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- Abstract：The objective of this study was to systematically evaluate the efficiency of haploid identification by oil content (OC) with new High-Oil Inducers.Ten hybrids were induced by two High-Oil Inducers CHOI1 and CHOI3 with OC 8.71% and 8.72% respectively in Beijing and Hainan.The haploid identification by OC and R1-nj markers were evaluated and compared.The results showed that the accuracy rate (AR) of OC system,which was not influenced by environments,was higher than that of R1-nj system.When OC system was used to identify haploids induced by CHOI1 and CHOI3,the difference in the mean OC of haploids and crossing seeds were respectively 2.21% and 2.02% and the ranges of variation were 1.86%-2.63% and 1.54%-2.46%,respectively.The haploid induction rates were 8.30% and 8.59%,with ranges of 6.25%-10.40% and 5.81%-11.19%,respectively.When indexes mean (μ) +1.645×standard deviation (σ) was used as the oil content threshold value to classify the haploids induced by CHOI1,the ARs were all beyond 90%.In addition,the missing rates were all below 10%.The ARs of all the crosses were more than 90% by using 4% seed oil as the general threshold.Keywords：maize;haploid;oil content;R1-nj;marker;High-Oil Inducer1|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
Analysis of the response intensity ofimmune-related gene promoters to the immune signaling molecules
Abstract：In order to compare the response intensity of different plant resistance genes to plant immune elicitors and screen reporter gene with high response intensity,the promoters of 5 plant immune related genes (WRKY33,FRK1,WRKY29,PR2 and PDF1.2) were cloned from Arabidopsis thaliana in this study.Luciferase expression vectors driven by target gene promoters were constructed and transformed into Arabidopsis protoplasts for transient expression.After the treatment with plant immune elicitors (FLG22 and PEP1),LUC activity was detected to determine the activation of the target promoters,and the response intensity to immune signal molecules was analyzed.The results showed that after treatment with FLG22 and PEP1,the response intensity of WRKY33 in Arabidopsis protoplasts was the highest,which was 11.2 times and 4.5 times higher than that of control,respectively.It was followed by that of WRKY29,which was 10.0 times and 3.1 times more respectively;Compared with WRKY,the response intensity of FRK1 was significantly lower,but neither PR2 nor PDF1.2 displayed apparent response.The above results indicated that WRKY33 efficiently responded to plant immune elicitors in the protoplast transient expression system of Arabidopsis and the pWRKY33::LUC protoplast expression system could be used as a highly efficient PTI reaction reporting system for the screening and identification of novel plant immune elicitors.Keywords：Arabidopsis thaliana;plant immunity;report gene;signal response intensity0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：In order to establish evaluation indexes of leaf canopy of high yielding maize population and theoretical basis,a field experiment was conducted including two maize hybrids ‘Xianyu 335’ and ‘Xundan 20’ with two planting densities of 67 500 and 97 500 plants/hm2,respectively.Regression analysis method was used to calculate the leaf droop coefficient of three different canopy layer including the whole canopy (a1),middle canopy (Leave length>60 cm,a2),and the bottom and the upper of canopy (Leave length ≤ 60 cm,a3).The results showed that there was a significant linear relationship between the leaf drooping distance and leaf length.The a1,a2 of leave regression relationships were negatively and significantly correlated with leaf angles at the middle canopy leaves,and a1,a2 and a3 were negatively and significantly correlated with that of upper canopy leaves.The drooping coefficient is negatively and significantly associated with the thousand kernel weight and bareness.The a2 of ‘Xianyu 335’ increased by 0.13 with the increasing of planting density,while other drooping coefficient differences were less than 0.04.The a3 values of two varieties were smaller than a1 and a2,indicating leaves with a length less than 60 cm drooped more easily and the leaves that flat.Among the drooping leave linear regression relationships,the coefficient R2 (decision coefficient) decreased with the increasing of planting density.At the same planting density,‘Xianyu 335’ had a smaller R2 than ‘Xundan 20’ indicating that ‘Xundan 20’ had a high capacity for maintaining leaf morphology,thus increased grain yield.In conclusion,the leaf drooping characteristic could reflect the changes of leaf morphology in space and time as well as the effects of high planting density.Adjusting leaf drooping characteristic is very important for high yielding variety to adapt high planting density.Keywords：maize;variety;density;leaf morphology;leaf drooping coefficient;yield2|7|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
