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- Abstract：The aims of this study were to understand the evolution of grain production pattern and the matching of grain and land under the current production pattern in China. Based on the grain production data of 31 provinces(The data do not include those of Hong Kong, Macao and Taiwan regions. The same below)across the country from 2003 to 2019, this study analyzed the evolution trend of the spatial pattern of grain production and the degree of resource matching by adopting GIS geographic information system, Gini coefficient and imbalance index from the perspective of land resource allocation. The results showed that: Rice and corn planting gradually shifted to the northeast, and wheat planting gradually shifted to the northwest; The main production areas such as Heilongjiang Province and Inner Mongolia did not make full use of land resources, resulting in lower than average land production efficiency, while the development speed of grain production in Henan Province and Hebei Province exceeded the rapid development of land resources, causing huge pressure on grain farmland. From the perspective of development trends, factors such as human-land conflicts and policy influences will further increase the pressure on land resources and pose greater challenges to the matching of food production and land resources. Coordination is required to avoid extensive development and management and alleviate the pressure on high land resources in production areas. Under the pressure of production, enrich the planting structure and realize the matching of grain production and land resources.Keywords：food production;land resources;grain-land matching;Gini coefficient6|12|6<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the causes of spatial mismatch between grain production and water resources in China, a measurement index system was constructed to comprehensively evaluate the carrying capacity of water resources in each region and measure the degree of spatial mismatch between grain production and water resources in the evaluation area of agricultural water pressure. Additionally, from the perspective of comparative advantage theory, a panel data was used to conduct empirical tests and explore the possible causes of the spatial mismatch between grain production and water resources. The results show that: 1)According to the calculation results, the spatial distribution of grain production between water resources in 31 provinces of China from 2003 to 2018 is mismatched, and the spatial distribution mismatch between grain production and water resources in north East China, Huang-Huai-Hai region, South China and Northwest China is more serious. 2)According to the regression results of the benchmark model, the positive effect of land advantage, labor advantage and capital advantage on regional agricultural water pressure exceeds the negative effect of water resource advantage on regional agricultural water pressure, which makes the comprehensive comparative advantage of grain production increase the regional agricultural water pressure. Under the similar market and policy environment, the internal cause of the spatial distribution mismatch between grain production and water resources is the result of the above accumulative effects. Quantile regression is adopted to test the results. It is found that the intensification effect of grain production comparative advantage on agricultural water pressure is not obvious in the regions with the maximum or minimum agricultural water pressure, but is significant in the other sub-loci. 3)According to the results of the moderating effect model, agricultural water efficiency has a negative moderating effect on the impact of comparative advantage of grain production on agricultural water pressure. Sample regression shows that agricultural water efficiency has a greater regulating effect in areas with higher agricultural water pressure, indicating that higher agricultural water efficiency can effectively mitigate the impact of regional comparative advantage of grain production on the spatial distribution mismatch between grain production and water resources, and the mitigating effect is more obvious in areas with higher agricultural water pressure. Therefore, based on the research results, this study puts forward three suggestions, e. g. optimizing the spatial distribution mismatch degree of grain production and water resources, increasing the constraint weight of water resources factors in grain production layout, and improving water efficiency of grain production by region, to ensure grain security and sustainable use of water resources.Keywords：grain production;comparative advantage theory;agricultural water pressure;agricultural water efficiency;water resources carrying capacity10|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analysis the impact of storage losses on households' storage decision, based on the survey of 1 199 households from 23 provinces in China, this study introduced storage losses into the household storage decision model, and used the quantile regression method to analysis the effect on storage loss on households' storage. In order to overcome the potential endogeneity problems, this study selected the average annual rainfall of the household's location and whether bad weather appeared in the grain drying stage as the instrumental variables of storage loss analysis. The results showed that: First, the household storage was significantly affected by the storage losses. Second, the absolute value of the coefficient of storage loss showed a downward