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- Abstract：In order to reduce the carbon emission in the process of jet fuel preparation and utilization,this review analyzes 56 published literatures from 1999 to 2017,and summarize several key paths and their characteristics of biomass preparation of aviation fuel.Among all these routes,pathways of carbohydrates catalytic conversion in liquid phase are highlighted.The results show that carbohydrates can be used to produce aviation-range alkanes with favorable physicochemical properties by preparing different kinds of platform compounds and controlling the condensation conditions.An effective route for lignin conversion to jet fuels is also emphasized,which involves an oxidative activation of the side chains in lignin to facilitate the degradation of lignin under mild conditions,followed by the hydrodeoxygenation of the degraded products to jet fuels.Finally,several promising research directions are emphasized,including those of the development of highly efficient and mild biomass pretreatment methods,synthesis of hydrothermal stable and inexpensive catalysts that can meet comprehensive needs,reduction of hydrogen input,decrease of the reaction temperature,and conversion of biomass in a "one-pot" reaction to promote large-scale production.Keywords：biomass;jet fuel;oxidation pretreatment;hydrodeoxygenation;lignin;alkane4|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In this study,targeted editing sites of MSTN gene were used as object,and a qualitative and quantitative detection method for gene editing products based on pyrosequencing technology was established.The key parameters of the method included PCR and sequencing primers,dispensation order,standard curve and linearity.The results showed that this method could accurately detect the AG deletion site of exon 3 of MSTN gene and had the functions of qualitative genotyping determination and quantitative detection of allele frequency to accurately determine whether the sample was MSTN gene editing pig product or not and the content of gene editing product.This study would provide technical support for the regulation of gene editing products.Keywords：gene editing pig;MSTN;gene;pyrosequencing;molecular detection;genotyping3|9|4<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
Effects of paclobutrazol and ethephon on photosynthetic characteristics and yield of ‘Zhangza Gu 10’
Abstract：In order to study the effects of paclobutrazol and ethephon on photosynthetic characteristics and yield of foxtail millet.Millet cultivar ‘Zhangza Gu 10’ was taken as the research object.Paclobutrazol and ethephon were sprayed on the leaves of millet at different growth stages under random block design.Main agronomic traits including the SPAD value,photosynthetic parameters and yield of millet were measured,and the effects of single application and interaction of two plant growth regulators were compared.The results showed that the plant height of foxtail millet decreased significantly under the single application of paclobutrazol and ethephon.It reached the minimum value under A1 treatment:The plant height decreased by 4.61%;Stem diameter increased significantly;The thicknesses of first,second and third section of the base respectively increased by 11.30%,13.26% and 14.44%;Leaf area also increased by 11.76%.The SPAD value,net photosynthetic rate,transpiration rate and stomatal conductance of foxtail millet leaves increased significantly,and reached the maximum under the treatment of A2,which increased respectively by 6.81%,22.85%,18.78% and 3.48%,while the intercellular CO2 concentration decreased by 6.84% compared with the control.Except the panicle length and panicle code number,panicle diameter,panicle weight,panicle grain weight and yield were significantly different to those of the control.Among which,the panicle diameter was the best under A1 treatment,the panicle weight,panicle grain weight and yield were the largest under B2 treatment,which increased respectively by 14.10%,11.75% and 11.09% compared with the control.The plant height of foxtail millet under the interaction of paclobutrazol and ethephon reached the minimum value under A1B2 treatment,which was significantly reduced by 6.05% compared with the control.The stem diameter reached the maximum value under A1B2 treatment.The internode diameter of first,second and third section of the base increased by 11.96%,15.88% and 14.00% compared with the control.The leaf area was also the largest under A1B2 treatment,which increased by 13.11%.The SPAD value,net photosynthetic rate,transpiration rate and stomatal conductance of foxtail millet leaves reached the maximum under the treatment of A1B2,which increased by 8.37%,49.41%,22.64% and 10.75% respectively.The intercellular CO2 concentration was significantly lower than that of the control group by 8.14%.Except the panicle length and panicle number,the panicle diameter,panicle weight,panicle grain weight and yield had significant changes compared with the control.Among which,the panicle diameter was the best under A1B2 treatment,panicle weight,panicle grain weight and yield were the best under A1B2 and A2B2 treatment,which increased 20.87%,18.72% and 20.73% and 15.60%,16.11% and 16.82% respectively.The panicle grain weight and yield of millet treated with A3B3 and A3B1 were significantly lower than those of the control,which decreased by 5.54%,6.58%,7.73% and 8.81% respectively.The results showed that the interaction effect of the two regulators was more significant than that of single application.It was most suitable to spray 400 mg/L ethephon at heading stage after spraying 300 mg/L paclobutrazol before jointing stage or at jointing stage of millet.However,after spraying paclobutrazol at booting stage,topdressing ethephon at booting stage or filling stage would decrease panicle grain weight and yield.Keywords：foxtail millet;paclobutrazol;ethephon;SPAD value;photosynthetic parameters;yield0|7|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27- Abstract：In order to select suitable quinoa cultivars for Beijing,a total of 15 introduced resources were evaluated in three test sites located in Yanqing and Changping districts.The yield,plant traits,resistance,growth period and landscape effects of these cultivars were compared.The results showed that ‘Hongli-1’,‘Hongli-2’,‘Longli-1’ and ‘Longli-3’ performed well and were suitable as food landscape crops to be further tested and demonstrated in the suburbs.