Effects of different tillage and mulch treatments on the soil environment and yield of dryland maize
Abstract：In order to solve the problems of drought and water shortage,low temperature and cold,soil fertility decline and so on in dryland maize production in cold climate areas,the split plot design was adopted in 2011-2014.In the demonstration base of dry farming and water saving agriculture in He village,Yangqu County,Shanxi Province,the effects of different tillage and mulch treatments on soil water,fertilizer,heat and yield of dryland maize with 4 different tillage mulching treatments were studied.The results showed that:1) Deep tillage in autumn plus straw returning (DTS) obviously increased the 5 cm ground temperature at seedling stage compared with rotary tillage in spring with no straw returning (RTN).The average daily ground temperature and average daily minimum ground temperature increased by 1.1 and 1.3℃over 3 years,respectively.Plastic film mulching (PM) for 3 years improved the 5 cm at seedling stage compared with no plastic film mulching (NPM).The average daily ground temperature and average daily minimum ground temperature increased by 1.7 and 1.2℃,respectively.2) Compared with RTN,the soil moisture content of DTS at seeding stage in 0-10 cm increased by 1.9 percentage point.3) The soil compactness of DTS at seeding stage in 0-12.5 cm was equally 3 times of RTN.The soil compactness of the two treatments was basically the same from 15 cm.4) After 3 years of continuous tillage and mulching treatment,the soil fertility of DTS was obviously improved.The content of soil organic matter,total phosphorus and potassium in 0-20 cm were significantly higher than that in RTN (P<0.01),and the increases were respectively 5.8%,6.4% and 6.1%.Total nitrogen content in PM was significantly higher than that in NPM with an increase of 8.6%.5) DTS increased the yield significantly (P<0.01),and the economic yield increased by 12.2% on average in 4 years.The economic yield of PM in 4 years increased 25.3% compared with NPM equally.Among all the treatments,the yield of DTS plus PM was the highest.6) In PM treatment,the WUE of DTS increased by 5.4% compared with that of RTN.And in NPM treatment,the WUE of DTS increased by 12.0% compared with that of RTN.In conclusion,DTS plus PM is appropriate for the area to store water and preserve soil moisture,increase and stabilize temperature,improve soil fertility,and get high yield and high efficiency currently.Keywords：maize;dryland;tillage and mulch;soil environment;yield1|8|15<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：In order to explore the mechanism of foxtail millet continuous cropping obstacle and investigate the effects of foxtail millet straw water extracts on the seed germination and seedling growth of foxtail millet,germination and pot experiments were completely randomly designed and conducted.The results displayed that the water extracts showed promoting effect at low concentrations while showed inhibition effect at high concentrations on the seed germination of foxtail millet.Compared with the control,the germination rates of the foxtail millet seeds treated with the undiluted water extracts were decreased by 73.2% and 56.6%,respectively.The root and bud length,fresh and dry weight of foxtail millet seedlings were significantly lower than those of the control.It indicated that the undiluted water extracts significantly inhibited the germination of the foxtail millet seeds and growth of the foxtail millet roots and buds.The allelopathic indexes of foxtail millet seeds treated with 10,50 and 100 fold diluted water extracts were all positive suggesting their promoting effects on the seeds germination and the root and bud growth of foxtail millet.After treated by the water extract,the plant height,leaf area,biomass,chlorophyll content,net photosynthetic rate and transpiration rate of foxtail millet seedling were significantly lower than those of the control,and their allelopathic indexes were all negative.In contrast,the plant height,leaf area and biomass of the seedlings under the treatment with 10 fold dilution were significantly higher than those of the control,and all with positive allopathic indexes.Compared with the control,the photosynthesis of the foxtail millet seedlings treated with water extracts at different concentrations was inhibited.With the increase of water extract concentration,the SOD and POD activity in the leaves of foxtail millet seedlings treated with water extracts were increased at first and then decreased,and increased at first,then decreased and finally increased again,respectively.In conclusion,the allelopathic substances in foxtail millet straws had strong autotoxic effects on foxtail millets at high concentration (undiluted water extracts),which inhibited the seeds germination and the seedlings growth,whereas it showed promoting effects at appropriate concentrations (10 fold,50 fold and 100 fold dilution).This study provided theoretical references for the efficient production of foxtail millet.Keywords：foxtail millet;water extract;germination;seedling growth;autotoxicity effect3|8|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In this study,the ecological risks for large-scale cultivation of four promising miscanthus species (Miscanthus sinensis,M.floridulus,M.sacchariflorus,M.lutarioriparius) and the European commercially used variety of Miscanthus×giganteus were quantified.The quantification procedure was conducted using formerly established ecological risk assessment system for bioenergy grasses (Hereafter referred to as ERAB system).According to the quantification procedure of ERAB system,the distribution characteristics (P1),reproductive characteristics (P2),diffusion characteristics (P3),genetic characteristics (P4) and adaptation characteristics (P5),damage characteristics (P6) and controlled features (P7) of the tested materials were reviewed and summarized firstly.The 33 evaluation indicators,which belong to the above seven characteristic groups,were assigned according to the assessment criteria defined in the ERAB system.The ecological risk score of each tested species was quantified by summing the assignments of its 33 evaluation indicators.The results showed that ecological risks of the large-scale miscanthus cultivation generally were M.sinensis > M.sacchariflorus > M.floridulus > M.lutarioriparius > M.×giganteus indicated by their ecological risk scores of 71,66,60,53 and 52,respectively.According to the risk definition criteria of the ERAB system,the M.lutarioriparius and M.×giganteus were defined as the ecological safe plant (i.e.accept for large-scale cultivation);while the M.sinensis,M.sacchariflorus,M.floridulus were defined as plants with uncertain ecological risk,indicating further deeply evaluations were required to clarify their ecological safety prior the large-scale cultivation.Keywords：eco-industrial plant;Miscanthus;ecological risk;invasion potential0|7|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To further study the molecular biology function of melatonin,we designed the gene specific primer based on the sequence information from the Tomato Functional Genomics Database,the full-length CDS (coding sequence) of a melatonin biosynthesis gene (SlSNAT) was from salt-tolerant tomato LA1401 (PI365967).The corresponding CDS is 768 bp in length and the deduced protein contains 255 amino acids.The over-expression vector was constructed through enzyme digestion and ligation.Tissue expression profile using Real-time quantitative PCR showed that SlSNAT expression level was the highest in leaves,being significantly higher than its expression in flowers,fruits,roots and seeds.Upon different abiotic stresses,SlSNAT expression level under drought treatment was the highest followed by mannitol osmotic stress,and its levels under the two stresses were significantly higher than these in the hydrogen peroxide,sodium chloride,cold and melatonin.In addition,under salt stress,SlSNAT expression level in roots was remarkablely inhibited.This gene is potential novel candidate for abiotic tolerance research in tomato.Keywords：tomato;melatonin synthesis;SlSNAT;gene expression0|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Recently,there was an outbreak of blight disease in strawberry nursery and production area in Beijing,which caused serious loss in strawberry seedling industry and producer.In order to identify the pathogen of strawberry blight disease and take appropriate control measures,‘Benihope’ strawberry with blight symptom was chosen as the experiment material in this study.Tissue separation method was conducted to isolate and purify the pathogen.The morphological identification,molecular biology identification,pathogenic determination and indoor screening of bactericide virulence were conducted.The results showed that:1) The pathogen was confirmed as Fusarium oxysporum;2) The toxic test showed the inhibitory effect of carbendazim,chlorothalonil,myclobuthanial and other fungicides was best for the mycelial growth of F.oxysporum.Keywords：strawberry;strawberry blight;pathogen identification;Fusarium oxysporum;fungicide disease1|10|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：This study was undertaken to evaluate the expression patterns and polymorphisms of GnRH gene in the hypothalamic-pituitary-ovarian axis (HPOA) and its association with litter size in Small Tail Han sheep.The real-time fluorescence quantitative PCR (RT-qPCR) method was used to detect the expression of the GnRH gene in reproductive tissues and brain tissues of six Small Tail Han sheep (Three polytocous