Forestry plays an important role in ecological environment protection and sustainable economic development， and forestry diseases and insect pests are the main factors restricting forestry development. In recent years， with the development of modern technologies such as remote sensing， machine vision， biology and the internet of things， an important means has been provided for accurate， rapid and large-scale forest pest monitoring and early warning. Therefore， a comprehensive review was made on the application of modern technology in forest pest monitoring and early warning， aiming at providing technical reference and auxiliary decision basis for relevant practitioners. In terms of remote sensing， the mechanism of forest pest monitoring based on spectral response was introduced， and the latest application progress of remote sensing technology in forest pest monitoring was discussed from different scales. In the aspect of machine vision， the advantages and disadvantages of traditional machine learning and deep learning were compared， and the help of transfer learning to network training and the feasibility of lightweight model in improving monitoring efficiency were analyzed. In biology， how to use the biological characteristics of insects and biological changes in plants to monitor insect pests and diseases were analyzed. On this basis， the combined application of internet of things， 5G and other network technologies with modern monitoring technology was expounded for remoting monitoring and early warning of forest pests and diseases. Finally， in view of the current forest disease and pest monitoring was not timely， the evolution was not clear， the early warning was not accurate， the prevention and control was not accurate and other problems， it should be urgent to establish the ground and air three-dimensional pest monitoring network with the internet of things technology as the core in the future， build a complete pest and disease database， and establish a multi-terminal online real-time information display monitoring and early warning system.

Society has always been concerned with the safety and quality of agricultural products. Frequent food safety problems have serious impacts on consumers， making it especially important to establish a trustworthy traceability system fo agricultural product quality and safety. The existing challenges associated with the traceability system for agricultural product quality and safety were analyzed from 4 different perspectives： participating entities and centralized management modes， the integrity， authenticity， and reliability of traceability data， incorporation of traceability details into the supply chain， and accurate monitoring of data. The use of blockchain technology as a decentralized， reliable way to share and manage information， offering fresh insights for establishing a reliable traceability system that guarantees the quality and safety of agricultural products were explored. Based on this， it proposed the strategic policy of establishing a “dual-brand dual-chain” agricultural product quality and safety traceability system， agricultural product certification identification system， agricultural product quality and safety intelligent supervision system， traceability service system for agricultural entrepreneurship， and application demonstration system construction. Measures such as establishing a consortium blockchain for the trustworthy traceability system of agricultural product quality， developing smart contracts， selecting a consensus mechanism， and choosing encryption algorithms could be taken to accelerate the integration of blockchain and agricultural product quality and safety traceability systems，which would comprehensively enhance the ability of the agricultural product quality and safety traceability system and ensure the safety of agricultural products.

Lactococcus lactis is an important model strain in application and research of lactic acid bacteria in heterologous expression of proteins. L. lactis is an ideal host for heterologous protein expression due to its generally recognized as safe （GRAS） status， probiotic properties， the absence of inclusion bodies and endotoxins， surface display， and extracellular secretion. In view of the properties of L. lactis stimulating mucosal immunity， it has been widely used in presenting viruses and bacterial antigens.The recent research of L. lactis expression system was reviewed， with emphasis on the secretion and anchoring strategies of alloprotein expression of L. lactis， and the application of L. lactis as a microbial cell factory in food， medicine， especially antigen presentation were summarized. Finally， an outlook on the future research direction of the L. lactis expression system were provided.

