Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in ...Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL>MSP>KP, the returning amount of Cu is DL>KP>MSP, the returning amount of Fe and Mn are MSP>DL>KP, (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles,dead branches and bark scales also play an important role in the return of nutrient elements; (3)A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.展开更多
Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance ...Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.展开更多
[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in...[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in the production, Yangdao 6 （an indica） and Yangjing 4038 （a japonica）, were field grown using a direct-seeding method, and four treatments, wheat straw incorporation into soil and traditional flooding （SlF）, non-flooding and wheat straw mulching （NSM）, non-flooding and wheat straw incorporation into soil （NSl） and traditional flooding （no straw returned, Control, TF）, were imposed after sowing to maturity. Effects of direct-seeding with non-flooding and wheat residue returning patterns on CH4, N20 and CO2 emissions were investigated by using the method of static chamber-gas chromatographic tech- niques. [Result] Grain yield showed no significant difference between non-flooding and flooding treatments, but was significantly higher under the SlF than under any other treatments. The emission flux of CH4 and CO2 under TF and SlF exhibited a single peak curve, while changed little under the NSl and NSM The emission flux of N2Oshowed multiple perk curves for all the treatments. Compared with TF, SlF significantly increased mean emission flux of CH4 or N2O, decreased emission of N20, while NSl and NSM significantly decreased the mean emission flux of OH4, and increased emission flux of N2O and CO2. SIF also increased Green Warm Potential （GWP） of CH4, N2O and CO2 and the GWP per unit grain yield by 47.3%- 53.7% and 32.2%-39.4%, respectively. Both NSl and NSM decreased GWP by 24.2%-29.6% and 30.1%-35.5%, and the GWP per unit grain yield was decreased by 21.7-27.2% and 25.6%-31.1%, respectively. [Conelusion] both NSl and NSM could significantly reduce greenhouse effect of CH4, N2O and CO2 meanwhile maintain a high grain yield.展开更多
In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different ...In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows： in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was？recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.展开更多
In the research, effects of straw returning to fields on soil temperature, water, volume-weight, porosity, trace elements, and organic matters were reviewed and countermeasures were proposed to promote straw returning...In the research, effects of straw returning to fields on soil temperature, water, volume-weight, porosity, trace elements, and organic matters were reviewed and countermeasures were proposed to promote straw returning on basis of straw resources and present status in Anhui Province.展开更多
Based on advances in returning rice and wheat straw to fields at home and abroad, environmental physical, chemical and ecological effects of returning rice and wheat straw to fields were analyzed. The results show tha...Based on advances in returning rice and wheat straw to fields at home and abroad, environmental physical, chemical and ecological effects of returning rice and wheat straw to fields were analyzed. The results show that returning straw to fields can enhance soil porosity, reduce soil bulk density, and increase the ca- pacity of soil to preserve water, fertilizer and temperature. Besides, it can improve the content of organic matter, nitrogen, phosphorus and potassium in soil, of which the increase of potassium content is the most obvious. Meanwhile, it can provide energy and nutrients for microorganisms in soil and change the activity of soil enzymes, of which it affects invertase most greatly and enhances the activity of ure- ase but has no effect on neutral phosphatase. In addition, it can enhance the total quantity of microorganisms in soil obviously, and the increase correlates positively with the quantity of straw returning to fields. Finally, returning straw to fields can promote the sustainable development of agriculture.展开更多
Soil structure and nutrient ingredient before and after shattering and returning sugarcane leaf as well as its technologies and methods were comparatively analyzed in this study to discuss the main reasons primarily,w...Soil structure and nutrient ingredient before and after shattering and returning sugarcane leaf as well as its technologies and methods were comparatively analyzed in this study to discuss the main reasons primarily,while the controlling technologies were proposed by combining cultivation,management and technical measures.展开更多
The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged a...The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged as a central force shaping youth decision-making across work,consumption,relationships and lifestyle choices.Unlike traditional economic rationality that prioritises income and material security,emotional value focuses on how choices make individuals feel and how they align with personal meaning.This shift is particularly evident in rapidly transforming societies such as China and Ghana,where economic restructuring,globalisation and social change have reshaped pathways to adulthood.展开更多
BACKGROUND There has been an increasing focus in recent years on health-care disparities.Studies investigating return to work(RTW)or sports are often performed in large,urban areas.Relatively few studies have investig...BACKGROUND There has been an increasing focus in recent years on health-care disparities.Studies investigating return to work(RTW)or sports are often performed in large,urban areas.Relatively few studies have investigated rates of return to farming or other heavy labor that is of interest to patients in rural areas.AIM To evaluate the literature regarding RTW in farming or heavy labor after orthopedic hip,knee,or shoulder surgery.METHODS A search was performed in the PubMed and EMBASE databases using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.Studies were included if they reported patients employed in farming or heavy labor,RTW rates after orthopedic surgery of the hip,knee,or shoulder,and had a minimum 6-month follow-up.A meta-analysis of proportions using a random-effects model was performed on three single-arm observational studies to estimate the pooled RTW rate following arthroscopic shoulder surgery.RESULTS Ten studies were included,and 101 farmers were identified among 440 total patients.One study involved hip surgery,two studies involved knee surgery,and seven studies involved shoulder surgery.RTW rates across studies varied by type of surgery and follow-up