Taking ‘Jinyuan 89’‘jinyujing 22’ and ‘Jinyuanxiang 98’ as materials, with two sets of crab raising and non-crab raising paddy fields, the yield, quality and economic benefits of the two planting modes were compared. The results showed that different varieties had different performances in yield characters, appearance, principal components and taste evaluation under the two planting modes. Head rice rate of the three rice varieties significantly increased through the crab-rearing treatment, and significantly reduced the chalky grain rate of ‘Jinyuan 89’. The contents of protein and amylose in ‘Jinyujing 22’ were significantly lower than those in non-crab culture. There were no significant differences in rice taste value and comprehensive evaluation of rice taste among the three rice varieties under crab and non-crab treatments. The yield of ‘Jinyuan 89’ and ‘Jinyujing 22’ was slightly higher than that of non-crab-raising treatment, while the yield of ‘Jinyuan Xiang98’ was slightly lower than that of non-crab-raising treatment. From the analysis of economic benefit, the crab raising mode of three varieties was significantly higher than that of non-crab raising.

This article analyzed the chicken price fluctuations by taking the chicken market price in China as the research object, based on the chicken market price data from 2013 to 2021, and using census X12 seasonal adjustment method and HP filter method. The study found that chicken price had obvious seasonal trend, with the price in January and February higher, but in June lower and showed a gradual upward trend in the long term. Then, the ARMA model was used to forecast the chicken price from December 2021 to April 2022. The conclusion showed that during the period from December 2021 to April 2022, the chicken price in China was basically stable, but showed a downward trend. Finally, according to the research conclusions, some policy suggestions were put forward, such as the establishment of multi-category price monitoring and early warning system, the improvement of major epidemic disease monitoring, prevention and control management mechanism, the establishment of chicken production and sales guidance and suggestion systemto guide consumers’ reasonable expectations.

Pharmaceutical Analysis is a required course for animal pharmacy major in the College of Animal Science and Veterinary Medicine. Since Animal pharmacy as a major in national agricultural colleges has been established for a short time, there is only one textbook “Pharmaceutical Analysis Experiment and Training” in 2015 for the 12th Five-Year Plan of the Ministry of Agriculture. According to the characteristics of this course, this paper explores and studies the contents of teaching materials, teaching methods and strategies, and curriculum ideological and political education to establish a new teaching method and teaching system suitable for the experimental training course of pharmaceutical analysis for animal pharmacy major; This paper also digs deeply for some ideological and political elements in pharmaceutical analysis, and explores the ways and means of integrating ideological and political education into this professional course, aiming at cultivating students’ innovative consciousness and ability and enhancing the students’ sense of responsibility and professional literacy.

The construction of curriculum ideology and politics in agricultural colleges and universities should serve the goal of cultivating professionals and the mission of strengthening and rejuvenating agriculture. The effect of courses ideological and political education depends on how to answer the question of “What to integrate” from the perspective of curriculum, the question of “How to integrate” from the perspective of teachers, and the question of “Why to integrate” from the perspective of students based on teaching and service orientation. Concentrating on all aspects of teaching and learning, the evaluation system of curriculum ideology and politics should be explored to promote its standardization and scientific reform.

Rural grass-roots party organizations which are the basis of the party’s work in rural areas are the organizers and practitioners of the rural revitalization strategy. This paper clarifies the function orientation of rural grass-roots party organizations in rural revitalization and combs the new progress of rural grass-roots party organization construction in the new era. By analyzing the common problems of rural grass-roots party organizations through literature combing, field research, telephone interview and other methods, this study puts forward that to promote rural grass-roots party construction, we should optimize and improve the team of leaders of rural party organizations, build an excellent team of party members, promote the standardization of the operation of rural grass-roots party organizations, further develop and expand the rural collective economy, and better strengthen the construction of rural grass-roots party organizations to help rural revitalization.

Since the 18th CPC National Congress, a series of important discussions on China’s poverty management has been made by general secretary Xi Jinping and has become an important component of Xi Jinping Thought on Socialism with Chinese Characteristics for a New Era. The scientific connotation and spiritual essence of Xi Jinping’s poverty alleviation should be accurately grasped, and the historical logic and realistic logic contained therein should be combed out the unity of theory and practice, class nature and people's nature, inheriting and innovating and scientific and ideological should be adhered to, basic characteristics should be clarified, the effective links between poverty alleviation and the rural revitalization should be consolidated and expanded, so that China could contribute to the world the “China wisdom” and “China plan”.

