Central Gansu Research Articles

Optimized nitrogen and potassium fertilizers application increases stem lodging resistance and grain yield of oil flax by enhancing lignin biosynthesis

The lodging issue is a significant factor that hinders the enhancement of oil flax production efficiency in northern China. Crop lodging or not, and lignin content in the stems are closely related, and how nitrogen fertilizer and potassium fertilization interaction regulate lignin biosynthesis in the stems of oil flax requires further in-depth study. Therefore, the research aims to enhance the lodging resistance and facilitate an increased yield of oil flax. We are examined the interaction of different nitrogen fertilizers (75, 150, and 225 kg N ha-1) and potassium fertilizers (60 and 90 kg K2O ha-1) on oil flax lignin metabolism, lodging resistance, and grain yield in 2022 and 2023 growing seasons. The results indicated that nitrogen and potassium fertilizer levels and their interaction treatments are facilitated lignin accumulation, achievement of lodging resistance and high yield. Compared to CK, the 75-150 kg N ha-1 in combination with 60 kg K2O ha-1 treatments significantly enhanced the enzyme activities (TAL, PAL, POD, and CAD) and the gene expressions (4CL1 and F5H3) for lignin syntheses, lignin content dramatically increased 29.63-43.30%, improved stem bending strength and lodging resistance index, and grain yield increased 23.27-32.34%. Correlation analysis indicated that nitrogen and potassium fertilizer positively regulated the relative enzyme activities and genes expression for lignin to facilitated lignin biosynthesis and accumulation, and enhanced stem bending strength and lodging resistance index. Positive correlations were found among the relative enzyme activities and gene expressions for lignin, lodging resistance and grain yield. To summarize, 75-150 kg N ha-1 in conjunction with 60 kg K2O ha-1 treatment was promoted to lignin biosynthesis and accumulation, enhanced the lodging resistance and grain yield of oil flax in the dryland farming region of central Gansu. Furthermore, it served as a technical guide for cultivating stress tolerance and high-yield oil flax in the dryland farming region.

Taxonomic Reinstatement of the Endemic Chinese Species Iris thoroldii (Iridaceae) from I. potaninii and Reassessment of I. zhaoana.

Iris thoroldii is a perennial herbaceous plant with yellow, blue, or purple flowers. The species is native to the Tibetan Plateau and adjacent areas. In the literature and databases, I. thoroldii has long been treated in synonymy with I. potaninii. Currently, yellow-flowered plants of I. thoroldii are considered I. potanii, and blue-flowered plants are considered I. zhaoana, a replacement name for I. potaninii var. ionantha. This study aimed to clarify the taxonomic identity of I. thoroldii. A critical examination of original material, herbarium specimens, images of living plants, and the literature has shown I. thoroldii to be different from I. potaninii in some previously neglected macromorphological traits and to be conspecific with I. zhaoana. Thus, I. thoroldii is removed here from the synonymy of I. potaninii and accepted as a distinct species. This is endemic to China (central Gansu, Qinghai, and northwestern Sichuan provinces, and also Xinjiang Uygur and Tibet autonomous regions) and reaches the highest elevations compared with all other species in the genus Iris s.l. A revised taxonomy of I. thoroldii is provided, and two color forms, often co-occurring, are accepted: the autonymic yellow-flowered form (including a new synonym I. tigridia var. flavescens for which a lectotype was designated) and a form with blue or purple colors is proposed here, I. thoroldii f. ionantha. In addition, images of type specimens and detailed photographs of living plants for easy identification, along with the list of specimens of I. thoroldii that were examined, and also, comments on its distribution and habitats are provided.

Environmental factors influencing the diversity and distribution of dictyostelid cellular slime molds in forest and farmland soils of western China.

Soil protists are an essential yet seriously understudied component of the soil microbiome. In this study, 11 new records of dictyostelids belonging to 2 orders, 3 families, and 4 genera were identified from 99 soil samples collected from different elevations and habitats in central Gansu and the southeastern and southcentral portions of Guizhou Province, China. We found that dictyostelid communities were significantly different between Gansu and Guizhou Provinces, apparently in response to different environmental factors. Moreover, dictyostelids were found to have the highest species diversity in mixed forests. Soil pH, temperature, and elevation were determined to be the primary factors that affect the distribution and occurrence of dictyostelids in Guizhou and Gansu Provinces. This work supplements the survey data available for dictyostelids elsewhere in China. These new findings have significant implications for our understanding of the diversity of soil microorganisms.

