Agricultural equipment is an important scientific and technological support for stabilizing grain output and advancing rural revitalization in new era．Path of tackling key problems and innovation of domestic agricultural equipment were studied by analyzing global situation, domestic demand and difficulties．Autonomous and controllable development goals, and key areas for high performance intelligent major agricultural equipment research were proposed．These key areas included basic common technologies, field production, agricultural power, seedlings, factory facilities, smart agriculture, and other technologies or equipment．It provided reference for relevant technology management departments to optimize research layout．

Rotary tiller seeder is a compound operation machine that can complete multiple tasks such as rotary tiller, trenching, sowing, soil covering, and compaction at once．Composition and structure of rotary tiller seeders was introduced, current development status of rotary tiller seeders was described, three models of rotary tiller seeders and their parameters were listed, their shortcomings were pointed out, and development trend of rotary tiller seeders was prospected．

Load characteristic tests were conducted by installing an exhaust gas recovery smoke engine in exhaust pipe based on a YN series 38CRD2 diesel engine．Influence of engine speed, nozzle flow rate and aerosol concentration changes on atomization effect of smoke machine were studied．Exhaust energy recovery efficiency was obtained by changing temperature at the front and rear ends of exhaust pipe and fuel consumption before and after installing smoke machine．Test results indicated that when engine speed was 2400 r/min, droplet size was the best．Under constant engine speed conditions, when concentration of smoke agent was 30%, droplet size was the best．When nozzle flow rate was 7.5 L/min, nozzle atomization was better．After installing smoke machine, when engine speed was between 2200 to 2400 r/min, engine operated stably and droplet size of smoke machine was uniform．By collecting temperature data from front and rear ends of engine exhaust pipes, it was calculated that exhaust gas recovery and reuse rate was 11%, which meaned that 88 g diesel fuel was used more frequently．Fuel utilization efficiency was improved and energy saving and emission reduction was achieved．It provided a new direction for multifunctional development of agricultural machinery．

Weining County, Bijie City, Guizhou Province, is a typical hilly and mountainous area with complex terrain, small and scattered land, and low agricultural mechanization rate and land output rate．In recent years, with development of agricultural mechanization, agricultural machinery professional cooperatives in Weining County have developed rapidly．However, problems such as service functions, technical management, capital investment, maintenance and repair, and information blockage hindered development of agricultural machinery professional cooperatives in Weining County．Through a large amount of research, countermeasures for developing agricultural machinery professional cooperatives in hilly and mountainous areas were proposed, promoting healthy and rapid development of agricultural machinery professional cooperatives in hilly and mountainous areas, and providing a strong guarantee for realization of whole process of mechanization of agriculture in hilly and mountainous areas．

At present, China has entered era of rapid development of agricultural machinery informatization．Different from other countries in the world, due to diversity of terrain, agricultural machinery informatization in China shows obvious regional characteristics．Situation of agricultural machinery informatization in different scenarios was analyzed, and its common characteristics were studied based on current development status of agricultural mechanization, and key direction of future development of agricultural machinery informatization was predicted．

According to "Detailed Rules for Implementation of Rural Revitalization Strategy of Fujian Province", Department of Agriculture and Rural Affairs of Fujian Province has planned and constructed the "Fujian Rural Revitalization Information System", which was divided into background management subsystem, PC website application information subsystem and the WeChat official account application information subsystem．Overall system architecture, construction content, data flow, application architecture, and system functions were planned and designed．Advantages of system were discussed and its promotion and application was recommended．Suggestions for improvement were proposed in response to shortcomings of the system, and economic and social benefits of the system were summarized and analyzed, providing a mature planning approach for transformation and upgrading of the system．

A set of pesticide dispensing agricultural UAV based on STM32 control was designed．After setting path and pesticide information, it could automatically navigate and complete operation．Cooperating with the UAV, it could eliminate pests 360 ° without dead angle, without personnel operation and save time and labor．Automatic navigation design was based on control algorithm of GPS positioning and three-axis heading angle measurement, and used SDIO bus to operate SD card．In order to record navigation operation data, real-time self-test code was added, the path could be corrected, and obstacle avoidance system wass added to ensure safety of personnel and vehicles．This system was developed based on STM32 development board, which had strong expansibility and compatibility, and new functions could be added in the future．

