Abstract:Precision irrigation aiming at improving the agricultural water use efficiency is the main mode of future agricultural irrigation, with the accurate detection of crop water stress and the scientific irrigation decision being its prerequisite. For decades, fieldbased fixedpoint monitoring, onboard vehicle movement monitoring and satellite remote sensing were the information acquisition techniques for the quantitative detection of crop water stress and irrigation decisionmaking. The emergence of unmanned aerial vehicle (UAV) fundamentally solved the technical problems of satellite remote sensing caused by its low temporalspatial resolution, including instantaneous extension, spatial scale conversion, quantitative correspondence between remote sensing parameters and model parameters. At the same time, UAV remote sensing technology also solved the problems of ground monitoring methods, such as low efficiency and high cost. Research results in recent years showed that the UAV remote sensing system could obtain hightemporal resolution images of multiple plots with high throughput, making it possible to analyze the spatial variability of agrometeorological conditions, soil conditions, crop phenotypes and their mutual relationships accurately. It provided a new method for quickly sensing the spatial variability of crop water stress within a large area of farmland, which had obvious advantages and broad prospects in the application of precision irrigation. UAV remote sensing technology was successfully applied to obtain agricultural information, including fractional vegetation cover, plant height, lodging area, biomass, leaf area index and canopy temperature. However, study on quantitative indicator monitoring for crop water stress detection and irrigation decisionmaking has just started. At present, it mainly focuses on crop water stress index (CWSI), crop coefficient, canopy structural index, soil water content, PRI etc. Some of the above indicators were successfully applied to monitor the water stress status of various crops, but for most crops and indicators, further study is needed to improve the universality of the model. The technical process and key points of UAV application in precision irrigation were given. To meet the needs of highefficiency monitoring and accurate dynamic management of agricultural water at different scales, UAV remote sensing needs to be combined with satellite remote sensing and ground monitoring systems in the future. The optimization layout method and intelligent networking technology of skyintegrated agricultural water information monitoring network, fusion and assimilation technology of multisource information, comprehensive diagnosis model with multiple water stress indicators, and big data on agricultural irrigation would be the hotspots of future research.

Abstract:The intelligence of agricultural machinery is the hotspot of current agricultural intelligent research, and the visionbased environmentaware technology is the key technology to realize the intelligence of agricultural machinery. An algorithm based on wavelet transform was proposed to extract the illumination invariant features of farmland images. According to the Retinex illumination model, the image included two parts as the illumination component and the object reflection component. The illumination component can be regarded as the lowpass filtered image of the original image, that was, the lowfrequency part of the original image. Therefore, by removing certain low frequency components in the original image, it was possible to obtain the illumination invariant feature. The original farmland image was preprocessed, including clipping and normalization. The preprocessed image was multilevel decomposed by Haar wavelet base to obtain the high and low frequency components of the image. The highfrequency coefficients after wavelet decomposition were updated by the threshold method, and the multiscale reflection model was reconstructed to extract the illumination invariant features. Finally, the experimental study on illumination invariant feature extraction and crop route acquisition was carried out. The result proved that the feature image extracted by the proposed algorithm was little affected by natural illumination and can retain the object features in the scene to a great extent. At the same time, crop route extraction had high precision under different illumination conditions, and the route error was within ±2°, which can meet the accuracy requirements of agricultural machinery navigation. In addition, on NVIDIAs Jetson TX2 hardware platform, the proposed algorithm took less than 300ms, and the cameras forwardlooking distance can reach 20m, which can meet the realtime requirements of the normal operation of agricultural machinery.

Abstract:In order to design a highly efficient apple harvesting robot, an apple harvesting robot was proposed based on gaselectric hybrid that can work around the clock. The design and evaluation of an apple harvesting robot in the laboratory was introduced. The freedom manipulator with five degrees adopted both electric and pneumatic hybrid power as the power source. The electric motor ensured that the arm can accurately position the apple, and the pneumatic motor ensured the endeffector can quickly and flexibly grasp the apple. The apple recognition algorithm combined traditional machine learning methods with the recent popular deep neural network methods to optimize the detection speed while improving the robustness, and used the builtin lighting system to achieve longterm work. The control system included an industrial computer, an AC servo drive, and a pneumatic actuator that controlled the robot arm and the end effector to access and pick the apple. The system carried out visual and picking experiments in a laboratory environment. The average time for visual positioning of apples was 44ms per image. The harvesting system reached an accuracy of 81.25% with average picking time of 7.81s per fruit.

Abstract:Aiming at the problem of large fluctuation of the attitude and low tracking accuracy of the selfpropelled crawler robot in the rugged mountainous environment, a threedimensional rugged tracked robot control method was studied. The geometric model of dimensionality reduction kinematics was established by analyzing the kinematics model of the twodimensional flat road and threedimensional rugged road surface of the robot. Then, a sliding mode control method based on the dimensionality reduction coefficient was designed to realize the threedimensional rugged road track. The motion control of the robot and the path tracking simulation and experiment of the smooth road surface and the rugged road surface were carried out. The simulation results showed that the driving direction error was gradually decreased and approached 0 in the smooth road simulation, the lateral position deviation fluctuated within ±0.2m, and the attitude adjustment can be completed within 1s; the threeaxis position error in the rough road simulation was controlled in the range of ±10cm, the attitude adjustment can also be completed within 1s. Through the path tracking test of smooth road surface and rugged road surface, the lateral deviation after robot tracking stabilization was -2.9~8.8cm and -14.3~21.5cm, respectively, and the attitude error was controlled within ±2° and ±5°, respectively, which satisfied the actual tracking demand. 

Abstract:The seeding drill unit is mainly composed of working parts which include a seed and fertilizer opener, a seeding apparatus, a soil covering and pressure device, et al. The seeding operation is carried out, and when working under the condition of wet clay. The backfill performance of the fertilization shovel is weak, because of the soil fluidity is poor. The phenomenon of “burn seed” was occurred due to seed and fertilizer at the same seed bed. In addition, to ensure that soil has sufficient time to return the fertilizer ditch, the operation speed of the implement cannot be too fast. Moreover, the mechanical operation of highefficiency seeding and fertilization is restricted. Aiming at the existing problems and the background of the existing research, a forced soilreturning device was designed on the basis of the principle of brachistochrone. The optimal structure and the parameter combination of the forced soilreturn device were explored through the combination of theoretical analysis, the virtual simulation and the test, and the threefactor threelevel orthogonal test method were applied. Taking the working speed, distance of returnbaffle and included angle of returnbaffle and soil surface as the test factors. The soil backfill rate and the passthrough property of drill unit were used as evaluation indexes. And the related parameters affecting the operation performance of the forced soilreturning device were tested and optimized. The test results showed that for the soil backfilling rate Y1, the working speed and backflow baffle spacing had a significant effect on it (P<0.01), and the influence of the angle between the backflow baffle and the surface was not significant (P>0.05). To the passthrough property of drill unit Y2, the backflow baffle spacing and the angle between the return baffle and the surface were extremely significant (P<0.01), and the working speed had a significant effect on it (0.01<P<0.05). When the parameter combination was 1.5m/s, the return baffle spacing was 112mm, the angle between the return baffle and the surface was 60°, and the soil backfilling rate was 91.2%. There was no blockage of the drill unit during the operation. The comparison test showed that the optimized speedreducing line forced earthreturning device, soil backfill performance was increased by 16.5%. The forced earthreturning device designed based on the principle of the brachistochrone method can improve the soil backfilling rate without reducing the passability of notillage sowing, and effectively avoided the seeding of the seedbed due to poor fluidity in the soil wetadhesive environment. Tillage planter provided theoretical reference and technical support for high quality and high efficiency operation.