Impact of fine particulate matter 2.5 on hospitalization for upper respiratory tract infections in Lanzhou urban industrial area, China.

Abundant evidence has shown that an increase in the concentration of fine particulate matter 2.5 (PM2.5) leads to a simultaneous increase in the incidence of respiratory diseases. Xigu District is the main industrial district of Lanzhou, located in Lanzhou City in northwest China and central Gansu Province. Because of limited research and data in the region, the impact of PM2.5 on human health has not been systematically recognized. The aim of the study was to investigate the relationship between PM2.5 pollution and upper respiratory tract infections in urban industrial areas of Lanzhou City. Data on outpatient visits, air pollutants, and meteorological indices were collected in the Xigu District of Lanzhou City from 1 January 2013 - 31 December 2019. A generalized additive model was used to evaluate the association between PM2.5 and outpatient visits for upper respiratory tract infections. The results show that PM2.5 had the greatest impact on outpatient visits for upper respiratory tract infections on 7 cumulative lag days. At cumulative lag days 1, 3, and 5, the effects gradually increased. In the subgroup analysis, the effect of PM2.5 on visits for upper respiratory tract infections was significantly influenced by gender. Men were more susceptible to PM2.5 pollution. An increase in atmospheric PM2.5 concentration was associated with an increase in visits for upper respiratory tract infections with the lag effect. The obtained results can provide a reference for the development of prevention strategies to protect the population from the adverse effects of PM2.5 pollution.

Ecological Function Service Value and Quantity of Fruit-Tree Economic Forests in the Semi-Arid Loess Hilly and Gully Region of Central Gansu—A Case Study of the Hulu River Basin

Ecological Function Service Value and Quantity of Fruit-Tree Economic Forests in the Semi-Arid Loess Hilly and Gully Region of Central Gansu—A Case Study of the Hulu River Basin

Comprehensive evaluation on effect of planting and breeding waste composts on the yield, nutrient utilization, and soil environment of baby cabbage

Treatment of the planting and breeding waste is becoming a big issue due to their significant quantities. Composting could be an effective alternative for planting and breeding waste management which could be used as fertilizer. The purpose of this research was to evaluate the effect of planting and breeding waste on baby cabbage growth and soil properties, to establish a suitable agricultural cycle model for semi-arid area in central Gansu Province. The planting and breeding wastes [sheep manure (SM), tail vegetable (TV), cow manure (CM), mushroom residue (MR) and corn straw (CS)] were used as the raw materials in this study, which were designed 8 compost formulas for composting fermentation. With no fertilization (CK1) and local commercial organic fertilizer (CK2) as the control, the comprehensive evaluation of planting and breeding waste composts on the yield of baby cabbage, fertilizer utilization rate, soil physical and chemical properties and microbial diversity were studied to select the best compost formula suitable for the growth of baby cabbage. And the material flow and energy flow analysis of the circulation model established by the formula were carried out. The results showed that the biological yield and economic yield of baby cabbage, absorption and recycling utilization of total phosphorus (TP) and total potassium (TK) reached the maximum under the formula of SM: TV: MR: CS = 6:2:1:1. Compared with CK2, the formula of SM: TV: MR: CS = 6:2:1:1 significantly increased the richness of soil bacteria and beneficial bacteria Proteobacteria, and decreased the relative abundance of harmful bacteria Olpidiomycota. Principal component analysis showed the comprehensive score of SM: TV: MR: CS = 6:2:1:1 was the best organic compost formula suitable for producing high-quality and high-yield baby cabbage and improving soil environment. Therefore, this formula can be used as a reference organic fertilizer formula for field cultivation of baby cabbage.