In order to realize real-time and accurate adjustment of fertilizer conductivity and pH, improve accuracy of proportioning and remote intelligence of water-fertilizer integration, an IoT-based water-fertilizer integration control system was designed．The system adopted IoT module idea to collect environmental information for soil temperature and humidity, air temperature and humidity, EC value and pH value．It could realize data wireless transmission to the cloud by Zigbee technology and NB-IoT technology, control fertilizer application and irrigation area by remote control relay, realize data storage and monitoring by web server and human-computer interaction interface．Experimental results showed that the system had accurate data collection, stable data transmission, real-time abnormal alarms, and achieved accurate proportioning of water and fertilizer solutions during irrigation．The system is an important inspiration in improving yield, saving resources and enhancing efficiency．

Automatic detection of wheat spike is of great scientific value in wheat yield estimation and breeding, however there are still problems in current wheat spike detection such as high model complexity and low accuracy．Deep learning technology was applied to wheat spike detection, and an improved YOLOv5 model for accurate detection of wheat spikes was proposed．The model replaced convolution module in the YOLOv5 backbone network with Ghost convolution to achieve a lightweight model; used ACON activation function to replace default SiLU activation function, thus making activation function more flexible to expand design space; used the Alpha-IoU Loss, which increased alpha power for all IoU Losses, to replace default CIoU Loss of YOLOv5．Finally, by adding a weighted bi-directional feature pyramid（BiFPN）to the network, improved model achieved a 63.3% reduction in number of parameters and a 66.8% reduction in computation with only a 2.17% reduction in mAP, met requirements of practical applications and mobile deployments．Use of Decouple Head was proposed to replace default YOLO Head, which improved mAP by 1.83% over official YOLOv5, demonstrated that decoupling head ccould improve model accuracy．

Entering era of digital economy, blockchain technology is gradually being applied to agricultural industry chain．Blockchain technology has not only become an important tool for digital development of agriculture, assisting in effective flow of agricultural data elements, but also promoting upgrading and development of agricultural industry, achieving development of digital agriculture．Application scenarios and depth of blockchain technology in agricultural industry chain are still insufficient．Based on analysis of advantages and obstacles of blockchain technology in agricultural industry chain, application strategies of blockchain technology in agricultural industry chain in digital economy era were explored．

Alfalfa is a kind of forage with high use value and economic value．Widespread planting of alfalfa in Shuozhou City is of great significance to increase farmers' income and social and economic development．Based on research on characteristic indexes of alfalfa growth, combined with the 30 years' average temperature, precipitation, light, wind speed, evaporation, accumulated temperature and other data in Shuozhou City from 1991 to 2020 compiled by the China Meteorological Administration and Information Center of Shanxi Provincial Meteorological Administration, it was pointed out that annual accumulated temperature, annual average temperature, sunshine and other meteorological factors in Shuozhou City met growth and development needs of alfalfa, and annual precipitation was insufficient for normal growth and development of alfalfa, On the premise that irrigation conditions could be guaranteed, large-scale planting could be carried out．There were some differences between planting of alfalfa in pingchuan district and mountain areas of Shuozhou City．Pingchuan district was more suitable for planting than mountain areas．The planting of alfalfa in mountain areas, especially on uneven land, could be used for grazing or to improve local ecological benefits．The best time to plant alfalfa in Shuozhou City was from middle of June to middle of July．If soil moisture wass good or there was irrigation conditions, alfalfa could also be planted from April to June．Alfalfa in pingchuan district was suitable for cutting 4 times a year, and alfalfa in mountainous areas was suitable for cutting 3 times a year．The planting of alfalfa in Shuozhou City has good economic value and use value, which could be popularized in a large area．It could provide a certain basis for planting of alfalfa in Shuozhou City．

Rice fields are main source of methane（CH₄）emissions, accuracy of DNDC model was verified by eddy covariance, and then DNDC model was used to simulate methane emissions of Liaoning Province from 2016 to 2020．Results suggested that there was a good agreement between DNDC model and eddy covariance（P<0.001）．Average annual methane emission was 71 000 tons and mainly distributed in Shenyang City and Panjin City．Methane emission rate increased with temperature, soil organic carbon and soil bulk density．However, there was a threshold value for influence of precipitation on methane emission rate．When accumulated precipitation in June and July was from 158 mm to 317 mm, methane emission rate had a positive correlation with precipitation．Otherwise there was an negative correlation between methane emission rate and precipitation．Within threshold, precipitation changed soil enviroment and directly affected methane emission rate, but when precipitation was too much or too little, it indirectly affected methane emission rate through temperature．Maximum lengthening sun-drying time was an effective operation to reduce methane emission．Research results could provide theoretical support for assessment, prediction and control measures of methane emission of rice fields in Liaoning Province．