In order to efficiently carry out the screening of excellent wheat germplasms， a total of 163 wheat germplasms were used as materials to analyze their high molecular weight glutenin subunit composition （HMW-GS）， drought resistance during germination and seedling stages，and high-quality drought resistant germplasms were slected. Known functional genes/loci of high-quality drought resistant germplasm resources were detected. The results showed that among the tested materials， 11 and 1 germplasms were identified to contain the combination 1/7+8/5+10 and N/14+15/2+12 of high-quality noodle， and 5 and 53 were identified to contain the combination 1/7+9/5+10 and N/7+8/2+12 of high-quality steamed bun subunits， respectively. After combining the comprehensive evaluation resuits of drought resistance during the germination and seedling stages， a total of 14 wheat germplasms with strong drought resistance were identified. In addition， based on the HMW-GS identification results of these 14 drought-resistant germplasms， 9 high-quality drought resistant germplasms were ultimately selected， namely Zhong 41-42， Longyu 5， Longmai 079， Lantian 31， 92-47， Mianmai 367， Xikemai 531， Tongmai 3 and Linhan 5322. After testing， these 9 high-quality drought resistant materials contained genes/loci that increase grain weight and resistance to Fusarium head blight， stripe rust and leaf rust. 6 germplasms contained gene Ppo2-D1 that enhanced polyphenol oxidase activity. 6 germplasms contained the semi-dwarf gene RHT-8， and only Longmai 079 contained drought resistant gene TaSINA-2. The above results provide excellent germplasms and necessary theoretical support for wheat breeding.

To explore the effects of different agronomic traits on yield， and screen suitable varieties of foxtail millet for planting in western Jilin， 23 agronomic traits and yield of 20 millet varieties were tracked and measured on important growth stages. Variation analysis， partial correlation analysis， correlation analysis and path analysis were used to evaluate. The results showed that the coefficient of variation of single grain weight was the largest （15.3%）， while the coefficient of variation of growth period was the smallest （5.9%）. The number of stems during heading stage， number of stems during maturity stage， number of leaves during tillering stage， number of leaves during heading stage， length of the second last leaf during maturity stage， spike thickness， single panicle weight， single grain weight， and 1 000-grain weight jointly accounted for 98.6% of the variation in yield. The partial correlation analysis showed that the yield was significantly correlated with the number of stems during heading stage， number of leaves during heading stage， spike thickness， and single grain weight， with partial correlation coefficients of -0.687， 0.642， 0.647 and 0.573， respectively. The correlation analysis showed that spike length， single panicle weight， and single grain weight were significantly positively correlated with the yield， with correlation coefficients of 0.601， 0.958 and 0.962， respectively； the spike thickness was positively correlated with the yield， with correlation coefficient of 0.559. The path analysis showed that the number of stems during maturity stage， number of leaves during heading stage， length of the second last leaf during maturity stage， spike thickness， single grain weight， and 1 000-grain weight had direct positive effects on yield. In conclusion， Jigu 168， Zhonggu 9 and Nenxuan 18 were mid-maturing and high-yield cultivars suitable for planting in semi-arid areas of western Jilin. Single grain weight and single panicle weight should be the main selection criteria， with the number of stems during heading stage， number of leaves during heading stage and spike thickness as supporting criteria for field screening and cultivar selection. Above results provided a basis for breeding new foxtail millet varieties and screening high-yield strains in semi-arid areas of western Jilin.