Enzootic epidemiology of Brucella in livestock in central Gansu Province after the National Brucellosis Prevention and Control Plan

Brucellosis remains one of the most common zoonoses spread worldwide, inducing enormous economic losses to the livestock industry and posing serious health threats to humans. Brucellosis re-emerged in China in the mid-1990s and reached a historically high level in 2015. The National Brucellosis Prevention and Control Plan (NBPCP) was initiated from 2016 to 2020. However, the present epidemiological status in livestock has not been elucidated, and whether Brucella variation occurred remains unclear. This study performed an extensive serological investigation in ruminant livestock from 2019 to 2021 in central Gansu Province, China. In total, 11,296 samples from 337 farms were collected to detect the specific antibodies of Brucella. The yearly average serological prevalence of Brucella at the flock level and individual level declined from 11.32% to 8.26% and 1.17% to 0.57%, respectively. The apparent individual-level seroprevalence of small and large ruminants was 0.89% and 0.52%, respectively. The brucellosis distribution has shifted from pastoral areas to agro-pastoral areas. Flock size and gender may be major risks of Brucella infection. Then, the B. melitensis TZ strain was isolated from female Tibetan sheep blood cell lysates. Phonotypical characterization demonstrated that it belongs to B. melitensis. biovar 3, and multilocus sequencing typing results indicated that it belongs to ST8. The whole genome and subsequent phylogenetic analysis demonstrated that the B. melitensis TZ strain is genetically more closely related to the B. melitensis QH61 strain. The B. melitensis TZ strain has similar growth characteristics to the B. melitensis 16 M strain. Overall, our study suggests that after strengthening control and prevention measures based on the NBPCP, there is a very low prevalence or absence of B. melitensis in the central Gansu Province of China, and the genotype of an epidemic strain of Brucella in Northwest China is relatively stable.

Effects of different land use patterns on soil properties and N2O emissions on a semi-arid Loess Plateau of Central Gansu

Nitrous oxide (N2O) is one of the significant greenhouse gases in the atmosphere. Different land use patterns are the sink or source of N2O, which plays a vigorous role in controlling N2O emissions. Yet, how different land use patterns affect soil N2O emissions in the Loess Plateau of Central Gansu is still not clear. Therefore; in order to fill this gap, six different land use patterns, including Picea asperata (PA), Hippophae rhamnoides (HR), Medicago sativa (MS), No-tillage wheat field (NT) and Conventional tillage wheat field (T) were studied. The objective of this study was to examine the impact of different land use patterns on soil properties and N2O emission flux. Our results showed that compared with other treatments, Picea asperata woodland increased the soil bulk density, organic matter and soil water content, total nitrogen accumulation and microbial biomass nitrogen whilst reduced the soil pH. The wheat field is more favorable to accumulating soil nitrate nitrogen and ammonium nitrogen. Moreover, soil N2O emission rates followed the trend of T>NT>HR>GL>MS>PA. In addition, soil physicochemical properties were closely related to N2O emission flux and soil temperature was the most significant factor affecting N2O emission. General, Picea asperata woodland could significantly increased soil nutrient and reduce N2O emissions. We suggest that more forest land should be selected as the optimal site for nitrogen fixation and emission reduction for sustainable development of the terrestrial ecosystem on the Loess Plateau in Central Gansu.

Agricultural Eco-Efficiency Response and Its Influencing Factors from the Perspective of Rural Population Outflowing: A Case Study in Qinan County, China.

Agriculture is the source of human clothing and food, but it also brings negative externalities to the environment. The outflow of the rural population is one of the factors for changes in the characteristics of the rural population. Farmers' decisions on agricultural production can affect agricultural ecological efficiency. Therefore, it is necessary to study the relationship between the two in rural development. Taking Qin'an County in the Loess Hilly Region of central Gansu, China, as an example, this paper analyzed the demographic characteristics and the evolution characteristics of agricultural eco-efficiency under the background of rural population outflowing, and the impact of the former on the latter, based on the panel statistical data of 17 villages and towns from 2001 to 2020. The results show that (1) From 2001 to 2020, the non-agricultural level of Qin'an County's labor force showed an upward fluctuation trend. The level of aging was relatively stable, and the per capita disposable income was significantly increased. (2) From 2001 to 2020, the agricultural eco-efficiency of Qin'an County showed a wavy change, but there were some towns and villages that have not been effectively developed. The regional differences are significantly different. (3) The non-agriculturalization level of the labor force promotes agricultural eco-efficiency through the direct effect rather than the space spillover effect. The positive effect of aging on agricultural eco-efficiency was mainly reflected through direct effect rather than spatial spillover effect. Per capita, disposable income has a significant positive spatial spillover effect on agricultural eco-efficiency. Finally, this paper provides a scientific reference for promoting the improvement of agricultural eco-efficiency and sustainable development. This is of great theoretical and practical significance for the realization of rural revitalization.