In view of problems such as short storage period after ripening of fresh food pear jujube and commodity would decrease with longer storage period, the test was conducted using Taogu pear jujube as test material, and three treatments including oligochitosan-electrogenerated functional aqueous solution, electrogenerated functional aqueous solution, and oligochitosan aqueous solution were used for coating film preservation．Respiratory strength, hardness, chewability, weight loss, cell membrane permeability, soluble solid content, titratable acid content, vitamin C content, flavonoid content, malondialdehyde content, and catalase activity of the pear jujubes were tested in order to investigate effects of three treatments on quality of pear jujubes and related enzyme activities．Results showed that, oligochitosan electrofunctional aqueous solution reduced weight loss by 40.5% compared with control group after 50 days of storage．Soluble solids were 7% higher and catalase peak was 87.95% higher．All three treatments could reduce fruit rot rate, mass loss rate to different degrees, maintain higher fruit firmness and TSS content, obviously postpone arrival of respiratory peak and suppress malondialdehyde accumulation with lower membrane permeability of active cells．Meanwhile, decline of titratable acid content, vitamin C content, flavonoid content and catalase activity were significantly different（P< 0.05）, among which aqueous oligochitosan electro function treatment was the most beneficial for maintaining fruit storage quality, delaying fruit senescence and prolonging shelf life．

Due to shortage of agricultural water resources, extensive irrigation methods and unreasonable allocation of water and fertilizer, water and soil resources in middle reaches of Heihe River are seriously wasted．To save water and soil resources and improve local production level, technology of drip irrigation under film was adopted based on combination of field experiments and theoretical analysis．This technology could adjust deficit in middle reaches of Heihe River（Minle County Yimin Irrigation Station, Zhangye City）where water resources were scarce from May to September 2021, dry matter accumulation of soybean and its effect on yield under coupling of water and nitrogen under mulch drip irrigation were mainly studied．Results showed that under a certain amount of irrigation, appropriate amount of nitrogen fertilizer could promote dry matter accumulation of soybean, but excessive nitrogen would lead to a downward trend in accumulation process of dry matter of soybean．N₂W₂ treatment was a water nitrogen coupling mode to achieve better soybean yield．Compared with CK（no nitrogen application）, N₁, N₃（high nitrogen application）treatment significantly increased soybean yield by 39.94%, 13.11%, 20.73%．

Aiming at problems of difficult field head steering and easy compaction of working block of hilly and mountain tractor, an adaptive chassis of hilly tractor was designed．The engine was horizontally arranged on the frame．The power was transmitted from one end of engine through belt to transmission parts for chassis driving, and the other end was output for field harvesting and other operations．The steering system was designed with broken trapezoidal structure and adopted two steering modes: front wheel deflection and four-wheel deflection, which could realize all-hydraulic four-wheel out of phase steering．Results showed that the maximum and minimum driving speed of chassis were 10.98 and 0.91 km/h, respectively．The maximum and minimum transmission ratio of the chassis were 370.37 and 61.38, respectively．The minimum turning radius of front wheel deflection of the chassis was 2003 mm and the minimum turning radius of four-wheel deflection was 1494 mm．The hilly mountain tractor has good adaptability to small plot operation．

A new constant cross-section double-acting piston pump applied in water and fertilizer integration machine was designed．Experiments were carried out on change of workflow of piston pump under different plunger stroke ratios（20%, 40%, 60%, 80% and 100%） and irrigation pipe pressures（0.04, 0.08, 0.12, 0.16 and 0.20 MPa））, and response relationship between stroke ratio, pipe pressure and workflow was analyzed．Quantitative study of improvement degree in efficiency of new piston pump over traditional piston pump, comparative analysis of fertilization efficiency, space occupation and weight with traditional piston pump was carried out．New piston pump could make irrigation of water and fertilizer integrated equipment more accurate by adjusting plunger stroke ratio．At full stroke, new piston pump saved 33% to 38% of average time to deliver the same flow compared with traditional piston pump; when pipe pressure rose from 0.04 MPa to 0.20 MPa, mechanical efficiency of new piston pump was increased by about 18% compared with traditional piston pump, and fertilization flow was increased by 32% to 45%; compared with traditional piston pump, new piston pump has reasonable structure, long service life of components, reduced occupation space by about 60%, reduced weight by about 62%, and reduced processing and transportation costs．From comprehensive analysis of mechanical efficiency, occupation space and weight, performance of new piston pump was better than traditional piston pump, which provided a certain reference for development of piston pump with high efficiency and lightweight．