In order to study the differences of leaf area and photosynthetic fluorescence characteristics among different nitrogen efficiency island cotton cultivars under different nitrogen fertilizer levels， the high nitrogen-efficient variety Miancheng 10 （MC10） and low nitrogen-efficient variety Xinhai 14 （XH14） were as test materials， and 3 nitrogen application treatments were set up including 0 （N₀）， 320 （N₁） and 480 kg·hm^-2 （N₂）. The leaf area， photosynthetic fluorescence characteristics， yield and response characteristics to nitrogen fertilizer of different cultivars were studied. The results showed that the application of nitrogen fertilizer significantly increased the leaf area of single plant， net photosynthetic rate （P_n）， and stomatal conductance （G_s） of island cotton， and those of MC10 were higher than those of XH14， with the increase of 7.5%~22.4%， 14.5%~38.0%， and 32.4%~111.1%， respectively. The relative variable fluorescence curves （ΔV_t） of 2 varieties fluctuated greatly at K point， and N₂ and N₀ treatment were significantly higher than N₁， XH14 was lower than MC10 under N₀ treatment， and XH14 was higher than MC10 under N₁ and N₂ treatment. The proportion of variable fluorescence F_Kto F_J-F_O amplitude （W_K）， the relative variable fluorescence intensity （V_J） at J point and the initial slope （M_o） of OJIP fluorescence induction curve were all shown as N₂>N₀>N₁， the decrease range of N₀ and N₂ treatment compared with N₁ treatment was MC10>XH14. While the maximum photochemical efficiency （φ_Po） in photosystem Ⅱ （PSⅡ）， the ability to transfer electrons to downstream electron transport chains （ψ_o ） and the quantum yield （φ_Eo） used for electron transport showed opposite trend. The maximum photosynthetic quantum efficiency （F_v/F_m）， potential photochemical activity （F_v/F_o）， the performance index based on absorbing light energy （PI_ABS） and the potential performance index （PI_total） of energy reduction from photons absorbed by PSⅡ to PSⅠ terminal acceptors showed a trend of increase firstly and then decrease with the increase of nitrogen application rate， MC10 was higher than XH14. And both varieties had the lowest values of F_v/F_m， F_v/F_o， PI_ABS andPI_total under N₂ conditions， of which the decrease range of XH14 was the most. Nitrogen application could significantly increase the number of bolls， boll weight and yield per plant of island cotton. Compared with XH14， the yield per plant of MC10 increased by 16.9%~33.8%， 3.3%~7.7%， 19.4%~41.7% respectively. In conclusion， no nitrogen and high nitrogen treatment caused PSⅡ damage of island cotton leaves to varying degrees， reduced photosynthetic performance， and there was the difference among varieties. Above results provided a theoretical basis for the selection and cultivation of high-efficiency nitrogen varieties in the future.

To investigate the mitigating effect of rhamnolipids （RLS） on the physiological growth of cotton seedlings under salt stress， 2 salt gradients including low salt （3 g·L^-1 NaCl， T₁） and high salt （6 g·L^-1 NaCl， T2） and 4 RLS gradients including 0（R₀）， 200（R₁）， 300（R₂） and 400 mg·L^-1 （R₃）were set up to analysis the effects of RLS on the root morphology， antioxidant enzymes and osmoregulatory substances of cotton seedlings under salt stress. The results showed that the appropriate level of RLS under salt stress could promote the growth of total root length， root surface area and root tip number of cotton seedlings. Under low salt stress， the activities of superoxide dismutase （SOD）， peroxidase （POD）， catalase （CAT） and contents of proline （Pro）， soluble sugars （SS） in the roots of cotton seedlings firstly increased and then decreased with the increase of RLS content，with T₁R₂ showing an increase of 14.0%， 15.2%， 28.8%， 28.5% and 19.5%， respectively， compared with T₁R₀. The activities of SOD， POD， CAT and contents of Pro，SS in the roots of cotton seedlings under high salt stress showed a gradual decrease under high salt stress， with T₂R₁ treatment increasing 10.5%， 12.6%， 13.9%， 21.7% and 4.8%， respectively， compared with T₂R₀. Principal component analysis showed that the response of cotton seedling root surface area， SOD and Pro to the regulation of RLS under salt stress was high， and could be used as the main control indicators for the physiological growth regulation of cotton seedlings by RLS under salt stress. The optimum content of RLS applied under low salt stress to enhance the salt tolerance of cotton seedlings was 300 mg·L^-1， while the optimum content of RLS applied under high salt stress was 200 mg·L^-1. Above results provided a more suitable exogenous application strategy for cotton salt tolerance and stress tolerance planting.