trend, indicating that the storage decision of small and medium-scale farmers was greatly affected by storage loss. Third, yield, market price, the development of market and household income also significantly related to household storage. Thus, the government should pay more attention to the storage loss, and promote farmers to reduce the loss by promoting advanced grain storage technologies and methods.Keywords：household storage;storage losses;household storage model;instrumental variables2|10|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：DNA detection and quantitative analysis can be used as the basis for many research. Therefore, the separation and purification of DNA is a fundamental operation in molecular biology and clinical medicine. With the continuous development of nanotechnology, solid-phase DNA extraction using magnetic nanoparticles has become a popular research direction for DNA separation and purification. In order to understand the application of magnetic nanoparticles, the research progress of magnetic nanomaterials with iron oxides as the core from 1997 to 2021 is presented by using literature review and generalization. The effects of modification of material structure and active functional groups of the surface on the extraction efficiency of DNA were also compared. The results show that: 1)The solid phase extraction using magnetic nanoparticles has various advantages such as safe and non-toxic, simple operation, reusable, capable of automation and high throughput operation. The extraction efficiency of DNA is higher compared with commercial kits. 2)Magnetic nanomaterials have been relatively comprehensively studied. The size of magnetic nanoparticles, pore size, magnetization strength and the introduced active functional groups all have impact on the extraction efficiency of DNA. Changing these factors to develop new and efficient functionalized magnetic nanoparticles, or changing the experimental conditions such as the preparation method of magnetic nanomaterials, morphological properties of the extracted DNA and pH or salinity to improve the desorption rate of DNA from the material, can continuously optimize the magnetic separation process and improve the efficiency and quality of DNA separation. 3)Besides, commercial nucleic acid extraction procedures based on the excellent adsorption capacity for nucleic acids of magnetic nanoparticles is promising for magnetic solid-phase extraction. 4)In addition to the application in nucleic acid extraction, extensive research has also been conducted in other biomedical applications of magnetic nanoparticles. All these results indicate that magnetic nanomaterials have an extremely promising prospect of research development.Keywords：magnetic solid-phase extraction;magnetic nanoparticles;active functional group modification;DNA separation;biomedicine3|11|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to identify the core promotor region of Forkhead box transcription factor 1(FoxO1)and its key transcription factors, the promoter sequence of bovine FoxO1 gene was amplified by PCR. At the same time, seven segment by segment deletion fragment primers were designed to amplify the segment. Furthermore, a dual luciferase reporter vector was constructed to transfect C2C12 and 3T3-L1 cells, respectively. The core region of the bovine FoxO1 promoter was determined by detecting the activity of luciferase reporter vectors of different deletion fragments. Additionally, Genomatix and JASPAR online software were used to predict key transcription factors in the core region of the bovine FoxO1 promoter. The transcriptional regulation of FoxO1 by the predicted key transcription factors was preliminarily identified in mouse C2C12 cell line by site directed mutation test. The results showed that: 1)The 1 920 bp sequence of bovine FoxO1 promoter and seven truncated promoter sequences were successfully amplified. 2)Dual-Luciferase assay further confirmed that the core promoter was located in the -285/-27 region. 3)MEF2A, KLF4, HOXA5 and KLF5 transcription factors were predicted and identified by site-directed mutation as key regulatory factors of FoxO1 gene transcriptional activity. In summary, the study preliminarily identified that the transcription factors MEF2A, KLF4, HOXA5 and KLF5 in the core region -285/-27 of bovine FoxO1 gene promoter have important transcriptional regulation effects on FoxO1 gene, which laid a theoretical foundation for the transcriptional regulation mechanism of FoxO1 gene in the process of muscle and fat production in bovine.Keywords：bovine;FoxO;1;gene;promoter activity;transcriptional regulation;transcription factors4|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To screen the single chain antibody of gP48 protein of bovine viral diarrhea mucosal disease virus(Bovine virtual diarrhea virus, BVDV), a single chain antibody clone library of gP48 protein was constructed by phage display technology. The antibody library was enriched and screened for three rounds by microporous screening method. In order to obtain gP48 protein single chain antibody to protein. The affinity of single chain antibody was determined by ELISA technology, and the clones with high affinity were sequenced and analyzed for binding activity. The results show that: 1)The library capacity was 4. 3×107, and the recombination rate of phage scFv library was 83. 3%. After three rounds of screening, the phage antibody library was enriched, and the enrichment multiple was 1. 