In view of current problems of high labor intensity of manual harvesting and high damage rate of ordinary corn harvester during fresh corn harvesting, principle of bionic ear picking was used to develop fresh corn harvesters, key components such as clamping device, ear-picking device, and cutting device were designed and studied, and their parameters were determined．Field experiment showed that it could meet requirements of fresh corn harvesting, and had prospect of promotion and application．

Performance of cooling system is crucial to ensure stable operation of engine at a suitable temperature, and to improve its service life and fuel economy．Based on actual parameters of tractor engine, theoretical calculation of cooling system was carried out to determine heat dissipation, ventilation and water flow ; then parameters of each module of cooling system were selected to determine matching scheme of cooling system; performance of cooling system was verified．Test results showed that matching design of cooling system could meet cooling requirements of engine, and could provide a reference for matching design of the same type of cooling system．

In view of current problems of complex structure, low automation level, and high manufacturing cost of power shift transmission, a simple version of power shift device was designed based on mountain full crawler tractor transmission．It was mainly composed of hydraulic clutch and planetary wheel mechanism, had a simple structure, reduced manufacturing costs, realized power shift function of tractor's traditional manual transmission, greatly solved problem of power interruption and reduced impact load in shifting process, and improved shifting quality．

As a powerful means for collaborative education, curriculum ideology and politics is expansion and strengthening of professional knowledge education and ideological and political education．Under strategy of rural revitalization, for agricultural colleges and universities, how to improve integration of professional and ideological education plays an important role in cultivating students' devotion to family and country and serving rural revitalization．Taking cultivation of students majoring in agricultural mechanization and automation as an example, cultivation status, existing problems, talent cultivation means, and preliminary results of them were discussed, and their talent cultivation were explored from perspective of curriculum ideology and politics, to provide a reference for education of ideological and political thinking and agricultural mechanization and its automation in colleges and universities, and to provide theoretical and practical support for talent cultivation in agricultural colleges and universities．

Curriculum ideology and politics is a new mode of ideological and political education in colleges and universities．Take a demonstration class of curriculum ideology and politics in engineering drawing as an example to explain section view in method of expressing shape of a machine part．Firstly, overall framework of construction of curriculum ideology and politics in engineering drawing was constructed, ideological and political elements in teaching knowledge points were fully excavated, organic integration mode of knowledge points and ideological and political elements was discussed through case implementation, and teaching effectiveness of curriculum ideology and politics was evaluated through anonymous questionnaire survey of students and classroom feedback from teachers' representatives．Several suggestions were put forward in curriculum ideology and politics construction．

Combustion science is an important compulsory course for energy and power engineering majors under background of carbon peaking and carbon neutrality．In view of current teaching and scientific research status of engineering majors in agricultural universities, combined with characteristics of complexity, interdisciplinary, and rapid technology update of this course, teaching content and teaching design to meet demand of talents under background of carbon peaking and carbon neutrality were discussed, and more applicable teaching methods and practical means were proposed to broaden students' horizons, stimulate their autonomous learning initiative, mastertheir knowledge application ability, and cultivate innovative and competitive engineering professionals to adapt to new energy strategy．

To explore effects of conservation tillage measures on farmland soil wind erosion, Chinese journal papers published by the end of 2020 were retrieved through CNKI with the theme of "no-tillage or conservation tillage and soil wind erosion", and retrieved papers were compiled and analyzed．Results showed that field experiments of soil wind erosion by conservation tillage in China were all from arid and semi-arid farmland in the north, and research method was mainly field measurement with sand collector; research on soil wind erosion in conservation tillage was relatively small, and yield effect had always been focus of conservation tillage research; comprehensive analysis of relevant studies showed that conservation tillage could reduce soil wind erosion of farmland by 71.2% on average; conservation tillage was universal to reduce soil wind erosion on farmland, and a few studies concluded that conservation tillage could not reduce amount of soil wind erosion on farmland．