and three monotocous ewes from the FecB++ genotype) in this study.380 Small Tail Han sheep and 380 in total for Small Tail Han sheep,Tan,Sunite,Cele Black,Hu and Prairie Tibetan sheep were selected and Sequenom MassARRAY® SNP assay was applied to genotype 2 single nucleotide polymorphism sites (SNPs) of GnRH gene.Then the association was analyzed between GnRH and litter size in Small Tail Han sheep.The results showed that GnRH gene was expressed in hypothalamus,ovary and uterus tissues and among which,GnRH was highly expressed in hypothalamus.The expression of GnRH gene in ovary,hypothalamus and uterus of polytocous Small Tail Han ewes was extremely significant higher (P<0.01) than that of monotocous ewes,and the GnRH gene might be involved in the regulation of multiple lambs in Small Tail Han sheep.From genotyping,we found the genotype frequencies and allele frequencies of the 2 SNPs were not significantly different between uniparous and multiparous sheep (P>0.05),association analysis showed that these 2 SNPs in GnRH gene were not significantly correlated with litter size in Small Tail Han sheep (P>0.05).The population genetic analysis indicated that 2 SNPs showed low polymorphism in all sheep breeds (PIC<0.25),and the result of chi-square test showed that 2 SNPs were at Hardy-Weinberg equilibrium in most sheep breeds (P>0.05).Keywords：sheep;prolificacy;GnRH;gene;tissue expression;SNP;association1|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the amino acids substitution and genetic variation of influenza viruses in Hubei Province,two H9N2 isolates were identified.The whole genome sequence of the isolated strains were amplified by RT-PCR,cloned into vector pMD18-T by PCR and analyzed by bioinformatics software.The results indicated that:These two H9N2 isolates were highly identical.The HA and NA genes of the two H9N2 isolates belonged to Y280-like lineage,PB1,PA,NP and NS genes belonged to SHF98-like lineage,and PB2 and M genes belonged to G1-like lineage;Molecular analysis of whole genome sequence found that the amino acid sequence of HA genes of the two isolates had -RSSR↓GLF- cleavage site,which represented low pathogenic avian influenza virus strain;Compared with the prevalent strain Y280,the two H9N2 isolates contained 313 (NCS) potential glycosylation site in HA protein.The position L234Q (H9 numbering) of HA gene of the H9N2 isolates was mutated;The position N31S in M2 protein of the H9N2 isolates were mutated.In conclusion,the two H9N2 isolates belonged to Y280-like lineage virus,suggesting that the Y280-like branch avian influenza virus might also be prevalent in Hubei Province,which was a low pathogenic avian influenza virus (LPAIV),but had the potential risk of infecting mammals.Keywords：avian influenza;H9N2;genetic evolution;amino acid site1|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the immune function changes of grass carp after feeding with broad bean and switching to artificial feed,immune organs including intestinal tract,head kidney and liver,and immune genes like C-type lysozyme,IFN-I,TNF-α,etc.were detected at for 30,60,90 and 120 and 150 d of feeding with broad bean (feeding with artificial feed for 30 d after feeding with broad bean for 120 d) in this study.The results showed that,the intestinal tract,head kidney and liver of tested grass carp were severely damaged after feeding with broad bean,and the damaged ultrastructure were not significantly improved after switching to artificial feed.The expression of immune genes C-type lysozyme,IFN-I TNF-α,IgM and MHC-I were all inhibited,and the expression of C-type lysozyme,IL-1β,IFN-I,IgM,MHC-I in the head kidney and IL-1β,TNF-α,IFN-I,IgM,and MHC-I in the liver increased after feeding with artificial feed.In summary,the immune function of grass carp was significantly inhibited after feeding with broad bean,and damaged immune function of crisp grass carp were slightly improved after feeding with artificial feed.This study would provide theoretical basis for the immune improvement of crisp grass carp and reference to investigate the impact of broad bean on the immune function of other animals.Keywords：grass carp;broad bean;immune organ;ultrastructure;expression of immune gene0|11|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the current research status of tripartite interactions of Rice stripe virus (RSV) -host-vector from home and abroad, recent researches are summarized and compared by literature search. The results show that:1) The complex and direct interactions between the RSV encoded proteins ensured the orderly connections of the viral life cycle. 2) The indirect interactions of RSV-host-vector are mostly consistent with the characteristics of virus infection symptoms on the plant and virus transmission through the planthopper's eggs. 3) The direct interactions between viral proteins and vector factors participate in the life cycle of virus replication, transmission, and resistance to the planthopper's immunity. 