CCCH （C3H） type zinc finger proteins are evolutionarily conserved RNA-binding proteins， which primarily bind to DNA and RNA and play a role on the regulation of gene expression. They are not only involved in plant growth and development and hormone regulation， but also in response to biotic and abiotic stresses. 47 SlC3H genes in tomato were identified by bioinformatics approach， which were unevenly distributed on 12 chromosomes and mainly localised in the nucleus. They were divided into 3 subclades （Ⅰ~Ⅲ） based on phylogenetic relationships. The covariance analysis revealed the presence of gene duplication in the SlC3H gene family， which suggested that SlC3H genes might have undergone family member expansion through duplication during evolution. The tomato SlC3H gene contained 1~14 exons with elements responsive to hormonal and abiotic stresses in its promoter region. The Ka/Ks analysis indicated that members of the SlC3H gene family and C3H genes had undergone strong evolutionary selection during evolution. The qRT-PCR analysis revealed that the expression of more than half of the SlC3H gene family was up-regulated under salt stress， with SlC3H1 reaching a maximum expression at 8 h， 30 times higher than at 0 h. And the expressions of all SlC3H genes were up-regulated under 0.1 mol·L^-1 2，4-epibrassinolide （EBR） treatment， with 8~150 times higher than control. In especial， the expression of SlC3H28 in other stages was almost zero， but it’s expression in green ripening stage was 150 times higher than control. Above results provided a reference for further insights into the function of the C3H gene family in tomato in response to abiotic stresses and fruit development.

Significant progress has been made in computer vision and deep learning technologies in various scenarios，such as object recognition and image classification，and showed extensive applicability and development potential in tobacco production in recent years. The current state of applications of computer vision and deep learning technologies in tobacco production were reviewed，with a particular focus on their methods and means to solve problems in tobacco disease recognition，tobacco harvesting and curing， and tobacco grading. By analyzing different algorithms and their application in key stages of tobacco production，and considering the challenges and development directions this technology faces in the field of tobacco production，theoretical support and references were provided for intelligent tobacco production.

The visible light vegetation index is a method for vegetation extraction applied to RGB images. Various visible light vegetation indices have been utilized for vegetation extraction in unmanned aerial vehicle （UAV） images. However， it still need to improve in terms of extraction efficiency and accuracy. Based on the analysis of the spectral characteristics of green healthy vegetation and 8 different land cover types in UAV RGB images， this study proposed a visible light vegetation index based on the green and blue bands， named as enhanced green-blue ratio index （EGBRI）. The effectiveness of EGBRI was compared with 8 commonly used visible light vegetation indices， and the accuracy was quantitatively evaluated by combining the results of visual interpretation of land cover and confusion matrix. The results indicated that the vegetation index calculated by EGBRI could effectively extract green vegetation in the study area and had a suppressive effect on other land cover types. Compared with other commonvisible light vegetation indices， EGBRI enhanced the discrimination between vegetation and other land cover types， demonstrating higher classification accuracy. The overall accuracy of EGBRI was 95.06%， the Kappa coefficient was 0.889 5， which was at a relatively high level， enabling rapid and accurate extraction of vegetation cover in the study area. In conclusion， the proposed EGBRI could effectively， rapidly， and accurately extract green vegetation information from UAV RGB images， demonstrating good applicability and extraction accuracy.

The selection and configuration of discrete element parameters for wood powder particles have direct impacts on the reliability of simulation results when studying the homogenization of wood powder at various moisture levels during wood panel production using EDEM software. This study focused on pine wood powder and conduct experimental research to establish a mathematical model relating moisture content to the repose angle， a key response parameter. Based on the Hertz-Mindlin JKR contact model， 2 distinct discrete element particle models were developed to conduct simulation. Using Plackett-Burman experimental design， 3 significant parameters-inter-particle collision restitution coefficient， inter-particle rolling friction coefficient， and JKR surface energy were selected from an initial set of 10 parameters related to wood powder particles that influence the repose angle. Mathematical models correlating the repose angle to these significant parameters are constructed through response surface analysis， and their statistical significance was confirmed （P value=0.000 1） with relative errors N≤4.07%. Furthermore， by deriving models that link moisture content to repose angle and subsequently to discrete element parameters， a comprehensive framework for predicting discrete element parameters was established based on moisture content. Experimental validation using a cylinder lifting method yields relative errors N≤4.34%. These results indicated that moisture content could be used to derive discrete element parameters for wood powder， offering a method for determining discrete element contact parameters for simulation in wood panel manufacturing processes. This study provided insights for optimizing wood panel production processes and designing efficient mixing equipment.