With the rapid development of facility agriculture, the scale proportion of new greenhouses is increasing, but there is a big gap between the soil fertility of new greenhouses and the requirements of facility efficient production. This paper makes a systematic and comprehensive study on the evaluation index of soil fertility, different soil fertilization techniques and existing problems of the new greenhouse. The results showed that the evaluation of new greenhouse fertility could refer to organic matter, total nitrogen, available phosphorus and potassium, pH, soil enzymes, micro biomass carbon and nitrogen and other indicators. The effect of organic fertilizer application technologies such as livestock and poultry manure, conditioner application and green manure turning and pressing on the improvement of soil fertility of new greenhouses is relatively stable, sustainable and comprehensive. The application technology of inorganic fertilizer based on the application of chemical fertilizer is an important way for the rapid improvement of soil available nutrients in new greenhouses. Organic-inorganic combined fertilization techno- logy integrates the advantages of the above two and has become a widely selected technical measure in greenhouse fertilization. At the same time, it is pointed out that there are some problems in soil fertility in the new greenhouse, such as the coexistence of excessive and insufficient fertility, the imbalance of fertilization structure, and the lack of in-depth research on soil fertility evaluation factors. Finally, it is proposed that building a stable, sustainable and effective fertilizer supply and retention system should be the most important for soil fertility in the new greenhouse. The research on reasonable and efficient soil fertility technology such as biological fertility, application of high-efficiency conditioning materials and combination of organic and inorganic is the main direction to improve the quality of soil fertility in the future. It can provide a reference for improving soil quality in new greenhouses and promoting the sustainable development of facility agriculture.

In order to study the competition and allelopathy among Microcystis aeruginosa, Closteriopsis longissima and Scenedesmus quadricauda, the growth parameters such as maximum environmental capacity（K）and growth rate（r）of three microalgae cultured individually and in combination were qualitatively analyzed by using the logistic equation. The competition inhibition parameters（ α and β）among microalgae were further quantitatively compared by using the Lotka-Volterra competition model, and the effects of filtrate culture on the growth of the three microalgae and the maximum light energy conversion efficiency（ Fv/ Fm）of PSⅡ were preliminarily discussed by using filtrate culture. The results showed that the growth of M. aeruginosa was inhibited in the mixed culture, and the mixed culture of three algae had the strongest inhibition on the growth of M. aeruginosa. The inhibition of C. longissima on the growth of M. aeruginosa was stronger than that of S. quadricauda. In filtrate culture experiments, the filtrates of C. longissima and S. quadricauda showed obvious allelopathic inhibition on M. aeruginosa; The cell density and chlorophyll fluorescence parameter Fv/ Fm of M. aeruginosa in the 100% filtrate group were under certain stress at the later stage of the experiment（ P<0.05）. With the increase of concentration, the cell density and photosynthesis of M. aeruginosa in the filtrate were significantly inhibited and stressed（ P<0.05）.

In order to find out how hydration would affect hatching of Artemia salina cysts at early stages in Bohai Bay, an experiment had been designed in which different water temperatures and different action times were involved. In the experiment, there were five different temperatures which were 20 ℃, 25 ℃, 30 ℃, 35 ℃ and 40 ℃, and each with five different action times which were 1 hour, 2 hours, 3 hours, 4 hours and 5 hours. The experiment result showed that hydration had an obvious impact on hatching of Artemia cysts. Under temperature of 30 ℃, hydration could help shorten hatching process. Time of umbrella-shaped period and time of Artemia larvae stage were both advanced at different experimental times and temperatures except for temperature of 40 ℃, so did time of 5% and 95% hatching completeness. The result also indicated that as temperature gone up above 35 ℃ gradually, this effect started to reduce. In addition, hydrating temperature and time had a significant effect on hatching when water temperature was between 25℃ and 35 ℃. In this temperature range, the higher temperature was, the higher the hatching rate was. Longer-hour experiments like 4-hour and 5-hour were the most significant compared with the control group. Yet opposite result was observed at temperature of 40 ℃ at all times. Base on this, hydrating condition of 25 ℃ with the action time of 3 hours was considered to be the most beneficial for hatching Artemia cysts in Bohai Bay. Under this experimental condition, the hatching rate reached up to（86.41±0.03）%, which was（6.84±0.04）% higher than that of the control group and the hatching time of completing most of the incubation was reduced by 2 hours.

Based on the survey data of 230 vegetable growers in Tianjin, the factors affecting vegetable farmers’ adoption of water-saving irrigation technology, their logical structure and hierarchical relationship were analyzed using binary Logit model and ISM model. The results showed that the root factors influencing vegetable farmers’ choice of water-saving irrigation technology were the degree of agricultural co-occupation, cultivated land and government publicity and promotion efforts. The cognition of water price and the understanding of water-saving irrigation technology were the direct factors that affected the choice behavior of water-saving irrigation technology of vegetable farmers. According to the conclusion of the study, some suggestions were put forward to provide reference for the sustainable development of agriculture in China, such as guiding vegetable growers to join industrial organizations and give full play to the advantages of large-scale and specialized operation, perfecting the agricultural water price mechanism, and improving government publicity efforts.

