 gene were detected in all vegetable fields. The absolute abundance of sulfonamide resistance genes (9.96×109 copies·g−1 in dry soil) was significantly higher than that of tetracycline resistance genes (1.07×109 copies·g−1 in dry soil). The application of livestock manure and chemical fertilizer both significantly increased the abundance of ARGs in vegetable fields. The highest abundance of ARGs (6.34×109 copies∙g−1 in dry soil) was found in vegetable fields with higher chemical fertilizer amendment, while the lowest abundance of ARGs (3.09×108 copies∙g−1 in dry soil) was found in vegetable soil with commercial organic fertilizer. In addition, the Shannon and Chao1 indices, representing the α diversity of the soil bacterial community, were significantly higher in soil fertilized with livestock manure compared to high-chemical fertilizer application but not in low-chemical fertilization soil, indicating that livestock manure application significantly increased the abundance and diversity of the soil bacterial community. Pearson’s correlation analysis showed that soil bacterial community structure was an important factor influencing the distribution of ARGs. Proteobacteriota, Bacteroidota, Actinobacteriota, and Firmicutes were the dominant potential hosts of ARGs and were significantly correlated with sulfonamide and tetracycline resistance genes (P<0.05). The distribution of ARGs was also affected by soil organic matter and total nitrogen content. The intI1 gene had significant and positive correlations with the sul2, tetG, tetQ, and tetW genes, suggesting its crucial role in ARGs dissemination. In the present study, the use of higher concentrations of chemical fertilizers led to a significantly increased abundance of ARGs in the soil of vegetable fields, whereas the application of commercial organic fertilizers had the least effect on ARGs abundance. This study serves as a guide for evaluating the status of ARGs pollution in vegetable fields with different fertilizer types.
Energy is a major component in enhancing agricultural productivity. Accounting for energy efficiency at the production stage of crop is essential for achieving sustainable agriculture. Due to the high level of production and consumption of oil in China, it is of great importance to pay attention to energy consumption and its negatively environmental impacts in the oil production process. Measures of optimizing energy utilization structure, reducing excessive and ineffective energy consumption and improving energy utilization efficiency can be used, in order to increase income, save cost and reduce greenhouse gas emissions synthetically. Academically, a large number of previous studies have contributed to energy use and environmental impacts in the production of oil crops, fruits, vegetables, and food crops on various scales. However, there is a lack of studies related to energy use efficiency and greenhouse gas emissions in oil production which concentrate in major oil crops production areas nationally so far. Generally, in terms of models used in relevant study areas, methods including life cycle assessment (LCA), data envelopment analysis (DEA), process analysis, energy analysis have been used commonly, which provide valuable references to the present study. Given that oil crops production is inherently a life process, this paper combined LCA+DEA methods to estimate the energy utilization efficiency and greenhouse gas emissions of oil crops, which helped to rank efficient and inefficient provincial production units. In further, the underlying reasons which caused inefficient energy use were deeply identified in different provinces. Additionally, for purpose of practical application, this paper explored the possibility and potential of energy saving and GHG emission reduction in each province. The results showed as follows. 1) There was no significant difference in the output capacity per unit energy consumption among the three studied oil crop systems. However, the energy use efficiency of three oil crops displayed remarkably differently, which showed peanut > oilseed rape > soybean. 2) Among the three oil crops, peanut had the highest GHG emissions [874.96 kg(CO2 eq)∙hm−2], followed by oilseed rape [660.16 kg(CO2 eq)∙hm−2] and soybean [507.07 kg(CO2 eq)∙hm−2]. In addition, the contributions of substantiality inputs and agricultural operations to GHG emissions varied greatly from different oil crops. Specifically, the significant GHG emission source of oilseed rape and peanut was fertilizer. Nevertheless, contribution of fertilizer, diesel fuel and irrigation to the GHG emissions of soybean showed less difference. 3) There was great potential for energy utilization optimization and GHG emission reduction. Estimates resulted from this study displayed that about 11.97%, 16.38% and 15.89% of resources invested to oilseed rape, soybean and peanut in inefficient provinces could be saved respectively, which were capable of reducing 20.60−616.32 kg(CO2 eq)∙hm−2 GHG emissions as well. Therefore, it is necessary to optimize the energy utilization structure of low efficiency areas according to the actual situation, and explore the production mode of double optimal yield and carbon emissions. This will play an important role in saving money and increasing income for regional oilseed cultivation, as well as green development.