Abstract:In order to solve the technical problem of extracting rice row curvature information in paddy field environment, a tactile sensing method was proposed. According to the mechanical difference and the physiological height of rice and weeds during the weeding period, a kind of tactile beam which was based on bending sensor was designed. Though the mechanical analysis, a dynamic model of the contact between tactile beam and rice seedlings was established. Combined with the bending strength of rice seedling, the principle of the bending rigidity of the tactile beam was determined. Through building the tactile beam calibration test bench, the functional relationship between the device offset and the pressure difference of tactile beam was obtained. On this basis, based on multisensor technology, according to the voltage characteristics generated by the four tactile beams, the calculation method of rice seedling bending was proposed. In order to verify the measurement accuracy and the stability of the device, several field experiments were carried out. The test of speed of travel showed that the acceleration of travel speed was harmful to the stability. At the speed of 1.5m/s, the average relative error was 5.90mm and the maximum error was 830mm. The test of rice hole number indicated that the measurement error became lowest when the number of rice hole was more than 6 and the average error was 2.56mm. The average error was 6.17mm when the number of rice hole was between 1 and 3. The average error was 4.36mm when the number of rice hole was between 4 and 5. The test of water layer thickness indicated that there was no significant correlation between measurement errors and water layer thickness and the lateral offset of neighboring rice seedlings can be controlled within 14mm. The measurement result of this device can satisfy the requirement of accurate control such as rice mechanical weeding avoiding plants and provide new ideas and examples to solve the problem of crop identification and detection in the paddy field environment. 

Abstract:In order to achieve light and simplified precision seeding for rapeseed, the hillseeding centralized metering device was carried out. According to the mechanical and physical properties, and precision seeding requirements of rapeseed, the involutetype modelhole which could contain 1~3 seeds was designed by using empirical equations. The main structural parameters of involutetype modelhole and hillseeding wheel were determined. Effects of modelhole structure on seed feeding performance were investigated by using the EDEM simulation approach and using EDEM software. It was found that the involutetype modelhole was helpful for seed filling, and each modelhole was filled with one or two seeds for modelhole’s length of 3.5mm, the type Ⅱ modelhole and modelhole’s depth of 2.6mm. The consistency of seeding’s time improved through the seed guard belt and the hill diameter was lower while the gap between guard belt and seeding wheel was 0.2mm. The bench test results showed that seed varieties, rotational speed of metering wheel and their interaction had significant effects on the qualified rate of seeding. The qualified rate of seeding was increased first and then decreased with the increase of rotational speed. When rotational speed was 20~40r/min, the qualified rate of seeding was larger than 94% with 1~3 seeds in each modelhole, and the variation coefficient of hill spacing was less than 12%. The standard error of the seeds’ number of 50 hills was within 10, and the variation coefficient of uniformity of seeds’ quantity was less than 100%. The field experiment results showed that the average seedlings per hill was 2.05, which can realize adjustment of precision seeding for rapeseed. The seed hillseeding device could ensure the performance of filling and protecting seeds, and realize six rows of hillforming seeding. This research can provide basis for structural design of hillseeding centralized metering device and precision hillforming seed sowing for rapeseed. 

Abstract:Existing rapeseed cultivation in the midlower Yangtze River area in China, which is planted after the ricegrowing season with sticky soil and a large number of straw, has a persistent challenge that the traditional deep fertilization device of rapeseed combined seeder obsessed with straw entanglement and soil adhesion, highlighting a need for deep fertilization technology and equipment. The purpose was to design an active antiblockage and deep fertilization device for rapeseed combined seeder. Based on the principle of active scraping and preventing plugging, the center of movement curve of the fertilizer shovel contacting soil was determined as the center of the rotary cultivator axis and the shape of the movement curve was set as enveloping the trajectory of the end of rotary cultivator. According to the requirements of antiblocking function of deep fertilization device and the requirements of fertilizer particle movement, the key parameters and allowable range of the design of fertilizer shovel structure were determined, such as the diameter of arc at the lower end of transition section d1, the angle of arc at the center of entry section θ2 and the diameter of arc at the upper end of transition section d2. Taking the maximum instantaneous velocity of fertilizer outflow from the end of fertilizer shovel as the optimization objective, the key structural parameters of fertilizer shovel as design variables and its allowable scope as constraints, a mathematical model for optimum design of fertilizer shovel structure was established. Through the simulation analysis of the fertilization process by the discrete element method, the factors of the center angle of circular arc section of fertilizer shovel entering soil θ2, the diameter of the transition section d1, d2 were taken as test factors. With vz as the response index, a quadratic regression orthogonal rotational combination test was carried out to establish the objective function of the mathematical model. The optimum design parameters of the fertilizer shovel structure were obtained as follows: the arc center angle of the entry section θ.2 was 36°, the arc diameter of the upper end of the transition section d2 was 93mm, and the arc diameter of the lower end of the transition section d1 was 66mm. The field test results showed that the flatness of rear chamber of direct seeder with deep fertilizer applicator was 17.96~21.37mm, the adhesion weight of single fertilizer shovel was stable below 1.5kg, the mean of fertilization depth was 91.10mm, the qualified rate of fertilization depth was 93.33%, the rate of fertilization broken strip was 1.08%, and the machine passed well, which met the agronomic requirements of rape planting and fertilization in the ricerape rotation area. 

Abstract:Aiming at the difficulty of designing longitudinal seedling feeding mechanism of pot seedling transplanter by traditional method and the lack of efficient longitudinal seedling feeding mechanism of potted seedling transplanter for upland field, a longitudinal seedling feeding mechanism of ratchetconnecting rod pot seedling transplanter was designed. According to the characteristics of the mechanism and the requirement of longitudinal feedingseedling for upland field, the kinematics model and mathematical optimization objective were established, and the software for optimum design of longitudinal seedling feeding mechanism was developed to obtain the structural parameters that met the design requirements. According to the software optimization, the horizontal value range of each factor was obtained, the threedimensional model of the mechanism was established and the physical prototype was manufactured. The optimum design of ratchet structure was carried out and the quadratic orthogonal rotation center combination test method was used to optimize the parameters with the success rate of seedling delivery as the test index, which taking the height of ratchet driving surface, the height of ratchet positioning surface and the speed of seedling harvesting as test factors. The results showed that expected success rate of seedling delivery was 9985%, when x1=2.32mm, x2=3.5mm and x3=100r/min. To verify the test, setting up x1=2.3mm,x2=3.5mm and x3=100r/min, the success rate of seedling delivery was 99.17%, which met the design requirements. 

Abstract:Existing rice pottedseedling transplanting mechanisms with compound planetary gear trains face difficulty in providing both the satisfactory trajectory and orientation during transplanting seedlings at the same time. Therefore, a design method based on the combination of forward design and reverse design was proposed to overcome the problem. The principles of the design method were discussed and illustrated by the design of a rice pottedseedling transplanting mechanism with a compound planetary gear train with a noncircular gear. The design requirements of rice pottedseedling transplanting mechanism with a compound planetary gear train with a noncircular gear were established, and its work principle was studied. On the basis of the previous forward design, fine tuning its static transplanting trajectory, and the reverse design was developed to further optimize the design of transplanting mechanism. The kinematics analysis of the transplanting mechanism in reverse design section was carried out and its kinematic model was set up. The computer aided analysis and design software of the transplanting mechanism based on Matlab was developed. A set of design parameters of the transplanting mechanism were obtained by using this software by means of humancomputer interaction. According to the final mechanism parameters, the transplanting mechanism structure was designed, a 3D model of the mechanism was created by using Pro/E software, and a virtual simulation test was performed by using ADAMS software. Finally, a physical prototype of the mechanism was developed for benchscale testing. The trajectory obtained by theoretical calculation was compared with trajectories obtained by virtual simulation and benchscale tests. The design parameters, including the trajectory criteria, takingseedling angle and pushingseedling angle, and the difference between the takingseedling angle and the pushingseedling angle were compared with the corresponding design requirements. The results met the specified design requirements, thus the transplanting mechanism designed with this method not only satisfied the orientation requirement, but also provided satisfactory transplanting trajectory.