The purpose of this study was to evaluate the effects of compound lactic acid bacteria, LP（ Lactobacillus plantarum）combined with LR（ Lactobacillus reuteri）as feed additive on the prevention of bacterial diarrhea and growth performance of weaned piglets. Twelve 28-day-old weaned piglets with an average body weight of（6.77±1.30）kg were divided into two groups with 6 replicates per group and 1 pig per replicate. The piglets in the control group were fed with basic diet from 0 to 28 days; 1×10 ⁹ CFU/kg compound lactic acid bacteria preparation were added to the basic diet of piglets in the experimental group for 0~14 days and 5×10 ⁸ CFU/kg compound lactic acid bacteria preparation for 15~28 days. The experiment lasted for 28 days. Body weight was measured weekly and feed intake was checked every day. The incidence of diarrhea was assessed daily by stool score and diarrhea index was calculated. Fecal samples were collected at 14th and 28th days for the counting of lactic acid bacteria and coliform bacteria. The results showed as follows: compared with the control group, the ADG, ADFI and FCR of weaned piglets supplemented with compound lactic acid bacteria preparation had a trend of improvement（ P>0.05）, the number of intestinal LAB（lactic acid bacteria）was significantly increased（ P<0.05）and intestinal coliform bacteria was significantly decreased（ P<0.05）. The ratio of intestinal LAB to coliform bacteria was significantly increased（ P<0.05）. In addition, fecal consistency score, diarrhea incidence and diarrhea index were significantly decreased（ P<0.05）after weaned piglets were fed diets supplemented with compound lactic acid bacteria preparation. The fecal consistency score, diarrhea incidence and diarrhea index of weaned piglets decreased significantly when LP and LR were added 5×10 ⁸ CFU/kg respectively in the basic diet.

This paper focuses on China’s national conditions and characteristics, summarizes the research experience and practical experience on digital twin, and proposes feasible research theories and practical countermeasures for the rapid development of China’s industry and the construction of intelligent economy. Based on the visualization software CiteSpace, this paper conducts a quantitative analysis of the digital twin related literature included in China National Knowledge Infrastructure （CNKI）, to obtain the hotspots and trends of digital twin research in China through the summary and analysis of the number of published papers, the co-occurrence map of authors and institutions, the co-occurrence of keywords and emerging words. The research showed that: （1）China’s digital twin research has mainly gone through two stages: start（2016—2018）and development （2019—2022）. （2）Application of digital twin technology in manufacturing workshops, application of digital twin and artificial intelligence algorithms in real-time forecasting and research on digital transformation based on digital twin technology are the current hot research fields;（3）The future research trends are smart factories, industrial Internet of Things, information Physical Systems, digital twin model and smart economy. Digital twin has become a research hotspot in the fields of intelligent manufacturing and industrial Internet, and China will gradually draw the world’s attention for digital twin research.

In order to explore the physiological characteristics of ramets of Fragaria vesca under low light, and to reveal the physiological effects of mother ramets on the stolon ramets in heterogeneous and homogenous habitats, different shade gradients were used to imitate the natural growth status at forest fringe（heterogenous habitat）and under forest（homogenous habitat）. The photosynthetic characteristics, antioxidant enzyme activities, and osmotic substances of ramets were measured. The results showed that the total amount of photosynthetic pigments in full-shading was greater than that in half-shading. With the increase of shading rate, the net photosynthetic rate（ Pn）, stomatal conductance（ Gs）and transpiration rate（ Tr）of ramets decreased while Pn, Gs and Tr in 30% full-shading group were higher than those in control and other treatments. Under natural light, CK and 30% shading stress were dominant in summer, and the malondialdehyde（MDA）content of 30% half-shading strains increased sharply, which was negatively affected by the heterogeneous high light parent plants. With the increase of shading rate（>30%）, the plant changed from natural high light stress to low light stress. The MDA content of both treatment groups reached the trough value at 50% shading, and the total antioxidant enzyme activity was the highest at this time, while the MDA content in daughter plants under half-shading group was significantly lower than those under full shading in F. vesca, showing that the mother plant protected the daughter plant under low light stress. The content of soluble protein（WSP）was the lowest at 70% shading, and the physiological balance was destroyed in F. vesca. When both mother and daughter plants were under 30% shading, it was beneficial for plants to utilize light resources. 50% shading was suitable for plant survival under natural light. When the plant was under heterogeneous light, the mother plant under high light would obtain resources from the daughter plant with better growth conditions due to photoinhibition. But when the low light stress（>30%）of the daughter plant was dominant, the mother plant would positively protect the daughter plant. This bi-directional transfer of stolon resources effectively alleviates environmental stress and makes stolon ramet have stable ecological adaptability.

In order to solve the problem that citizens, lack professional knowledge of garbage sorting , can not accurately judge the type of garbage, which leads to the unsatisfactory effect of garbage sorting, this paper introduces a system that can independently identify the type of garbage. This system uses visual recognition technology to compare the collected images with the trained model, calculates the garbage types with the highest similarity through the algorithm, and sends the results to the control center. The control center works according to the garbage type control delivery module. After testing, the range of recognition includes more than ten kinds of garbage common in all four categories and their different forms, and the recognition accuracy is about 78%.

In order to determine the dynamic changes of nutrient element content in leaves of different winter jujube orchards（high-yield orchard and low-yield orchard）in each phenological period, and the dynamic trend of nutrient elements in Tianjin Dongzao in each phenological period was explored. The results showed that the contents of nitrogen and phosphorus in the leaves showed a decreasing trend, and the contents of potassium, calcium, magnesium, iron, manganese, and boron showed an increasing trend. The annual average content of nutrient elements except magnesium and manganese in high-yield orchards was higher than that in low-yield orchards. The research results showed that in the production and management of winter jujube orchards, nutrient can be supplemented by spraying leaves, which provide theoretical basis for the nutritional diagnosis and reasonable fertilization of winter jujube.