Effect of different biochar addition rates on Soil Physical Properties in rain-fed farmland

Biochar is extensively used for ameliorating soil structure. However, the evaluation of soil physical properties influenced by its large-scale use is still unclear. Moreover, research on biochar is mainly based on laboratory tests, lacking medium and long-term field positioning tests. In this study, a local field trial was conducted for 3 years on the Loess Plateau in central Gansu, China. Six levels of biochar treatment were set with application amounts of 0 t·ha-1, 10 t· ha-1, 20 t·ha-1, 30 t·ha-1, 40 t·ha-1, and 50 t·ha-1 (CK, T1, T2, T3, T4, and T5, respectively). The influence of various input levels of biochar on soil porosity, bulk density, aggregate stability, and soil saturated hydraulic conductivity from the 0 cm to 30 cm layer were studied during the three years of wheat field experiments. The experimental study indicates that the increase of biochar addition can significantly (p < 0.05) reduce soil bulk density and increase not only soil saturated hydraulic conductivity but also total soil porosity, content of soil mechanically stable aggregates, and its MWD from the 0 cm to 30 cm soil layer. Among them, T5 treatment is the most significant (p < 0.05). While its content determination of Water Stable aggregates and its MWD only have an obvious (p < 0.05) improvement effect from the 0 cm to 20 cm soil layer, and T5 is the most significant. Therefore, large-scale biochar application is conducive to the improvement of farmland soil physical properties in this region.

Effects of different vegetation types on ecosystem respiration in semiarid Loess Hilly Region, Central Gansu Province, China

The principal channel of carbon export from ecosystems to the atmosphere, and an important connection in carbon exchange between land and atmosphere, is ecosystem respiration (ER). It has a significant impact on the global carbon cycle and the rate of CO2 increase in the atmosphere. The effects of different vegetation types [Medicago sativa grassland (MS); Xanthoceras sorbifolium forestland (XS); Caragana korshinskii bushland (CK); Hippophae rhamnoides shrubland (HR); and Stipa bungeana grassland (SB)] on ecosystem respiration fluxes in Loess Hilly Region (LHR) were studied via the static chamber technique. The results showed that different vegetation types had significant effects on ER fluxes, and the decreasing order of the cumulative fluxes was HR > MS > SB > CK > XS. Throughout the study period, the largest value of ER occurred in the summer and the lowest value occurred in the winter. Temperature (air temperature, soil temperature) and soil moisture were both significantly and positively linked with ER. For the temporal change of ER, the joint effect of soil temperature and moisture was a key regulating factor. The temperature sensitivity of ecosystem respiration varies greatly between vegetation types and seasons. In the process of LHR vegetation restoration, the ER, carbon sequestration capacity and ecological benefits of different plant types should be considered in order to select the vegetation type that is most conducive to reducing the greenhouse effect.

An evaluation of the spatial rationality of provincial territory: a case study of Gansu Province.

In China, utilization and evaluation of territorial space have become national strategic issues. Evaluating the rationality of urban, ecological, and agricultural space is significant in the development of territorial space and provides a theoretical basis for the optimization of provincial territorial space. The strategic positioning of Gansu Province as a national ecological environment safety barrier is significant to the protection of the ecological environment of northwest China. This study used the entropy method to evaluate the rationality of territorial space development in 14 cities in Gansu Province in 2019, using 50 indicators of urban, ecological, and agricultural space. Results reveal that in the evaluation of these three spaces, the most important influencing indicators are water supply penetration rate, proportion of desert area, and proportion of agricultural population, respectively. In the total evaluation of territorial space rationality, the city with the highest comprehensive index is Qingyang (2.0521), followed by Zhangye (1.5635), while Lanzhou (1.1553) has the lowest evaluation. In Gansu, cities with the best territorial spatial conditions are concentrated in the east, whereas those with poor territorial spatial environmental security are located in central Gansu and the Hexi Corridor. Collectively, these findings suggest that the equity and rationality of urban, ecological, and agricultural space in territorial space should be considered in territorial space planning strategies. The balance and harmony of these three spaces play a positive role in the sustainable development of the economy, society, and the environment in urban areas.