4) The studies of RSV-host-vector interactions have already become a hot topic in plant virology and high-level researches are emerging now in China. In view of the immature genetic system of RSV and planthopper in studies of RSV-vector interactions, solutions such as accelerating the construction of the full-length cDNA infectious clone or the mini-replicon of RSV and optimizing of the existing CRISPR/Cas9 technology to achieve high-through gene knockout of planthopper are proposed.Keywords：Rice stripe virus;virus-host-vector interactions;siRNA;host factors0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The possibility of SHR gene as a vaccine candidate antigen and early diagnostic antigen was preliminary discussed in this research.The total RNA was extracted from Parabronema skrjabini and SHR gene was cloned by RT-PCR.The PCR product was cloned into pMD19-T and a prokaryotic expression vector pET-30a(+)-SHR was then constructed.The protein structure and antigenic epitopes of SHR gene were analyzed by using online bioinformatics software.The results indicated that SHR gene was 1 083 bp in length,encoding 360 aminoacids and its theoretical pI is 6.09.Transmembrane structure and signal peptide analysis showed that the SHR protein contained a type of hydrophilic no transmembrane domains and signal peptide region and 29 phosphorylation sites.The secondary structure of SHR was mainly composed of alpha helix and the proportion of hydrophilic amino was over 60%.The antigenic epitopes prediction results indicated that SHR protein was a hydrophilic protein with high antigenicity.These results suggested that the SHR antigen has strong potential to be a candidate for immune diagnostics and used as a vaccine against P.skrjabini.Keywords：prokaryotic expression vector;SHR;gene;antigenic epitopes;bioinformation analysis0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the convolutional neural network for identifying tomato diseases needs more training parameters and the training is very time-consuming,transfer learning is applied to the AlexNet convolutional neural network,and 9 types of disease leaves including healthy tomato leaves are classified.Using 14 529 tomato leaf images,70% randomly selected as the training set and 30% as the validation set,the AlexNet convolutional neural network model structure was migrated and the mature AlexNet model and its parameters were trained on the Imagenet image dataset for tomato disease identification.During the training process,the fixed low-level network parameters are unchanged,the high-level network parameters are fine-tuned,the tomato disease image is input into the network to train the high-level parameters of the network,and the trained model is used to classify the 10 types of tomato leaves,and 20 groups of experiments are carried out.The results show that the proposed algorithm converges well in the network of 474 training iterations,and the average accuracy of the network to the verification set is 95.62%.Compared with the AlexNet convolutional neural network trained from zero,the training time is shortened and the average accuracy is increased by 5.6%.In conclusion,the disease classification model established by transfer learning can quickly and accurately classify 10 types of tomato leaf diseases.Keywords：tomato;convolution neural network;transfer learning;feature extraction;SVM;diseases classification6|9|10<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to realize the automatic operation of users and prevent user churn,interval estimation and machine learning modeling methods are adopted to analyze user churn by data records of pig farm users.The results show that:1) The smaller the pig farm is,the greater the possibility of user churn is.The least possible churn of pig farm users,whose number of sows x is at 500Keywords：pig farm;internet+agriculture;users churn;machine learning;decision tree1|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to thoroughly analyze the thermal insulation characteristics and application prospects of the new heterogeneous composite wall in solar greenhouse,the general regression neural network algorithm was used to process the sample data,and the results were fitted by cubic spline interpolation method.A prediction model for the greenhouse temperature field in winter was established and a retention-optimal method for determining the number of packets of the optimal smoothing factor is proposed.The data of a new heterogeneous composite wall solar greenhouse designed and constructed by Hebei Academy of Agricultural Sciences in 2017 were selected for experimental verification.The results showed that the model had good prediction effect,and the training was optimal when the number of packets is about 1/16 