Abstract:Cleaning is one of the most important working processes of rice harvester. However, the sieve is often adhered and blocked by rice threshed mixtures in cleaning process. The problem of adhesion and blockage is caused by wet and sticky properties of rice threshed mixtures. In order to solve above problems, the modified cleaning sieve coated with PTFE was designed. Firstly, the reciprocating friction characteristics of rice straw, rice leaves and modified sieve with PTFE coating were tested. The average friction factor between modified sieve with PTFE coating and rice straw was decreased by 32.2%~32.7%, compared with unmodified sieve. The average friction factor between modified sieve with PTFE coating and rice leaves was decreased by 39.1%~40.2%, compared with unmodified sieve. The modified sieve with PTFE coating had good resistance reduction characteristics. Then, the wetting and adhesion properties test of modified sieve with PTFE coating was carried out. The contact angle of modified sieve with PTFE coating was 110.6°, and the contact angle was increased by 26.8%, compared with unmodified sieve. The interface adhesion force between modified sieve with PTFE coating and rice straw was decreased by 62%~67%. The interface adhesion force between modified sieve with PTFE coating and rice leaves was decreased by 63%~65%. Finally, the field cleaning performance test of the modified sieve with PTFE coating was carried out by using rice harvester. When the working amount of rice harvester was 2.0hm2, the mass of adhesion material on modified sieve with PTFE coating was decreased by 67.8% compared with the unmodified sieve, and the adhesion materials were mainly small debris with scattered distribution. The test results showed that the problem of adhesion and blockage of rice threshed mixtures in cleaning process were solved effectively by modified sieve with PTFE coating.

Abstract:In order to improve the alignment quality of corn harvester and reduce the driver’s labor intensity, an autofollow row system of corn harvester was designed, which included sensing system and path tracking control system. The sensing system consisted of laser radar, mechanical sensor using for autofollow row system and gyroscope. The lateral deviation between harvester and corn boundary line was detected by laser radar when the harvester moved to corn field, and the lateral deviation was detected by mechanical sensor during harvesting operation, and the heading angle was detected by gyroscope. Pure pursuit model was used as the control method of path tracking, and the forwardlooking distance of pure pursuit model was dynamically adjusted by fuzzy control. The desired steering angle was determined by the kinematics model of the harvester. The model was simulated and analyzed by Matlab/Simulink. The 4YZ-6 corn harvester with autofollow row system was tested in the field and the results were as follows: the average deviation of laser radar static detection test was 0.0775m, the average standard deviation was 0.1309m, and the proportion of deviation between -15cm and 15cm was 80.5%，and the proportion of deviation between -30cm and 30cm was 95%; the average adjustment distance of autofollow row test based on laser radar was 7.89m, the average deviation was 0.146m; in autofollow row test based on mechanical sensor, the average deviation was 0.0876m and average standard deviation was 0.0976m, the proportion of deviation between -15cm and 15cm was 83.1%, and the proportion of deviation between -30cm and 30cm was 100%. The test results met the requirements of autofollow row of corn harvester, and provided theoretical support for corn harvester’s autofollow row.

Abstract:Whether the contact parameters between materials are set correctly affects the reliability of the results of discrete element simulation test. At present, the calibration method of contact parameters in discrete element simulation is still in the exploratory stage. Plackett-Burman multifactor significance screening test was carried out for four kinds of particle characteristics test methods: split cylinder method, tilt method, drawing plate method and inclined plane method. The analysis of variance of test results showed that the significant factors and factors influencing the measurement results were different from each other. According to the results of variance analysis of split cylinder method, inclined method and inclined plane method, a method of friction coefficient calibration based on the overall characteristics of particulate materials was proposed. The simulation test was combined with the real test, and the static friction coefficient between the urea particles and the PVC material was 0.41, the static friction coefficient between the particles was 0.36, and the rolling friction coefficient between the particles was 0.15. The calibrated coefficients were validated by the bottomless cylinder method. The angle of repose simulation test results was 30.57 degrees, the real test results was 31.74 degrees and the relative error was 3.69%. Under different water content conditions, the relative error between the actual test angle of repose and the simulated angle of repose under the calibrated coefficients was not greater than 4.59%. There was no significant difference between the simulation results and the real test results. The validity of the calibration coefficients was verified by the test results. This method can be used to calibrate the friction coefficient of other granular materials.

Abstract:Panax notoginseng is a kind of precious medicine and mainly grown in Yunnan Province. Aiming to study the mechanical filling performance and optimize the cell hole size of precise Panax notoginseng seed metering device based on EDEM software. It is necessary to accurately establish the seed discrete element model of Panax notoginseng and define the contact parameters of simulation model in EDEM software. Reverse engineering technology was used. Based on bonded particle model, the seed discrete element model of Panax notoginseng was established in EDEM software. Combined with bench experiment and simulation experiment, the contact parameters were calibrated in EDEM software. The restitution coefficient between Panax notoginseng seed and ABS plastic was 0611 by the impact bounce test method. The static friction coefficient between Panax notoginseng seed and ABS plastic was 0473 by the inclined plane sliding test method. The rolling friction coefficient between Panax notoginseng seed and ABS plastic was 0067 by the inclined plane rolling test method. Based on the response surface optimization of quadratic orthogonal rotating combination test method, the optimal contact parameters between the Panax notoginseng seeds in EDEM simulation experiment were determined. The restitution coefficient, static friction coefficient and rolling friction coefficient between Panax notoginseng seeds were 0.492, 0.202 and 0.083 by stacking test method, respectively. The Wenshan Panax notoginseng seeds were chosen for seeding object. The precise Panax notoginseng seed metering device were selected for verification experiment. The qualified index, missing index and multiple index of seed filling were taken as the experiment indexes of seed metering device. Under the experiment conditions of different rotation speeds, the measured and simulated values of the experiment indexes were compared. The relative error of the experiment indexes was less than 5.0%. The results showed that the seed discrete element model of Panax notoginseng and contact parameters can be used in the simulation experiment. It provided basis for the research of precise seed metering device based on EDEM software.

Abstract:Prime cropland construction is helpful for the protection of cultivated land and national food security. Most previous studies were focused on the natural quality of cultivated land, while the locational condition, stability and spatial agglomeration pattern was far from totally understood which reduced the rationality and resulted in frequently adjustment of prime cropland, and also could restrict the development space of urban and rural. A comprehensive evaluation indicator system of cultivated land was constructed by selecting 11 indicators from the aspects of natural condition, locational condition and stability. Based on the evaluation of cultivated land, the local indicators of spatial autocorrelation method was applied to identify the spatial agglomeration pattern of cultivated land quality. Furthermore，the matrix grouping method was applied to classify the type of prime cropland. The score of location condition of cultivated land was higher than that of natural condition and stability. The high quality and relative high quality were the dominant type in Ji’nan, which occupied 35.12% and 22.67% respectively and mainly distributed in the north of Ji’nan, such as Shanghe, Jiyang and Zhangqiu. The area of the lowquality cultivated land was only 47598km2, accounting for 11.98% and mainly located in Licheng and Changqing. Consequently, the cultivated land in Ji’nan was classified into three types, which was priority type, suitable type and reserve type. The cultivated land distributed in Jiyang, Shanghe, north of Zhangqiu, southeast of Pingyin had high quality and significant cluster pattern which were classified into priority type. The cultivated land area of priority type was 212123km2, accounting for 5338% of the total cultivated land area of Ji’nan. The quality of suitable type was also high, and most were distributed around the priority type. Besides, the suitable type had a role of protection and buffering for the priority type. Thus, it should be classified into prime cropland together with the priority type in order to improve the concentration of highquality prime cropland. The area of the reserve type was the least as 98898km2. It was mainly distributed in downtown and the southern mountains. The quality and concentration were relative lower. The development and utilization of reserve type should pay attention to the protection of the ecological environment. 