‘Hongli-1’ and ‘Hongli-2’ were late-mature series with growth periods of 140 to 149 d and viewing periods of 26 to 45 d.The two varieties were droop wheat ears with wheat panicle colors of red and orange.They were highly resistant to leaf spot disease and lodging,with higher yields of 2 390.26 and 2 039.56 kg/hm2 respectively in Fenshuiling Viliage,Yanshou Town,Changping District.‘Longli-1’ and ‘Longli-3’ were early-mature cultivars with growth periods of 89 to 108 d and 90 to 100 d respectively,and viewing period of 15 to 17 d.The two cultivars had upright wheat ears,red and yellow wheat panicle colors and higher yields of 1 295.23 and 1 095.02 kg/hm2 respectively in Shangguang Village,Xiangying Town,Yanqing District.Keywords：quinoa;variety;yield;landscape effect;adaptability2|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analyze the changes of DNA methylation level,the DNA methylation levels and genetic patterns in F1,BC1 and their parents were detected using methylation sensitive amplification polymorphism (MSAP) and capillary electrophoresis technology (CE).The results showed that:MSAP ratios in the maternal parent GT05-3256,paternal parent GXN1 and in the hybrid F1 were respectively 59.6%,60.5% and 56.4%-59.0%,showing the MSAP ratio in F1 was lower than that in the both parents;the MSAP ratios in the maternal parent YC94-46,paternal parent T6-3 and BC1 were respectively 59.4%,59.0% and 56.9%-69.8% in with the average of 62.8%,showing that the MASP ratio of BC1 was higher than that in the both parents.The total methylation level in the BC1 generation is slightly higher than that in the F1 generation;the methylation of CCGG loci in sugarcane genome of the individuals in F1 and BC1 mainly occurred on the internal cytosine double-strand.A total of 70 different methylations were detected in the F1 and BC1 populations,and they were further divided into 5 types:type A,the methylation patterns in the hybrids were the same as their parents;type B,demethylation,the methylation in the hybrids was weaken compared to that in the parents;type C,hypermethylation,the methylation in the hybrids was enhanced corresponding to the parents;type D,hypomethylation,the degree of methylation in the hybrids was lower than that in the both parents;and type E,uncertain type.Among them,type A is the genetic transfer type from the parent to the hybrid,and types B,C,D and E are the methylation variants of the hybrids.The results showed that the rate of methylation type A in the F1 individuals was significantly lower than that in the BC1 while types B,C,D,and E were higher than those in the BC1.In conclusion,during the F1 and BC1 hybridization,the hypermethylation occurred in the whole genome.1|7|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this study was to explore the effects of nutrient supply and sowing date on the growth and fruit quality of watermelon in wheat/watermelon/maize intercropping system,and therefore to provide a scientific basis for improving quality and nutrient use efficiency of intercropped watermelon.A field trial with single-factor randomized block design was conducted.It included three treatments:Conventional management (Con),nutrient optimization management (Opt1),and comprehensive optimization management (Opt2).The results showed that:Compared with the Con,the Opt1 decreased the length of the main and the lateral vines,number of leaf and number of flowering of intercropped watermelon.The single fruit weight and fruit soluble solids content of intercropped watermelon were increased by 10.8% and 10.5%,respectively;Compared with the Opt1,the Opt2 decreased the length of the main and lateral vines,number of leaf and flowers (except for the flowers number on lateral vine) of the intercropped watermelon grown 20 and 40 d after transplanting.However,it enhanced those traits of the intercropped watemelon grown 60 d after transplanting while increased the single fruit weight and fruit soluble solids content by 12.4% and 13.4%,respectively.In conclusion,the comprehensive management integrating nutrient optimization and sowing date adjustment would not only improve fruit yield but also promoted fruit quality of the watermelon in wheat/watermelon/maize intercropping system.Keywords：watermelon;nutrient management;sowing date;growth dynamic;quality5|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To investigate the species composition of Pythium and Phytopythium in Beijing water system,strains of Pythium and Phytopythium were collected from the Beijing river system by leaf baiting method.A total of 182 strains were isolated and analyzed by Single-strand conformation polymorphism (SSCP).Representative strains of different genotypes were then selected and identified base on their morphological characteristics and ITS sequences.The resulted showed that six known species and three