In order to study the power consumption of furrow plough in the agricultural machinery operation process， a method of interpolation using diesel engine bench data and controller area network（CAN） data was proposed to obtain the diesel engine power of the plough agricultural machinery for ploughing operations. The power of the plough was measured by the tension sensor and GPS instrument. Then， with fixed tillage depth of 23 cm， a field experiment was carried out with 3 types of target tillage speeds of 5.7， 7.1 and 8.9 km·h^-1. With fixed tillage speed of 5.7 km·h^-1， a field experiment was carried out with 3 types of tillage depths of 20， 23 and 26 cm. The results showed that the actual tillage speed of plough agricultural machinery fluctuated greatly around the target tillage speed， which caused the furrow plough power， the furrow plough power ratio， the diesel engine power， the fuel consumption and other performance parameters were changed， and the diesel engine power variation rate was up to 15.93%. With the increase of tillage speed and tillage depth， the power of the plough and diesel engine both increased， and the proportion of the power of the plough was relatively stable. The percentage of plow power to diesel engine power ranged from 56.24% to 67.30%. The results of this study were expected to provide a reference for the matching， optimization and selection of agricultural machinery power systems.

To identify the pathogen of anthracnose in avocado and screen the suitable fungicides， fruit samples of Hass avocado suspected anthracnose disease from Danzhou city， Hainan province were sampled. And the pathogen was isolated and identified. The pathogenicity of strain was confirmed according to Koch’s postulate. And the sensitivity of pathogenic strain to 9 fungicides were evaluated in vitro using mycelium radial growth assay. The results showed that the 4 pathogenic strains were identified as Colletotrichum siamense according to the morphological and phylogenetic analyses of multi-locus sequences. All of 4 strains showed virulence and high pathogenicity to avocado fruits. Among 9 fungicides， prochloraz was the most effective with the mean effective inhibitory medium concentration （EC₅₀） values of 0.11 mg·L^-1， and azoxystrobin， difenoconazole， pyrazoxystrobin， penthiopyrad and carbendazim followed with mean EC₅₀ values ranged from 2.09 to 4.29 mg·L^-1. So these 6 above-mentioned fungicides exhibited strong inhibitory activities against the mycelial growth of C. siamense， which could be used as candidate agents for the control of avocado anthracnose. Above results should help in developing strategies for the management and control of anthracnose in avocado.

To clarify the taxonomy of the pathogen causing a new bacterial leaf spot disease on fig （Ficus carica） in Fuzhou in 2020， diseased fig leaves were collected as test materials. The bacterial strains were isolated from the diseased leaves by streak plate method， and then the pathogenicity of the strains was determined by tobacco allergic reaction， spray inoculated fig leaves and Koch’s rule. The pathogen was identified based on morphological characteristics， physiological and biochemical determination， and phylogenetic tree analysis using partial sequences of 16S rDNA， gyrB and rpoD. The results showed that 10 bacterial strains were isolated and purified from the diseased leaves， healthyfig leaves demonstrated similar symptoms as the specimen collected from fields， and the identical morphological bacterial strains were re-isolated from diseased fig leaves. Thus， all of the bacterial strains were identified as the causal pathogens of bacterial leaf spot disease by Koch’s rule. The colony morphology was light yellow， round， and flat on the NA medium after 2 d of culture， and the gram staining reaction was negative. The bacterial strains could produce green water-soluble fluorescent on KB medium. The sequencing analysis based on 16S rDNA， gyrB and rpoD showed that the test strains were clustered with Pseudomonas cichorii； and the results of physiological and biochemical characteristics， Biolog phenotypes instrument， and specific primers were similar to the P. cichorii strain 5707， therefore the 10 isolated bacterial strains were identified as P. cichorii. It was the first report that P. cichorii could naturally cause the leaf spot disease in F. carica.

