Abstract:Cattle industry is an important part of animal husbandry and a pillar industry for agriculture and rural development in China.However， the prevalence of important infectious diseases in cattle seriously restricts the healthy and sustainable development of cattle industry and public health security.With the continuous expansion of domestic and foreign trade related to cattle， its impact is on the rise.In this paper， the epidemic characterization， control status and challenges of important bovine diseases in China were reviewed from three aspects， including important infectious diseases， emerging infectious diseases and re-emerging infectious diseases.It is considered that the prevalence of important infectious diseases in cattle is associated with complex and changing natural， social， and economic factors， which is characterized by following aspects： unclear epidemiological background， the continuous emergence of new diseases， the re-emergence of some controlled diseases， the frequent co-infection with multiple pathogens， diagnosis， and treatment difficulties etc.Finally， based on the current internal and external challenges for the effective prevention and control of important bovine infectious diseases， the prevention and control suggestions were put forward， in order to provide reference for the effective prevention and control of important bovine infectious diseases in China.

Abstract:In August 2019，lumpy skin disease （LSD） broke out firstly in Yili，Xinjiang Uygur Autonomous Region，China，and then spread throughout the country.Due to lack of comprehensive knowledge and experience in prevention and control of LSD，clinically，they are often lack of targeted measures，leading to the spread of the disease and causing significant economic losses to the cattle industry.Therefore，in order to identify the key risk factors and the key links of prevention and control of LSD，this paper comprehensively reviewed the etiological characteristics，pathogenic mechanism，clinical characteristics，transmission rules，diagnosis，prevention and control measures，and put forward suggestions for the effective prevention and control and elimination of LSD in China.

Abstract:Bovine respiratory disease complex （BRDC） is one of the most important infectious diseases that endangers domestic and international cattle industry.The etiological factors include multiple pathogens such as viruses，bacteria，mycoplasmas，as well as various stressors.Clinical diagnosis is preliminarily drawn by observing the abnormal signs such as dyspnea and the accuracy of pathogen diagnosis is low.Furthermore，because the disease has the characteristics of multi-etiologic mixed infection，the laboratorial diagnosis is often not specific，which makes it difficult to judge the therapeutic effect and prognosis of the disease.In order to provide reference for early and accurate diagnosis，timely treatment and effective prevention and control of BRDC，this paper outlined the etiology，epidemiology，hazards，and diagnostic methods of BRDC，including both conventional clinical and molecular biological diagnostics，as well as new methods based on host biomarkers such as acute phase proteins，stress-related hormones，and transcriptomic diagnosis.Further，the practical application，advantages and disadvantages of these methods were briefly described，and the future direction of diagnostic methods and the problems to be solved were also prospected.

Abstract:To evaluate the dynamics of antibodies production after subcutaneous and intradermal inoculation of attenuated goat pox vaccine （AV41 strain） in cattle and optimize the immunization program of cattle，25 healthy beef cattle were randomly assigned into 5 groups and inoculated subcutaneously and intradermally at 5 and 10 times of goat dose，respectively.The standard single dose was 1.0 × 10^3.5 TCID₅₀ AV41 strain.At 0，15，30，45 and 60 days post vaccination，the serum antibody level was detected by both virus neutralisation test （VNT） and a commercial ELISA kit.The PCR results of nasopharyngeal swabs and blood were negative without shedding vaccine strain.The results of VNT and ELISA antibody detection were similar，60% of the cattle in the subcutaneous inoculation with 5 times dose group seroconverted on day 30 post vaccination，with the maximum neuralising antibody titer of 1∶640，followed by the intradermal inoculation with 10 times dose group and subcutaneous inoculation with 10 times dose group （40%），while only 20% seroconverted in the intradermal inoculation with 5 times dose group.The neutralisation index of VNT was significantly positively correlated with the S/P value of ELISA.The above results suggest that similar to the inoculation route and dose of relevant international vaccines，subcutaneous inoculation of AV41 at a 5 times goat dose is safe and effective and can be used as a clinical vaccination protocol for lumpy skin disease.

Abstract:In order to establish a quick and efficient visual LAMP （loop-mediated isothermal amplification） molecular method for detecting Mannheimia haemolytica in cattle， specific software tool was used to design LAMP primers including inner primers， external primers and loop primers targeting M. haemolytica conservative gene lktC. The reaction temperature， Mg²⁺ concentration， dNTPs concentration and other conditions were optimized. Both bacteria and recombinant plasmids were used to evaluate sensitivity， and 15 related pathogens were used to evaluate specificity. The applicability was evaluated using mice lung tissue samples with clear background. The results showed that the developed LAMP assay achieved the best results under the conditions of 68.2 ℃， 6 mmol/L Mg²⁺， 1.6 mmol/L dNTPs for 40 min and could be judged by naked eyes. The minimum detection limits were 6.7×10^-1 CFU/μL for bacteria and 7.9×10² copies/μL for lktC recombinant plasmid， and there was no cross reaction with 15 other pathogens， indicating high sensitivity and specify. The results of lung tissue samples from mice with clear background showed that the method was better than ordinary PCR method. The above results indicate that this method was successfully constructed and could be used for rapid and efficient detection of M. haemolytica in cattle.