43×104; 2)The indirect ELISA method was optimized, and three scFvs with high affinity for BVDV gp48 protein and their gene sequences were screened. IgBLAST analysis showed that the three scFvs were mouse IgG. In conclusion, a total of three scFvs with high affinity were identified from the scFv Library of gP48 protein, which can be used for the establishment of subsequent BVDV detection methods.Keywords：bovine viral diarrhea virus;gP48 protein;phage antibody library;single-chain antibody;affinity screening3|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the effects of different animal models on the estimation of genetic parameters of growth traits of one-year-old growth traits of Angus cattle in Ningxia, and to identify the best animal model for estimating genetic parameters of growth traits, six animal models were distinguished by the inclusion or exclusion of maternal genetic effects, maternal permanent environmental effects and the presence or absence of covariance between maternal and direct genetic effects in the study. The constrained maximum likelihood method(AI-REML)with the help of the DMU_AI module of DMU software was used to estimate genetic parameters for the one-year-old growth traits of Angus cattle. The Akaike information criterion(AIC)and likelihood ratio test(LRT)were used to determine the best animal model for each growth trait. The results showed that: 1)For the model without maternal effects(model 1), the direct heritability of body weight, body height, body length and chest circumference were 0. 59±0. 02, 0. 52±0. 03, 0. 20±0. 04, and 0. 52±0. 03, respectively; 2)For the model of considering maternal additive heritability effects and covariance with direct additive heritability effects(model 4), the values of direct heritability and maternal effects heritability increased, and the total heritability decreased; 3)The direct heritability of body weight, body height, body length and chest circumference estimated by model 4 were 0. 77±0. 01, 0. 73±0. 03, 0. 33±0. 04 and 0. 70±0. 03, respectively, and the maternal effects heritabilitis was 0. 50±0. 05, 0. 51±0. 05, 0. 10±0. 04 and 0. 23±0. 04, respectively, and the total heritabilitis was 0. 16±0. 06, 0. 12±0. 05, 0. 11±0. 01 and 0. 32±0. 01. In conclusion, it was found that model 4 was the best for estimating genetic parameters for growth traits of one-year-old growth traits of Angus cattle, which can provide the theoretical basis for the breeding and improvement of Angus core group in Ningxia.Keywords：Angus cattle;growth traits;animal models;genetic parameters;maternal effects4|8|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To analyze the molecular mechanism of skeletal muscle response to acute cold stress in domestic pigs, the cold stress model of Min pigs and RNA-seq sequencing technology were used to analyze the expression changes, functional annotations, and regulatory relationships of genes and lncRNAs in the longissimus dorsi muscle of Min pigs after acute cold stress. The results showed that: 1)After three days of severe cold stress(-17 ℃ - 26 ℃), the expressions of 53 genes of longissimus dorsi muscle were significantly up-regulated, the expressions of 35 genes were significantly down-regulated and 38 IncRNA were significantly down regulated. Among the differentially expressed genes, many genes are related to inflammatory response, such as AREG, HAS1, MMP25 and SLC11A1, were significantly up-regulated expression. TREH is related to low temperature stress, TRIB3 is related to stress response, HGFAC is related to carbohydrates. The expressions of glucose and lipids were also significantly up-regulated. 2)The biological processes the differentially expressed genes involved in were collagen metabolism, wound healing epidermal cell proliferation and muscle hypertrophy regulation. Most of them were located in extracellular region. There was only one MAPK pathway was significantly enriched. 3)There were 91 differentially expressed lncRNAs, which were cis-regulation, and 750 genes were trans-regulation. The interaction between lncRNAs and target genes was complex. The predicted target genes were significantly enriched in two biological pathways of MAPK and TNF. In conclusion, acute cold stress led to an inflammatory response in the longissimus dorsi muscle of Min pigs, changed the expression of partial genes related to inflammation, low temperature stress, stress response and nutrient metabolism. And it also changed the expression of partial lncRNA and activated MAPK and TNF signaling pathway.Keywords：Min pig;longissimus dorsi muscle;cold stress;RNA-seq;lncRNA11|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to illustrate the mechanism of the spiral growth characteristic in the helical-shaped pepper(Capsicum annuum L. ). Two inbred pepper lines, helical-shaped pepper and horn-shaped pepper, were taken as study objects. Freehand section method, paraffin section method and transcriptome sequencing were used. Mature fruit shape, cell division and expansion of ovary wall and pulp, and the transcriptome differences in ovary at anthesis were investigated. The results showed that: The onset of the spiral growth occurred in the early stages of ovary development. The spiral growth of pepper was attributed to the inclined arrangement of the cells in the ovary wall. In addition, significant differences were also observed in cell number and size in the longitudinal and transverse directions between the two lines. It is speculated that the difference of fruit shape between the two samples is comprehensively regulated by cell division and expansion. Transcriptomic analysis showed that, the expression of KIN, NPH3 and some of IQ67 pathway related genes was changed in the anthesis ovaries of the helical-shape fruit line, which may