Soil nematode community characteristics of alfalfa field with different growing ages in the semi-arid Loess Plateau of Central Gansu, Northwest China

To clarify the impacts of long-term alfalfa plantation on the soil nematode community, soil samples were collected from different alfalfa growing ages (2 a, 9 a, 18 a) in the semi-arid area of Loess Plateau in Central Gansu by Illumina Miseq sequencing technology. The main controlling factors affecting its community change were also explored. The results showed that soil nematode belongs to 2 classes, 7 orders, 16 families and 21 genera. Among them, Chromadorea was the dominant group (44.6%-81.4%), the relative abundance of which decreased with alfalfa growing ages. Paratylenchus, Helicotylenchus, Xiphinema, Pristionchus, Ditylenchus, Panagrolaimus, Longidorus, Aprutides, Isolaimium and Aglenchus were the special nematode species of alfalfa, among which Paratylenchus (54.1%), Helicotylenchus (23.9%) and Xiphinema (21.9%) were the dominant nematodes in 2 a, 9 a and 18 a alfalfa soil respectively. Plant-parasitic nematode was the dominant group in alfalfa soil (31.8%-67.1%), and its relative abundance decreased at first and then increased with alfalfa growing ages. Results of redundancy analysis showed that soil available phosphorus and total nitrogen were the dominant environmental factors affecting community structure of soil nematodes in the region.

Substituting Inorganic Fertilizers with Organic Amendment Reduced Nitrous Oxide Emissions by Affecting Nitrifiers’ Microbial Community

Excessive inorganic fertilizers are one of the main causes of nitrous oxide (N2O) emissions. Organic fertilizers can not only reduce the use of nitrogen (N) fertilizers by increasing soil organic matter but are also safe for the environment. The partial replacement of nitrogen (N) fertilizers with organic fertilizers can potentially reduce N2O emissions. To illuminate the best ratio for the nitrogen replacement of inorganic fertilizer, the present experiment was conducted in dryland areas of central Gansu Province and different portions of inorganic N fertilizers (200 kg ha−1); i.e., 0, 50, 37.5, 25, and 12.5% were replaced with commercial organic fertilizers to test their effects on soil physicochemical properties, the grain yield of maize, N2O emissions, and the diversity of ammonia-oxidizing archaea (AOA) and bacterial (AOB) communities. Results showed that the maximum N2O emission was obtained by 100% inorganic fertilizers and the lowest was obtained at the control (no fertilizer). Substituting inorganic fertilizers with organic manure not only reduced N2O emissions but also improved soil organic carbon content and soil moisture and typically improves grain yield and biomass. The highest reduction in N2O emissions was recorded by 50% substitution. Furthermore, 37.5% and 12.5% substitutions did not reduce the grain yield and biomass compared to 100% inorganic fertilizer, and a 37.5% substitution performed better in improving soil fertility. Organic fertilizer increased the amoA copy number of AOA but decreased that of AOB. Nitrososphaera (AOA) and Nitrosospira (AOB) were the most dominant ammonia-oxidizing communities. Structural equation modeling indicated that AOB contributes more N2O emissions than AOA and is more sensitive to changes in pH, moisture, and NO3−−N, and the input of organic fertilizers may affect AOB by influencing soil physicochemical traits. In summary, replacing a reasonable proportion (37.5%) of inorganic fertilizers with organic manure improves soil fertility, reduces N2O emissions, and stabilizes production.