In order to improve the removal rate of nitrogen and phosphorus in artificial wetland systems and to enhance the knowledge of heterotrophic nitrifying aerobic denitrifying bacteria species and performance in artificial wetlands, a heterotrophic nitrifying-aerobic denitrifying strain KL1 was isolated from an artificial wetland culture tailwater treatment system to investigate its growth factors and its nitrogen and phosphorus removal performance. The results showed that the optimal growth conditions of strain KL1 were as follows: temperature 30-37 ℃, pH 5-7, carbon source with sodium succinate, C/N of（7∶1）-（7∶18）, and C/N/P of（14∶2∶1）-（7∶1∶4）. During the heterotrophic nitrification-aerobic denitrification process of KL1 strain, the removal rate of NH ₄-N was 92%, and the removal rate of TN was 81%. There was no accumulation of NO ₃-N, and the accumulation of NO ₂-N was 2%. In the denitrification process, the NO ₃-N and TN removal rates were up to 95% and 44%, and no accumulation of NH ₄-N was found. When NaNO ₂ was used as the only nitrogen source, the removal rates of NO ₂-N and TN were 56% and 41%, and no NO ₃-N accumulation was observed. When NH ₄Cl was used as the only nitrogen source, the phosphorus removal rate was up to 31%. It was found that strain KL1 had strong heterotrophic nitrification-aerobic denitrification ability and good denitrification and phosphorus removal effect.

In order to explore the digestive enzyme activities in different digestive organs of Euthynnus affinis Juvenile fish under artificial breeding conditions, the activities of lipase, amylase and protease were tested. The optimum temperature for lipase, amylase, pepsin and trypsin are 30~50 ℃, 30~45 ℃, 30~60 ℃ and 30~50 ℃, respectively. The results showed that lipase activity and protease activity could be detected in the stomach, liver, foregut, midgut and hindgut, and amylase activity could be detected in the stomach, liver, pancreas, foregut, midgut and hindgut. The results showed that lipase activity, amylase activity and protease activity were high in liver; Amylase activity and protease activity in pancreas were significantly higher than those in other digestive organs. In the optimum temperature of digestive enzymes, different digestive enzymes could be detected, and their activities were not exactly the same in different digestive parts. The liver plays a major role in the digestion of lipase, amylase is secreted mainly by the pancreas, and the pancreas is also the main organ for protease metabolism. The results of this study will provide reference data for the follow-up artificial culture of Euthynnus affinis.

In order to establish a rapid propagation system for tissue culture of Sorbaria sorbifolia,in this study the stem segments of Sorbaria sorbifolia were used as explants to study the effects of different disinfection times, different basic media, hormone types and concentrations on in vitro culture of Sorbaria sorbifolia. The results showed that using a 2% effective chlorine sodium hypochlorite solution for disinfection for 8 minutes and inoculating the stem segment disinfectant had the most ideal effect; using WPM+GA3 5 mg/L as the primary culture medium, the germination rate of axillary buds was the highest, with an average growth length of 6.01 cm, and the growth effect was the most ideal; using MS+BA 0.5 mg/L+IAA 1.0 mg/L as the proliferation medium, the proliferation coefficient reached 8.13 after 30 days of cultivation, indicating the best effect; the optimal rooting medium is 1/2 MS+NAA 0.5 mg/L; using peat∶vermiculite∶perlite=1∶1∶1（v/v）as the transplant substrate, the survival rate of transplantation can reach over 90% after 30 days, while ensuring the integrity of the root system.

In China, with the application of various antibiotics and chemical synthetic feed additives, the total output of aquaculture has been increasing, providing people with a large amount of high-quality, high-nutrition and low-cost animal protein. However, in recent years, with the improvement of people's material living standards and safe consumption awareness, there are higher requirements for the quality of aquatic products. In today's aquaculture, the side effects of antibiotics and chemical synthetic feed additives, such as drug residues, have attracted more and more attention, which has prompted the gradual transformation of feed additives from chemical synthetic types to natural plant types. Plant-derived feed additives are rich in resources and various types, rich in a variety of active ingredients, and have the functions of improving animal growth performance, enhancing anti-stress ability, and improving the quality of aquatic products. This paper introduces the effects of different plants and their extracts on the quality of aquatic products, and briefly reviews the application and development prospects of plants and their extracts as feed additives in aquaculture, in order to promote the green and healthy development of the aquaculture industry and provide reference for the research.

In order to explore the effects of different environmental factors on the growth and phosphorus utilization of Chlorella vulgaris, the growth, phosphorus utilization and chlorophyll fluorescence parameters of C. vulgaris under different salinity, biomass, phosphorus concentration, and pH were investigated in this work. The results showed that the specific growth rate of algae, the maximum light energy conversion efficiency（ F_v/F_m）, the actual light energy conversion efficiency（ ΦPSII）, the potential activity（ F_v/F₀）and the phosphorus adsorption efficiency showed a tendency to rise first and then decrease with the increase of salinity, and the photosynthetic activity and phosphorus adsorption efficiency of the algae were the best at salinity of 15. The adsorption efficiency of phosphorus by algae increased first and then decreased with the increase of algal density and pH, and the adsorption efficiency was best when the algal density was 0.75×10 ⁶ cells/mL and the pH was 7. Moreover, the adsorption kinetics of algae on phosphorus showed that within 1 h of the initial stage of adsorption, the phosphorus adsorption efficiency of C. vulgaris could reach 61%, which was a rapid adsorption period. Therefore, C. vulgaris has the highest growth rate, the highest photosynthetic activity and the highest phosphorus adsorption efficiency at salinity of 15, pH 7 and algal density of 0.75×10 ⁶ cells/mL.