To explore effects of bacterial fertilizer application on morphological characteristics of Long pepper under different water conditions, a two-factor field experiment of water management and bacterial fertilizer application was conducted with "Long pepper No.11" as research object．Three soil moisture gradients were set for whole growth periods: W₁ with 45%～55% field capacity, W₂ with 55%～65% field capacity, W₃ with 65%～75% field capacity, and three bacterial fertilizer application gradients: F₀ with 0 g/m² fertilizer application, F₁ with 3 g/m² basal application and equal amount of bacterial fertilizer in later period, F₂ with 6 g/m² basal application and equal amount of bacterial fertilizer in later period．A total of nine combinations of water management and fertilizer application were set up to measure plant morphology（plant height, stem diameter, leaf area）, fruit morphology（fruit length, fruit shoulder width, fruit thickness）, and yield of Long pepper．Results showed that W₃ treatment was beneficial to morphological development of plant and fruit．Application of bacterial fertilizer under different water conditions had different effects, but all had positive effects on morphological characteristics and yield of Long pepper．There was a threshold for application amount of bacterial fertilizer, and F₁ treatment had the best overall performance．Under all water and bacteria fertilizer management, W₃F₁ treatment performed the best．In study area, a combination of water and fertilizer with a soil water content of 65%～75% field capacity, a basal application of 3 g/m² and an equal amount of bacterial fertilizer during flowering and fruiting was the best cultivation method．

Based on sensitivity of kiwifruit to climate change during its whole growth period, meteorological data and historical meteorological disaster data from National Meteorological Observing Station of Wulian County, Shandong Province were cited, taking external environmental conditions in Wulian County that meet growth needs of kiwifruit into account, characteristics of major meteorological disasters such as freeze injury, high temperature, waterlogging, wind damage and hail occurred in Wulian County since introduction of kiwifruit were analyzed, and corresponding defensive measures were put forward to guide fruit farmers to proactively prevent meteorological disasters, enhance defensive ability of kiwifruit planting against climate change, and improve fruit yield and quality．

Based on Qujing's resource endowment, regional fruit industry characteristics and main constraints, comparative advantages of three characteristic fruits were analyzed, and corresponding development strategies for leading characteristic fruits were put forward to provide a reference for sustainable development of fruit industry in Qujing City．

Grape is an important variety of forestry and fruit industry of the Xinjiang Production and Construction Corps（XPCC）, which occupies an important position in Xinjiang Uygur Autonomous Region and China．According to ecological suitability evaluation of table grapes based on analytic hierarchy process and comparative advantage analysis and cost benefit on market demand analysis of table grapes, comprehensive evaluation of table grape planting layout of XPCC was carried out: excellent planting areas of table grape were concentrated in the Fourth, Sixth, Eighth and Thirteenth Division of northern piedmont of the Tianshan mountains, Yili river valley and Turpan basin, which were consistent with actual production, providing a quantifiable reference for optimization of table grape planting layout in XPCC．

Creating brand advantages of characteristic agricultural products, building regional public brands of agricultural products, realizing brand premiums of agricultural products, and helping agricultural products go global, are important guarantees for realizing strategy of rural revitalization．By studying influencing factors of brand effect of Huanghekou Produce, it was concluded that key to obtaining regional public brand effect was to increase brand awareness and improve brand reputation．Countermeasures such as focusing on quality of agricultural products, promoting development of agricultural products in various fields, increasing protection of regional public brands and broadening sales channels of agricultural products were proposed with a view to providing new ideas for improvement of regional public brand benefits and promoting rural economy development．

Development of digital agriculture plays an important role in promoting process of agricultural modernization．According to relevant data and literature of digital agriculture in Shaanxi Province, development status of digital agriculture in Shaanxi Province was analyzed．Results showed that digital agriculture in Shaanxi Province had progressed a lot, but there were still some deficiencies, such as weak infrastructure supporting, development environment to be optimized, farmers' weak literacy on digital information, and talent shortage in digital agriculture．On this basis, some targeted countermeasures were put forward to further improve overall development level of digital agriculture in Shaanxi Province．