Abstract:In order to improve the clinical diagnosis efficiency of bovine respiratory disease complex （BRD） with multiple pathogen mixed infection，this study established a real-time quantitative PCR （qPCR） for multiple and rapid detection of seven common pathogens of BRD including Mycoplasma bovis （M.b），Pasteurellae multocida （P.m），Mannheimia haemolytica （M.h），bovine infectious rhinotracheitis virus （IBRV），bovine syncytial virus （BRSV），bovine parainfluenza virus type 3 genotype a （BPIV-3a） and c （BPIV-3c），the specific primers and TaqMan probes were designed and synthesized for the oppD/F gene of M.b，gcp gene of M.h，ompH gene of P.m，gB gene of IBRV，N genes of BRSV，BPIV-3a and BPIV-3c，respectively. After optimizing the reaction conditions，a multiple qPCR was established for simultaneous detection of the above seven pathogens in three tubes. This method specifically amplified these seven pathogens，rather than other major pathogens commonly found in cattle，indicating a high specificity. For M.b，P.m，M.h，IBRV，BRSV，BPIV-3a and BPIV-3c，the analytical sensitivity as limit of detection （LOD） was 10² copies /μL，10² copies /μL，10¹ copies /μL，10² copies /μL，10² copies /μL，10² copies /μL，10² copies /μL and 10¹ copies /μL，respectively，suggesting a high sensitivity. In addition，the coefficient of variation of the method was less than 2.5% within group and 5.5% between groups，indicating a good repeatability. Furthermore，115 clinical nasal swabs were parallelly detected by this method and conventional PCR，and the positivity was 27.83% for M.b，36.65% for P.m，25.22% for M.h，11.30% for IBRV，0.95% for BRSV，8.57% for BPIV-3C，with the proportion of coinfection was 26.1%. A total of 11 mixed infection patterns were detected，among them，the coinfection rate of M.b with other pathogens was the highest，accouning for 72.7% （8/11）. Within the 30 coinfection cases，the detection rate of M.b/P.m coinfection was the highest （60%，18/30）； the top three pathogens present in the coinfection were M.b，P.m，and M.h with frequency of 73.3% （22/30），73.3% （22/30） and 43.3% （13/30），respectively； followed by IBRV （26.7%，8/30） and BPIV-3c （13.3%，4/30）. Overall，this method has high sensitivity and specificity，and potential application in the clinical detection of single pathogen and multiple pathogens causing BRD.

Abstract:Bovine viral diarrhea virus （BVDV） is one of the most important pathogens in cattle diseases，causing serious economic losses to the cattle industry worldwide. A comprehensive assessment of the prevalence of BVDV in cattle herds in China is of great significance for the prevention and control of BVDV infection. We conducted a systematic review and Meta-analysis on the BVDV detection rate in cattle in China by searching the literatures published from 1981 to September 1，2021 on China National Knowledge Infrastructure （CNKI），Wanfang Database，VIP Chinese Journals Database，PubMed and ScienceDirect. A total of 93 studies on BVDV pathogenic detection were selected and included in this Meta-analysis. The overall prevalence rate of BVDV in cattle herds in China was estimated to be 9.8% （95%CI：7.8-11.9），among which the prevalence rate of BVDV antigen was 3.1% （95%CI：2.1-4.4），and the prevalence rate of BVDV nucleic acid was 19.5% （95%CI：7.5-23.3）. In the subgroup of sampled province，Jilin Province had the highest combined prevalence rate （26.3%，95%CI：24.3-28.4），followed by Hubei Province （24.6%） and Fujian Province （22.4%）. Subgroup analysis and Meta regression analysis showed that breed （yak vs dairy cattle； OR=1.37，95%CI：1.05-1.79），breeding mode （free-ranging vs large-scale；OR=1.41，95%CI： 1.08-1.85），diagnosis method （RT-PCR vs ELISA； OR=1.64，95%CI： 1.38-1.94），and animal health （clinical symptoms vs asymptomatic； OR=1.42，95%CI： 1.20-1.68） were the factors that significantly increased the prevalence rate of BVDV. In addition，plateau alpine （OR=1.54，95%CI： 1.20-1.97） and high altitude （>3 000 m； OR=1.64，95%CI： 1.21-2.21） geographical and climatic factors may promote the prevalence of BVDV. The above results show that BVDV is widely prevalent in dairy cattle，beef cattle，and yak populations in China. Therefore，it is necessary to continuously monitor the prevalence of BVDV infection. In addition，according to the risk factors identified in this study，the corresponding prevention and control programs should be made to prevent the spread of BVDV in cattle herds in China.

Abstract:In order to investigate the role and application potential of Terminalia chebula in the prevention and control of livestock and poultry diseases， three species of common pathogenic bacteria， Escherichia coli， Klebsiella pneumoniae and Enterobacter cloacae were selected as test organisms. The inhibition circle diameter and minimum inhibitory concentration （MIC） of T. chebula and 11 other Chinese herbal extracts were compared， the total leakage rate， electrical conductivity， protein concentration in the supernatant， and the effects of T. chebula on the DNA and protein content of bacteria were analyzed. The results showed that T. chebula had stronger antibacterial effect than other Chinese herbs， with larger circle diameter and lower concentration of bacteriostatic. The conductivity and leakage rate of culture supernatant increased. The protein concentration of the supernatant of E. coli and K. pneumoniae significantly increased （P<0.05） after 2-fold MIC T. chebula treatment for 8 h. T. chebula inhibited the protein synthesis of E. coli， resulting in the deletion of a protein with a molecular weight of about 80 ku. However， T. chebula had no obvious effect on protein synthesis of K. pneumoniae and E. cloacae. T. chebula had no significant gel-blocking effect on bacterial DNA， but could degrade DNA. The above results indicate that T. chebula could exert its antibacterial effect by disrupting the permeability of bacterial cell membrane and inhibiting the synthesis of bacterial nucleic acid and protein.Therefore， the rational application of the T. chebula extract is a new idea for the prevention and control of livestock and poultry infectious diseases in China.