With annual grafted jujube seedlings (rootstocks were sour jujube) of two jujube varieties, ‘Yueguang' and ‘Fucuimi', as test materials, the growth and photosynthetic characteristics of the two jujube varieties in Tianjin were analyzed by measuring their heads, leaf growth indexes and photosynthetic indexes, with a view to provide references for their introduction and planting in Tianjin area. The results of the study showed that the length and thickness of the jujube heads of both jujube varieties showed a “double S-shaped” growth curve with two growth peaks throughout the growth period, both around the 18th day. ‘Yueguang' reached its second growth peak around the 65th day, and ‘Fucuimi' reached its second growth peak around the 60th day. Both varieties stopped growing around the 110th day（late August）. The annual growth rate of head length and thickness of ‘Fucuimi' was significantly higher than that of ‘Yueguang'. During the whole growth period, the average growth rate of length and thickness of jujube heads was higher in ‘Fucuimi' than in ‘Yueguang'. The leaf water content and leaf thickness of ‘Fucuimi' were significantly higher than ‘Yueguang'. The leaf shape index of ‘Yueguang' was significantly higher than that of ‘Fucuimi'. The photosynthetic indexes of both varieties were not significantly different. The comprehensive analysis concluded that ‘Fucuimi' is more adaptable than ‘Yueguang' in Tianjin area.

Dermatomycosis are common zoonotic diseases that affect the health of animals and humans while affecting appearance. In this study, the disease condition of canines and felines in Taixing's three pet hospitals who were diagnosed with dermatomycosis from November 2020 to October 2021 were investigated and analyzed. The relationships between dermatomycosis of canines and felines in Taixing and factors such as season, sex, age, breed, hair length and so on have been illustrated. The results showed that three pet hospitals in Taixing received a total of 2 008 cases in one year, in which canines and felines with dermatomycosis were 371 cases, accounting for 18.48% of the total cases. Summer was the peak period of the incidence, and the incidence rate accounted for 53.10% of the whole year. The winter incidence was low at 3.77%. The incidence of canines and felines under the age of one was higher than that of other ages, 58.17% and 77.06% respectively. The infection sites were mainly in the abdomen and extremities in canines, and around the eyes and ears in felines. The female-to-male ratio of affected canines was 82∶71, and the female-to-male ratio of affected felines was 89:129. Poodles and British Shorthairs were the common diseased breeds, with incidence rates of 28.10% and 44.50% respectively. These data provide a reference for the prevention and control of dermatomycosis in canines and felines.

Dark tea is a special post fermentation tea category in China, including Pu-erh tea, Liubao tea, Kang brick tea, Fu brick tea, Qing brick tea and so on. Tea aroma is one of the important indexes to evaluate tea quality. Therefore, the detection and analysis of aroma components is very important for the evaluation of dark tea quality. At present, the detection of aroma components of dark tea mainly includes gas chromatography-mass spectrometry（GC-MS）, comprehensive two-dimensional gas chromatograph-time of flight mass spectrometry（GC×GC-TOFMS）, gas chromatography-olfactometry（GC-O）, electronic nose （e-nose）, etc. This paper summarizes the extraction, detection and analysis technology of volatile components of dark tea in recent 5 years, and tracks the research progress of aroma components of five kinds of dark tea, such as Pu-erh tea, Fu brick tea, Qing brick tea, Liubao tea and Kang brick tea, and privide theoretical guidance for the study of aroma component in black tea.

The comparative fertilization experiment of eggplant was conducted in the greenhouse of Xiqing District, Tianjin. Taking single compound fertilizer as the control（T0）, three different treatments were designed with different ratios of reduced mass of compound fertilizer and microbial fertilizer: T1（compound fertilizer∶microbial fertilizer =3∶1）, T2（compound fertilizer∶microbial fertilizer =1∶1）, T3（compound fertilizer∶microbial fertilizer =1∶3）. SPSS software was used to analyze the plant height, stem diameter, maximum leaf area, yield, relative chlorophyll content（SPAD value）of eggplant in four different treatments, and high-throughput sequencing technology was used to analyze the microbial diversity in eggplant growth substrate in T0 and T3 treatments.The results showed that after applying microbial fertilizer to eggplant growth substrate, the number of dominant microbial communities in the substrate changed, the sequence number of microbial populations increased, the relative abundance of species increased, and the diversity of microbial communities improved. At the same time, the yield of eggplant in T3 treatment was the highest, and plant height, stem diameter, maximum leaf area, relative chlorophyll content and other physiological indicators were more prominent. So T3 is the best fertilizer proportion scheme, and the results provide theoretical basis and practical guidance for the application and sustainable production of eggplant microbial fertilizer.