change the division direction of ovary cells and eventually lead to the spiral growth of fruit. Meanwhile, the helical-shaped fruits may also increase the number of longitudinal and transverse cells and affect the shape of cells by regulating the expression of OFP8 and the IQ67 pathway related genes and as well as the cytokinin-related genes, and finally elongated the helical-shaped fruits. In conclusion, the results of this study can provide scientific references for revealing the mechanism of the spiral growth of helical-shaped pepper and also for deepening our understanding about the mechanisms of plant organ morphogenesis.Keywords：pepper;fruit shape;rotation;histology;transcriptome7|10|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Bacterial canker, a systematic disease caused by Clavibacter michiganensis (Cm), is one of the most serious bacterial diseases in tomato worldwide. To establish an accurate and effective artificial inoculation and phenotype identification system for the resistance breeding, five artificial inoculation methods, including top-pruning, spraying, complex leafstalk injection, stem top injection and stem base injection, were adopted to inoculate plants of five different tomato lines with the Cm pathogen. The time of disease emergency, average incidence, disease index and average death rate were recorded and compared. The results showed that: Top-pruning and stem injection were the most effective methods to induce disease with 100. 0% incidence and greater than 75. 0 disease index. However, top-pruning caused the 96. 7% death rate of infected plants at 40 days post inoculation, which was not suitable for subsequent genetic analysis and obtaining seeds. Thus, the pathogenic effects of the pathogen introduced by top and base stem injection methods were further compared. The result showed that the pathogen spread faster in plants by stem base injection than by stem top injection. To verify this result, a total of 742 plants from three susceptible tomato lines, two resistant lines and two segregated populations were subjected stem base injection of the pathogen. The data showed that stem base inoculation accurately distinguished the resistance and susceptible phenotypes based on the inducing the distinct average incidence and disease index. In conclusion, this study indicated that the stem base injection method is suitable for evaluation of resistance to bacterial canker and genetic analysis, which provides a tool for screening sources resistant to bacterial canker and resistant cultivar breeding.Keywords：bacterial canker of tomato;inoculation method;stem base inoculation2|12|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To reveal the inhibitory effect and mechanism of piperine on Botrytis cinerea, the colony diameter, sporulation, spore germination rate of B. cinerea under different concentrations were analyzed in this study. The changes of mycelia morphology, soluble protein content, enzyme activity, cell membrane permeability of B. cinerea after piperine treatment were studied. The results showed: Piperine displayed obvious inhibitory effect on B. cinerea. The inhibitory rate of 200 mg/L piperine was 80. 6%. Its inhibitory rates on spore production and spore germination of B. cinerea were 88. 5% and 88. 8%, respectively; The inhibition rates of superoxide dismutase(SOD), catalase(CAT)and peroxidas(POD)were 82. 7%, 69. 1% and 70. 4%, and the inhibition rates of Succinate dehydrogenas(SDH)and NAD-malate dehydrogenase(NAD-MDH)were 89. 5% and 94. 9%, respectively; The result of microscopic observation showed that the hyphae of B. cinerea became thinner, the internodes elongated, the hyphae withered and collapsed, the protein content of B. cinerea was lower than that of the control group. There was an enhancement of cell membrane permeability of B. cinerea under piperine treatment; Therefore, piperine inhibits the growth of B. cinerea effectively. This study provides a theoretical basis for the development of new plant derived pesticides and the prevention of B. cinerea related diseases.Keywords：piperine;Botrytis cinerea;antifungal activity;enzyme activity;membrane permeability5|11|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to overcome the barrier of intergeneric hybridization more effectively and improve the success rate of intergeneric hybridization, a comprehensive review on the germplasm resources of related genera, the situation of intergeneric hybridization breeding, the problems of intergeneric hybridization, the measures to overcome the obstacles of intergeneric hybridization, etc. is presented in this study. On this basis, the development trend of Phalaenopsis intergeneric hybridization is prospected. The results show that: 1)There are 21 germplasm resources of the related genera successfully intergeneric hybridization with Phalaenopsis; 2)The intergeneric cross combination is first registered on the Royal Horticultural Society in the United Kingdom on January 1, 1931, and a total of 546 intergeneric cross combinations are registered on RHS as of December 31, 2020; 3)According to the reports, the efficiency of hybridization between Phalaenopsis and its relative genera is not high, the success rate of intergeneric hybridization is between 2. 78% and 12. 