interval,ranging from 24%to 100%.The RTW rate was only 53.6%at 1 year following total hip arthroplasty.No studies investigated RTW in farmers following total knee arthroplasty.Among non-comparative studies,meta-analysis revealed a pooled RTW rate of 89%following arthroscopic shoulder surgery,with low heterogeneity(I^(2)=30.1%).Among comparative studies,one study reported significantly higher RTW odds for patients undergoing anatomic total shoulder arthroplasty compared to reverse shoulder arthroplasty(odds ratio=5.45).Overall,surgical intervention for shoulder pathology was associated with a high likelihood of RTW across multiple techniques,with particularly favorable outcomes for anatomic total shoulder arthroplasty.CONCLUSION This systematic review highlights the high rates of RTW in farmers and heavy laborers after shoulder surgery.However,our findings also underscore the need for more rural-specific research to guide patient counseling,rehabilitation expectations,and shared decision-making in this underserved population,particularly for orthopedic surgery of the hip and knee.展开更多
In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edg...In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edge of the grounding grid, was observed and analyzed under artificially triggered lightning conditions. Based on circuit theory and measured current data, a π-equivalent circuit was established to simulate the transient response of the grounding grid.Nineteen return strokes from three artificially triggered lightning events were analyzed. The peak currents of the 19 return strokes range from -6.7 to -25.1 kA, and the mean value was -14.3 kA. The GPR decreased rapidly and formed a subpeak after reaching the initial peak, with the mean value of the initial peak being -148.65 kV and the mean value of the subpeak being -92.87 kV. The GPR induced by the triggered lightning currents exhibited a subpeak phenomenon. Simulation results indicate that the subpeak phenomenon is related to localized corrosion of the vertical grounding electrode. The potential difference at the grounding grid edge exhibited a multi-pulse waveform with alternating polarity, dominated by positive pulses. The peak values of both the positive and negative polarity pulses gradually decreased, with the first positive pulse displaying a significantly higher intensity than that of subsequent pulses.展开更多
Some patients with systemic lupus erythematosus experience neuropsychiatric symptoms.Although magnetic resonance imaging can detect abnormal signals in the white matter of the brain,conventional methods often struggle...Some patients with systemic lupus erythematosus experience neuropsychiatric symptoms.Although magnetic resonance imaging can detect abnormal signals in the white matter of the brain,conventional methods often struggle to accurately capture microstructural changes.Various diffusion models have been used to study white matter in systemic lupus erythematosus;however,comparative analyses of their sensitivity and specificity for detecting microstructural changes remain insufficient.To address this,our team designed a diagnostic trial that used multimodal diffusion imaging techniques to observe white matter microstructural changes in patients with systemic lupus erythematosus who had neuropsychiatric symptoms,with an aim to identify key diagnostic biomarkers for these patients.Patients with active lupus who received treatment at the Department of Rheumatology and Immunology,The First Affiliated Hospital of China Medical University,from September 2023 to March 2024 were recruited.According to the standards of the American College of Rheumatology,patients with systemic lupus erythematosus who had neuropsychiatric symptoms were assigned to the systemic lupus erythematosus group,whereas those without neuropsychiatric symptoms were assigned to the non-systemic lupus erythematosus group.Additionally,healthy volunteers matched by region,sex,and age were recruited as controls.All three groups underwent the same diffusion magnetic resonance imaging examination protocol to compare differences in diffusion parameters.Advanced diffusion imaging models were able to sensitively detect microstructural changes in the white matter fibers of patients with systemic lupus erythematosus who had neuropsychiatric symptoms,with specific diffusion parameters showing significant abnormalities in key brain regions.In the left superior longitudinal fasciculus subregion and the right thalamic radiations of patients with systemic lupus erythematosus who had neuropsychiatric symptoms,we also identified abnormal diffusion characteristics that were clearly correlated with disease activity,suggesting that microstructural changes in these areas may reflect the dynamic process of neuroinflammatory damage.The present study addresses critical challenges in the diagnosis of systemic lupus erythematosus by identifying specific white matter imaging biomarkers and elucidating the association between microstructural damage and clinical manifestations.The main contributions of our study include:1)establishing axial regression probability parameters from mean apparent propagator magnetic resonance imaging as sensitive biomarkers for systemic lupus erythematosus,particularly in the third subregion of the left superior longitudinal fasciculus;2)demonstrating that multimodal diffusion imaging may be superior to conventional diffusion tensor imaging for detecting white matter microstructural abnormalities in patients with systemic lupus erythematosus;and 3)integrating tract-based spatial statistics with clinically relevant analyses to link imaging findings to pathological mechanisms.展开更多
BACKGROUND:Prolonged on-scene Advanced Life Support(ALS) in out-of-hospital cardiac arrest(OHCA) patients may enhance return of spontaneous circulation(ROSC),but the optimal duration of cardiopulmonary resuscitation(C...BACKGROUND:Prolonged on-scene Advanced Life Support(ALS) in out-of-hospital cardiac arrest(OHCA) patients may enhance return of spontaneous circulation(ROSC),but the optimal duration of cardiopulmonary resuscitation(CPR) without initial prehospital ROSC remains unclear.We investigated the association between on-scene CPR duration and outcomes using nationwide data.METHODS:This prospective,multi-regional study(2015–2022) included medical cause OHCA patients who underwent Smart ALS(SALS).Data from emergency medical services(EMS) records,SALS logs,and hospital outcomes were analyzed.Logistic regression models were developed for prehospital ROSC,survival to discharge,and good neurological outcome(Cerebral Performance Category [CPC] 1–2).RESULTS:Among 98,569 patients,34,989 were SALS-eligible and 16,052 received SALS.Predictors of ROSC included younger age,male sex,public arrest,witnessed arrest,bystander CPR,shockable rhythm,and shorter response/scene times.Longer on-scene CPR reduced probabilities of ROSC,survival,and neurological recovery at hospital discharge.Model AUROCs were 0.697(95%CI 0.676–0.717) for ROSC,0.836(95%CI 0.810–0.861) for survival,and 0.925(95%CI 0.904–0.946) for neurological outcome.CONCLUSION:On-scene CPR duration is a critical prognostic factor in OHCA.The proposed models highlight on-scene predictors that may inform decisions about CPR continuation and support individualized resuscitation strategies.External validation in other EMS systems is warranted.展开更多