Effects of Plant Community Type on Soil Methane Flux in Semiarid Loess Hilly Region, Central Gansu Province, China

Effects of Plant Community Type on Soil Methane Flux in Semiarid Loess Hilly Region, Central Gansu Province, China

Pathogens of patients with fever with rash syndrome in Gansu province, 2009 – 2019: a multiple correspondence analysis

Objective To examine characteristics of pathogens identified among patients with fever and rash syndrome (RFIs) in Gansu province from 2009 to 2019, and to provide a reference for implementing targeted prevention measures and conducting pathogen surveillance. Methods Sentinel surveillance data on 5 822 RFIs cases reported in Gansu province from 2009 through 2019 were extracted from the Information Management System for Prevention and Treatment of AIDS and Viral Hepatitis and other Major Infectious Diseases. Multiple correspondence analysis was adopted to analyze characteristics of pathogens isolated from the RFIs patients. Results Enterovirus infection was confirmed in 1 653 (28.39%) of the all RFIs patients reported during the period and the number (proportion) of the patients confirmed with other pathogen infections were 548 (9.41%) for measles virus, 201 (3.45%) for rubella virus, and 495 cases (8.50%) for varicella-zoster virus, respectively. No pathogen infection was confirmed in 2 925 (50.24%) RFIs patients. The results of multiple correspondence analysis showed that enteroviruses infection was more frequently diagnosed in hospitalized cases in western and central Gansu province, during summer/autumn season, among scattered children aged ≤ 5 years and kindergarten children, among patients hospitalized in provincial and county-level hospitals; measles virus infection was more frequently confirmed among the patients in eastern and southern areas of Gansu province, during winter/spring season, in the adults (≥ 18 years) with some specific occupations, and among patients seeking medication at municipal hospitals; and more varicella-zoster virus and rubella virus infections were detected among the students aged 6 to 17 years. No pathogen infection was identified among the majority of the RFIs patients visiting doctors in outpatient/emergency departments. Conclusion The main pathogens inducing RFIs incidents in Gansu province from 2009 to 2019 include enterovirus, measles virus, varicella-zoster virus and rubella virus, and there were disparities in the detection rate of the pathogens among various populations, in different seasons and in various geographical areas.

Simulation of the responses of spring wheat yield to the rates and depths of nitrogen application in dryland based on APSIM model

Nitrogen limitation is an important factor for the improvement of crop water production potential in rain-fed areas of the Loess Plateau. The reasonable deep application of nitrogen fertilizer is a promising method to increase yield of rain-fed crop. Based on APSIM model, this study simulated spring wheat yield under different nitrogen application rates and depths, by using meteorological observation data from 1990 to 2020 in the semiarid areas of central Gansu Province, aiming to provide theoretical reference for optimizing wheat fertilization strategy. The results showed that the determination coefficient of simulated spring wheat yield, biomass and soil water content in 0-200 cm soil profile was greater than 0.80, the normalized root mean square error was less than 0.2, and the model validity index was greater than 0.5. These results indicated that the model had good fitting and adaptability in the test area. Across all the levels within the experimental design, increasing nitrogen application rates could significantly increase the yield of spring wheat in different precipitation years, and increasing nitrogen application depth could significantly increase spring wheat yield in wet and normal years, but had no effect in dry years. The rate and depth of nitrogen application had significant interaction effects on spring wheat yield in wet and normal years, but not in dry years. According to the binary quadratic regression fitting equation, when the potential maximum yield reached 2749 kg·hm-2 in wet year, nitrogen application depth was 22.7 cm, and nitrogen application rate was 245 kg·hm-2. When the maximum potential yield reached 2596 kg·hm-2 in normal year, nitrogen application depth was 20.6 cm, and nitrogen application rate was 235 kg·hm-2. Integrating the effects of nitrogen application rate and depth on yield, biomass and agronomic efficiency of nitrogen fertilizer, and farmer's fertilizer application habits, the recommended nitrogen application depth was 20-23 cm, and nitrogen application amount was 120-150 kg·hm-2, which could further improve water productivity and nitrogen use efficiency of spring wheat in arid areas of central Gansu Province.