Abstract:Ratooning rice as a cultivation mode of rice with low cost and high benefits has been promoted in China， but the effects of the mode on carbon footprint of rationing rice production are unclear. A field experiment was conducted to study the effects of different cultivation modes of ratooning rice including conventional cultivation mode （CK）， two optimized cultivation modes （OM1 and OM2）） on the emission of methane （CH₄） and nitrous oxide （N₂O） ， grain yields， carbon footprint and economic benefits in central China. The results showed that the OM1 and OM2 modes were optimized from the perspectives of water and fertilizer managements， stubble height， straw treatment in the first season and winter management compared with CK. The cultivation modes significantly affected CH₄ emissions but had no effect on N₂O emissions. OM2 significantly reduced the annual cumulative CH₄ emissions by 43.5% and 26.3% relative to CK and OM1， respectively. Cultivation modes significantly affected grain yields and carbon footprint. Compared with CK and OM1， OM2 significantly increased the yields of first rice season by 15.2% and 5.8， and the yield of ratooning rice season by 44.2% and 34.7%， respectively. OM2 significantly decreased the carbon footprint by 40.0% and 24.0% relative to CK and OM1， respectively. The highest net ecosystem economic benefit of OM2 was 20 768 CNY/hm²， which was 1.38 and 1.28 times of those of OM1 and CK， respectively. It is indicated that OM2 mitigates CH₄ emissions， reduces carbon footprint， increases rice yields and improves NEEB compared with other modes. OM2 is a sustainable cultivation mode of ratooning rice with low-carbon emission， high yield and high economic benefit. It will provide scientific basis for cultivating ratooning rice with low carbon and high yield.

Abstract:Six treatments including straw returning with feeding （SF），straw returning without feeding （SNF），straw removal with feeding （NSF），straw removal without feeding （NSNF），rice monoculture with straw returning （CK-S），and rice monoculture with straw removal （CK-NS） were set up to study the effects of straw returning to field and feeding on rice quality under rice-cray co-culture mode. The results showed that feeding （F） significantly increased the yields of rice and crayfish，and the nutritional quality of rice. In the case of straw returning （S） and straw removal （NS），the content of protein in the F treatment was increased by 27.41% and 36.16%，respectively，significantly improved the nutritional quality of rice. The interaction between S treatment and F treatment significantly affected the processing quality of rice. The whole milled rice rate and milled rice rate were the highest under NSNF treatment，significantly higher than those under SF，SNF and NSF treatment. Straw returning，feeding and their interaction had no significant impact on the quality of cooking and eating. There was no significant difference in RVA viscosity spectrum of rice. Rice-crayfish co-culture mode improved the appearance quality of rice. Compared with CK-S，the chalky grain rate and chalkiness degree of SF decreased by 15.09% and 15.65%，respectively. It is indicated that straw returning and feeding can improve rice quality under rice-crayfish co-culture mode to a great extent.

Abstract:To explore the effects of rice-crayfish co-culture system on the contents of heavy metals in paddy soil and rice，field experiments were carried out under different soil backgrounds in Jingmen city and Xishui county of Hubei Province，with Xiangwanxian 12，Huanghuazhan and Yuzhenxiang as experimental materials under rice monoculture as control. The results showed that under the background of weak alkaline soil，the contents of Cr，As，Cd，Pb，and Hg in paddy soil decreased，and the contents of Cd and Pb in roots，stems，spikes，and brown rice decreased. Under the background of weak acid soil，the contents of Cr，As，Cd，Pb and Hg in paddy soil increased，the contents of Cd and Pb in rice roots increased，the contents of Cd in stems，leaves and spikes of rice increased，while the contents of Pb in stems，leaves，and spikes of rice decreased，and the contents of Cd，Pb in brown rice decreased. The results showed that the effects of rice-crayfish co-culture system on the contents of heavy metals in paddy soil and rice under different pH soil backgrounds are inconsistent，but rice-crayfish co-culture system can significantly reduce the contents of Cd and Pb in brown rice.

Abstract:Nanjing 9108 and Huanghuazhan were used as materials under machine direct seeding. Under total nitrogen 210 kg/hm² in the field， three different nitrogen fertilizer treatments including N1 （base fertilizer 5∶tiller fertilizer 2∶young spike fertilizer 3）， N2 （3∶4∶3） and N3 （none∶6∶4） were set up， and no nitrogen fertilizer （N0） was used as the control to study the effects of different nitrogen management on the yield， quality and nitrogen fertilizer utilization efficiency of rice with machine direct seeding. The results showed that the yield of the two rice varieties was the highest when the fertilization ratio was 3∶4∶3. The average yield of Nanjing 9108 and Huanghuazhan was as high as 9 691.2 kg/hm² and 11 596.1 kg/hm²， significantly different from that of other treatments. The brown rice rate， milled rice rate and head rice rate of rice were not significantly different among treatments， but the content of amylose and protein increased with the increase of panicle fertilizer ratio in the decreasing order of N3 > N2 > N1. The chalkiness rate and chalkiness decreased with the increase of panicle fertilizer ratio in the decreasing order of N1 > N2 > N3. The rice quality of N3 （none∶6∶4 ） was significantly higher than that of other treatments. The nitrogen absorption of rice at stage of each growth under the treatment of 3∶4∶3 was significantly higher than that of other treatments. The nitrogen agronomic efficiency and nitrogen use efficiency were N2 > N3 > N1， reaching a significant level. It is indicated that， N2 （3∶4∶3） significantly affect the yield and nitrogen use efficiency of rice under the same nitrogen application rate， and N3 （ none∶6∶4 ） significantly affect the rice quality.