The return capsule of the Shenzhou-20 spaceship,carrying no astronauts,touched down at the Dongfeng landing site in north China’s Inner Mongolia Autonomous Region at 9:34 a.m.(Beijing Time)on January 19,according to ...The return capsule of the Shenzhou-20 spaceship,carrying no astronauts,touched down at the Dongfeng landing site in north China’s Inner Mongolia Autonomous Region at 9:34 a.m.(Beijing Time)on January 19,according to the China Manned Space Agency(CMSA).展开更多
Northeast China as one of important agricultural production bases is an area under reclamation and returning cultivated land to forests or pastures. Therefore, it is of great practical significance in guaranteeing the...Northeast China as one of important agricultural production bases is an area under reclamation and returning cultivated land to forests or pastures. Therefore, it is of great practical significance in guaranteeing the sustainable development and national food security to study the spatial and temporal variation of cultivated land in Northeast China under future climate scenarios. In this study, based on data of land use, natural environment and social-economy, dynamics of land system（DLS） model was used to to simulate the spatial distribution and changing trends of cultivated land in the typical areas of reclamation and returning cultivated land to forest or pastures in Northeast China during 2010-2030 under land use planning scenario and representative concentration pathways（RCPs） scenarios quantitatively.The results showed that the area of cultivated land had an overall decreasing trend under the land use planning scenario, but the area of upland field increased slightly from 2000 to 2010 and then declined greatly, while the area of paddy field continuously declined from 2000 to 2030. Under the Asia-Pacific Integrated model（AIM）scenario, the total area of cultivated land had a tendency to increase considerably,with the upland field expanding more obviously and the paddy field declining slightly.In addition, the cultivated land showed a greater decreasing trend under the model for energy supply strategy alternatives and their general environmental impact（MESSAGE） scenario compared to the land use planning scenario. Moreover, analysis on the conversion between different land use types indicated that the reclamation and returning cultivated land to forests or pastures was likely to continue under future scenarios, but the frequency of occurrence could decrease as the time goes by. The conclusions can provide significant decision-making information for the rational agricultural planning and cultivated land protection in Northeast China to adapt to the climate change.展开更多
By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were ...By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were studied,and soil productivity was tested with yield and agricultural traits of late rice. The results showed that straw returning with the microbial agent could significantly improve the quantity of bacteria,fungi and actinomyces in soil,enhance the activity of sucrase,urease,catalase and cellulase,and improve the number of grains per spike,setting percentage,thousand seed weight and yield of late rice. The combination of rice straw returning and the microbial agent has a good prospect of application.展开更多
The persistence of Cry1 Ac protein in the soil and its effect on soil microbial communities are a core issue in assessing the ecological risk of transgenic Bacillus thuringiensis(Bt) cotton. In this study a field expe...The persistence of Cry1 Ac protein in the soil and its effect on soil microbial communities are a core issue in assessing the ecological risk of transgenic Bacillus thuringiensis(Bt) cotton. In this study a field experiment was conducted on the cultivation of transgenic Bt cotton(Jin 26 and BtJ i 668) with the immediate returning of residues to the fields, in order to quantify the Cry1 Ac protein content in the fields and investigate its effects on the functional diversity of soil microbial communities. Cry1 Ac protein in the residue-soil mixture was gradually degraded in the transgenic Bt cotton fields. After transgenic Bt cotton straw was returned to the fields for 30 d, 63.73%and 58.33% of the initial amounts of Cry1 Ac protein were degraded in the Jin 26 and BtJ i 668 fields, respectively. Before the crops were sown in the following year(180 d after returning the straw), no Cry1 Ac protein was detected in the fields. After returning the cotton straw to the fields for 30 d, the Shannon-Wiener and McIntosh indices of soil microbial communities in the transgenic Bt cotton fields were significantly higher than those in the non-transgenic cotton fields. Meanwhile, the utilization of carbon sources including amino acids, amines, and carbohydrates by the soil microbial communities significantly increased. Both the McIntosh index and the utilization of carbohydrates increased until 180 d. Principal component analysis revealed that amino acids, amides, and carbohydrates were the main carbon sources distinguishing the two principal component factors. These findings indicated that Cry1 Ac protein did not accumulate in the fields after transgenic Bt cotton was planted for one year and the residues were immediately returned to the fields; however, the original functional diversity of soil microbial communities was affected continuously.展开更多