Abstract:Attempting to study the classification and spatial evolution of rural ecological space in traditional agricultural areas, in order to lay a foundation for the utilization of natural resources and the reconstruction of spatial pattern in traditional agricultural areas. Taking hilly areas of central Sichuan Province as an example, based on the rural ecological space classification system, the spatiotemporal evolution of ecological space in traditional agricultural areas in terms of quantity, composition and spatial distribution were analyzed by using the change rate, dynamic attitude, transfer matrix and lorenz curve. The results showed that the rural ecological space accounted for about 98% of the total land area in the hilly area of central Sichuan Province, and the per capita ecological space area reached 164068m2. The rural ecological space was reduced from 8829872km2 to 8732222km2 between 2000 and 2018, with an average annual decrease of 5425km2. The comprehensive dynamic attitude of ecological space was 0.41%, and the transfer rate of ecological space from 2000 to 2018 was 0.20%, the farmland and forest ecosystems was the main structure of ecological space in the study area, the retention rate were more than 90% in the past 20 years, it was shown that with the passage of time, although the amount of ecological space in traditional agricultural areas was decreasing, the structure of ecological space was still stable overall. The Gini coefficient of the two type ecological space was 0.08 and 0.34 respectively, which indicated absolute average and relatively reasonable spatial distribution, it was shown that ecological space presented a balanced and stable spatial distribution pattern in the traditional agricultural areas. The overall habitat quality in the hilly area of central Sichuan Province was not high. In 2000, 2010 and 2018, the mean value of habitat quality was 0.310, 0.311 and 0.309, respectively. The values showed a trend of first decline and then rise, which was positively correlated with the quantity change of rural basic ecological space.

Abstract:The marginalization of farmland is the progression from high to low net profit of farmland utilization, and the abandonment of farmland is its extreme expression. This research was based on the perspective of farmland parcelization while also taking into account the natural suitability of the farmland, farming conditions, opportunity costs, and other relevant factors. Using a stepwise algorithm, a multidimensional analysis on the various factors that influencing the marginalization of farmland was performed, which was followed by verification of the outcome of analysis using remote sensing image data to identify the main factors that influencing the marginalization of farmland. The results of natural suitability evaluation showed that areas with high suitable, medium suitable and low suitability were 18900km2, 14164km2 and 8881km2, respectively, and natural suitability was the basic condition that affected the marginal utilization of cultivated land. The adjustment of cultivated land with poor natural suitability would be restored to forest land, which was conducive to the restoration of the regions fragile ecology. The areas with highly convenient, moderately convenien and inconvenient were 10369km2, 21405km2 and 10171km2, respectively. It was an important way to improve the utilization efficiency of cultivated land to carry on comprehensive management to the cultivated land with high natural suitability and inconvenient cultivation. And the areas with high opportunity cost, medium opportunity cost and low opportunity cost were 11932km2, 16457km2 and 13556km2, respectively, and the utilization of cultivated land in the area of high opportunity cost in Mengjin County can maintain a high profit, so the abandonment of cultivated land was rare. Using an overlay analysis of the database statistics of farmland and reforested land, it was discovered that currently, natural suitability and farming conditions had a more significant influence on farmland marginalization in Mengjin County. The research results may be used as a reference to formulate a more effective farmland utilization policy locally in the future.

Abstract:Aiming to investigate the uncertainty of parameter sensitivity analysis results at the regional scale due to management measures, climatic conditions, etc., three stations, including Huanghua, Shangqiu and Zhumadian under temperate monsoon climate were selected in different accumulated temperature zones in the Huang-Huai-Hai dry farming region, and extended Fourier amplitude sensitivity test (EFAST) method was used for analyzing the sensitivity of winter wheat and summer corn parameters in WOFOST model based on the data from agricultural meteorological stations and field sampling, and then the consistency test of the sensitivity ranking of the two crops under different production levels and different climatic conditions were performed. The results showed that the main sensitive parameters of winter wheat yield at the potential production level were the lower threshold temperature for aging of leaves (TBASE), efficiency of conversion into storage (CVO), and the reduction factor of gross assimilation rate at 3℃ (TMNFTB3), while the parameters related to the evapotranspiration correction factor (CFET) and efficiency of conversion into storage (CVO) affected considerably simulated yield under water limited production level. There was no significant difference in the sensitivity parameters of summer maize yield at the two production levels, which involved the reduction factor of gross assimilation rate at 10℃ (TMNFTB10), lightuse efficiency of single leaf as daily mean temperature at 40℃ (EFFTB40), life span of leaves growing at 35℃ (SPAN); the topdown concordance coefficient （TDCC）values of winter wheat and summer maize at different production levels were 0.82 and 0.98, respectively, P values were less than 0.01, indicated that the parameter sensitivity ranking had good consistency; under potential production levels, the TDCC values of winter wheat and summer maize with different climatic conditions were 092 and 098, respectively, and the P values were all less than 001, the TDCC values under the water limited production levels were 0.61 and 0.86, respectively, and the P values were all less than 0.01. The results indicated that the WOFOST model simulated yield had obvious differences in sensitivity among different crop parameters, different production levels had little effect on parameter sensitivity, but it was affected by the degree of water stress, different climatic conditions had a great influence on the sensitivity of parameters, and had different effects on the sensitivity of parameters under different production levels, which were mainly related to the differences in climatic conditions and time and space.

Abstract:In order to quickly and accurately monitor crop growth, winter wheat was used as research object, and UAV hyperspectral images of different growth stages were acquired. Firstly, the hyperspectral data of UAV were used to construct the spectral index, and the indices of four growth stages were analyzed respectively, which were related to the biomass, leaf area index and the new growth monitoring indicator (GMI) constructed by the two physiological parameters of biomass and leaf area, and then a single exponential regression model was established with four spectral indices that were strongly correlated with GMI, and GMI inversion models of winter wheat growth stages were established by using three machine learning methods: multiple linear regression, partial least square and random forest. Finally, the best model was applied to the UAV hyperspectral image to obtain the growth monitoring map. The results showed that the correlation between the spectral index and GMI of winter wheat was high, and most of the indices reached significant levels. The correlation between NDVI, SR, MSR and NDVI×SR and GMI was higher than that of biomass, leaf area index and GMI. The regression model established by the single spectral index of each growth stage, the best performing model corresponding to the spectral indices were NDVI×SR, NDVI, SR, NDVI and NDVI×SR; compared with GMI inversion model constructed by three methods, the flowering stage model MLR-GMI had the best effect. The model modeling R2, RMSE and NRMSE of this stage were 07164, 00963 and 1590%, respectively.