50%, and the main parents are the Phalaenopsis hybrids. Due to the complicated genetic background of phalaenopsis hybrids, sterile seeds are often produced in the hybridization, which shows the incompatibility barrier of hybridization; 4)The intergeneric incompatibility of Phalaenopsis can be effectively overcome by expanding the range of parent, repeated pollination, positive and negative hybridization, embryo rescue and so on. Therefore, the intergeneric hybridization of Phalaenopsis can provide some new ideas and direction for Phalaenopsis breeding.10|10|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to solve the problem of unbalanced soil nutrients in the forest, this study used two kinds of organic fertilizer produced from pure plant source materials to carry out organic fertilizer application on the biennial medicinal plant ［Panax notoginseng(Burkill)F. H. Chen］ organically grown under the pine forest. The effect of these two kinds of organic fertilizer on the growth and quality of P. notoginseng was investigated, and the application method and application rate of organic fertilizer suitable for the growth of P. notoginseng under the forest were clarified. Through a one-year field experiment, the effects of the two kinds of organic fertilizers on the growth, saponin content, yield and soil chemical properties of P. notoginseng were explored, and the application effects of the two kinds of organic fertilizers were evaluated. The results showed that: 1)The application of 30 000 kg/hm2 Guangzhou plant-derived decomposed organic fertilizer in the way of base fertilizer and top dressing resulted in a significant decrease in seedling survival rate. 2)The Guangzhou plant-derived decomposed organic fertilizer was more conducive to the synthesis of chlorophyll of P. notoginseng under forest and the accumulation of dry matter in roots. 3)Both organic fertilizers significantly increased the mass fraction of organic matter and available potassium in the understory soil, and improved the yield and quality of P. notoginseng under the forest. Among them, application of 3 750 kg/hm2 of base fertilizer and 3 750 kg/hm2 of top-dressing fertilizer Guangzhou plant-derived decomposed organic fertilizer obtained the highest yield, which was 54. 38% higher than the control, and the saponin content increased by 39. 88%. In conclusion, both kinds of organic fertilizers can significantly improve the soil nutritional status and increase the yield and quality of P. notoginseng under the forest. The best fertilization method is 3 750 kg/hm2 of base fertilizer and 3 750 kg/hm2 of top-dressing fertilizer.Keywords：Panax notoginseng;organic fertilizer of plant origin;content of saponins3|12|12<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming at the problem of falling damages in the process of picking, sorting and packing apples, the parameter combinations to slow down the falling impact of apples were investigated. Taking buffer material, buffer thickness and drop height as the influencing factors, and the impact force and damage volume as the response values, the influence law of each factor on the response value was determined through single-factor test. Based on the results of the single factor test, the response surface test was used to obtain the optimal buffer parameter combination. The results of single factor test showed that the buffering effect of buffering materials on apples changed from strong to weak in the order of pearl cotton > false lawn > silicone rubber > bubble film; When the buffer thickness is respectively 3, 5, 8, 10 and 12 mm, with the increase of buffer thickness, the falling impact force and damaged volume of apples gradually decreased. When the falling heights were 10, 20, 30, 50 and 70 mm, respectively, with the increase of falling heights, the falling impact force and damaged volume of apples gradually increased. The response surface test results showed that the optimal combination of cushioning parameters was pearl cotton with cushioning thickness 12 mm and falling height 10 cm. At this time, the impact force was 2. 61 N and the damage volume was 8. 52 mm3. In conclusion, the optimal combination of buffer parameters are verified by experiment, the absolute error of the optimal combination of cushioning parameters is less than 5%, and the optimized combination of cushioning parameters is reliable.Keywords：buffer material;drop impact;collision force;damage volume;response surface test3|10|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the expression law and determination method of ash content and calorific value in biomass energy utilization, the ash and higher calorific value data of 380 different types of biomass samples were obtained from literature published from 2001 to 2021. The determination methods were analyzed statistically. The results showed as follows: 1)The influence of different calorific value determination standards on the determination of calorific value was negligible, but the outcome of ash content determination according to solid fossil fuels standard was significantly lower than those of biomass fuels. 2)The ash content of herbaceous biomass ranged from 7. 96% to 9. 19%, which was significantly higher than that of woody biomass from 2. 26% to 3. 37%. Its average calorific value(17. 45 MJ/kg)was lower than that of woody biomass(19. 61 MJ/kg). 3)The high calorific absolute value of herbaceous plants was negatively correlated with ash content(r 0. 567-0. 918), which was higher than that of woody plants(0. 136). The coefficient(R2)of determination between high calorific value and chemical elements(carbon, hydrogen, nitrogen, sulfur, oxygen)content was 0. 936 7-0. 973 7, higher than 0. 812 0-0. 971 4 with ash, volatile, and fixed carbon. The former function had better fitting effect. 