To explore the effects of farming methods,straw returning and their interaction on corn yield and nitrogen utilization,the experiment was conducted for two consecutive years from 2016 to 2017 at the Xiangyang Experime...To explore the effects of farming methods,straw returning and their interaction on corn yield and nitrogen utilization,the experiment was conducted for two consecutive years from 2016 to 2017 at the Xiangyang Experimental Base of Northeast Agricultural University in Heilongjiang Province of China.The method of combining farming with straw returning was used and six treatments as rotary tillage(R)+no straw returning(K),rotary tillage(R)+straw returning(S),tillage(T)+no straw returning(K),tillage(T)+straw returning(S),tillage(T)+subsoiling(D)+no straw returning(K)and tillage(T)+subsoiling(D)+straw returning(S)were set to study the effects of different tillage methods and straw returning on corn yield and nitrogen accumulation and utilization.The corn yield,nitrogen accumulation,nitrogen transport,grain weight and dry matter accumulation of tillage(T)+subsoiling(D)and tillage(T)were significantly higher than those of rotary tillage(R)treatment.Meanwhile,the corn yield,nitrogen accumulation and dry matter accumulation of TD treatment were significantly higher than those of T treatment;the corn yield,dry matter accumulation,kernel weight,nitrogen dry matter production efficiency and nitrogen grain production efficiency of S treatment were significantly higher than those of K treatment.Among the treatments,the yield,nitrogen accumulation and utilization efficiency of TDS,TS and TDK were the highest.The yield,nitrogen accumulation and nitrogen transport of TDS were significantly higher than those of TS.In 2016,TDS production increased by 7.30%and 8.20%compared with TS;and TDS nitrogen accumulation increased by 6.78%and 9.50%compared with TS,while the yield and nitrogen grain production efficiency were significantly higher than those of TDK.Therefore,under the conditions of this experiment,on the basis of straw returning,tillage+subsoiling was the suitable farming method.展开更多
China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragil...China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragility and risk susceptibility have increased the risk of returning to ecological poverty.In this paper,the Liupan Mountain Region of China was used as a case study,and the counties were used as the scale to reveal the spatiotempora differentiation and influcing factors of the risk of returning to poverty in study area.The indicator data for returning to ecological poverty from 2011-2020 were collected and summarized in three dimensions:ecological,economic and social.The autoregressive integrated moving average model(ARIMA)time series and exponential smoothing method(ES)were used to predict the multidimensional indicators of returning to ecological poverty for 61 counties(districts)in the Liupan Mountain Region for 2021-2030.The back propagation neural network(BPNN)and geographic information system(GIS)were used to generate the spatial distribution and time variation for the index of the risk of returning to ecological poverty(RREP index).The results show that 1)ecological factors were the main factors in the risk of returning to ecological poverty in Liupan Mountain Region.2)The RREP index for the 61 counties(districts)exhibited a downward trend from 2021-2030.The RREP index declined more in medium-and high-risk areas than in low-risk areas.From 2021 to 2025,the RREP index exhibited a slight downward trend.From 2026 to2030,the RREP index was expected to decline faster,especially from 2029-2030.3)Based on the RREP index,it can be roughly divided into three types,namely,the high-risk areas,the medium-risk areas,and the low-risk areas.The natural resource conditions in lowrisk areas of returning to ecological poverty,were better than those in medium-and high-risk areas.展开更多
The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw retur...The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.展开更多
In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test ...In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.展开更多
文摘Comparative analyses were conducted on the nutrient element content and returning amount of main fractional compositions of litter in Korean pine (KP), Mongolian Scots pine(MSP) and Dahurian larch (DL) plantations in Laoshan Plantation Experiment Station of Maoershan Experiment Forest Farm of Northeast Forestry University. The results are as follows: (1) The nutrient element content and returning amount in litter varies among different fractional compositions and tree species, the total returning amount of all nutrient elements and the returning amount of K, Ca, Mg, N and P are DL>MSP>KP, the returning amount of Cu is DL>KP>MSP, the returning amount of Fe and Mn are MSP>DL>KP, (2) To KP and DL plantations, the main nutrient element returned is dead needles; dead branches, bark scales and dead cones account for a little proportion; whereas to MSP plantation, besides dead needles,dead branches and bark scales also play an important role in the return of nutrient elements; (3)A little deal of dead leaves can provided a great deal of returning amount of nutrient elements.
基金financial support of the Science and Technology Program in Gansu province(25JRRA347,24ZDNA008)the Natural Science Foundation of China(32372238,U21A20218,32460547)+4 种基金the Industrial Support Project of Educational Committee of Gansu province(2025CYZC-037)the Research Program Sponsored by State Key Laboratory of Aridland Crop Science(GSCS-2023-Z03)the Agricultural Research System of China(CARS-22-G-12)China Agricultural University Corresponding Support Research Joint Fund(GSAU-DKZY-2024-001)the UPTAKE Project on EU Horizon(101081521).
文摘Improving crop yield and N utilization while mitigating environmental pollution is a key goal in sustainable agriculture.Integrating green manure with reduced chemical N application is a promising strategy to enhance N utilization efficiency and minimize reactive N losses.However,the agronomic mechanisms through which green manure incorporation affects soil N retention and N loss under reduced N application remain unclear.This study aimed to uncover the compensatory mechanisms of green manure in improving wheat yield and N utilization under reduced N application,and to identify the principles behind reduced N loss in wheat fields.We conducted a split-plot experiment in the Hexi Oasis irrigation area of Northwest China from 2019 to 2024,using two cropping systems(W,fallow after wheat;W-G,green manure returning after wheat)combined with three N application levels(N1,local conventional N application rate;N2,N-reduction 15%;N3,N-reduction 30%).Our results demonstrated that green manure returning improved soil quality and compensated for the yield and N use efficiency losses caused by 15%chemical N reduction.Specifically,compared to the W-N1,W-GN2 increased soil organic matter content and soil water content by 6.5%and 9.4%,respectively,while reducing soil bulk density and pH by 8.9%and 6.7%.Meanwhile,W-GN2 increased soil nitrate N and total N content in the 0–40 cm soil layer by 8.4%and 8.7%,respectively.Moreover,W-GN2 reduced NH3 volatilization by 13.8%,N_(2)O emissions by 8.8%,and N leaching by 9.4%.It also enhanced microbial biomass N by 50.7%,urease activity by 10.2%,and decreased nitrate and nitrite reductase activities by 19.9%and 32.6%,respectively.Additionally,W-GN2 improved soil bacterialα-diversity and increased the abundance of functional bacteria.Green manure can sustain wheat yield and improve N utilization efficiency under reduced chemical N input by improving the soil environment,enhancing soil N retention and minimizing N losses,which presents a sustainable,yield-stabilizing strategy for Oasis agroecosystems in northwestern China.