Habitat protection and planning for three Ephedra using the MaxEnt and Marxan models

As renowned species for use in sand fixation and traditional Chinese medicines, Ephedra sinica Stapf, Ephedra intermedia Schrenk ex Mey and Ephedra equisetina Bunge have important ecological and medicinal value. However, although conservation measures have been implemented, the suitable habitat for these species has been shrinking at a remarkable rate in recent years due to climate change and anthropogenic activities. The identification of suitable habitats for these three Ephedra is essential for their protection and cultivation. Thus, this study proposed a new method for planning the best species conservation habitat through fitting errors caused by a single model. The method modeled the current suitable habitats of the three Ephedra species using the MaxEnt model and evaluated the key environmental variables defining the Ephedra distribution based on recorded occurrence data for Xinjiang, Inner Mongolia, Gansu, and Qinghai. The results showed that human activities were the most important environmental parameter affecting the distribution of the three species, and land cover, ground frost frequency and precipitation accounted for an important proportion of the model evaluation. Second, the results obtained with the MaxEnt model were coupled with the finding from the Marxan model to identify priority conservation areas for the three Ephedra species. The results revealed that the most suitable habitats for E. sinica were mainly concentrated in eastern and central Inner Mongolia, E. intermedia was relatively distributed in southern and central Gansu, and the areas of E. equisetina were mainly distributed in northern Xinjiang. The priority conservation areas for E. sinica, E. intermedia, and E. equisetina were 38068.12 km2, 26446.74 km2 and 36360.6 km2, respectively. The comprehensive analysis indicated that be use of MaxEnt coupled with the Marxan model to model the suitable habitat of these Ephedra species eliminates the distribution errors introduced by each model alone. The protection of wild Ephedra should be a priority, and the scale of the artificial planting of Ephedra should be enlarged. Given these results, the three Ephedra species included in our study urgently need to be subjected to targeted conservation management to ensure the renewal of Ephedra communities and to maintain the supply of medicinal materials. This study provides a useful reference for the protection and cultivation of these three Ephedra.

Lag effects of size-fractionated particulate matter pollution on outpatient visits for respiratory diseases in Lanzhou, China.

A large body of evidence suggests that an increase in atmospheric particulate matter (PM) concentrations will lead to an increase in morbidity due to adverse health conditions, such as respiratory diseases (RESD). Lanzhou is located in northwest China, central Gansu Province. Due to limited research and data, the impact of PM on human health have not been systematically acknowledged. The aim of the study is to investigate the association between size-fractionated PM pollution and outpatients visits for RESD. Data on outpatient visits for RESD, air pollutants and meteorological indices in Lanzhou were collected from 1 February 2014 - 31 December 2017, and the associations of three types of PM (PM2.5, PMC, and PM10) with outpatient visits for RESD were evaluated using generalized additive models (GAMs). Findings showed that PM2.5 and PMC had the most significant impact on outpatient visits for RESD at seven cumulative lag days. PM10 was not significantly associated with outpatient visits for RESD. In subgroup analysis, the impact of atmospheric PM on outpatient visits for RESD was significantly modified by gender and age; men, and children aged 0-5 years old, were more sensitive to PM2.5 pollution. Increased atmospheric PM concentration is associated with an increase in outpatient visits for RESD, and it has a lag effect. The increase in outpatient visits for RESD appears to be driven by increased PM2.5 concentrations. The results obtained may provide reference values for formulating preventive strategies to protect the population from the adverse impact of PM pollution.

Life Cycle Carbon Emission Analyzing of Rural Residential Energy Efficiency Retrofit-A Case Study of Gansu province

Objective To study and analyze the life-cycle carbon emissions of existing rural residential energy retrofit projects to provide theoretical and data support for local rural green development and sustainable construction. Methods Life cycle analysis (LCA) was used to analyze and compare the life cycle carbon emissions (LCE) of a rural residential envelope energy efficiency retrofitting project in central Gansu. Results It was found that rural dwellings have a very high potential for energy efficiency retrofitting, and the contribution of retrofitted homes to CO2 emissions reduction can reach more than 30% over the whole life cycle. Secondly, during the retrofitting process, neglected in previous studies, carbon emissions account for about a quarter of the LCE. It is concluded that introducing LCA into evaluating rural residential energy retrofit projects' energy-saving and emission reduction benefits is more scientific, reasonable, and necessary.