Abstract:Taking the rice variety “Quanliangyou Efeng Simiao” as the material，the treatments including no fertilization （N0），the one-time side deep basal application of controlled-release fertilizer （N1），the one-time side deep basal application of controlled-release fertilizer by 10% nitrogen reduction （N2），the one-time side deep basal application of controlled-release fertilizer by 20% nitrogen reduction （N3），and the traditional and fertilization （CK） were set up to develop the simple and efficient cultivation technology of machine-transplanted rice with one-time deep foundation application. The tillering dynamics，leaf area index and dry matter accumulation at stages of major growth，root index at stage of heading，various nitrogen use efficiencies and yield were measured to study effects of one-time side deep application with controlled-release fertilizer on the growth，nitrogen utilization and yield of rice. The results showed that the N1 and N2 treatment significantly increased the yield by 12.99%-14.85% and 5.47%-6.09% compared with the treatment of CK. The yield of N3 treatment was not significantly different from that of CK. After fitting analysis of fertilization amount and yield，the yield was the same as that of CK when the nitrogen was reduced by 18.72%. Compared with CK，the one-time side deep application of controlled-release fertilizer significantly increased the tiller percentage of ear bearing，the leaf area index and dry matter accumulation at stages of the middle and late growth of rice，promoted root growth and expanded the distribution range of roots. Compared with CK，N1，N2 and N3 treatment increased the apparent nitrogen use efficiency by 1.21%-46.57%，agronomic nitrogen use efficiency by 18.85%-61.73%，physiological nitrogen use efficiency by 8.90%-17.71% and partial factor productivity nitrogen by 12.99%-23.61%. It is indicated that the one-time side deep application of fertilizer release promotes root growth，increases panicle number，improves the efficiency of various nitrogen use，and greatly reduces the number of fertilizations. The high and stable yield of rice can be achieved within the scope of reducing nitrogen by 18.72%.

Abstract:In order to effectively control jujube dry rot disease，47 fungal isolates of jujube dry rot plaques from different sources were identified and characterized by using sequence analysis of internal transcribed spacer （ITS） and elongation factor 1 α （EF-1α） genes and indoor inoculation method，and their distribution characteristics and virulence differences were analyzed. The distribution characteristics and differences in pathogenicity were also studied. The results showed that Botryosphaeria dothidea，Spencermartinsia viticola，Diplodia mutila，D. seriata，and Phaeobotryon rhois were identified as the major pathogens causing jujube dry rot. Among them，the isolation frequency of S. viticola was the highest （65.96%），followed by that of B. dothidea （17.02%）. The dominant pathogens were different in different regions. B. dothidea and D. seriata were the predominant species in Henan and Hebei areas，and S. viticola was the predominant species in Shanxi，Gansu，and Ningxia areas. The pathogenicity of different pathogens to jujube tree was different，and the results indicated that the pathogenicity of B. dothidea was the highest and that of P. rhois was the weakest. The results of this study showed that the pathogens of jujube dry rot were mainly composed of 5 species in the Botryosphaericeae family，and the dominant pathogens were different in different regions. In terms of pathogenicity，the pathogenicity of different strains of the same pathogen varies in different regions，and the pathogenicity of different strains of pathogens in the same region also varies. The results of this study provide reference for the precise prevention and control of jujube dry rot in different areas.

Abstract:To identify the dominant strains in the intestinal tract in female adults of the quarantine fruit fly pest， Zeugodacus tau （Walker）， and their effects on feeding ability， nutritional status and fecundity， here traditional microorganism isolation and molecular identification techniques were use to isolate and identify the culturable bacteria， and then antibiotic treatment and intestinal dominant strains supplementation were carried out to detect the intake， hemolymph amino acid content and egg production of Z. tau.The results indicated that the elimination of intestinal bacteria significantly reduced the oviposition， food intake and hemolymph amino acid content of female adult fruit flies to 34.9%， 43.2% and 60.8% of the control （without antibiotic treatment） levels.Subsequently， 9 cultivable strains were isolated and identified as Proteobacteria and Firmicutes， and are mainly distributed in the genera of Enterococcus， Enterobacter and Bacillus.The dominant strains were Enterococcus sp.ZYY 2-97 （57.41%） and Bacillus sp.ZYY 1-83 （17.59%）.In addition， after supplemented with ZYY 2-97 and ZYY 1-83 strains， the total fecundity of the female adults were significantly recovered to 75.00% and 86.98% of the control level， and the food intake were significantly recovered to 117.53% and 117.85% of the control level， respectively.Meanwhile， the amino acids contents in hemolymph were recovered to 94.80% and 87.81% of the control level.Our findings demonstrated that the intestinal bacteria could affect the fecundity of Z. tau by regulating the feeding capacity and nutritional status of the female adults， and the dominant culturable strains play a key role in this process.