基金Supported by National Natural Science Foundation of China(31371562,31301276)Special Fund for Fundamental Scientific Research Business of Central Public Research Institutes(Agriculture)(201103003+2 种基金201203079)Key Projects in the National Science&Technology Pillar Program during the 12thFive-year Plan Period(2012BAD04B08)Fund for Independent Innovation of Agricultural Sciences in Jiangsu Province(CX(14)5021)~~
文摘[Objective] This study aimed to investigate the effect of direct-seeding with non-flooding and wheat residue returning patterns on greenhouse gas emission from rice paddy. [Method] Two rice cultivars currently used in the production, Yangdao 6 （an indica） and Yangjing 4038 （a japonica）, were field grown using a direct-seeding method, and four treatments, wheat straw incorporation into soil and traditional flooding （SlF）, non-flooding and wheat straw mulching （NSM）, non-flooding and wheat straw incorporation into soil （NSl） and traditional flooding （no straw returned, Control, TF）, were imposed after sowing to maturity. Effects of direct-seeding with non-flooding and wheat residue returning patterns on CH4, N20 and CO2 emissions were investigated by using the method of static chamber-gas chromatographic tech- niques. [Result] Grain yield showed no significant difference between non-flooding and flooding treatments, but was significantly higher under the SlF than under any other treatments. The emission flux of CH4 and CO2 under TF and SlF exhibited a single peak curve, while changed little under the NSl and NSM The emission flux of N2Oshowed multiple perk curves for all the treatments. Compared with TF, SlF significantly increased mean emission flux of CH4 or N2O, decreased emission of N20, while NSl and NSM significantly decreased the mean emission flux of OH4, and increased emission flux of N2O and CO2. SIF also increased Green Warm Potential （GWP） of CH4, N2O and CO2 and the GWP per unit grain yield by 47.3%- 53.7% and 32.2%-39.4%, respectively. Both NSl and NSM decreased GWP by 24.2%-29.6% and 30.1%-35.5%, and the GWP per unit grain yield was decreased by 21.7-27.2% and 25.6%-31.1%, respectively. [Conelusion] both NSl and NSM could significantly reduce greenhouse effect of CH4, N2O and CO2 meanwhile maintain a high grain yield.
文摘In order to study the effect of rice straw returning and seeding patterns on seedling emergence and grain yield, field experiment was conducted to investi- gate the effects of straw mechanized returning and different seeding patterns on e- mergence rate, emergence uniformity and yield traits of wheat after rice. The results were as follows： in rice straw removal treatments, the emergence rate of mechani- cal seeding in drill was lower than that of mechanical uniform planting and manual broadcast sowing, which were 51.84%, 90.89% and 88.87%, respectively; the emer- gence uniformity of manual broadcast sowing was inferior to mechanical seeding in drill and mechanical uniform planting, which were 0.49, 0.26 and 0.23, respectively. As for the treatments with rice straw returning to the field, the emergence rate and emergence uniformity all decreased in the three seeding patterns, of which mechan- ical seeding in drill dropped markedly with emergence rate decreased by 36.54%. The emergence rate and emergence uniformity affected grain yield by affecting pan- icle, grains per spike and 1 000-grain weight. The grain yield for the treatment with rice straw removal was 6 091.34 kg/hm2, while that with rice straw returning to field was 6 476.20 kg/hm2, and both were higher than the yields of the other two seed- ing patterns. Therefore, mechanical uniform planting was？recommended for its higher emergence rate, better emergence uniformity, which was conductive to increase grain yield in wheat after rice production with rice straw returning to field.
基金Supported by National Water Pollution Control and Management Technology MajorProject(2013ZX07103006)Anhui Land Resource Technological Project(2012-K-18)~~
文摘In the research, effects of straw returning to fields on soil temperature, water, volume-weight, porosity, trace elements, and organic matters were reviewed and countermeasures were proposed to promote straw returning on basis of straw resources and present status in Anhui Province.
文摘Based on advances in returning rice and wheat straw to fields at home and abroad, environmental physical, chemical and ecological effects of returning rice and wheat straw to fields were analyzed. The results show that returning straw to fields can enhance soil porosity, reduce soil bulk density, and increase the ca- pacity of soil to preserve water, fertilizer and temperature. Besides, it can improve the content of organic matter, nitrogen, phosphorus and potassium in soil, of which the increase of potassium content is the most obvious. Meanwhile, it can provide energy and nutrients for microorganisms in soil and change the activity of soil enzymes, of which it affects invertase most greatly and enhances the activity of ure- ase but has no effect on neutral phosphatase. In addition, it can enhance the total quantity of microorganisms in soil obviously, and the increase correlates positively with the quantity of straw returning to fields. Finally, returning straw to fields can promote the sustainable development of agriculture.
基金Supported by Agricultural Science and Technology Stride Plan(2009-16)Natural Science Fund in Hainan(808202)Scienceand Technology Project from Chinese Academy of Tropical Agricultural Sciences(Rky09)~~
文摘Soil structure and nutrient ingredient before and after shattering and returning sugarcane leaf as well as its technologies and methods were comparatively analyzed in this study to discuss the main reasons primarily,while the controlling technologies were proposed by combining cultivation,management and technical measures.