of the number of samples.The average error between the predicted temperature and the actual temperature was 0.276 5℃,and the correlation coefficient was greater than 0.99 indicating better accuracy and stability.In conclusion,the model can effectively predict the greenhouse temperature field and it can be used to predict the minimum temperature of greenhouse in winter for determining the optimal planting time of crops.Keywords：solar greenhouse;general regression neural network;leave-one-out method;temperature field prediction0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to improve the seeding performance of the flax ridging and covering film combined seeder in dry-land,the Box-behnken experiment principle is adopted by taking the speed of machine,number of discharge hole and diameter of discharge hole as the influence factors based on the Design-Expert software.The consistency variability coefficient of seeding quantity of each row and the stability variability coefficient of the full seeding quantity are the response values.A three-factor and three-level experiment optimization scheme is designed,and two regression models of each factor and interaction function are established for the apiece row consistency variability coefficient of seeding quantity and the stability variability coefficient of the full seeding quantity.The results show that the significance order of factors according to priority of the apiece row consistency variability coefficient of seeding quantity and stability variability coefficient of the full seeding quantity are as follows:The diameter of discharge hole,the speed of machine and the number of discharge hole,the diameter of discharge hole,the number of discharge hole and the speed of machine.The optimal working parameters of the machine are as follows:The speed of machine is 0.53 m/s,the number of discharge hole is 11,and the diameter of discharge hole is 8.5 mm.The results of field experiment showed that under this optimized parameter,the apiece row consistency variability coefficient of seeding quantity and the stability variability coefficient of the full seeding quantity for flax combine seeder with ridging and covering film in dry-land are 3.63% and 4.09%,respectively,which meets the basic working quality standard requirement of small grain seeder.Keywords：flax;seeder;performance experiment;parameter optimization1|9|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
A multi-objective optimization model solving method based on genetic algorithm and scheme evaluation
Abstract：In order to obtain the satisfactory solutions of multi-objective programming (MOP) problems,two steps are taken:1) A improved multi-objective genetic algorithm is used to deal with more complex constraints of MOP,and thus the Pareto solution set can be obtained.2) The entropy weight method is used to select a more suitable scheme based on evaluation index system.To prove its practicality and applicability,this method is applied to the water allocation model in Yingke Irrigation District.The results show that the Pareto solution set can fully reflect the relationship between different objectives.According to the practical situation,the ratio of grain to economic,the information entropy of water structure and the amount of fertilizer used are selected as the indicators to value the schemes from Pareto solution set.The water productivity obtained by this method reaches 1.46 kg/m3 and the total yield reaches 86.67×106 kg.Compared with the traditional solution method,the method proposed in this study has stronger optimization ability and can obtain a more reasonable solution.The multi-objective optimization problem solving method based on genetic algorithm and scheme optimization can obtain more satisfactory schemes to solve more complex MOP problems.This method can also provide a new idea to solve other MOP problems.Keywords：MOP solving method;genetic algorithm;schemes evaluation;entropy weight method;irrigation water allocation3|7|14<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：To promote the application of domestic Gaofen data in land-use change detection,taking the two GF-2 images in 2015 and 2018 of Zhangshanying Town as the data source,the object-oriented change vector analysis(OCVA) was adopted in this study.First,the objects were obtained by different segmentation modes,and the Euclidean distance of the weight was used to build the mold of change vector.Second,the optimal detection threshold which was determined by the objective function was used to detect the whole study area.Finally,the "from-to" change type was obtained by the object-oriented classification of the change region.The results showed that:1) The accuracy of OCVA method in multi-temporal combined segmentation mode was higher than that in segmentation mode;2) The optimal detection threshold was easier to determine