：A group of sick chicken suspected to be infected by Escherichia coli（ E. coli）were found in a large-scale chicken farm in Tianjin. In order to isolate the pathogenic bacteria of the chicken disease and analyze its pathogenicity, a comprehensive analysis was conducted including clinical diagnosis, collection of tissue samples, bacterial isolation and culture, identification of culture medium and biochemical methods, 16S rRNA detection, analysis of phylogenetic tree and homology, antimicrobial susceptibility tests, virulence gene detection, mice pathogenicity test and histopathological observation. The results showed that typical peritonitis, perihepatitis and pericarditis and other symptoms were found in clinical autopsy. The isolate was negative short bacillus by Gram staining and was consistent with the growth characteristics of E. coli via the culture medium and biochemical identification. PCR amplification with 16S rRNA specific primers, phylogenetic tree and homology analysis showed that the isolate was related to E. coli in the same branch, and the homology was more than 99.99%. The isolate was susceptible to florfenicol and moderately susceptible to tetracycline and doxycycline. E. coli virulence genes including fimC, hlyF, ompT, and iroN were amplified by PCR. Animal pathogenicity test showed that all mice inoculated with the isolate died within 16 h, and the bacteria were detected in the liver and blood of the infected mice. Histopathological observation showed that the liver, heart, lung, kidney, spleen and intestine of infected mice were damaged to varying degrees. The results showed that the isolate was E. coli, and the isolate had multiple antibiotic resistance and carried a variety of virulence genes, which had strong pathogenicity to animals. The results of this study provide reference for the prevention and control of E. coli and reasonal use of antibiotics in chicken farms.

Water pollution and climate warming are important environmental problems facing the world today. Microalgae have the ability to purify water and fix CO ₂ at the same time. In order to explore the removal rate of three mixed nitrogen sources and the fixed rate of CO ₂ by algae, this study took Scenedesmus obliquus, Chlorococcum sphacosum GD and Chlorella vulgaris as experimental objects. Microalgae were inoculated in BG-11 medium with urea nitrogen, nitrate nitrogen and ammonium nitrogen （mass concentration 247 mg/L） as mixed nitrogen sources, and the removal rate of different nitrogen sources and the fixation efficiency of CO ₂ were studied under the condition of 300 mL /min air supply carbon source. The results showed that there were differences in the utilization of nitrogen sources among the three microalgae, and the absorption and utilization of ammonium nitrogen were inhibited. Urea nitrogen, nitrate nitrogen, ammonium nitrogen removal rate of Scenedesmus obliquus were 92.90%, 79.28% and 22.86% respectively, and utilization of urea nitrogen was the highest. The nitrate utilization rates of Chlorococcum sphacosum GD were 78%, 80.10% and 39.45%, respectively, and those of Chlorella vulgaris were 62.00%, 81.04% and 34.66%, respectively. The maximum CO ₂ fixation efficiency were 0.125, 0.142, and 0.217 g/（L·d）, respectively. The average carbon fixation rate were 0.067, 0.097, and 0.115 g/（L·d）, respectively. The carbon fixation efficiency of the Chlorella vulgaris was the highest, followed by the Chlorococcum sphacosum GD, and that of Scenedesmus obliquus was the lowest.

Based on the requirement of “New Agricultural” construction connotation, this paper analyzes the problems existing in the teaching contents, teaching methods and teaching modes of postgraduate mathematics courses. This paper focuses on how to reconstruct the public mathematics course teaching system and how to improve teaching quality by using a variety of teaching mode. An innovative ability training system that integrates active learning, conscious practice, and emphasis on practice should be constructed. This paper deepens the reform of the talent training model and strives to cultivate innovative talents for rural revitalization.

Plant can adjust leaf microstructure to adapt to different environment. Here, we studied leaf vasculature and stomatal characteristics of Iris at different leaf age and leaf position. The results showed that vascular density and adaxial/abaxial stomatal density in newly developed leaves was higher than in young and mature leaves, whereas stomatal size was smaller. From leaf base to leaf tip, adaxial/abaxial stomatal density, longitudinal/transverse vein density, and total vein density gradually increased, whereas adaxial/ abaxial stomatal size and areolar area gradually decreased. It is concluded that metabolism is faster in newly developed leaves, and compared to leaf base and leaf tip, the middle part of leaf blade is more representative for the state of the whole leaf.

With the country's comprehensive victory in poverty alleviation, the focus of the “three rural” issues has also shifted to comprehensively promoting rural revitalization. Rural tourism is an important carrier for comprehensively promoting rural revitalization and accelerating agricultural and rural modernization. However, the shortage of talents in rural tourism is very prominent, and has affected the development of rural tourism to some extent. As an important force for cultivating agriculture- related talents, agricultural and forestry universities have the advantage of cultivating rural tourist talents. Therefore, this paper analyzed the currentsituation of rural tourist talents cultivation in agricultural and forestry universities. The problems of being lack of distinctive-featured talent training, mismatched talent supply and demand, grim employment situation, and deep-seated reasons were mainly discussed. Corresponding suggestions of innovating the training path of rural tourist talents, deepening teaching reform, cultivating and shaping practical innovation ability, and actively meeting the needs of the talent market for improvement were put forward. In general, it is expected to improve the training mode of rural tourist talents in agricultural and forestry universities, and provide talent guarantee for promoting the development of rural tourist industry and assisting the overall revitalization of rural areas.