Abstract:In the previous studies，the global transcriptome databases of Mesorhizobium huakuii 7653R in free living and in symbiotic condition were constructed respectively. Some differential expression genes in free living and symbiotic condition were identified with RNA-Seq and Microarray. Among these genes，MCHK_7135 belongs to the peroxiredoxin （Prxs） family. Its expression was significantly up-regulated at the stage of symbiotic nitrogen fixation.In this article，the replacement mutants and complementary strains of MCHK_7135 were constructed by homologous recombination to study the function of MCHK_7135 gene in symbiotic nitrogen fixation between rhizobia and host plants. The phenotypes of mutant and complementary strains were investigated under free living and symbiotic condition with Astragalus sinicus. Results showed that the mutant strain of MCHK_7135 gene was more sensitive to H₂O₂ stress compare with the wild-type strain. The growth of A. sinicus plant inoculated with the mutant was inhibited，the number of infect thread and nodule primordia decreased，the number of nodule was small，and the activity of nitrogenase was low. However，when the mutant strain was complemented by complete MCHK_7135 gene，some symbiotic phenotypes were restored to different degree. It is indicated that the peroxiredoxin gene MCHK_7135 of M. huakuii plays an important role in the symbiotic nitrogen fixation between rhizobia and host plants.

Abstract:FIP-fve is a low molecular-mass protein identified from Flammulina filiformis， which has many biological activities including immunomodulation. Our previous studies found that FIP-fve had certain growth-promoting effect on F. filiformis mycelia. We constructed an over-expression vector pCAMBIA1301-pGPD-FIP-fve， and transformed it into Agrobacterium tumefaciens LBA4404 strain to study the native biological function of FIP-fve to F. filiformis. FIP-fve gene overexpressed F. filiformis was obtained via Agrobacterium transformation. By comparing the biological characteristics of FIP-fve gene-silent F. filiformis （RNAi：FIP-fve）， FIP-fve gene-overexpressed F. filiformis （pGPD：FIP-fve） and wild F. filiformis （CK） in mycelium and fruiting body stages， we found that the growth speed of pGPD：FIP-fve was faster than that of CK， whereas the growth speed of RNAi：FIP-fve was the lowest. After cultivating the fruiting body， yield-related traits of pGPD：FIP-fve were significantly better than that of CK in terms of fruiting body numbers， stalk length， fruiting body yield and biological efficiency， and those traits of RNAi： FIP fve were the worst. It is indicated that FIP-fve significantly promote the growth of F. filiformis mycelia and affect the final yields of F. filiformis.

Abstract:The changes of microbial biomass carbon，microbial biomass nitrogen，microbial diversity，microbial community structure and driving factors were analyzed in four different years including Y1 （flue-cured tobacco planting 1 a），Y2 （flue-cured tobacco continuous cropping 3 a），Y3 （flue-cured tobacco continuous cropping 5 a） and Y4 （flue-cured tobacco continuous cropping 7 a） of tobacco planting soils in Shangluo area，the hinterland of Qinling Mountains to study the changing characteristics and driving factors of microbial community structure of flue-cured tobacco soil under different continuous cropping conditions.The results showed that the microbial biomass carbon，nitrogen and carbon nitrogen ratio decreased with the increase of planting years，with the decrease of 37.16%，20.40% and 21.10%，respectively.The abundance and diversity of bacteria in soil decreased significantly.The dominant bacteria were Actinobacteriota，Proteobacteria，Chloroflexi，Acidobacteriota and Firmicutes，with the total relative abundance accounting for 80% or more.The abundance of fungi in soil increased significantly.The dominant fungi were Ascomycota，Basidiomycota and Mucoromycota，with the total relative abundance accounting for 90% or more.Under the condition of Y4 continuous cropping，the relative abundance of beneficial microorganisms such as Firmicutes and Desulfobacterota in the soil decreased.The relative abundance of pathogenic microorganisms such as Mucoromycota and Chytridiomycota increased.Long term continuous cropping will reduce the relative abundance of beneficial microorganisms in soil，increase the relative abundance of pathogenic microorganisms，and decrease the carbon nitrogen ratio of soil microbial biomass，thereby increase the risk of tobacco disease.Therefore，the establishment of a good farming system or the construction of microbial community is the key technical way to alleviate or solve the imbalance of microbial community structure in continuous cropping tobacco fields.

Abstract:Root exudates are the main medium of communication between crops and soil，play important roles in the activation of nutrients in soil，the nutrient uptake and growth of crops.This article summarized the classification and function of root exudates，and their effects on the activation of nutrients including nitrogen，phosphorus，potassium and iron in soil，the nutrient absorption and growth of crops to study the relationship between root exudates，crops，soil and microorganisms，and to use different root exudates to achieve interspecific promotion，improve the utilization rate of natural resources and agricultural productivity.The different mechanisms of crop response to nutrient stress were discussed.The prospects including strengthening the identification means of root exudates to realize the in-situ damage-free identification and analysis of root exudate components，using interdisciplinary knowledge to further reveal the root-soil interface biological interaction process of efficient utilization of crop nutrients mediated by root exudates，focusing on functional localization of target genes and microorganisms that verify that root exudates affect plant response to biotic and abiotic stresses，using genetic engineering to effectively improve plant health，promoting the process of transforming research results into scientific and technological applications，and applying beneficial root exudates to practical production via using bionics principle were put forward.