suspected new species were identified.Among them,Phytopythium litotale and Pythium pectinolyticum were new records in China,while Pp.helicoides,P.diclinum,P.torulosum and P.marsipium were new records in Beijing.This study provided basic data for the future monitoring of the plant pathogen in Beijing water system.Keywords：Pythium;Phytopythium;species identification;water system;Single-strand conformation polymorphism0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The purpose of this study was to evaluate whether the mixture of alkali-treated maize straw in soybean meal could improve the production of cellulase,amylase,xylanase and pectinase by Bacillus velezensis 157 under solid-state fermentation.The mixture ratio of alkali-treated maize straw and soybean meal were optimized by using DNS method.The ratio of substrate to water,fermentation temperature and time were optimized by the method of single factor among single fermentation soybean meal,alkali-treated maize straw and mixed fermentation of alkali-treated maize straw and soybean meal,respectively.The growth curve of B.velezensis 157 during fermentation was also determined.The results showed that:After optimization of fermentation conditions,alkali-treated maize straw and soybean meal were treated as substrate in a ratio of 1.0:1.0,and the ratio of substrates to moisture is 1.0:0.5.The cellulase,amylase,xylanase,pectinase and colony number in the mixed fermentation group by B.velezensis 157 was higher than that the single fermentation of the alkali-treated maize straw and soybean meal at 37℃ and 24 h,and the activities of cellulase,amylase,xylanase,pectinase in mixture fermentation are 56.83±1.47,1 949.28±14.41,16.52±0.79 and 14.53±0.56 U/g,respectively.The corresponding enzyme activity of mixed fermentation group was 7.81,6.41,1.23 and 2.53 times higher than that of alkali-treated maize straw group,and 1.17,1.35,1.07 and 1.21 times than the soybean meal group,respectively.Meanwhile,the number of B.velezensis 157 colony in mixed fermentation group was higher than both of them.In conclusion,it can be seen that the mixture of alkali-treated maize straw and soybean meal under solid-state fermentation at certain conditions improved the yield of cellulase,amylase,xylanase and pectinase produced by B.velezensis 157.This method saved time and reduced cost.This study laid a foundation for the research and development of animal feed additives and biological feed.Keywords：Bacillus velezensis;157;solid-state fermentation;enzyme production;fermentation condition optimization0|9|0<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the early warning function and significance of serum energy balance index for ketosis in dairy cows on 14 and 7 d before delivery during early prenatal.A total of 60 prenatal dairy cows' tail venous blood were collected respectively at 7 days interval from 21 days before delivery to 21 days after delivery,and 21 healthy dairy cows and 17 ketosis cows were screened.The levels of BHBA,NEFA,GLU,TG,INS,ADP,LEP,resistin,IL-6 and TNF-α in serum were detected.The binary logistic regression model was used to screen the indexes that could alert ketosis and ROC curve was then used to determine the diagnostic effect and the optimal demarcation value of the risk assessment indexes.The results showed that:On 14 days before delivery,the levels of BHBA and NEFA in serum could be used as early warning indicators for ketosis.The optimal threshold value of BHBA was >0.42 mmol/L and its corresponding sensitivity was 58.8% and specificity was 81.0%.The optimal threshold value of NEFA was >0.47 mmol/L,its corresponding sensitivity is 58.8% and specificity is 90.5%;On 7 days before delivery,the levels of BHBA and NEFA in serum could be used as early warning indicators for ketosis.The optimal threshold value of BHBA was > 0.34 mmol/L,its corresponding sensitivity was 76.6% and specificity was 66.7%.The optimal threshold value of NEFA was > 0.32 mmol/L,corresponding sensitivity was 94.1% and specificity is 47.6%.However,the levels of ADP,LEP,resistin,IL-6 and TNF-α in serum of dairy cows on 14 and 7 days before delivery were found not suitable for the early warning for ketosis.But when the time approaching of the expected delivery period,the significance of logistic curves of the five adipokines gradually displayed statistical significances,indicating that they might be potential early warning indexes.Keywords：dairy cow;prenatal period;ketosis;adipokine;ROC curve1|9|9<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to determine the causes of disease and death of yak in Naqu,Tibet,26 visceral tissues of sick and dead calves from Ando,Bange,Nierong and Seni were taken as research object from July to November 2018.The identification of isolated bacteria were conducted by using conventional bacterial culture and specific gene PCR and the capsular serotype,virulence gene and pathogenicity were studied by PCR.The results showed that a total 13 bacteria strains were purified,the colony characteristics,morphology and biochemical identification results of the isolated bacterias were consistent with those of Pasteurella. multocida.The specific gene Kmt-1 and 16S rDNA of P.multocida were amplified.The homology of Kmt-1 gene sequence of strains Pm-1 and Pm-2 with P.multocida from cattle in India,Iran,Pakistan and Russia was over 98%.The results of capsular typing of 13 strains of bacteria showed that they were all B-type.The results of 23 known virulence genes showed that the number of virulence genes of 13 strains was 16-19.The detection rates of 16 virulence genes such as ptfA and fimA were 100%,The detection rates of other four virulence genes such