In order to solve the problems of low efficiency and high labor intensity in the packaging process of black gadfly larvae, this design takes Mitsubishi FX3U PLC as the control core, and builds a real-time monitoring system of black gadfly larvae packaging production line based on MCGS Pro configuration software. By utilizing multi-sensor modules to collect operational status, real-time tracking and monitoring of feeding, weighing, bagging, bagging, and packaging actions during the packaging process can be achieved, thereby achieving remote monitoring of the production line. The simulation operation results indicate that: the system can realize man-machine interaction, has good real-time performance and high reliability, and will have broad demand space and application prospect in factory packaging production line operation.

The effects of 7 different kinds of winter green manure on soil organic nitrogen components were studied by Bremner acid hydrolysis method using 7 kinds of winter green manure and mixed sowing methods in fluvo-aquic soil of northern China. The results showed that total acidolysis nitrogen accounted for 74.81% of total nitrogen in the soil organic nitrogen. In the soil organic nitrogen, the content of nitrogen in various forms was ranked as unknown nitrogen>amino acid nitrogen>amide nitrogen>amino sugar nitrogen. The nitrogen in the soil of winter green manure under long-term overturning pressure was mainly transformed into acidolysis nitrogen. The total nitrogen of different winter green manure increased significantly in RG, OV and VR+OV. In 2020, the soil amino acid nitrogen and amino sugar nitrogen were lower than those in 2013, while the soil under winter green manure treatments were higher than those in 2013, with RG and OV increasing the most. In 2020, the soil amide nitrogen and unknown nitrogen were higher than those in 2013, and the soil under different green manure treatments were higher than those in winter fallow field. Correlation and path analysis showed that the positive correlation coefficient and direct path coefficient between amino acid nitrogen and alkali-hydrolyzed nitrogen were the largest in soil, and the positive correlation between amino sugar nitrogen and unknown nitrogen and alkali-hydrolyzed nitrogen was also significant, and the direct path coefficient was above 2.

Collaborative education holds that human society has three education systems, namely family education system, school education system and social education system. Labor education is a very important part and essential link in the collaborative education model. This study analyzes the theoretical origin of labor education and collaborative education, takes Tianjin Agricultural University as an example, summarizes the construction path of labor education system in agricultural universities, and comprehensively presents the highlights and achievements of the practice of labor education in Tianjin Agricultural University.

Students' practical ability is an important aspect of improving teaching quality in undergraduate education. According to the certification standards of engineering specialty, this paper analyzed the existing problems in the traditional hydrological test practice teaching. Based on the concept of results-oriented, student-centered and continuous improvement, this paper put forward a practical teaching system of hydrology test which conforms to the engineering education certification of hydrology and water resources engineering specialty. The teaching reform and practice were carried out from the aspects of optimizing the practical teaching content of hydrological test, strengthening the practical exercise, integrating multi-dimensional water conservancy spirit of the new era and applying information technology. It could provide reference for colleges and universities to adapt to engineering education certification in practical teaching.

In order to improve the yield and sensory quality of braised and stewed beef, based on the company's original technology of braised and stewed beef（thawing, slitting, blanching, cleaning and boning, stewing and other processes of beef ribs）（control check, CK）, brine injection（BI）and vacuum rolling（VR）（expressed by BI-VR）were added. The amount of saline injection in BI-VR1 group and BI-VR2 group was 20%, and the total rolling time was 40min, but the order of bone removal was different; the saline injection volumes of BI-VR3, BI-VR4, BI-VR5 and BI-VR6 were 20%, 15%, 10% and 5% respectively, and the total rolling time was reduced to 30 min. The results showed that the sensory quality of CK group was poor, with roughtaste, poor tenderness , light taste and the lowest product yield（42.43%）. There was no significant difference in yield among BI-VR1 group, BI-VR2 group and BI-VR3 group（ P>0.05）, indicating that the order of bone removal did not affect the yield. The yield of the three groups（48.23%~48.34%）was significantly higher than that of CK group（ P<0.05）, but the product was too soft and rotten due to the high amount of saline injection（20%）; the sensory quality of BI-VR4 group was the best（24.1 points）, and the yield reached 50.78%, which was 8.27 percentage points higher than that of CK group. Secondly, the taste elasticity of BI-VR5 group was also good, and the yieldwas 49.33%. The test showed that taking beef ribs as raw material, by injecting 15% of the pre prepared pickling solution, putting them into vacuum rolling and kneading with the vacuum degree 0.06mpa and the total rolling and kneading time 30min（forward rotation for 15min, stop for 10min, reverse rotation for 15min）, putting them into 0~4 ℃ cold storage for static pickling for 10~12 h, after the process of blanching, cleaning, boning, stewing, vacuum packaging, secondary low-temperature sterilization and quick freezing, the high-quality stewed beef products can be obtained. This process can be suitable for large-scale industrial production.