文摘The Double Take column looks at a single topic from an African and Chinese perspective.This month,we discuss how to understand the growing emphasis on emotional returns among young people.Emotional value has emerged as a central force shaping youth decision-making across work,consumption,relationships and lifestyle choices.Unlike traditional economic rationality that prioritises income and material security,emotional value focuses on how choices make individuals feel and how they align with personal meaning.This shift is particularly evident in rapidly transforming societies such as China and Ghana,where economic restructuring,globalisation and social change have reshaped pathways to adulthood.
文摘BACKGROUND There has been an increasing focus in recent years on health-care disparities.Studies investigating return to work(RTW)or sports are often performed in large,urban areas.Relatively few studies have investigated rates of return to farming or other heavy labor that is of interest to patients in rural areas.AIM To evaluate the literature regarding RTW in farming or heavy labor after orthopedic hip,knee,or shoulder surgery.METHODS A search was performed in the PubMed and EMBASE databases using Preferred Reporting Items for Systematic reviews and Meta-Analyses guidelines.Studies were included if they reported patients employed in farming or heavy labor,RTW rates after orthopedic surgery of the hip,knee,or shoulder,and had a minimum 6-month follow-up.A meta-analysis of proportions using a random-effects model was performed on three single-arm observational studies to estimate the pooled RTW rate following arthroscopic shoulder surgery.RESULTS Ten studies were included,and 101 farmers were identified among 440 total patients.One study involved hip surgery,two studies involved knee surgery,and seven studies involved shoulder surgery.RTW rates across studies varied by type of surgery and follow-up interval,ranging from 24%to 100%.The RTW rate was only 53.6%at 1 year following total hip arthroplasty.No studies investigated RTW in farmers following total knee arthroplasty.Among non-comparative studies,meta-analysis revealed a pooled RTW rate of 89%following arthroscopic shoulder surgery,with low heterogeneity(I^(2)=30.1%).Among comparative studies,one study reported significantly higher RTW odds for patients undergoing anatomic total shoulder arthroplasty compared to reverse shoulder arthroplasty(odds ratio=5.45).Overall,surgical intervention for shoulder pathology was associated with a high likelihood of RTW across multiple techniques,with particularly favorable outcomes for anatomic total shoulder arthroplasty.CONCLUSION This systematic review highlights the high rates of RTW in farmers and heavy laborers after shoulder surgery.However,our findings also underscore the need for more rural-specific research to guide patient counseling,rehabilitation expectations,and shared decision-making in this underserved population,particularly for orthopedic surgery of the hip and knee.
基金National Natural Science Foundation of China(42575091)Marine Meteorological Science and Data Center Program (2024B1212070014)。
文摘In this study, the ground potential rise(GPR) phenomenon caused by a lightning current injected into a field-shaped artificial grounding grid, as well as the potential difference between two different nodes at the edge of the grounding grid, was observed and analyzed under artificially triggered lightning conditions. Based on circuit theory and measured current data, a π-equivalent circuit was established to simulate the transient response of the grounding grid.Nineteen return strokes from three artificially triggered lightning events were analyzed. The peak currents of the 19 return strokes range from -6.7 to -25.1 kA, and the mean value was -14.3 kA. The GPR decreased rapidly and formed a subpeak after reaching the initial peak, with the mean value of the initial peak being -148.65 kV and the mean value of the subpeak being -92.87 kV. The GPR induced by the triggered lightning currents exhibited a subpeak phenomenon. Simulation results indicate that the subpeak phenomenon is related to localized corrosion of the vertical grounding electrode. The potential difference at the grounding grid edge exhibited a multi-pulse waveform with alternating polarity, dominated by positive pulses. The peak values of both the positive and negative polarity pulses gradually decreased, with the first positive pulse displaying a significantly higher intensity than that of subsequent pulses.
基金supported by the National Natural Science Foundation Joint Fund,No.U22A20309(to PY)the Natural Science Foundation of LiaoningProvince,No.2023-MS-07(to HuL)the Unveiling Key Scientific and Technological Projects of Liaoning Province,No.2021JH1/10400051(to HuL).
文摘Some patients with systemic lupus erythematosus experience neuropsychiatric symptoms.Although magnetic resonance imaging can detect abnormal signals in the white matter of the brain,conventional methods often struggle to accurately capture microstructural changes.Various diffusion models have been used to study white matter in systemic lupus erythematosus;however,comparative analyses of their sensitivity and specificity for detecting microstructural changes remain insufficient.To address this,our team designed a diagnostic trial that used multimodal diffusion imaging techniques to observe white matter microstructural changes in patients with systemic lupus erythematosus who had neuropsychiatric symptoms,with an aim to identify key diagnostic biomarkers for these patients.Patients with active lupus who received treatment at the Department of Rheumatology and Immunology,The First Affiliated Hospital of China Medical University,from September 2023 to March 2024 were recruited.According to the standards of the American College of Rheumatology,patients with systemic lupus erythematosus who had neuropsychiatric symptoms were assigned to the systemic lupus erythematosus group,whereas those without neuropsychiatric symptoms were assigned to the non-systemic lupus erythematosus group.Additionally,healthy volunteers matched by region,sex,and age were recruited as controls.All three groups underwent the same diffusion magnetic resonance imaging examination protocol to compare differences in diffusion parameters.Advanced diffusion imaging models were able to sensitively detect microstructural changes in the white matter fibers of patients with systemic lupus erythematosus who had neuropsychiatric symptoms,with specific diffusion parameters showing significant abnormalities in key brain regions.In the left superior longitudinal fasciculus subregion and the right thalamic radiations of patients with systemic lupus erythematosus who had neuropsychiatric symptoms,we also identified abnormal diffusion characteristics that were clearly correlated with disease activity,suggesting that microstructural changes in these areas may reflect the dynamic process of neuroinflammatory damage.The present study addresses critical challenges in the diagnosis of systemic lupus erythematosus by identifying specific white matter imaging biomarkers and elucidating the association between microstructural damage and clinical manifestations.The main contributions of our study include:1)establishing axial regression probability parameters from mean apparent propagator magnetic resonance imaging as sensitive biomarkers for systemic lupus erythematosus,particularly in the third subregion of the left superior longitudinal fasciculus;2)demonstrating that multimodal diffusion imaging may be superior to conventional diffusion tensor imaging for detecting white matter microstructural abnormalities in patients with systemic lupus erythematosus;and 3)integrating tract-based spatial statistics with clinically relevant analyses to link imaging findings to pathological mechanisms.