as tadD and toxA were 0.The distribution of virulence genes of the isolates in each region was similar.In the pathogenicity test,all the mice in the control group survived.The death time of the mice in the treatment group was 24 to 72 h,and the mortality rate was 100%.The lesions mainly showed in the spleen,lung,liver and heart hemorrhage of mice.In conclusion,the cause of the death of yaks in Naqu was capsular B-type P. multocida.This study provides a basis for the prevention and treatment of the disease,and also provides a dominant strain for the next step of vaccine prevention research.Keywords：Yak;Pasteurella multocida;capsule;virulence gene0|7|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：The aim of this study was to find microsatellite markers of Tibetan horse population in high altitude area of Tibet.The biotin-labeled microsatellite probes were used to hybridize with Tibetan horse genomic fragments.DNA fragments 150-1 000 bp containing microsatellite sequences were captured by streptavidin-coated magnetic beads and ligated into pEASY-T1 vector.An microsatellite sequences enriched insert library was constructed.The results showed that:A total of 112 positive clones were picked from 2 380 transformants for sequencing and 39 microsatellites were indentified from the Equine genomic satellite library out of 62 microsatellites.Ten pairs of Tibetan horse microsatellite primers were successfully designed.Three polymorphic microsatellite markers were detected by PCR-SSCP method,and two of which had PIC values greater than 0.5.In conclusion,the three microsatellite markers could be applied to the study of genetic polymorphism detection of Tibetan horses and the genetic structure of the population.This study provided genetic bases for the linkage map construction,breeding,population genetic analysis,genomic structure analysis and molecular evolution research of Tibetan horse.Keywords：Tibetan horse;microsatellite markers;genetic diversity6|10|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To evaluate the difference of the nutrient composition of muscles between the wild and domesticated Schizothorax oconnori,the common nutritional component contents,amino acid and fatty acid composition of these two kinds of fish were analyzed.The results showed that the crude fat of the domesticated group was extremely significantly lower than that of the wild group (P<0.01),while there was no significant difference in the crude protein,ash and water in muscles between the wild and domesticated S.oconnori (P>0.05).The contents of essential amino acids (EAA),total amino acids (EAA) and the ratio of EAA and TAA showed no significant differences (P>0.05).Tryptophan was the first limiting amino acid both in the wild and domesticated fishes.The essential amino acid indices of wild and domesticated S.oconnori were 61.10 and 58.63,respectively.The contents of stearic acid (C18:0) and arachidonic acid (C20:1) in the domesticated group were extremely significantly higher than those in the wild group (P<0.01),and the contents of ARA (C20:4) were significantly higher than those in the wild group (0.01 ≤ P<0.05).The content of C17:1 was significantly lower than that in the wild group (0.01 ≤ P<0.05).The total saturated fatty acid (SFA),total monounsaturated fatty acid (MUFA) and total polyunsaturated fatty acid (PUFA) in muscles showed no significant differences between the wild and domesticated groups (P>0.05).In conclusion,the contents of unsaturated fatty acids in the muscle of wild and domesticated S.oconnori were respectively 68.59% and 74.50%,and both rich in EPA,DPA and DHA.Keywords：Schizothorax oconnori;muscle;nutrient composition;fatty acids;amino acids0|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Web of Science was chosen as retrieval database and literatures of the water,energy and food nexus as the research object in 2006-2018 with the aid of the theory of bibliometrics and CiteSpace.Systemic analysis was conducted from five aspects including the spatial and temporal distribution of literatures,main research institutions and funding agencies distribution,major disciplines and research direction and research journals distribution,the hot topic analysis based on noun phrases,and the Co-citation analysis of journals and authors.The results showed that:The United States and European developed countries were leading research on the nexus both in quantity and quality of the published literature and the support of research institutions and funding agencies;In recent years,the nexus research in China has developed rapidly,but the quality of the literature and support of the nexus research have yet to be improved;The current research tended to focus on water resources through the statistical analysis of major disciplines,research direction and research journals."Water Resources and Environment Sciences were main subjects of study,and Environmental Sciences & Ecology,Engineering and Water Resources were primary research directions;‘Climate change’,‘sustainable development’,‘food production’,‘food security’ and ‘nexus approach’ were important research topics.The theme related to ‘climate-change’ and ‘life cycle assessment’ were important for interdisciplinary research.Energy Policies,Environmental changes and Water Resources Research were cited the most frequently,and Hoff H Bazilian M,Ringler C,FAO and The World Bank played important roles in promoting the development of this research.Keywords：water,energy and food nexus;bibliometrics;research status and hot spots;Web of Science;CiteSpace0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Aiming at the problems of low efficiency of cotton stalk