To explore the physiological response of tobacco plant infected by Phytophthora to Trichoderma harzianum application sequence， the pot experiments were carried out with different treatments including inoculated with Phytophthora spore suspension （T1）， inoculated with T. harzianum spore suspension （T2）， inoculated with Phytophthora spore suspension first and then inoculated with T. harzianum spore suspension （T3）， inoculated with T.harzianum spore suspension first and then inoculated with Phytophthora spore suspension （T4）， inoculated with Phytophthora spore suspension and T. harzianum spore suspension at the same time （T5）， and clear water （CK） as controls. The effects of T. harzianum application sequence on biological characteristics， physiological characteristics and induced resistance of tobacco infected by Phytophthora were analyzed. The results showed that， in the growth of tobacco plants， the agronomic characters of tobacco plants with T4 treatment increased the most， and the dry and fresh weight of underground parts increased by 103.73% and 8.30% compared with CK. In the physiological characteristics of tobacco plants， T. harzianum could reduce the inhibition of Phytophthora on photosynthetic pigment accumulation and root activity of tobacco plants， and significantly increase both of them， and it could also strengthen the activities of enzymes related to carbon and nitrogen metabolism in tobacco plants. After transplanting 21 d， the activities of nitrate reductase and glutamine synthetase with T4 treatment increased by 13.14% and 6.40%， respectively. In the control effect， T4 treatment had the lowest incidence and disease index， which were 39.39% and 13.89%， and the highest antioxidant enzyme activity. In conclusion， there were significant differences in the physiological response of tobacco plants to the inoculation sequence of T. harzianum. In production， T. harzianum should be inoculated in advance to promote the growth and development of tobacco and inhibit the incidence of black shank disease. Above results laid a theoretical foundation for the regulation of tobacco growth and development and the comprehensive prevention and control of black shank.

In order to explore the differences in conventional quality and volatile components of different varieties of cabbage， the appearance quality， physical and chemical quality and volatile components of 8 varieties of cabbage were detected by physiological and biochemical methods and gas chromatography-ion mobility spectrometry （GC-IMS）， and their quality was comprehensively evaluated. The results showed that ‘Nissen’ had the largest leaf head weight. The vertical diameter and respiratory intensity of ‘Tanchun’were higher than those of other varieties. The highest transverse diameter and vitamin C content were‘Wanfeng’； the contents of total soluble solids， titratable acidity and soluble sugar in ‘Chenggong 65’were the highest. A total of 99 volatile substances were identified in 8 varieties of cabbage， among which aldehydes， alcohols and heterocyclic substances were the main components of the characteristic aroma of cabbage. The key volatile substances of cabbage mainly included anethole， 2-isobutyl-3-methyl pyrazine， 5-methyl-2-furanmethanol， linalool， 3-methylbutyl acetate， benzene acetaldehyde， 2-decenal and so on. The comprehensive evaluation model was constructed， and the highest comprehensive score was ‘Zhonggan 107’， which could be considered as an excellent variety for new variety breeding and directional breeding. Above results provided a direction for the subsequent development and utilization of 8 varieties of cabbage， and provided a theoretical basis for the quality evaluation， directional breeding and production and processing of cabbage in the mountainous area of southern Ningxia.

In order to enhance the head space-solid phase micro extraction （HS-SPME） extraction efficiency of volatile components in honey， and for more accurate qualitative and quantitative analysis using gas chromatograph-mass spectrometer （GC-MS）， the total peak area of volatile components of the chromatogram in Ziziphus jujuba Mill honey was used as the index. Plaekett-Burman design and response surface methodology were used to optimize extraction conditions （extraction temperature， extraction time， sample amount， deionized water amount， NaCl additive amount， stirring speed）. The results showed that extraction temperature， extraction time and sample amount significantly impacted the total peak area in the chromatograms. The optimized extraction conditions were extraction temperature of 68.5 ℃， extraction time of 51.6 min and sample amount of 5.1 g. Under the optimal extraction conditions， the total peak area of chromatogram could reach 2.20×10⁹ mAU·min^-1. Above results provided certain technical guidance for the further profile analysis of volatile components in honey.