苹果作为山东优势果品之一,其生产受农业气象灾害影响较大.探究厄尔尼诺-南方涛动(ENSO)事件下山东农业气象灾害演变规律及其对山东苹果产量的影响,对指导当地苹果生产具有重大意义.本文基于山东1991-2019年逐日气象观测数据、地市级苹果种植统计数据及ENSO事件数据,利用数理统计分析和ArcGIS空间表达,得出以下结论:1)1991-2019年不同ESNO年型下农业气象灾害发生情况区域差异显著.6-8月果实膨大期厄尔尼诺年干旱灾害发生较为频繁,共计78次,干旱频率最高约50％;中性年雨涝灾害较为严重,高达60次.鲁西、鲁中等热量资源充足地区,干旱发生较为频繁;鲁南降水资源较为充沛地区,雨涝灾害发生频繁.鲁东、胶东半岛等地3-5月苹果花期极端低温灾害发生较为频繁,发生日数约7～9 d·a-1,频率约为60％—100％.鲁西等地是6-8月苹果果实膨大期高温热害的高发区,发生天数11～15d·a-1.2)不同ESNO年型下,干旱与厄尔尼诺年呈正相关,与拉尼娜年呈负相关.3-10月苹果可生长期厄尔尼诺年南方涛动指数与雨涝呈正相关,拉尼娜年、中性年南方涛动指数与雨涝呈负相关.3-5月苹果花期低温灾害与厄尔尼诺年南方涛动指数呈负相关;与拉尼娜年、中性年南方涛动指数呈正相关.3)3-10月苹果可生长期,厄尔尼诺年,胶东半岛地区干旱加剧,导致苹果减产率上升;中性年,雨涝灾害使得苹果减产减收的影响加重.6-8月苹果果实膨大期,拉尼娜年、中性年,鲁西地区干旱与苹果减产率呈正相关;中性年,山东大部分地区雨涝与苹果减产率呈正相关.厄尔尼诺年苹果减产率受极端低温灾害影响较小,高温热害影响较大;拉尼娜年、中性年山东大部分地区低温冷害、冻害天数增加,导致苹果减产率上升,风险加大.苹果生产中谨防厄尔尼诺年高温、干旱,拉尼娜年、中性年应预防低温、雨涝灾害对苹果产量、品质的损害,确保苹果产业健康可持续的生产.
滨海湿地处于海陆生态系统交错地带,研究湿地面积变化带来的生态系统服务和人类福祉的变化,可为湿地生态系统服务提升、近海岸生态环境保护与生态安全管理提供参考.本文通过分析河北滨海湿地面积变化,对2000-2020年河北滨海湿地生态系统服务的供给量和社会对湿地生态系统服务需求量进行评估,并以供需比定量分析了滨海湿地生态系统服务供需特征,最后利用情景分析预测了2030年河北滨海湿地供需安全.结果表明:1)河北滨海湿地生态安全受到威胁,主要表现为自然湿地面积和湿地生态廊道面积减少.2)除水产品供给服务增加外,河北滨海湿地的水资源供给、净化环境、调节洪水、固碳、释氧和美学景观等生态系统服务供给量均降低,河北滨海区社会对湿地生态系统服务需求量均呈增加趋势.3)河北滨海湿地面积仅占河北滨海区全域面积的 6.3%,但其提供的调节洪水服务可以满足河北滨海区全域对其需求.4)河北滨海湿地调节洪水服务的生态安全状况较好,水产品供给服务、水资源供给服务和净化环境服务是目前需要重点关注的生态安全问题,是未来可能影响河北滨海湿地生态安全的隐患,固碳、释氧和美学景观服务是未来河北滨海湿地生态安全发展中的短板.5)情景分析下,湿地严格保护情景下生态系统服务供给量和供需比最高,是河北滨海湿地生态系统未来发展的最好情景模式.
氮是与菠萝产量关系密切的大量营养元素之一.本试验分别在4月和9月两个生长季节,选择了广东省徐闻县田间生长的'巴厘'和'台农17'两个菠萝品种不同年龄的植株为研究对象,测定了不同年龄植株的形态、生理和生长特征,并利用稳定性同位素15N示踪技术分析了菠萝对3种形态氮素[铵态氮、硝态氮和氨基酸态氮(甘氨酸)]的获取策略,以探讨菠萝吸收氮素的偏好.结果表明,在4月份果实收获期,与'巴厘'相比,'台农17'菠萝的产量(单个鲜果重)和根生物量较低,但其植株高度、单株生物量、叶片N、K含量和比叶面积无显著差异,叶片碳稳定性同位素(δ13C)和P含量较高.在4月和9月,两菠萝品种间对不同形态的氮素吸收均有显著差异.总体而言,'台农17'比'巴厘,的氮吸收能力强(P＜0.05).'台农17'菠萝较强的氮吸收能力和水分利用效率更有助于将其分配到地上以促进光合作用,从而维持其植株在较短生命周期内的生长.两菠萝品种都偏好吸收铵态氮(36.8％～64.6％),其次是甘氨酸(23.2％～47.1％),对硝态氮吸收速率最低(9.1％～31.5％).处于营养生长阶段的菠萝植株(5～8个月)比果实收获时期的氮吸收速率高.随着年龄的增长,铵态氮贡献率逐渐增大,而甘氨酸贡献率逐渐降低.不同季节和年龄条件下,不同形态氮素的吸收速率与土壤氮含量和其他所测得植物性状的相关性不显著.总之,本研究首次证实田间菠萝的根系具有较强直接吸收利用有机氮的能力,菠萝的品种和生长阶段都是影响氮素获取策略的重要因素.