through using weighted combination method to build the mold of change vector,and its overall accuracy was higher than the traditional OCVA method;3) Compared with the object-oriented post classification change detection and the single OCVA method,the OCVA method combined with object-oriented classification could effectively reduce the pseudo-change,and the detection accuracy of which reached 92.50%.Keywords：land use;change vector analysis;object-oriented;GF-2;Euclidean distance1|8|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To evaluate the effect of land use changes on the value of ecosystem services (ESV) in Lingqiu County,Shanxi Province,this study analyzed the temporal and spatial changes of land use and ESV from 2010 to 2016 using the method of evaluating the value equivalent factor in unit area.The results showed that:1) Land use change in Lingqiu County was small.The area of construction land and grassland changed a lot compared with other land use forms,which increased by 163.91 hm2 and decreased by 137.92 hm2,respectively.2) The total ESV of Lingqiu County was more than 3 billion yuan at present,though it declined slightly over the past 7 years,which was reduced by 6.67 million yuan and mainly caused by the reducing of water ecological value;3) ESV was positively related to waters,forest,garden plot,grassland,unutilized land and negatively related to crop land,construction land and other land.In general,land use in Lingqiu County did not cause significant damage to the ecological environment.However,the environmental impact could not be ignored because of the human activities.In conclusion,it is necessary to further optimize the growth of construction land,protect ecological land and actively explore the ecological asset operation models and mechanisms based on the ecological protection,and finally achieve the society-economy-ecology's sustainable development.Keywords：ecosystem service value;land use change;rural revitalization;poverty alleviation0|7|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Using the survey data of 1 039 grain farmers in four provinces in China on 2015,and taking land plots as the study object,this study empirically analyzes the impact of the behavior of participation in the agricultural insurance on farmers' application of pesticides.The results show that times of pesticide application in insured plots was significantly lower than that in uninsured plots.Using instrumental variables (IV) and propensity score matching (PSM) to resolve the endogeneity,the results are robust.Specifically,the use times of pesticide of insured plots are lower about 0.25 to 0.75 times than the time of uninsured plots.This indicates that China's "Low guarantee,wide coverage" food crop insurance system has limited impact on pesticide application.In the long term,with the increase of the guarantee level of crop insurance,this disincentive may become more magnified.This means that agricultural insurance can not only achieve the policy goal of dispersing agricultural risks,but also have a positive impact on reducing pesticide application.Keywords：agricultural insurance;pesticides application;grain farmer;input behavior0|7|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the weekly price data of the cotton and wool market from January 2004 to December 2017,this study analyzed the spillover effect and dynamic relevance of agricultural textile raw material market under different policy backgrounds by using BEKK-GARCH model and a DCC-GARCH model.The results showed that the price of both cotton and wool influenced each other,but the spillover effect between cotton price and wool price varied in different periods.The implementation of cotton temporary storage policy reduced the mean spillover effect and volatility spillover effect between cotton price and wool price.The mean spillover effect between cotton price and wool price was recovered,but the volatility spillover effect was still affected after the implementation of cotton target price policy.The correlation between cotton price and wool price displayed obvious time-varying characteristics.The correlation between cotton price and wool price went through the trend of "N" which first increased and then fluctuated fell and slowly increased finally since 2004.The temporary storage and purchase policy as an underpinning type of policy reduced the correlation between the two prices while stabilizing the price of cotton.But it stabilized the degree of price correlation between cotton price and wool price.The target price policy as a subsidy policy led to the price of cotton gradually returned to the market and increased correlation coefficient between cotton price and wool price at the same time.Keywords：agricultural textile raw materials;product substitution;price;dynamic correlation;spillover effect0|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To