To explore the effects of different amounts and duration of straw return on the composition， stability， and carbon storage characteristics of soil aggregates，utilizing 4 treatments from a long-term field experiment， full straw return （1XG）， 1/2 straw return （1/2XG）， 1/3 straw return （1/3XG） and root stubble return （CK），the stability and the organic carbon content of aggregates were dynamically monitoring for 3 consecutive years. The results showed that compared to CK， straw returning increased the content of >0.25 mm soil aggregates. The best effect was observed with full straw return. With the years of straw returning increased， the content of <0.053 mm soil aggregates showed an increasing trend. Straw returning could significantly increase the mean weight diameter of soil aggregates， playing a role in enhancing the stability of the aggregates. The straw returning enhanced the organic carbon content of soil aggregates， and the full straw return showed best effect. The organic carbon content of >0.25 mm soil aggregates was highest in all treatments， indicating that after straw returning， organic carbon was preferably sequestered in large aggregates. The organic carbon contribution rate of >0.25 mm aggregates was the highest， between 60.90%~82.09%， while that of <0.053 mm aggregates was the lowest， between 2.39%~6.28%. In conclusion， straw return to the field promoted the formation of soil aggregates and increased the organic carbon content of soil aggregates. Among them， the full straw return had the best carbon sequestration effect. Above results provided data support for determining the appropriate amount of straw return， and provided a theoretical basis for improving and enhancing soil fertility in black soil areas.

Water-retaining agent has low degradability in soil and will cause harm to soil environment. In this study， polyaspartic acid and bentonite were used as raw materials to prepare a new type of degradable soil water-retaining agent. 2 groups of water treatment were set up including water stress treatment and normal irrigation treatment，under the 2 groups of water treatment， commercial humic acid water retaining agent（TA） and 12.5（TB₁）， 17.5（TB₂）， 22.5（TB₃）， 27.5（TB₄）， 32.5 kg·hm^-2 （TB₅） new soil water retaining agent were applied respectively， using no water retaining agent as control （CK）， and the effects were discussed on the growth and development of maize seedlings. The results showed that the application of water retaining agent could increase the soil moisture content in maize seedling stage. The best effect was achieved when the amount of water retaining agent was 22.5 kg·hm^-2， and the effect was significantly inhibited when the amount of water retaining agent was 32.5 kg·hm^-2. Under water stress conditions， plant height， stem diameter，chlorophyll content and superoxide dismutase， peroxidase and catalase activities of each treatment treated with water retaining agent were significantly increased compared with CK； and the contents of malondialdehyde and proline were reduced. Among them， the water retaining agent dosage of 22.5 kg·hm^-2 （TB₃） had the best effect. Above results showed that the effect of the new soil water retaining agent was obviously better， and it would further promote the agricultural water saving in China.

To study plant diversity and community stability during vegetation restoration in the mining area of alpine steppe， and explore the evolution regularity of plant communities， Baiyinhua mining area of Wuzhumuqin Banne in Xilin Gol League and nearby grasslands were as the research object. The dynamic changes of plant community characteristics， species diversity and community stability were studied. The results showed that the number of plant species in grasslands was higher than that in ecological restoration area of dump. There were 32 species of plants in the restoration area， including 5 shrubs belonging to 3 families and 4 genera （mainly legume） and 27 species of herbs belonging to 7 families and 21 genera （mainly gramineae and legumes）. The proportion of perennial herbs in the total species number increased from 40.0% to 62.5%. The constructive species in the ecological restoration area of dump were consisted of Leymus chinensis， Elymus dahuricus， Medicago sativa and Agropyron cristatum， and the average important value of Leymus chinensis was 30.96%， whose ecological niche had obvious advantage. The Margalef index， Shannon-weiner index， Pielou evenness index of grasslands were significantly higher than those of the ecological restoration area of dump. The restoration area of the dump was unstable state in the early stage of succession， among which the stability of the south dump was the best， and the stability of the east dump was the worst due to the large slope and slight degradation of the land surface， which made it difficult for plants to colonize. In conclusion， the management and protection of the ecological restoration area of dump should be strengthened to improve habitat quality， promote community succession process， improve community stability， and improve the effect of vegetation restoration.