Abstract:Two kinds of deactivators including biochar and sepiolite were used to study the deactivation effects of different compound ratios （mass ratios of 1∶1，1∶2，2∶1），application amount （1% and 3%） and deactivation time （45 d and 90 d） on the content of Cd and Zn in contaminated soil to restore the cadmium （Cd） and zinc （Zn） co-contaminated soil around a landfill in Sichuan. The effects of compound deactivators on the availability and speciation distribution of Cd and Zn in contaminated soil were analyzed. The changes of stability and mobility of Cd and Zn in soil were investigated with the stability index （I_R value） and mobility index （M_F value）. The results showed that the deactivation effect of Cd and Zn in soil significantly increased with the increase of deactivation time and application amount. The deactivation effect of Cd and Zn in soil was the best when the ratio of biochar to sepiolite was 2∶1，and the deactivation rate was 31.1% and 23.1%，respectively. After the application of compound deactivators，the proportion of weak acid extractable and reducible fractions of Cd and Zn in soil decreased while the proportion of oxidizable and residual fractions increased. The application of compound deactivators enhanced the stability and decreased the mobility of Cd and Zn in soil compared with the control. When the ratio of biochar to sepiolite was 2∶1，the M_F value of Cd in soil decreased by 17.5% and the I_R value increased by 9.0%. The M_F value of Zn in soil decreased by 6.1% and the I_R value increased by 18.7% at 3% application amount. In general，biochar and sepiolite mixed at a mass ratio of 2∶1 and a dosage of 3% had the best remediation effect on the content of Cd and Zn in the co-contaminated soil.

Abstract:The subtropical yellow brown soil column was leached with 0-0.08 mol/L of pH 3.5 (molar concentration ratio of 4︰1, 2︰1 and 1︰1) FeSO₄ and MnCl₂ single or mixed solution for 40 times (7 days interval each time） to study the leaching and deposition characteristics of iron and manganese in soil under alternating dry and wet conditions. The content changes of pH, Fe and Mn of the leached solution, the content of Fe, Mn, Ca and Mg in the soil were analyzed. The results showed that the pH of leachate from soil column treated with Fe and Mn decreased by 1.10-2.68 with the increase of leaching times, even lower than that of leaching solution. The content of iron in the leachate was lower than that in the leaching solution, while the content of manganese in the leachate was opposite after 7 times of leaching. The total amount of Fe and Mn, the content of free and amorphous iron oxides in the soil increased at the first stage (20 times) and the second stage (40 times) of leaching. The content of iron and manganese oxides in the soil increased after leaching with high concentration of iron and manganese solution. The highest content of free iron and manganese oxide was 89.14 mg/g and 13.35 mg/g, respectively. Iron oxides were easier to form than manganese oxides under the alternate wetting and drying leaching conditions. The contents of iron oxides and manganese oxides were higher in the upper layer (5 cm) and the lower layer (25 cm), respectively. The content of Ca and Mg in soil after being leached decreased by 0.45-4.89 g/kg and 8.68-14.45 g/kg, respectively.

Abstract:Under the background of beautiful countryside construction and digital village strategy, the digital integration, management, expression and application of rural landscape resources are the basic work to improve digital management of rural ecology and human settlements in China.A big data application platform for rural landscape resources was constructed to solve the multi-source heterogeneity and difficulty in integrating rural landscape resource data, applying 3S and multi-source data fusion technology.The overall functional structure was described around the construction process of the core modules of the three platforms including the integration and storage of multi-scale rural landscape resource data, the function of classification and evaluation of rural landscape resources, and the visualization of rural landscape resource data.The integration and display of multi-scale and multi-source rural landscape resource data in the national territory-region-local -village domain was realized by building a distributed “space-attribute integration” rural landscape resource big data application platform.On one hand, the platform offers data channels and digital platform support for rural planning, construction, and management; on the other hand, it will provide methods and ideas for constructing rural big data platforms in other fields to help the development of digital villages.

Abstract:The observation data of 18 national meteorological stations in western Hubei Province were used to conduct risk index analysis of tobacco high impact meteorological disasters in recent 60 years based on the established risk index system of damages caused by drought, chilling, steady rain, rainstorm, high temperature and high heat, and make comparison between the previous and the last 30 years to identify the effects of climate changes on tobacco meteorological disaster risk in western Hubei. The results showed that the risk of drought, steady rain and rainstorm in tobacco growing areas in western Hubei Province reduced overall in the past 30 years in term of time dimension. But the risk of drought in southwestern Hubei Province increased, indicating that water condition had gradually become one of the main factors affecting local tobacco production. Under the background of climate warming, the risk of chilling and high temperature and heat damage had shown a trend of partial mitigation and general aggravation. Regionally, Zaoyang, Nanzhang and other places were continuously affected by drought. The chilling damage was concentrated in high altitude areas, while high temperature and heat damage was distributed in river valleys. Wufeng and Xingshan were relatively high incidence centers of hail and gale, so it was necessary to prevent the damage brought by severe convective weather. It could be seen that the main meteorological disasters and climate changes affecting tobacco production in western Hubei Province were different due to different geographical locations. From the distribution of comprehensive meteorological disaster risk, except the northeastern Badong and the northern part of Jianshi, the comprehensive risk level of meteorological disasters in most areas of Enshi in last 30 years was still “medium” or above, with Hefeng being the most serious.