harvesting and low baling density,a self-propelled non-aligned cotton stalk combined harvest baler was designed,which can implement simultaneously removal,conveying,cutting,compression and baling of cotton stalk.The whole plant removal with regardless of row of cotton stalk by means of combination work of pulling-stalk roller with V type toothed plate and cleaning roller in the pulling-stalk platform was implemented to improve cotton stalk pulling rate.Cotton stalk was cut into (20±5) cm relied on roller type cutting mechanism in the machine to realize the compression and baling after cutting of cotton stalk and improve the compression density of cotton stalk.According to the characteristics and harvest requirement of cotton stalk,the parameters of the key components were identified,and the simulation is carried out.The simulation results showed that the key parts of the design can meet the harvest performance requirements of cotton stalk.The main performance of the machine was tested.The experimental results showed that the combined operation of removal with regardless of row,cutting,compression and baling of cotton stalk is feasible,and the operation performance of the machine was good.The qualified rate of cut length of cotton stalk was 95.24%,and the bale density was up to 159.3 kg/m3.The factors affecting pulling rate of cotton stalk in descending order were the speed of pulling-stalk roller,the depth of pulling-stalk roller into the soil and the forward speed of the machine.The pulling rate of cotton stalk was 97.83%,and the operation efficiency of the machine was 0.98 hm2/h,when the rotation speed of pulling-stalk roller was 390 r/min and the depth of pulling-stalk roller in the field was 3 cm,the forward speed of the machine was 1.2 m/s.Keywords：cotton stalk;removal with regardless of row;cut off;compression and baling;harvester1|8|7<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In the process of mechanized recycling of residue film,most of the residue film was temporarily left in the field in the form of strips (heap) after recycling.Due to the problems of loose texture and high cost of storage and transportation,it is difficult to reclaim and utilize the residue film.The optimization of the relevant molding process parameters were carried out to solve the problem of residue film's recycling in this study.The relaxation ratio and specific energy consumption were took as the test indexes,and the compression force,holding time,soil content and water content were adopted as the influencing factors in this study.An orthogonal experiment of multi-factors were carried out to analyze the influence of each factor on the compression moulding of residue film,and the regression model of multi-factor influence on the relaxation ratio and specific energy consumption of residue film compaction were established and analyzed.The results showed that the compressive force was the biggest effect factor of relaxation ratio,followed by soil content,holding time and water content.The compressive force was the biggest effect factor of specific energy consumption,followed by holding time.The influence of soil content and water content on specific energy consumption was not significant.The optimal technological parameters of residue film's compression moulding were as following:the compression force was 13.3 MPa,the holding time was 25 s,the soil content was 53.9% and the moisture content was 16.7%.Under those optimum conditions,the relaxation ratio of residue films compaction was 1.321,and specific energy consumption was 26.92 J/g.The results provided references for the design and operation parameters optimization of the following plastic film recycling and molding machines.Keywords：residue film;compression molding;relaxation ratio;specific energy consumption;optimization1|11|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to study the soil-rolling performance of the whole film double ditch laminating machine,combined with the whole film double ditch seedbed to construct the agronomic requirements,this study discusses the interaction and influence between the rolling parts of the operating machine and the soil of the seedbed.The three-dimensional finite element model of the interaction between the rolling wheel group and the seedbed soil of the soil-rolling device is established by using ABAQUS/EXPLICIT analysis software,and the numerical simulation of the soil-rolling process is carried out.The simulation results show that:When the forward speed is 1 m/s,the maximum contact stress between the wheel group and the seed bed soil of the suppression device is 1.20×10-2 MPa.And under the action of the soil-rolling wheel,the soil of the large ridge is sinking 16.61 mm,the seepage hole formed by punching wheel operation is offset 6.62 mm in the forward direction of the machine,the average depth of the seepage hole is 31.84 mm,the adjacent seepage hole is 225.75 mm,and the maximum resistance of the ridge to the soil-rolling wheel occurs at 1.15 s after contact,and the maximum soil resistance is 137.156 N;The maximum resistance of the punching wheel to movement in the ditch is 51.38 N,and the average soil resistance in the whole process of the suppression wheel and punching wheel is 104.78 and 15.02 N.The comparison of field verification operation results show that the three-dimensional finite element model can be used to predict the working condition in the working process of the suppression device.Keywords：soil-rolling;whole film double ditch;simulation;ABAQUS0|10|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In view of the lack of online detection means for the impurity rate of soybean combined