4)The deviation of biomass moisture, ash content and calorific values predicted by the model established by NIR technology was basically less than the repeatability limit of the reference method. The method established in this study was faster and had great application potential in the biomass industry.Keywords：biomass;calorific value;ash;correlation;near infrared spectrum technology5|10|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the suitable thickness of films for recycling, two new silver-black mulching films generated by different processing techniques were selected. Films with thickness of 0. 010 mm, 0. 015 mm and 0. 025 mm were compared with the common black mulching film that meets the requirements of the national standard in greenhouse. The mechanical properties of the mulching films in different covering periods were tested by electronic tensile testing machine, and the recovery performance of the mulching films was evaluated comprehensively with the combination of impurity rate and pick-up rate. The results show that: In terms of mechanical properties, the fracture elongation and the maximum tensile load of plastic film increase gradually with the increase of the thickness of plastic film. The retention rate of the mechanical properties of plastic film with thickness over 0. 015 mm is above 70%. Therefore, the plastic film still has good mechanical properties when recycled; In terms of impurity rate, the film thickness of 0. 015 mm and 0. 025 mm is lower than 80%, which meets the demand of recycling of enterprises and reduces the reuse cost of recycling treatment to a certain extent; In terms of the pick-up rate, the same two thicknesses of mulching film showed good characteristics, and the pick-up rate is more than 95%, which effectively reduced the residual amount mulching film in the year. This study further constructs the comprehensive recycling of plastic effect evaluation method, and evaluate the effect of plastic recycling The results show that the total score of the two new plastic films is 60% higher than that of the control film when it was used for 123 days longer than that of the control film, showing good recovery characteristic. The larger the thickness, the higher the comprehensive score. In conclusion, the mechanical properties of the new mulching film are improved, and it is more suitable for long-season cultivation. The mulching film with thickness of more than 0. 015 mm has better comprehensive recovery effect, which plays a positive role in reducing the residual amount of greenhouse mulch film and promoting the recycling of recycled plastic film.Keywords：thickness of mulching film;mechanical properties;impurity rate;pick-up rate;recovery effect7|10|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the problems of the absence of regulatory function and the low measurement accuracy of traditional sluices, this study designed a new measuring sluice with airfoil-shaped measuring flume as sluice pie. Based on the experimental observation parameters determined by the analysis of flow measurement principle, the pattern of flow regime passing the sluice and new flow formulas were investigated by the hydraulic performance tests under different flow rates(Q)and sluice opening levels(e). The results show that: 1)The flow in front of the airfoil-shaped-pier measuring sluice are stable under various flow regimes. The water depth of upstream and the top of water-wing increases as the flow rate increases but decreases as the sluice opening increases. However the changes of the upstream water surface line is more obscure as the flow rate increases and more pronounced as the angle of the sluice opening increases. 2)The threshold value(sluice relative opening)of the weir flow and the orifice flow has changed because of the streamline shape of the pier, it decreases as the flow rate increases and then tends to be stable. It has the minimum value 0. 75 but is higher than 0. 65 of the traditional slab sluice. 3)The flow formulas of the weir flow and the orifice flow are obtained through a fit, and the relative error is less than 5% compared with the observed flow rate. In conclusion, the airfoil-shaped-pier measuring sluice in this study realizes the function of measurement and control integration as well as ensures accurate flow measurement, which can provide a reference in the application and investigation of flow measurement devices in irrigation district.Keywords：flow measurement;sluice-flume combination;rectangular channel;sluice opening;hydraulic performance3|10|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to understand the effect of venturi nozzle application in unmanned aerial vehicle(UAV)on rice disease control, a venturi anti-drift nozzle was installed to a UAV to analyze the droplet deposition characteristics and the control efficiency of rice blast and rice sheath blight. The results showed that: The deposition of droplets in the upper and lower part of canopy and the overall deposition of droplets with venturi nozzle exceeded those with the conventional fan nozzle; The use of large droplets in UAV improved the penetration of droplets in the canopy and the uniformity of droplet distribution within the spray area compared with small droplets; In terms of grain blight disease control, the application of venturi nozzles in UAV for plant protection was 80% as effective as that of the backpack sprayer, and 30% more effective than the conventional fan nozzles. Therefore, rice foliar diseases can be controlled by the application of venturi nozzle in UAV.8|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Acceleration signals generated from wearable behavior monitoring systems are susceptible to noise interference. Moreover, the distribution characteristic of acceleration signals of various behaviors is not yet clear, which significantly restricts automatic behavior recognition. In this study, a wearable behavior monitoring system was constructed to collect behavioral acceleration signals of the laying hens inside the 3D space of an aviary system. The performances of three denoising methods on accelerations were compared, including wavelet threshold, CEEMDAN and CEEMDAN combined with wavelet threshold. Moreover, the acceleration signal characteristic of six typical behaviors of laying hens was analyzed. Results showed that: 1)Wavelet Stein's unbiased risk estimation(Rigrsure)threshold had better denoising performance. The signal to noise ratio(SNR)and root mean square error(RMSE)of the denoising signals were 17. 