examine the relations among industrialization,agricultural labor migration and rural labor price,the mediating effect model with panel data of 29 provinces from 1995 to 2015 was introduced in this study.The results showed that agricultural labor migration was a mediating variable between industrialization and rural labor price change.The industrialization level increases by 1%,the rural labor price would rise by 0.19%.Specifically,the industrialization displayed a significant positive impact on the rural labor price in the middle stage of industrialization,whereas it had a negative correlation with the rural labor price in the later stage of industrialization.Meanwhile the industrialization brought higher labor price through the promotion of labor migration,which was mainly in the eastern region followed by the central region and the weakest in the western region in China.Keywords：rural labor price;industrialization;agricultural labor migration;mediating effect model0|10|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analyze the influence factors of potato farmers' satisfaction with insurance service in Dingxi Gansu Province,362 commercial potato farmers' satisfaction with insurance service were studied by adopting multiple order Probit model from the perspective of farm size.It was found that large farm households who joined farm cooperatives and trusted the insurance company and small farm households who trusted the insurance company and whose local government implemented prevention measures against potential disasters intended to satisfy with potato insurance service.Therefore,it might be effective to improve farmers' satisfaction with potato insurance by improving the service quality of insurance companies,guiding large farm households to join cooperatives and encouraging local governments to carry out disaster prevention measures.Keywords：agricultural insurance service;satisfaction;potato industry;farm size0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the optimal structure of land management right under the efficiency scale,based on the micro survey data of Northeast China,this study uses two-stage OLS method to analyze the impact of land conversion rate on grain yield of households.The results show that the relationship between large households' land transfer rate and land output rate is inverted "U" type.After searching for tool variables and using two-stage OLS to estimate,the relevant conclusions are still robust.For different land factors endowment,the optimal management right structure of farmers is different,which leads to different optimal scale;under the existing technology and scale conditions,the increase of land transfer rate can improve the land output rate of large scale households,but its impact on ordinary scale farmers is not obvious.Keywords：farmland transfer rate;land productivity;structure of rural land management right;two stage least square method0|7|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：“Blue granary” is the realistic demand to ensure the national food security and optimize the national food structure.In order to analyze the potential of construction of "Blue granary" in China,a total of 23 factors affecting the construction of "Blue granary" are selected from the prospects of resources and environment carrying capacity,marine disaster,the diversity of related industries,the degree of associated industrial agglomeration,marine fisheries economic development level,Marine Fisheries Technology Level and marine fisheries management.AHP and entropy methods are used to determine the weight of each factor and build "Blue granary" construction index.Cluster analysis method is then used to evaluate and classify the comprehensive results of China's "Blue granary" construction.The results show that:The resources and environment carrying capacity of Hainan,Zhejiang and Fujian province are large While it is weakest in Tianjin.Four provinces,Shandong,Fujian,Zhejiang and Guangdong,have high levels of fishery economic development,while Hebei and Guangxi lag behind.Shandong and Jiangsu have advantages in marine fishery science and technology.Hainan's marine fishery science and technology investment is seriously insufficient.The 11 provinces and cities along the coast of China are divided into 3 categories:The first category is the key promotion area for the construction of the "Blue granary",including Shandong,Jiangsu,Fujian,Guangdong,Zhejiang and Liaoning;The second category includes Hebei,Guangxi and Hainan,which belong to the "Optimal development zone" for the construction of the "Blue granary";The third category includes Shanghai and Tianjin,which are grouped into different treatment areas for the "Blue granary" construction.Keywords：Blue granary;construction index;entropy method;AHP0|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