Abstract:Remote sensing technology is an effective means of obtaining surface information quickly, nondestructively and on a large scale, and plays an important role in agricultural surveys and crop growth monitoring. The crop growth model systematically quantifies the growth and development process of crops according to crop growth patterns and environmental effects, and establishes a dynamic mathematical model that can accurately simulate the growth and development of crops at a single point scale. Data coupling effectively combines the advantages of remote sensing technology and crop growth model, and has great application potential in crop growth monitoring. Dry aerial mass (DAM) is one of the important physiological parameters in crop growth and development, which is of great significance for crop growth monitoring and yield estimation. In order to explore an accurate and efficient method for estimating the DAM of winter wheat, experiment data of winter wheat in two growing seasons of 2013—2014 and 2014—2015 were obtained. The leaf area index (LAI) remote sensing inversion model was constructed by using the 2015 experimental data, and the 2014 data was used to verify the accuracy of the inversion model, and the optimal estimation model was screened according to the modeling and verification accuracy. The results showed that the regression model constructed by NDVI705 performed the best, and the R2, RMSE and NRMSE of modeling and verification were 0.755, 0.769, 24.23% and 0.668, 0.869, and 26.96%, respectively. LAI was the coupling variable between remote sensing and simple algorithm for yield estimates (SAFY) model. By using the shuffled complex evolution with PCA (SP-UCI) algorithm, three sensitive parameters such as emergence date (D0), effective lightuse efficiency (ELUE) and sum of temperature for senescence (STT) were optimized, and then the dynamic growth simulation was performed for the whole growth period of winter wheat. The results showed that the LAI of winter wheat simulated by SAFY model showed an increasing trend in the vegetative growth stage. It was increased significantly after the returning green stage (about 160 days after sowing) and reached its maximum at the end of vegetative growth (about 200 days). Later, LAI began to decay and approached zero at the end of grain filling (about 250 days), which was highly consistent with the actual growth of winter wheat. The R2, RMSE and NRMSE of the winter wheat leaf area index simulated by the model 2014—2015 and 2013—2014 were 0.760, 0.769, 24.22% and 0.677, 0.879, 27.25%, respectively. During the whole growth period, SAFY model simulated that the winter wheat DAM had an overall upward trend, and the growth accelerated after the returning green stage, reaching the maximum growth rate at the end of vegetative growth (about 200 days), and then the growth was gradually slowed down, and the DAM growth ended at the end of grouting (about 250 days). The R2, RMSE and NRMSE of the winter wheat DAM simulated by the model in 2014—2015 and 2013—2014 were 0.887, 1.001t/hm2, 19.41% and 0856, 1033t/hm2, 19.86%, respectively. The results showed that the coupled hyperspectral remote sensing and SAFY crop growth model can accurately simulate the dynamic change of winter wheat growth, and the estimation accuracy of winter wheat DAM was high, which can provide reference for remote sensing monitoring of winter wheat growth.

Abstract:The primary purpose was to investigate the influence factors on stress wave propagation in larch standing trees and pave a foundation for further study on the propagation mechanism of stress wave in standing trees. Standing trees were considered to be a twolayers material only consisted of heartwood and sapwood, and the propagation of stress wave in standing trees was simulated. The effect of loading impulse frequency, diameter at breast height (DBH) and ratio of heartwood on stress wave propagation in standing trees were studied by using COMSOL Multiphysics finite element analysis software based on stress wave propagation theory in the solid medium and orthotropic assumption of standing trees. It was found that the velocity of stress wave in standing trees was decreased with the increase of impulse frequency; for a tree model with 10cm DBH, the wave front of stress wave was changed into onedimensional plane wave as the propagation distance was increased to 12m, however, the stress wave still propagated as threedimensional dilatational wave for a tree model with DBH over 30cm though the propagation distance was increased to 12m; DBH had an influence on the propagation speed of stress wave, wave velocity was firstly small and almost no change as DBH was less than 10cm, and then it was increased when DBH was changed from 10cm to 40cm, finally, slightly increased and remained relatively stable as DBH was over 40cm; the velocity of stress wave in standing trees was decreased with the increase of ratio of heartwood. DBH had an impact on the propagation patterns and shapes of stress waves in standing trees, however, the impulse frequency and the ratio of heartwood had no effect on the propagation patterns and shapes of stress. But all of them had an influence on wave propagation velocity. The optimal loading impulse frequency was 25kHz. The propagation velocity of stress wave in standing trees was not only depended on the mechanical properties of sapwood, but in fact relied on both heartwood and sapwood.

Abstract:Aiming at the problem of large fitting error of manual calibration data for FDR sensors, the data from other regions were introduced as auxiliary data, and an automatic calibration model based on migration learning was established. In this model, historical data from other regions were introduced as auxiliary data. Data collected from FDR targets were used as source data. Combined with auxiliary data and a small amount of source data, an accurate FDR sensor calibration model can be obtained by using TrAdaBoost algorithm. TrAdaBoost algorithm for classification problem was improved to TrAdaBoost algorithm for regression. The basic learner of TrAdaBoost algorithm was changed from AdaBoost to XGBoost, which improved the calculation method of error rate when updating weight. Firstly, XGBoost was used to train the auxiliary data to get the initial calibration model, and then a small amount of data was collected from the target location of FDR, and the improved TrAdaBoost algorithm was used to calibrate the initial calibration model, so that the accurate FDR calibration model can be obtained. The data of 10 different regional sites were trained as auxiliary data to obtain the initial calibration model. For the six sites in Shenyang, the target sites were used respectively. Totally 80% of the data were used as the source domain data for model correction, and the remaining 20% were used for testing. The results showed that the average preparation rate using the calibration method was 99.1%, which indicated that the automatic calibration model using migration learning was effective and accurate. 

Abstract:Compilation of landcover maps needs high qualified landcover data with precise classification. Traditional techniques to obtain these have the problem of high cost, heavy workload and unsatisfied results. To this end, a semantic segmentation method was proposed for unmanned aerial vehicle (UAV) images, which was used to segment and classify different types of land areas to obtain landcover data. Firstly, the UAV images were annotated which contained various land use types at pixel level according to the latest national standards, and the highresolution complex landcover image data set of UAV was established. Then, several significant improvements based on original design of semantic segmentation model DeepLabV3+ were made, including replacing the original backbone network Xception+ with the deep residual network ResNet+; adding joint upsampling unit after backbone network to enhance the encoder’s capability of information transfer and conduct preliminary upsampling; adjusting dilated rates of atrous spatial pyramid pooling (ASPP) unit to smaller ones and removing global pooling connection of the module; and improving the decoder by fusing more lowlevel features. Finally, the models were trained and tested on the UAV highresolution landcover dataset. The presented model achieved good experimental results with pixel accuracy of 95.06% and mean intersectionoverunion of 81.22% on the test set, which was 14.55 percentage points and 25.49 percentage points higher than that of the original DeepLabV3+ model respectively. The proposed method was also superior to the commonly used semantic segmentation methods FCN-8S (pixel accuracy was 32.39%, mean intersectionoverunion was 8.39%) and PSPNet (pixel accuracy was 87.50%, mean intersectionoverunion was 50.75%). The results showed that the proposed method can obtain more accurate landcover data and meet the needs of compiling fine landcover maps. 

Abstract:In order to realize the identification of corn disease images in complex field background for small data samples, a corneal disease image recognition model based on transfer learning was proposed. Based on the VGG-16 model, a new fully connected layer module was designed. The VGG-16 model was migrated to the model in the trained convolution layer of the ImageNet image data set. The collected corn disease image data set was divided into a training set and a test set according to a ratio of 3∶1. In order to expand the data set of the image, the original set of the training set was rotated, flipped, and the like. Based on the training set before and after the expansion, the two layers of the training model, the full connection layer and the training model, all the layers (convolution layer + full connection layer) were tested. The results showed that all the layers of the data expansion and training model can improve the recognition ability of the model. Under the condition of all the layers of the training model and the expansion of the training set data, the average recognition accuracy of the image of corn healthy leaves, large spot disease leaves and rust leaves was 95.33%. Compared with the new learning, transfer learning can significantly improve the convergence speed and recognition ability of the model. Finally, the trained model was developed into a visual user interface, which can realize the intelligent recognition of corn leaf spot and rust images in the complex background of the field.