harvesting machinery operation,the soybean samples harvested by Yafeng 4YZL-5S combine harvester were taken as the research object,and the online recognition arithmetic of impurity rate based on spectral inversion was carried out in this study.Firstly,the impurity rate of soybean samples was determined in laboratory.Second,the ASD FieldSpec 4 wide-res was used to measure the spectral data of soybean samples.After data preprocessing and mathematical transformation,two spectral indexes were obtained,the original spectral data (REF) and the data after reciprocal and logarithmic preprocessing of the original spectrum (LR).Thirdly,the characteristic wavelength of the spectrum of soybean samples with different indexes was selected by using the inter-band autocorrelation analysis.Finally,support vector machine (SVM) regression analysis was used to construct the inversion model of soybean sample impurity rate based on different indexes.On this basis,the precision of the inversion results was verified and compared.The results showed that the sensitive bands of soybean impurity content were different under different pretreatment conditions.The characteristic bands of REF were 512,738,851,1 104,2 003,and 2 179 nm,respectively.The characteristic bands of LR are respectively 519,637,820,924,1 121,1 933,2 050,and 2 138 nm.The modeling determination coefficient of the inversion model established in this study is greater than 0.86,the verification determination coefficient is greater than 0.79,the root-mean-square error is less than 0.32,and the relative analysis error is greater than 1.7,indicating that the model has a strong fitting effect and prediction ability.In comparison,the inversion effect of the inversion model established by REF is slightly better than that of LR.The spectral inversion model established in this study can realize online prediction of the impurity rate of soybean samples,providing a new way for online rapid monitoring of the impurity rate in soybean mechanized operation.Keywords：soybean;impurity rate;mechanized operations;support vector regression;hyperspectral remote sensing0|8|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to effectively protect cultivated land,based on remote sensing technology,different types of cultivated land,including unchanged cultivated land,newly added cultivated land,abandoned cultivated land and returned cultivated land were identified and tested.Taking Minqin as an example,this study adopted Landsat TM/OLI data obtained in spring,summer and early winter of 2010 and 2015 to reflect different landscape characteristics of ground object as the main data source of this study.According to the seasonal phase variation rule of different cultivated land evolution types and the characteristics of internal factors,the endmember abundance and feature endmember abundance change with physical significance were selected to establish a two-year mixed decision tree to classify different evolution types of cultivated land.At the same time,the land evolution types by the ratio of change detection of land use/cover classification results in the respective decision tree in 2010 and 2015 were compared.The classification results showed that most cultivated land in Minqin County was changed,and the newly added cultivated land had a certain amount of distribution in all regions and mainly distributed downstream.Large areas of returning cultivated land were located in the region of Baqu.The abandoned land was mainly distributed in the transition zone of desert oasis.In conclusion,the decision tree could be established through the endmember abundance and feature endmember abundance change,which were connected with prior knowledge of ground objects effectively to detect the evolution types of different cultivated land.Keywords：cultivatd land;spectral mixture analysis;abundance value;decision trees3|9|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to analyze and master the spatial distribution of cultivated land resources and its temporal and spatial changes,and improve the level of cultivated land protection and construction,based on the data of land use in 2009 and 2015 in Lishan Town,Sui County,Hubei Province,the cultivated land concentration index,nuclear density and spatial autocorrelation analysis were adopted to study the spatial distribution and temporal and spatial variation characteristics of cultivated land.The results showed that:1) In 2009 and 2015,the spatial distribution density of cultivated land in Lishan Town displayed obvious agglomeration characteristics,and its maximum nuclear density were 31 and 38 per km2,respectively.There is a trend of further increase on the time scale.2) During 2009 to 2015,the total amount of cultivated land in Lishan Town decreased,which reduced by 434.20 hm2,accounting for 89.20% of the total area of cultivated land reduction.The area of area reduction was mainly concentrated in the north and southwest of Lishan Town.3) In 2009 and 2015,the scale of cultivated land in Lishan Town was mainly concentrated in medium-sized cultivated land,but the cultivated land in the administrative village where the large-scale cultivated land concentrated area accounted for the largest proportion of total cultivated land,which were 55.55% and 56.08%,respectively.It was larger than the sum of the proportion of the total cultivated land in small and medium-sized cultivated land.4) The global spatial autocorrelation Moran's I of the area ratio of cultivated land in the administrative village of Lishan Town in 2009 and 2015 were 0.5251 and 0.3970 respectively,and the spatial distribution of cultivated land had significant spatial self-positive