基金supported by Soonchunhyang University research fund。
文摘BACKGROUND:Prolonged on-scene Advanced Life Support(ALS) in out-of-hospital cardiac arrest(OHCA) patients may enhance return of spontaneous circulation(ROSC),but the optimal duration of cardiopulmonary resuscitation(CPR) without initial prehospital ROSC remains unclear.We investigated the association between on-scene CPR duration and outcomes using nationwide data.METHODS:This prospective,multi-regional study(2015–2022) included medical cause OHCA patients who underwent Smart ALS(SALS).Data from emergency medical services(EMS) records,SALS logs,and hospital outcomes were analyzed.Logistic regression models were developed for prehospital ROSC,survival to discharge,and good neurological outcome(Cerebral Performance Category [CPC] 1–2).RESULTS:Among 98,569 patients,34,989 were SALS-eligible and 16,052 received SALS.Predictors of ROSC included younger age,male sex,public arrest,witnessed arrest,bystander CPR,shockable rhythm,and shorter response/scene times.Longer on-scene CPR reduced probabilities of ROSC,survival,and neurological recovery at hospital discharge.Model AUROCs were 0.697(95%CI 0.676–0.717) for ROSC,0.836(95%CI 0.810–0.861) for survival,and 0.925(95%CI 0.904–0.946) for neurological outcome.CONCLUSION:On-scene CPR duration is a critical prognostic factor in OHCA.The proposed models highlight on-scene predictors that may inform decisions about CPR continuation and support individualized resuscitation strategies.External validation in other EMS systems is warranted.
文摘The return capsule of the Shenzhou-20 spaceship,carrying no astronauts,touched down at the Dongfeng landing site in north China’s Inner Mongolia Autonomous Region at 9:34 a.m.(Beijing Time)on January 19,according to the China Manned Space Agency(CMSA).
基金Supported by the Major Research Project of National Natural Science Foundation Committee(91325302)China Postdoctoral Foundation(2014M560110)Hebei Social Science Foundation(HB15GL087)~~
文摘Northeast China as one of important agricultural production bases is an area under reclamation and returning cultivated land to forests or pastures. Therefore, it is of great practical significance in guaranteeing the sustainable development and national food security to study the spatial and temporal variation of cultivated land in Northeast China under future climate scenarios. In this study, based on data of land use, natural environment and social-economy, dynamics of land system（DLS） model was used to to simulate the spatial distribution and changing trends of cultivated land in the typical areas of reclamation and returning cultivated land to forest or pastures in Northeast China during 2010-2030 under land use planning scenario and representative concentration pathways（RCPs） scenarios quantitatively.The results showed that the area of cultivated land had an overall decreasing trend under the land use planning scenario, but the area of upland field increased slightly from 2000 to 2010 and then declined greatly, while the area of paddy field continuously declined from 2000 to 2030. Under the Asia-Pacific Integrated model（AIM）scenario, the total area of cultivated land had a tendency to increase considerably,with the upland field expanding more obviously and the paddy field declining slightly.In addition, the cultivated land showed a greater decreasing trend under the model for energy supply strategy alternatives and their general environmental impact（MESSAGE） scenario compared to the land use planning scenario. Moreover, analysis on the conversion between different land use types indicated that the reclamation and returning cultivated land to forests or pastures was likely to continue under future scenarios, but the frequency of occurrence could decrease as the time goes by. The conclusions can provide significant decision-making information for the rational agricultural planning and cultivated land protection in Northeast China to adapt to the climate change.
基金Supported by National Key Research and Development Program of China(2017YFD0200808)National Key Technology R&D Program in the 11th Five-Year Plan of China(2006BAD02A04)+1 种基金Innovation Foundation for Postgraduates in Jiangxi Province(YC10A056)Free Declaration Project of Jiangxi Agricultural University
文摘By using red soil and late rice Wufengyou T025 as the tested materials,the influences of straw returning with a microbial agent on the quantity of microorganisms and enzyme activity in rhizosphere soil in fields were studied,and soil productivity was tested with yield and agricultural traits of late rice. The results showed that straw returning with the microbial agent could significantly improve the quantity of bacteria,fungi and actinomyces in soil,enhance the activity of sucrase,urease,catalase and cellulase,and improve the number of grains per spike,setting percentage,thousand seed weight and yield of late rice. The combination of rice straw returning and the microbial agent has a good prospect of application.