Abstract:Citrus jam was prepared by vacuum concentration and atmospheric boiling respectively. The changes of physicochemical indicators，color，microorganism，rheological properties and texture properties of jam with different concentration treatments were studied to optimize the process of jam concentration. The results showed that the concentration treatment significantly increased the contents of total soluble solid，titratable acid，total sugar，total phenolics，total flavonoids，total carotenoids and pectin of jam samples （P<0.05） compared with the untreated group. Among them，the content of total phenolics，total flavonoids，and total carotenoids in vacuum concentrated samples was the highest，42.93，63.32 and 36.33 μg/g，respectively. The degree of browning was slight，and the brightness value （L^*） was the largest. The results of rheological and texture test showed that the citrus jam was a yield-pseudoplastic fluid，showing positive thixotropy in the shear range of 0.1-100 s^-1. Its storage modulus （G'） and loss modulus （G"） increased with the increase of oscillation frequency，and G'>G"，showing the characteristics of viscoelastic body dominated by elasticity. In the frequency scanning range of 0.1-100 rad/s，G' in the atmospheric boiling group was the largest （1 435-4 005 Pa），followed by G' in the vacuum concentration group （722.6-2 082 Pa），and G' in the untreated group was the smallest（59.04-214.1 Pa）. The vacuum concentrated jam sample has smaller hardness，stickiness and chewability，and better taste. It is indicated that vacuum concentration can greatly maintain the quality and color of citrus jam，and has the potential to replace traditional atmospheric boiling.

Abstract:In order to improve the stability and application potential of corn oil emulsion and explore the influence of insoluble citrus fiber on the properties of corn oil emulsion，the corn oil Pickering emulsion was constructed with insoluble citrus fiber as stabilizer，and the rheological properties，morphological structure，stability and other properties of the emulsion were characterized and analyzed to improve the stability and application potential of corn oil emulsion and study the effects of insoluble citrus fiber on the properties of corn oil emulsion. The results showed that the viscosity，energy storage modulus and loss modulus increased with the increase of the content of insoluble citrus fiber in corn oil Pickering emulsion. The emulsion had the properties of pseudoplastic non-Newtonian fluid. The network structure formed by insoluble citrus fiber in the system resulted in the gradual increase of the particle size of the system. When the content of insoluble citrus fiber was 0.2%（w/w） and 0.3%（w/w），the absolute potential of Pickering emulsion exceeded 30 mV，and the effect of emulsification was better. The centrifugal stability and freeze-thaw stability of emulsion increased with the increase of the content of insoluble citrus fiber. When the content of insoluble citrus fiber in the emulsion was greater than 0.1%，no stratification occurred in the emulsion for 30 days. It is indicated that insoluble citrus fiber has good stability of emulsification. 0.2%-0.3% insoluble citrus fiber can be mixed with corn oil emulsion to build stable Pickering emulsion. It will provide a new direction for the application of corn oil emulsion.

Abstract:A method of extracting watercore feature and calculating proportion based on BiSeNet was proposed to solve the problems of low precision and complex methods of evaluating watercore quality during the planting process due to the irregular distribution of watercore characteristics in the cross section of watercore apple. Four models including BiSeNet， FCN， PPLiteSeg and DeepLabV3 were used to extract the watercore characteristics in the cross section of 380 watercore apple samples. Each evaluation index in theoretical research and practical research were calculated separately. The comprehensive evaluation and comparison was conducted. The results showed that BiSeNet was superior to the other three network models in both training time and training accuracy. It took 130 s， with the accuracy rate of 98.36% and the intersection and combination ratio of 85.1%. In the actual proportion calculation， the average proportion calculation error was 4.04%， lower than that of the other three models， and there was no large deviation. It is indicated that the method of extracting and calculating watercore characteristics in the cross section of watercore apple based on BiSeNet can provide more accurate methods of evaluation and comparison targets for nondestructive testing of watercore characteristics of watercore apples while providing specific proportion of watercore.

Abstract:Aiming at the problems of low automation level， high labor intensity and low feeding efficiency of piglet feeding， a piglet feeding system was designed， and an automatic control system with PLC controller as the core was developed to realize the automatic control of water addition， temperature control， stirring and feeding in the process of piglet feeding.The effects of pipe diameter， pipe material， inlet temperature and pipe flow rate on the pressure distribution and temperature distribution of milk water pipeline were investigated by CFD numerical simulation.Based on the simulation results， the basic parameters of the pipeline were determined， namely， the pipe material was PPR material， the pipe diameter was 6 branch pipeline （external diameter was 25 mm， wall thickness was 2.8 mm） and the pipe flow rate was 0.8 m/s.The performance test showed that the average relative error of the temperature control accuracy of the piglet milk jar was 0.91%， and the temperature variation was maintained at ± 1 °C.The standard deviation of temperature sample was 0.226 3 ℃， and the coefficient of variation was 0.499%； the temperature range of piglets feeding point was 36-45 ℃； the pressure distribution of piglet feeder ranged was 28.36-53.20 kPa.The results showed that the piglet feeding system could normally realize the functions of water supply， stirring， heating， circulation and drainage.The pipe pressure and temperature distribution at each feeding point met the requirements of piglet feeding.This study has important practical significance and application prospect for improving the level of feeding automation and feeding management of piglets.