correlation.According to the local autocorrelation,the areas with more cultivated land distribution were mainly concentrated in Tongxin Village and the Yuzhou Village,and the areas with less cultivated land were concentrated in the mountainous area north of Cheshuigou Village.Keywords：spatial distribution of cultivated land;index of cultivated land concentration;nuclear density;autocorrelation analysis1|8|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Reasonable the farmland facilities evaluation and the limiting factors analyses on farmland are important to improve the scientific remediation of land and the quality of farmland.Hailun City,Heilongjiang Province is taken as the research area.Based on the village-level questionnaire data obtained,the TOPSIS model and Least Square Error model are used to carry out the evaluation of farmland facilities and division of land remediation types.Based on the conditions of water conservancy,ecological protection and mechanization,the results indicate that:1) The levels of farmland facilities in the west,southwest,and central and northern parts of Heilongjiang are higher,and other areas are relatively lower.The overall shows a decreasing distribution trend from northwest to southeast;2) According to the number and type of constraints of different evaluation units,the farmlands are classified into three types including water conservancy conditions upgrading area,ecological water improvement area and comprehensive remediation area.This study provides a scientific basis for improving farmland facilities and scientifically preparing land remediation plans and improving the quality of cultivated land.Keywords：land use;farmland facility;TOPSIS;Least Square Error;type partition of land remediation1|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Based on the Cost-Benefit data of rapeseed planting in Hubei Province from 1978 to 2016,this study empirically analyzed the influencing factors on rapeseed planting income in Hubei Province from two aspects of sensitivity and contribution rate by unit root test,co-integration analysis and contribution rate analysis.The sensitivity analysis showed that yield was the most sensitive factor affecting the earning of rapeseed planting in Hubei Province,followed by labor cost,sale price and the cost of agricultural materials.The contribution rate analysis showed that the contribution rate of unit yield and the change of rapeseed planting income in Hubei Province was the largest,followed by the sale price,labor cost and the cost of agricultural materials.Under the linkage change of different factors,the rapeseed cultivation during 2009-2016 faced the dilemma of "double board extrusion",which led to less profitable space for rapeseed cultivation.In order to increase the income of farmers in Hubei Province and boost the willingness to grow rapeseed,this study put forward countermeasures and suggestions from the perspectives of yield,sale price,labor cost and the cost of agricultural materials in the end.Keywords：rapeseed;planting earning;co-integration analysis;sensitivity;contribution rate0|7|1<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：Taking green manure rotation in farmers' farmland in southern rice region as an example,binary logistic analysis was conducted on the decision-making behavior of green manure planting based on the micro survey of 506 households.The results show that:From the perspective of farmers' wishes,planting green manure to improve soil fertility and protect the environment can be supported by most farmers under the premise of fully respecting farmers' pursuit of maximization of individual or family utility.From the mechanism of the influence of various factors,the age of farmers,whether they are village cadres,family income,the social and ecological welfare awareness and external factors are important factors influencing their decision-making behaviors.Compared with individual characteristics and family endowment,external factors have a more significant positive effect on farmers' green manure planting decisions,especially policy publicity and planting subsidy.Based on the results above,the following policy implications are proposed:First,fully respect the wishes of farmers and guarantee their right to maximize their personal or family utility.Second,intensify policy publicity to raise farmers' awareness of the comprehensive welfare of planting green manure.Third,integrate the resources of all parties and strengthen the construction of the green manure demonstration base.Finally,establish the ecological compensation mechanism of planting green manure and raise the subsidy standard.Keywords：green manure;farmers' decisions behavior;southern China;binary logistic model2|7|14<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to promote the moderate scale management of grassland animal husbandry in China,by taking sheep as an example,this study explored the appropriate scale of grassland animal husbandry from 3 aspects of output level,output level and production cost based on the survey data of 371 sheep farmers in Inner Mongolia,Gansu,Xinjiang,Liaoning,Hebei and Sichuan.The empirical results showed that:Under the situation of government technical training and the implementation of the policy of prohibiting animal husbandry,the phenomenon of increasing returns to the production of villi in the present stage was discovered;The large-scale production of farmers and herdsmen had the phenomenon of scale economy,and it was identified as moderate operation scale;In addition,the technical training helped to increase the production and profit of farmers and herdsmen and reduced the cost of