基金supported by the Shanxi Provincial Natural Science Foundation of China (No. 2012011030-2)181 Cultivate Foundation of National Natural Science from Shanxi Agricultural University (No. 2017GPY07)
文摘The persistence of Cry1 Ac protein in the soil and its effect on soil microbial communities are a core issue in assessing the ecological risk of transgenic Bacillus thuringiensis(Bt) cotton. In this study a field experiment was conducted on the cultivation of transgenic Bt cotton(Jin 26 and BtJ i 668) with the immediate returning of residues to the fields, in order to quantify the Cry1 Ac protein content in the fields and investigate its effects on the functional diversity of soil microbial communities. Cry1 Ac protein in the residue-soil mixture was gradually degraded in the transgenic Bt cotton fields. After transgenic Bt cotton straw was returned to the fields for 30 d, 63.73%and 58.33% of the initial amounts of Cry1 Ac protein were degraded in the Jin 26 and BtJ i 668 fields, respectively. Before the crops were sown in the following year(180 d after returning the straw), no Cry1 Ac protein was detected in the fields. After returning the cotton straw to the fields for 30 d, the Shannon-Wiener and McIntosh indices of soil microbial communities in the transgenic Bt cotton fields were significantly higher than those in the non-transgenic cotton fields. Meanwhile, the utilization of carbon sources including amino acids, amines, and carbohydrates by the soil microbial communities significantly increased. Both the McIntosh index and the utilization of carbohydrates increased until 180 d. Principal component analysis revealed that amino acids, amides, and carbohydrates were the main carbon sources distinguishing the two principal component factors. These findings indicated that Cry1 Ac protein did not accumulate in the fields after transgenic Bt cotton was planted for one year and the residues were immediately returned to the fields; however, the original functional diversity of soil microbial communities was affected continuously.
基金Supported by the Special Fund for Agro-scientific Research in Public Interest in China(201503119-06-01)。
文摘To explore the effects of farming methods,straw returning and their interaction on corn yield and nitrogen utilization,the experiment was conducted for two consecutive years from 2016 to 2017 at the Xiangyang Experimental Base of Northeast Agricultural University in Heilongjiang Province of China.The method of combining farming with straw returning was used and six treatments as rotary tillage(R)+no straw returning(K),rotary tillage(R)+straw returning(S),tillage(T)+no straw returning(K),tillage(T)+straw returning(S),tillage(T)+subsoiling(D)+no straw returning(K)and tillage(T)+subsoiling(D)+straw returning(S)were set to study the effects of different tillage methods and straw returning on corn yield and nitrogen accumulation and utilization.The corn yield,nitrogen accumulation,nitrogen transport,grain weight and dry matter accumulation of tillage(T)+subsoiling(D)and tillage(T)were significantly higher than those of rotary tillage(R)treatment.Meanwhile,the corn yield,nitrogen accumulation and dry matter accumulation of TD treatment were significantly higher than those of T treatment;the corn yield,dry matter accumulation,kernel weight,nitrogen dry matter production efficiency and nitrogen grain production efficiency of S treatment were significantly higher than those of K treatment.Among the treatments,the yield,nitrogen accumulation and utilization efficiency of TDS,TS and TDK were the highest.The yield,nitrogen accumulation and nitrogen transport of TDS were significantly higher than those of TS.In 2016,TDS production increased by 7.30%and 8.20%compared with TS;and TDS nitrogen accumulation increased by 6.78%and 9.50%compared with TS,while the yield and nitrogen grain production efficiency were significantly higher than those of TDK.Therefore,under the conditions of this experiment,on the basis of straw returning,tillage+subsoiling was the suitable farming method.
基金Under the auspices of National Natural Science Foundation of China(No.42071230)。
文摘China has resolved its overall regional poverty in 2020 by attaining moderate societal prosperity.The country has entered a new development stage designed to achieve its second centenary goal.However,ecological fragility and risk susceptibility have increased the risk of returning to ecological poverty.In this paper,the Liupan Mountain Region of China was used as a case study,and the counties were used as the scale to reveal the spatiotempora differentiation and influcing factors of the risk of returning to poverty in study area.The indicator data for returning to ecological poverty from 2011-2020 were collected and summarized in three dimensions:ecological,economic and social.The autoregressive integrated moving average model(ARIMA)time series and exponential smoothing method(ES)were used to predict the multidimensional indicators of returning to ecological poverty for 61 counties(districts)in the Liupan Mountain Region for 2021-2030.The back propagation neural network(BPNN)and geographic information system(GIS)were used to generate the spatial distribution and time variation for the index of the risk of returning to ecological poverty(RREP index).The results show that 1)ecological factors were the main factors in the risk of returning to ecological poverty in Liupan Mountain Region.2)The RREP index for the 61 counties(districts)exhibited a downward trend from 2021-2030.The RREP index declined more in medium-and high-risk areas than in low-risk areas.From 2021 to 2025,the RREP index exhibited a slight downward trend.From 2026 to2030,the RREP index was expected to decline faster,especially from 2029-2030.3)Based on the RREP index,it can be roughly divided into three types,namely,the high-risk areas,the medium-risk areas,and the low-risk areas.The natural resource conditions in lowrisk areas of returning to ecological poverty,were better than those in medium-and high-risk areas.
基金Supported by the National Key Research and Development Plan Project(2016YFD0300909-04)。
文摘The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.
基金Supported by 2009 Youth Project of Social Science Planning in Guizhou Province (09GHQNHQ04)Agricultural Scientific and Technological Project in Guizhou Province (20103014)
文摘In this paper, we take Guizhou Province (the heart of southwestern Karst region in China) as the research object. By establishing gray forecasting model and time series forecasting model, we conduct the accuracy test on the actual production capacity of land and the forecasted production capacity of land in 2007 and 2008, and then conduct comprehensive forecast of the land production potential in Guizhou Province in 2020. On this basis, considering the nutritional standards needed by three kinds of life type (dressing warmly and eating one's fill, well-off life, relatively affluent life), we evaluate the land production potential in Guizhou Province under the project of returning farmland to forest. Based on the evaluation results, we put forth the relevant recommendations for achieving sustainable land use in the context of returning farmland to forest in Guizhou Province.