Abstract:Aiming to solve the problems that strawberry identification and localization were mostly carried out in a simple environment and the identification efficiency was low, the continuous identification and detection of strawberry in a complex environment was studied, and an improved YOLOv3 identification method was proposed. By training a large number of strawberry image data sets, the optimal weight model was obtained. The mean average precision (MAP) of the test set reached 87.51%, among which the average accuracy and the recall rate of mature strawberries was 97.14% and 94.46%, respectively, and that of immature strawberries was 96.51% and 93.61%. In the model test stage, aiming at the problem of strawberry image blurring in the night environment, the recognition accuracy of the original image was significantly improved by using Gamma transform image enhancement. The harmonic mean value (F value) was used as the comprehensive evaluation index, and the actual test results of various identification methods under different fruit numbers, time periods and video tests were compared. The results showed that the improved YOLOv3 algorithm had the highest F value, the average detection time of the picture was 34.99ms, and the average detection frame rate of the video was 58.1f/s, indicating that the recognition accuracy and rate of the model were better than that of other algorithms, and it had good robustness in complex environments such as fruit occlusion, overlap and density. This study can provide theoretical basis for continuous operation of strawberry picking robot under actual working conditions.

Abstract:China as the largest aquaculture country in the world, traditional aquaculture methods are vulnerable to light, water quality environment and complex background. In order to solve the problem of accurate feeding in fish culture and improve fish welfare, fish population was taken as the research object, and a method of fish feeding activity intensity evaluation based on feature weighted fusion was proposed by using computer vision and image processing technology. Firstly, according to the algorithm flow, the method of mean background modeling, median filtering and morphology were used to denoise and grayscale the ingested image to obtain the foreground target fish group, and the swimming trajectories of fish at different feeding stages were plotted by extracting the center of mass of the target area. Secondly, based on the pixel points of the image, the HSV color moment, canny detection and gray level cooccurrence matrix (GLCM) were used to extract the 13dimensional image features such as the color, shape and texture of the image. Then three feeding evaluation factors were selected by combining Relief feature selection and XGBoost algorithm, and the optimal weights of each evaluation factor were determined by weighted fusion method, which were 0.23, 0.40 and 0.37, respectively. Finally, the weighted fusion characteristics were compared with the traditional methods to evaluate the feeding activity intensity. The test results showed that compared with the area method, the mean square error was 0.0178, the detection accuracy was 98.89%, and the coefficient of determination was 0.9043. Compared with the traditional method based on single feature, this method not only enhanced the robustness of the algorithm, but also improved the efficiency of detection and feeding evaluation. It provided a reference for the precision feeding of aquaculture industry and the online detection of fish feeding behavior and the evaluation of feeding activity intensity. 

Abstract:Solar radiation (Rs) is a necessary input variable for Penman-Monteith (PM) formula recommended by FAO to calculate reference crop evapotranspiration (ET0-PM). The influence analysis of solar radiation (Rs-c) from Angstrom equation and its parameters on ET0-c calculation based on PM was taken as the objective in nine agricultural regions of China. Using monthly valid average solar radiation (Rs-o) (from dataset of monthly values of radiation data from Chinese Surface Stations) and relative sunshine duration data (from dataset of monthly values of climate data from Chinese Surface Stations) at 112 stations during Jan.1957—Mar.2017, through comparative analysis and correlation analysis, the spatiotemporal differences between Rs-c and Rs-o were mainly explored. Then the spatiotemporal differences between ET0-c and ET0-o were obtained by input Rs-c and Rs-o to PM respectively, and it was also analyzed for illustrating the applicability of Rs-c to ET0-PM calculation in different regions of China. The result showed that Rs-c and Rs-o in the nine agricultural regions had significant and unstable spatial and temporal differences. There may be a large error when Rs-c directly replaced Rs-o to participate in the calculation of ET0-PM. However, the analysis of the spatiotemporal difference of ET0-c and ET0-o showed that whether in the entire continent, or the agricultural regions, ET0-c and ET0-o were characterized by a significant and relatively stable linear correlation, the R2 was more than 067 and the error of mean ET0-c was only 006~026mm/d. Considering Chinas agricultural region types, dealing with the “spring drought” in the northern area of irrigation demand, the application can be directly to get ET0-PM by Rs-c, but for the “summer drought” period nationally, ET0-c was slants bigger than ET0-o, and the corresponding correction model was necessary in the application of high precision of watersaving agriculture. 

Abstract:In order to explore the optimal combination of water and fertilizer for strawberry, nine treatments were set from three levels of irrigation and fertilizer, and the effects of different water and fertilizer coupling on yield, fruit quality, water and fertilizer utilization efficiency of strawberry were analyzed. The analytic hierarchy process (AHP) and entropy weighted multilayer empowerment on nine indexes from three kinds of factors were introduced, combination method which derive from game theory was used to obtain the single final target weight, the comprehensive growth evaluation system for strawberry based on TOPSIS method was constructed, and mathematical fertilizer response model was established with the goal of achieve high yield, high quality and high efficiency. The results showed that the effect of water and fertilizer coupling on the weight of fruit per unit area, yield, water use efficiency and fertilizer use efficiency of strawberry was very significant, but not on the quality. The single fruit weight of strawberry was the highest under mediumwater and highfertilizer irrigation. The strawberry yield and soluble sugar were the best under mediumwater and mediumfertilizer irrigation. The strawberry had the best sugaracid ratio and soluble protein content under lowwater and highfertilizer irrigation. The soluble solids content and fertilizer utilization efficiency of strawberry were the best under lowwater and mediumfertilizer irrigation. The vitamin C content of strawberry was the highest under lowwater and lowfertilizer irrigation. The strawberry had the highest water use efficiency under lowwater and mediumfertilizer irrigation. Comprehensively coordinated the various indicators, the highest weighted value was yield (02641) and the lowest was soluble protein content (00595); the comprehensive evaluation of multiple indicators for optimal water and fertilizer treatment was mediumwater and mediumfertilizer (T5). Analyzing the response model of strawberry comprehensive growth to the coupling of water and fertilizer, the singlefactor effects of irrigation amount and fertilization amount were parabola opening downward. When the irrigation amount code value was -023 (23751m3/hm2), the fertilizer amount code value was -002. (182588kg/hm2), the strawberry comprehensive score was the highest. Dividing the optimal closed loop interval of water and fertilizer coupling based on a comprehensive evaluation of more than 90%, the irrigation amount of 2268~2520m3/hm2, and the fertilization amount of 175988~186987kg/hm2 were the most beneficial to strawberry growth.