production;The implementation of the prohibition policy increased the production cost of the farmers and had a negative impact on production profit.Therefore,we should expand the scale of grassland animal husbandry,increase the number of technical training,develop feed forage resources and promote the healthy development of grassland animal husbandry.Keywords：grassland animal husbandry;moderate scale;scale reward;output level;production cost0|7|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：In order to explore the reduction potential of China's pig breeding pollutants,based on stochastic frontier production function model,this study uses the provincial macro data on pig breeding in 2004-2016 to measure the environmental efficiency of pigs breeding of different scales,calculates the potential reduction of pollutants produced by pig breeding from time and space dimensions and explores the path of improving the environment efficiency of pig breeding in further.The results show that:1) The average environmental efficiency of small-scale,medium-scale and large-scale pig breeding are respectively 0.924,0.953 and 0.926.With the increasing of the breeding scale,the environmental efficiency shows an "inverted U-shaped" trend.And the environmental efficiency of three scale pig breeding has increased to varying degrees over time.2) In terms of time dimension,the pollutants produced by small-scale,medium-scale,large-scale pig breeding are reduced by 5.89,2.42 and 4.13 kg each year while the potential reduction of pollutants in three pig breeding scale is decreasing over time.3) In terms of spatial dimension,the potential reduction of pollutants in the eastern part of small-scale pig breeding is higher than that in the central and western regions;The potential reduction of pollutants of medium-scale pig breeding is relatively balanced in each region;The potential reduction of pollutants of large-scale pig breeding shows a two-level differentiation trend in different regions.4) The input production factors including the number of feeding days and environmental treatment costs display significant effects on the environmental efficiency of pig breeding.Finally,based on the research results obtained,relevant measures are proposed to improve the environmental efficiency of pig breeding.Keywords：pig breeding;breeding scale;environmental efficiency;potential reduction of pollutants;determinants1|9|3<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To increase the performance of livestock and poultry breeding waste treatment,a influencing factor system of the performance of the farmers' waste treatment was constructed to conduct empirical analysis using the Structural Equation Model and the survey data of the farmers in Beijing in 2017.The results showed that:The government intervention and the moral responsibility of farmers had significant positive impact on the farmers' behavior of livestock and poultry breeding waste treatment and it further positively affected the economic,social and environmental performance of livestock and poultry breeding waste treatment.The promoting effect of moral responsibility of farmers was higher than that of the government intervention.The behavior of farmers,a key role in the influencing factor system of livestock and poultry breeding waste treatment and the medium of government intervention and the moral responsibility of the farmers,directly play a maximum positive effect on the performance of livestock and poultry breeding waste treatment.Therefore,in order to comprehensively improve the performance of farmers,it is necessary to increase government intervention,adhere to both constraints and support,continuously promote the environmental ethical responsibility of farmers,and improve the policy system and performance evaluation system for livestock and poultry breeding waste treatment.Keywords：livestock and poultry breeding waste;government intervention;moral responsibility;treatment performance;structural equation model0|9|5<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
- Abstract：To assess the significance of detecting the information attribute of clenbuterol in meat products,the full profile conjoint analysis method was adopted to evaluate the relative importance of different attributes and the utility level based on a survey of 298 consumers in Wuxi City.The clenbuterol detection information,traceability information security,appearance,and price were set as four attributes.The research also estimated the market share of traceable pork under the 11 kinds of market simulation scheme.Results indicate that:The consumers valued the appearance most,followed by price and the detection information of clenbuterol,then the property of the traceability security information.Compared with the traceable pork without the detection information of clenbuterol,consumers were willing to pay a 10% premium price of traceable pork with the test of clenbuterol qualified,and the market share of the traceability pork which has qualified test results of clenbuterol increases about 30%.Therefore,On the basis of publicizing the contents of different levels of detection information,this study puts forward some countermeasures and suggestions,such as sticking detection information labels such as illegal additives of clenbuterol,strengthening the publicity of traceability information and food traceability system to perfect the construction of pork traceability system and prevent food safety risk from illegal additives of clenbuterol.Keywords：traceable pork;the detection information of clenbuterol;preferences;market simulation;willingness to pay0|8|2<HTML><L-PDF> <Meta-XML>Updated：2024-02-27