613 2 and 0. 045 0, respectively. 2)According to the distributions of standard deviation of X- and Y-axis accelerations, the activity levels were divided into four categories from low to high level, i. e. , lying and standing, eating and drinking, walking, jumping. The standard deviations of acceleration signals of various behavioral activities were significantly significant(P<0. 001). This study indicated that the wavelet Rigrsure threshold method could retain more effective information while reducing noises, and the activity levels of typical behaviors of laying hens could be classified according to the standard deviation of acceleration.Keywords：aviary system;laying hens' behaviors;acceleration signals;wavelet threshold;behavior classification2|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To delimit the ecological, living and agricultural production space scientifically and reasonably, under the restriction of water and soil resources carrying capacity, by taking the Horqin region an example, this study explored the optimal layout of territorial space with the “double evaluation” as the core. Firstly, the carrying capacity of region water and soil resources based on the fuzzy comprehensive evaluation method was evaluated, and the territorial space suitability evaluation system guided by agricultural production guarantee, urban construction potential and ecological barrier constraint was established. The ecological space, living space and agricultural production space in Horqin region were then determined based on the results of “double evaluation”. The results showed that: 1)The proportions of ecological, living and agricultural production areas in Horqin region were 50. 00%, 3. 55% and 46. 45%, respectively. 2)The largest area of agricultural production was in Fuxin city and Baicheng City, the largest ecological area was in Chifeng City and Xingan League, and the most suitable living areas were concentrated in Baicheng City. The study provided references for the protection of ecological space, the development of living space and the selection of agricultural planting areas in Horqin region.Keywords：double evaluation;production-living-ecological space;land and water resources;territorial space planning3|9|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the problems that the current evaluation methods for cultivated land fragmentation are not comprehensive and objective, and it is difficult to carry out plot scale evaluation. On the basis of summarizing the existing research, this study redefines cultivated land fragmentation. Based on the area, form, aggregation, topographic of the cultivated land, cultivated land fragmentation index(CLFI)is designed. Taking Xuanzhou District, Xuancheng City, Anhui Province as the study area, the CLFI is used to evaluate the fragmentation of cultivated land at the plot and township scale. The evaluation results are compared with remote sensing image and the evaluation results based on landscape metrics. The results show: At the plot scale, the evaluation results of CLFI are basically consistent with the actual fragmentation of cultivated land, and can combine the road, water system and other data to analyze the reasons for the fragmentation and the potential for improvement of regional cultivated land; At the township scale, the adjusted R2 of the regression equation between the landscape metrics and CLFI is 0. 44, through the significance test, CLFI has integrated the characteristics of the six landscape metrics to a certain extent. In conclusion, the CLFI proposed in this study reflects the fragmentation of regional cultivated land more comprehensively, intuitively and accurately, which can provide support for integrated land renovation and high-standard farmland construction for modern agriculture.Keywords：cultivated land fragmentation;terrain;landscape metrics;cultivated land fragmentation index109|264|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Land is the basic material condition on which human beings depend for survival and development. In order to explore the spatiotemporal variation characteristics of land sustainable development, an evaluation index system was constructed based on sustainable development goals. The middle and lower reaches of the Yellow River was taken as the research object. The weighted TOPSIS method and the obstacle factor model were then employed to quantitatively measure the land sustainable development level and identify the main obstacle factors in the middle and lower reaches of the Yellow River. The results show that: The land sustainable development level was on the rise generally, and the score increased from 0. 371 to 0. 