In order to provide an effective reference for phosphorus application in tomato upon soil testing， relevant experimental literatures on tomato fertilization were retrieved from database， and the abundance-deficiency index （ADI） of soil available P and the recommended phosphorus fertilizer application rate （RPFAR） for tomato in China were established by using “the piecemeal experiment data integration method” and “the new application formula of nutrient balance-soil fertility difference subtraction”. The results showed that the ADI of soil available P in open field for tomatoes in China from the first to sixth level were ≥296.9， 76.6~296.8， 19.8~76.5， 5.1~19.7， 1.3~5.0 and <1.2 mg·kg^-1， respectively； the ADI of soil available P in facility for tomatoes in China from the first to sixth level were ≥298.4， 79.0~298.3， 20.9~78.9， 5.5~20.8，1.5~5.4 and <1.4 mg·kg^-1， respectively； the ADI of soil available P in open field and facility for tomatoes in China from the first to sixth level were ≥313.0， 81.0~312.9， 20.9~80.9， 5.4~20.8， 1.4~5.3 and <1.3 mg·kg^-1， respectively. When the phosphorus fertilizer use efficiency in current season in 15%~35% and the target yield of tomatoes in 45~195 t·hm^-2， the RPFAR from the first to sixth level of soil phosphorus abundance-deficiency were 0， 13~130， 26~260， 39~390， 51~520 and 64~650 kg·hm^-2. The recommended phosphorus application system for soil available P ADI of tomato in China was established， which provided a scientific basis for tomato soil testing and phosphorus application in China.

In order to study the effects of adding different types of rice straw on soil bacterial communities under continuous cropping of flue-cured tobacco， fresh rice straw （FS） and rotted rice straw （RS） were added in soil， with no straw as control （CK）. The community composition and diversity of soil bacteria and fungi at different times （0， 7， 30， 60 and 90 d） under 3 treatments were studied by high-throughput sequencing. The results showed that fresh rice straw and rotted rice straw could significantly improve the diversity and richness of soil microbial community. After 90 d in FS and RS treatments， the Chao 1 index， Shannon index and Simpson index of bacteria and the Chao 1 index of fungi were significantly improved. The analysis of community structure composition showed that FS and RS treatments increased the relative abundances of Proteobacteria， Spirochaetes and Verrucomicrobia. FS treatment increased the relative abundance of Basidiomycota， and decreased the relative abundances of Chytridiomycota and Rozellomycota. RS treatment increased the relative abundances of Ascomycota and Basidiomycota， and decreased the relative abundances of Zygomycota and Chytridiomycota. In summary， the addition of fresh rice straw and rotted rice straw could change the community composition of soil bacteria and fungi， improve the health status of soil with continuous cropping of flue-cured tobacco. Compared with rotted rice straw treatment， fresh rice straw treatment increased the abundance of pathogenic fungi.

In order to use Hermetia illucens to efficiently treat food waste and improve the resource utilization rate， the response surface method（RSM） was used to optimize six parameters， including ambient temperature， moisture content of treated material， daily materials added， living space， initial larva age and permeability of materials， based on the Plackett-Burman（PB） test and the Box- Behnken（BB） test， with the larval yield of Hermetia illucens as the response value. The results of PB test showed that the significant factors in response to the larval yield were moisture content of treated meterial， ambient temperature， daily materials added， living space and initial larva age. The results of BB test showed that the optimal conditions for larval yield were ambient temperature 28 ℃， moisture content of treatment material 75%， daily materials added 26 g·1 000 larva^-1， living space 1 443 cm³·1 000^-1 larva， and initial larva age 6 days； under this condition， the maximum larval yield of 243.78 g could be obtained， with a relatively small error compared to the predicted value of 243.82 g by the model，which indicated that response surface methodology could accurately optimize process parameters. Above results provided theoretical basis for the production practice of kitchen waste treatment by Hermetia illucens.