Abstract:Emitter clogging is one of the obstacles that limits the application and popularization of drip irrigation technology. The computational fluid dynamic (CFD) method was regarded as the most effective method to research the water and sand movement in the labyrinth path of the drip irrigation emitter. Based on the highfrequency pulse with the same parameters (period and amplitude), and the jet tee was used as the boundary condition, and CFD software was used to simulate twophase flow sand concentration in labyrinth channel irrigator in order to improve emitter anticlogging performance. The k-ε turbulence model and Eulerian multiphase flow model were used to simulate the relationship between flow rate and pressure, the instantaneous distribution of particulate matter concentration under high frequency pulse condition, and the influence of high frequency pulse condition on the variation of particulate matter concentration in sediment area. The results showed that the high frequency pulse wave had a great influence on the average flow rate and anticlogging performance of the emitter, and the fluctuation and continuity of the high frequency pulse wave played a major role in the anticlogging ability of the emitter; the order of the high frequency pulse wave of anticlogging ability in descending order was sinusoidal wave, triangular wave, trapezoidal wave and rectangular wave; increasing inflow concentration would lead to sediment deposition in the vortices, and high frequency pulse wave can increase the erosion of the vortices to improve the blockage resistance. The concentration of each part of the emitter was increased with the increase of particle size, and the concentration distribution and variation were slightly different under different particle sizes. The research result can provide theoretical reference for the application and popularization of the drip irrigation system with high frequency pulsed flow.

Abstract:In order to solve the problem of rational application of water and nitrogen under irrigation conditions in Northeast China, an experiment with three irrigation levels (W1:40mm, W2:60mm, W3:80mm) and three nitrogen levels (N1:180kg/hm2, N2:240kg/hm2, N3:300kg/hm2) was carried out in the field conditions with 15N isotope tracer technique. The results showed that the accumulations of ammonia nitrogen and nitrate nitrogen in the 0~100cm soil layer was increased with the increase of nitrogen application, so did the contents in the different layers. The ammonia nitrogen accumulation in 60~100cm layer and the nitrate nitrogen accumulation in 80~100cm layer were increased due to the increase of irrigation amount. The soil inorganic nitrogen residue and nitrogen surplus were increased with the increase of nitrogen application, however, the crop nitrogen absorption was decreased first and then increased. The nitrogen surplus and apparent loss was decreased first and then increased with the increase of irrigation water amount. The accumulation of fertilizer nitrogen was increased first and then decreased with the increase of nitrogen application. The proportion of accumulated fertilizer nitrogen was 2127%~3123%, and the proportion of residual fertilizer nitrogen and nitrogen loss were increased when 300kg/hm2 nitrogen was applied. As the nitrogen in maize plants, of which 6670%~7505% came from the accumulation of soil nitrogen. The accumulation of soil nitrogen in maize plants was increased first and then decreased with the increase of nitrogen application. Combined with the effects of different water and nitrogen management on inorganic nitrogen residue in maize soil, soilcrop nitrogen balance and the fate fertilizer nitrogen, the water and nitrogen combination of 60mm irrigation and 240kg/hm2 nitrogen application can ensure the full utilization of fertilizer nitrogen and reduce the residue and loss of inorganic nitrogen.

Abstract:Magnetized water may improve the soil salt leaching efficiency. It is the basis for revealing the mechanism of salt leaching by magnetized water to explore the influence of magnetized water under different magnetic field intensity on the movement of soil water and salt. The effects of magnetized water with 0T, 01T, 02T, 03T and 05T magnetic field intensity on the characteristics of soil water and salt transport were studied through onedimensional vertical soil column infiltration test in the laboratory. The results showed that the soil water infiltration rate and the wetting front migration rate were decreased with irrigation by magnetized water, while the moisture content of the upper soil wetted zone was increased. With the increase of magnetic field intensity, the cumulative infiltration amount showed decreasing trend initially and then increasing. The cumulative infiltration amount was decreased the most when the magnetic field intensity was 03T. Moreover, the magnetic field intensity had a significant influence on the soil water infiltration parameters under the condition of magnetized water infiltration. The soil sorptivity S and saturated hydraulic conductivity Ks of the infiltration model showed the quadratic polynomial relationship with the magnetic field intensity, respectively. When the magnetic field intensity was 028T, both the soil sorptivity S and the saturated hydraulic conductivity Ks were minimized. In addition, magnetized water infiltration could increase the retention time of water in the upper soil, increase the water content of the upper layer soil, and reduce the water infiltration of deep soil. After the magnetization treatment, the salt leaching amount in unit volume of water was increased, and the desalination rate and magnetization desalination intensity were significantly improved. The magnetized water had the best effect on salt leaching when the magnetic field intensity was 03T. The results showed that the magnetic field intensity could significantly affect the characteristics of magnetized water infiltration and soil water and salt transport, which provided theoretical support and guidance for rational use of magnetized water in agricultural irrigation.

Abstract:The deterministic multiple objective optimization model was constructed based on the characters, including water shortage risk, economic benefit and fairness, existed in water resources management system. Besides, the Me measure multiple objective optimization model was proposed due to the uncertainties of water resources system. Moreover, the Me measure can be transformed into necessary measure, possibility measure and credibility measure according to different pessimisticoptimistic parameters. The two models were applied to the real case of interwater users water allocation of Ganzhou District, Linze County and Gaotai County. The results showed that the Me measure multiple objective optimization model was more practical for water resources management and had more robustness and provided more water allocation alternatives compared with the deterministic multiple objective optimization model. The results indicated that the total water allocation form high to low was possibility measure, credibility measure, and necessary measure. Besides, the structural water shortage risk had negative relationship with allocated water resources, while economic benefit and GINI were positively affected by allocated water resources. Therefore, the necessary measure had more advantages in minimizing the objectives, and the possibility measure was more applicable for maximizing the objectives, and the credibility measure had the comprehensive results. What’s more, the total water allocation, structural water shortage risk and economic benefit was lessened with the increase of measure levels, while the GINI coefficient was increased with the increase of measure levels. Therefore, the decision makers can choose best water allocation schemes with consideration of reasonable pessimisticoptimistic parameter and measure levels.

Abstract:In order to explore the sustainable effect of onetime application of biochar on the productivity of sloping farmland in black soil area, the threedegree slope farmland runoff plot in the black soil area of Northeast China was taken as the research object, the experimental study was carried out during 2016—2018, two treatments of CK (not applying biochar) and BC (2016, 75t/hm2 biochar, 2017, 2018, no longer applying biochar) were set, and the biochar sustainable effect of land production capacity was analyzed. The improved technique for order preference by similarity to an ideal solution (TOPSIS) model and GM(1,1) model were adopted to calculate and forecast the land productivity index, the results showed that the soil bulk density was decreased significantly (P<0.05) within three years of onetime application of biochar, and the most obvious reduction was 387% in the first year. The porosity, total organic carbon, ammonium N, available P, available K content were increased significantly (P<0.05), 〖JP2〗pH value was significantly increased in the first two years after charcoal application (P2016=0.034, P2017=0.038), and increased by 0.9 and 0.6 respectively, the third year and there was no significant difference in charcoal treatment (P2018=0.067). The application of biochar significantly improved the water holding capacity and soil retention performance of soil, and soil saturation moisture content, field water holding capacity and wilting coefficient were significantly increased (P<0.05), with the maximum growth rates of 558%, 478% and 7.29% respectively, and the annual runoff depth and soil erosion amount were significantly reduced (P<0.05), the maximum annual runoff depth reduction was 492mm, and the maximum soil erosion reduction rate was 5.71%. Soybean yield and water use efficiency were significantly improved (P<0.05), with maximum growth rates of 2901% and 1692% respectively. However, the sustainable effect of biochar on land productivity was weakened year by year. With the extension of biochar application period, the bulk density of BC treatment was increased linearly, the porosity was decreased linearly, and the pH value and total organic carbon were decreased in a power function. Ammonium N, effective P, available K content were decreased linearly, the saturated water content, field water holding capacity and the wilting coefficient were decreased linearly. The annual runoff depth and soil erosion were increased linearly. The soybean yield and water use efficiency showed a power function decline and a linear decrease, respectively. Based on the improved TOPSIS model and GM(1,1) model of grey correlation, the land productivity index was calculated and predicted. The results showed that the BC processed land productivity index was higher than CK, but its value was decreased year by year, and it was very close to CK treatment by 2021. It indicated that the impact of onetime application of 75t/hm2 biochar on land productivity can last for about 5~6 years. The research results can provide a theoretical basis for the application of biochar in the black soil region of Northeast China.