Abstract:3D reconstruction of trees is of great significance in the fields of plant phenotyping， digital orchards， and forestry resource planning. Kinect and lidar， a depth color camera based on infrared active structured light， are commonly used 3D reconstruction devices. In order to better establish a 3D color model of a single tree of cherry trees and obtain accurate phenotypic parameters， a detection method based on Kinect camera and lidar point cloud information fusion of single tree is proposed in this paper. Firstly， the complete environmental point cloud of the area where the single cherry tree is located is collected by the lidar to generate a point cloud map. Secondly， the multi-view point cloud of the single cherry tree is collected by the Kinect camera to obtain a complete 3D color point cloud. Based on the lidar point cloud position， the two point clouds were initially registered by selecting corresponding points with the same name， so that there was a good initial position relationship between the point clouds. Then， the point clouds were accurately registered by using the iterative closest point （ICP） algorithm. Finally， the color point cloud is used to perform point cloud coloring and fusion processing on the radar point cloud to realize the 3D reconstruction of the single-tree cherry tree. Compared with the single-tree phenotype parameters of cherry trees generated only by the Kinect v2 camera， the average relative errors of plant height， crown width and diameter at breast height of the integrated cherry trees were reduced by 1.52， 6.46 and 18.17 percentage points， respectively. The experimental results show that the Kinect v2 depth color camera and lidar can achieve complementary advantages in the 3D reconstruction of a single tree， improve the registration accuracy of the point cloud， and at the same time， it can not only reduce the influence of light and climatic conditions， but also increase the measurement distance， and the phenotype of a single tree can be improved. parameters are more accurate. The single-tree 3D reconstruction method of this complementary fusion technology has a good application prospect， and can be applied to the occasions such as fruit tree phenotype and growth monitoring， etc.， to provide technical support for the development of digital orchards.

Abstract:Aiming at the problem that mechanical vibration changes the force and transport state of seeds， which then leads to the reduction of precision seeding performance， an experimental study was conducted on the effect of vibration frequency and amplitude on the seeding performance of rapeseed precision seeder based on the vibration seeder performance testing test bench. The results showed that the critical negative pressure at 30 Hz vibration frequency is slightly lower than the state without vibration， and the qualification index is higher than 90% after the critical negative pressure， at 10 Hz and 20 Hz vibration frequency， the vibration causes the increase of vertical displacement of seed metering device， and the increase of seed feeding disorder， and the seed throwing qualification index is always less than 80%， which is obviously lower than no vibration and 30 Hz vibration frequency. Under the condition of 40 Hz vibration frequency and amplitude ≥8 m/s²， the seed filling chamber and seed suction area showed the state of “boiling”， and the higher qualification index can be obtained at a lower seed suction negative pressure， and the vibration under the higher negative pressure will reduce the resorption rate of shaped hole. With different combinations of frequency and amplitude conditions， the critical negative pressure of seed suction varied significantly， and the seed discharge qualification index corresponding to the negative pressure of seed suction before reaching the critical value was significantly different， and the influence of mechanical vibration was reduced after reaching the critical value. This study provides a reference for the improvement of the vibration adaptive structure of rape precision seed raiser， and provides a basis for the research on increasing the beneficial vibration interval or reducing the vibration interference in production.

Abstract:A set of automatic control system of sugarcane harvester cutter was designed to solve the problem that the sugarcane harvester cutter cannot automatically control the depth of cutting device， which affects the quality of harvest. The system mainly included angle profile mechanism， depth detection system， hydraulic system and control system. The fuzzy PID control algorithm optimized by genetic algorithm was used to adjust the depth of the soil in real time through Simulink step response and step response with random interference simulation. The results showed that the overshoot of fuzzy PID control algorithm optimized by genetic algorithm was 4.9%. The adjustment time was 1.535 s， being improved compared with PID control algorithm and fuzzy PID control algorithm. The results of comparing laboratory test showed that the error of fuzzy PID control algorithm optimized by genetic algorithm was （-0.5，0.5）， which was the smallest， indicating that it automatically control the depth of the cutter effectively.

Abstract:Steam blanching is needed to reduce the difficulty of peeling Citrus reticulata Blanco before peeling. Because the parameters of steam blanching depend mainly on experience, insufficient or excessive steaming often leads to poor peeling and damages quality of pulp. The heat transfer model of Citrus reticulata Blanco was established based on the finite element method. The variation law of the internal temperature field of citrus under steaming was studied. The steaming time of citrus with different fruit diameters was predicted. The results showed that the convection heat transfer between steam and the surface of citrus peel caused the temperature to increase sharply during steam blanching. The heat was transferred radially to the pulp center. With the extension of steaming time, citrus was heated more evenly along the radial direction, the surface temperature of pulp increased rapidly and then stabilized, and its heat transfer rate increased first and then decreased. The smaller the fruit diameter, the greater the heat transfer rate on the pulp surface, and the higher the pulp surface temperature at the same steaming time. In order to ensure that the quality of citrus pulp will not be damaged, the blanching time of citrus with small fruit diameter should be less than 77 s, and the blanching time of citrus with large fruit diameter should be less than 172 s. It will provide reference for optimizing steam blanched peeling process of Citrus reticulata Blanco.

Abstract:The phytoene desaturase gene （PDS） as a reporter gene was used to study the feasibility of applying virus-induced gene silencing （VIGS） on oil palm embryoid using the TRV as a vector， and to optimize the relevant parameters. The results showed that the effect of gene silencing was the best when EHA105 was used as the strain under the condition that the OD₆₀₀ of infected bacterial solution was 0.5， with infection time of 5 min， acetosyringone （AS） mass concentration of 20 mg/L， co-cultivation of 48 h， and post-infection incubation time of 12 d. On this basis， the VIGS system optimized was used to silence the diacylglycerol acyltransferase gene （DGAT）， and the expected gene silencing effect was achieved.