735 from 2005 to 2018. The land sustainable development presented obvious spatial differences, and the land sustainable development level in the eastern area of the Yellow River mainstream was improved rapidly. The land sustainable development obstacle factors changed dynamically with time in the study area from 2005 to 2018. Generally, the industrial sulfur dioxide emissions per area and the consumption of chemical fertilizer per cultivated land area were the main obstacle factors. Therefore, the ecological environment still showed a relative high restriction of the land sustainable development, which should be paid more attention to achieve high-quality development in the middle and lower reaches of the Yellow River.Keywords：land sustainable development;TOPSIS model;obstacle factors;the middle and lower reaches of the Yellow River5|11|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To explore the impact of expressway network construction on the formation of China's cross regional agricultural machinery operation service market, the study discusses the mechanism of the highway network construction to promote the development of the agricultural machinery cross-regional service market from the supply side and the demand side, and uses the panel data of the 17 major rice and wheat producing provinces from 2000 to 2019 to conduct empirical tests. The results show that: 1)In theory, the construction of expressway network improves the cross regional service willingness and ability of service subjects through the intermediate mechanism of traffic time convergence effect. The convenience and timeliness of service subjects entering a certain area are conducive to stimulate local farmers to form cross-regional agricultural machinery service demand. 2)The regression results from 2000 to 2013 show that the construction of expressway network plays a significant role in promoting cross-regional agricultural machinery service supply. The contribution rate of the increase of expressway network density to the growth of cross-regional machine harvesting area is 47. 78%, while the contribution rate of expressway density difference to regional differences in the supply capability of cross-regional agricultural machinery service is 13. 8%. 3)The regression results from 2014 to 2019 also show that the construction of expressway network plays a significant role in promoting cross-regional agricultural machinery service demand. For every 1 unit increase in expressway density, the cross-regional agricultural machinery service demand intensity increases by 8 percentage points, and the explanatory power of regional difference in expressway density to spatial differentiation of cross-regional agricultural machinery service demand is 12. 1%.Keywords：expressway network;cross-regional agricultural machinery service market;cross-regional harvesting;rice and wheat producing areas3|13|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to investigate the impact of identity cognition on villagers' participation in village human settlements governance and its mechanism, based on the analysis of 758 micro survey data in Shaanxi and Ningxia provinces, an empirical analysis is performed by using a regulated intermediary model and taking villagers' sense of belonging and cadres' closeness as two dimensions of insiders' identity cognition. The results show that: 1)The degree of insider identity cognition plays a significant positive role in promoting villagers' participation in village environmental governance; 2)The collective efficacy plays an intermediary role in the influence of insider identity cognition on villagers' participation in village environmental governance; 3)The prosocial tendency of villagers can significantly enhance the impact of collective efficacy on villagers' participation in environmental governance. Based on the analysis results, it is suggested to weaken the heterogeneity within the village community, enhance the villagers' sense of identity with the village community collective and village level organizations to create a good social environment for villagers' participation. At the same time, it is necessary to strengthen publicity and education to improve the willingness and level of villagers' participation in village public affairs.Keywords：insider identity recognition;villagers' participation;collective efficacy;prosocial tendency;moderated mediation2|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the growth law of sugar consumption in the context of aging, based on the data of the China Health and Nutrition Survey, the strategy of summing up the consumption of sugar-sweetened food was used to analyze the impact of aging on the consumption of sugar, and examine the impact mechanism and possible heterogeneity characteristics. The results show that: 1)Aging significantly inhibits residents' sugar consumption. The aging degree deepens by 1%, and the per capita sugar consumption decreases by 0. 62%; 2)The income variable is only part of the reason why aging inhibits residents' sugar consumption. The decrease in the income effect is hardly offset by the increase in the income effect. At the same time, aging can improve residents' preference for healthy food, thereby inhibiting the growth of residents' sugar consumption; 3)Although aging has different effects on residents' sugar consumption in the eastern and central and western, southern and northern regions, the conclusion that aging inhibits residents' sugar consumption is consistent among different regions. The findings of this study can not only help the public sector to formulate targeted nutrition intervention policies for the elderly, but also provide reference for the sugar-sweetened food industry's “sugar reduction” strategy.Keywords：aging;sugar consumption;sugary foods;health and nutrition0|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