With the development of information technology, the traditional teaching model has been greatly challenged. All subjects have to rely on informational mode to complete the teaching, especially during the epidemic period. This paper mainly describes how the virtual simulation, micro-class, teaching platform and other informational methods used in Veterinary Pharmacology practice teaching. It is proved that informational teaching has a lot of advantages of easy perception , convenience, interest, rich information, and resources and funds saving. At the same time the limitations of informational means are also obvious, including being distracting and requiring strong self-control. Thus, this study seeks to cultivate the strengths and avoid the weakness so that we could better apply the informational model to the practice teaching of Veterinary Pharmacology.

This paper evaluates the relative effectiveness of the modernization of the irrigation districts from the perspective of input and output, which is to provide theoretical guideline for the modernization of the irrigation districts. Based on the selected input and output index which can represent the characterization of modernized irrigation districts, the author used SE-DEA and Malmquist composite model to analyze the efficiency of modernization reconstruction of 18 large and medium-scale irrigation districts and sort the relative effectiveness. The author also calculated the changes in productivity before and after modernization of irrigation districts. The result showed that 11 irrigation districts which were all large irrigation districts were DEA effective in all 18 irrigation districts, the modernization reconstruction efficiency of large irrigation districts is higher than that of medium-scale irrigation districts. The average value of the Total Factor Producivity（TFP）of the districts is 1.057, the TFP index had increased by 5.7% because of the modernation measures. Therefore, it is feasible to evaluate the modernization effectiveness of irrigation districts by using the SE-Malmquist composite model and the current measures for modernized irrigation district are reasonable and effective. By optimizing and adjusting the total water consumption and the effective irrigation area of the irrigation district, the efficiency of resource allocation and utilization can be improved, and the modernization of the irrigation district can be more effective.

Trichopria drosophilae（Perkins, 1910）was first recorded in Tianjin, China. Identification of T. drosophilae based on morphological characters and molecular data was provided first in China. Detailed morphological description and adult photographs of the species were given, with a brief cladistic analysis on some Trichopria species with available mitochondrial gene COI sequences.

Ideological work is an extremely important task of establishing the heart and soul of the country and the nation. As the forefront of ideological work, it is necessary for universities to make firm ideals and beliefs the primary political task of ideological work. We must strengthen the education of ideals and beliefs among teachers and students, build a solid defense line for ideological security in universities with firm ideals and beliefs, maintain and consolidate the security of ideology in universities, firmly defend the forefront of ideological work in universities, and jointly shoulder the responsibility and mission of national rejuvenation.

Annual grafted seedlings（rootstocks were sour jujubes）of two jujube varieties, ‘Yueguang’ and ‘Fucuimi’, were used as the test material for the study. The morphological structures of young leaves of two jujube varieties were determined by microscopic micrometer, and their leaf physiological indexes and photosynthetic pigment contents were measured to explore the suitability of two jujube varieties in the Tianjin area and provide a reference for its introduction and cultivation in the Tianjin area. The results showed that no stomata were found on the upper epidermis of the leaves of either jujube variety, and stomata were mainly distributed on the lower epidermis. The thickness of young jujube leaves was 191.01 μm, the thickness of upper and lower epidermal cells were 28.69 and 22.29 μm respectively, the thickness of lower cuticle of leaves was 3.28 μm, the thickness of xylem of leaf veins was 107.99 μm, and all these indexes were significantly greater than those of ‘Yueguang’. Comprehensive analysis showed that compared with ‘Yueguang’, the leaf structure of young ‘Fucuimi’ jujube trees had enhanced water retention, water transport and photosynthetic capacity, making ‘Fucuimi’ more suitable for introduction and promotion in Tianjin area.

In order to understand the microdevelopment characteristics of intestine and liver of juvenile Cynoglossus semilaevis at different stages, paraffin sections, hematoxylin and eosin staining, microscopic observation and other methods were used to compare the intestinal microstructural characteristics of C. semilaevis with an average body weight of 2 g（W ₂）, 26 g（W ₂₆）, 59 g（W ₅₉）, and 228 g（W ₂₂₈）. The number of mucosal folds, the height of mucosal folds, the thickness of muscle layer, the relative density of mucinous cells and the height of monolayer columnar epithelium were measured. The results showed that the number of mucosal folds, the height of mucosal folds, the length of striatum margin and the single columnar epithelium of the four groups showed a consistent downward trend along the intestinal tract from front to back. Mucinous cells were distributed everywhere in the intestine, and their density gradually increased from front to back, and the change pattern of the four groups was consistent. Except for the number of mucosal folds and the density of mucinous cells, the other four morphological indexes showed a downward trend in the anterior part of the intestine, but gradually increased with ontogenetic development. The striatum border and the simple columnar epithelium of the midgut and hindgut decreased first and then increased in the four groups. The thickness of hindgut muscle layer decreased obviously, showing certain regularity. The liver was well developed in the four developmental stages, and the hepatocytes were polygonal. In conclusion, the intestinal and hepatic structures of C. semilaevis were gradually refined as the individuals developed, and in the W ₂₂₈ group the intestinal and hepatic structures were well developed.