Abstract:After the transformation of water saving, the soil salinity of Shenwu Irrigation Area was redistributed due to the change of groundwater level. Based on regional soil information fixed point monitoring, the classical statistics, spatial interpolation, buffer analysis and spatial autocorrelation analysis methods were used to study the spatial variability, temporal and spatial distribution of soil salinity and the difference of soil salinity change in regions for a fixed number of different transformation years. The results showed that after water saving transformation, the average salt content of the whole soil was decreased by 730% before autumn irrigation, the amount of water poured in autumn irrigation was decreased, and the leaching effect of soil salinity was decreased by 926% after autumn irrigation. In the space domain, the high value of soil salinity (great than 6g/kg) was located in the northeast and southern regions with shallow groundwater depth, and the low value of soil salinity (less than 2g/kg) was located in the southwest and eastern sand areas. After water saving transformation, the average increase amplitude of soil salt global Morans I index before autumn irrigation was 5%, the spatial correlation was enhanced. The water volume of autumn irrigation water quantity was decreased, and the global Morans I index was changed, but it was not significant, and the influence of autumn irrigation on soil salinity spatial autocorrelation was weakened. According to the analysis of LISA cluster map, it was revealed that the high-high spatial pattern in the south before autumn irrigation was changed to nonsignificant and high-low cluster area, and the cluster characteristics in the south after autumn irrigation were still very significant, there was salinization risk zone, and it was still the key area of salinization prevention and control after transformation. For moderately saltresistant crop, the proportion of crop growth safety zone and deep nonsaline soil area in Shenwu Irrigation Area was 4966% and 7157%, respectively, after transformation, the area of crop growth safety zone and deep nonsaline soil was increased by 482 percentage points and 185 percentage points, respectively, before autumn irrigation, and decreased by 502 percentage points after autumn irrigation, but the change in deep layer was not significant. The explanatory capability of the average soil salt content in different distance buffer was strong. The affecting radius of the longterm and shortterm transformation regions was 15km and 07km, respectively. The falling rate of average soil salinity content in the buffer of the longterm transformation region was higher than that in the shortterm transformation region, and the degree of homogenization was higher. In summary, since project of watersaving transformation, the degree of soil salinization was reduced, the area of crop growth safety zone was increased, the surface accumulation was weakened, the amount of autumn watering was reduced, the influence of autumn irrigation on soil salt spatial autocorrelation was weakened, and the soil environment was improved. It was suggested that subsurface pipe drainage and chemical improvement agent should be used in the risk area of local salinization.

Abstract:In order to quickly grasp the time and space distribution characteristics of the main environmental parameters in the pig house, a wireless multipoint and multisource remote monitoring system for the pig house environment was designed. The ZigBee mesh topology was used for wireless distributed networking, and the node devices achieved multipoint monitoring in the form of “one master, multiple slaves”. The slave node was designed with STM32 embedded control chip as the core, and equipped with various sensors such as temperature, relative humidity, ammonia concentration and carbon dioxide concentration, etc. Each slave node uploaded the data collected in real time to the server through the master node, and finally implement the function of remote monitoring of the system on the webpage. The system was tested on a largescale breeding farm in Guangdong Province. The spatial and temporal distribution characteristics of various environmental parameters in the farrowing pig house were summarized and analyzed. The results showed that temperature and humidity changes in each area of the farrowing pig house showed a negative correlation, and the relative humidity was high. The difference between changes in ammonia concentration and carbon dioxide concentration in the house was extremely significant (P<0.01). The system was stable in operation, the lithium battery can work continuously for 170h, and the average packet loss rate was 2.39%. The monitoring of each environment parameter was accurate and reliable, and the regional difference was significant. The system was beneficial to quickly perceive the distribution characteristics of pig house environment and provide reference for the optimization of pig house environment control.

Abstract:The cereal and oil food supply chain is characterized by long full life cycle, complicated links, diversified hazardous materials and multisource heterogeneous information. The cereal and oil food full supply chain information security management prototype system based on blockchain was put forward, which stored and managed the multisource heterogeneous cereal and oil food supply chain information via the tamperproof and informationtraceable features of blockchain. Through business process analysis of cereal and oil food supply chain, its newtype information security management model was built based on blockchain technology, the dualmode data storage mechanism suitable for it was studied and proposed, the supply chain data was stored by the combination of blockchain storage and offchain database storage. In addition, the supply chain information was managed through the smart contract, ensuring the security and credibility of information storage and transmission. Afterwards, based on Hyperledger Fabric, the system architecture of cereal and oil food full supply chain information safety management prototype was designed, thus realizing the functions of its information collection, query, monitoring and traceability. At last, the system was realized based on Browser/Server network structure. Besides, through the verification and analysis of specific application cases, it can provide a new solution and reference for the quality and safety of cereal and oil.

Abstract:Based on nearinfrared reflectance spectroscopy technology, a nondestructive testing and grading device for corn seed vigor was developed, including single granulation device, conveying pipeline, nearinfrared spectroscopy acquisition system, control system and grading device, etc. The seed granulation device consisted of an inclined turntable with holes and a fixed tray. The conveying pipe was connected with the fixed tray, and the end of it was a spectrum collecting unit. The seeds were separated by a single granulation device and then dropped into a spectral collection area through a delivery pipe for spectral analysis and viability determination, and then the classified seeds were classified by a classification device. The perforated disc was used for separating seeds, their working efficiency was key for seed detection and grading efficiency. According to analysis, there were three factors that determined the single granulation efficiency of the single granulation device: the tilt angle of the turntable, and the turntable speed and height of the hole. In order to improve the single granulation efficiency of corn seeds and improve the detection rate, the parameters analysis and optimization experiments were carried out on the single granulation device. The results showed that when the tilt angle of the turntable was 31°, the rotation speed was 05r/s, and the height of the hole was 22mm, the seed single granulation efficiency was optimal, and the single channel can reach 7 grains/s. In order to establish a corn seed vigor detection model, based on the device, spectral data of 100 normal viable corn seeds and 100 artificially aged nonviable corn seeds in the wavelength range of 980~1700nm were collected, and the qualitative discriminant model of seed vigor were established by utilizing the PLS-DA in different methods. When the number of principal factors was 5, the modeling comparison results under several different processing modes showed that the modeling effect under SG-smooth preprocessing was optimal. In the calibration concentration, there were one discriminant error of viable seeds and one discriminant error of nonviable seeds, and the discriminant accuracy rate was 987%. All the viable seeds in the predicted concentration were correctly discriminated, and the nonviable seeds had two judgment errors, the total discriminant accuracy was 96%. The stability and accuracy of the device were tested by selecting 100 seeds. The total accuracy of seed vigor prediction was 97%. The results indicated that the selfdesigned corn seed vigor particlefree nondestructive testing grading device had higher single granulation efficiency and stable spectrum acquisition. It was feasible to perform realtime nondestructive detection and grading of corn seeds.

Abstract:Aiming to investigate the effects of ultrasonic treatment on the structure and solubility of soybean lipophilic protein (LP). The extracted LP was ultrasonically separated under different conditions, and the effect of ultrasonic treatment on the structure and solubility of LP was analyzed by using sodium dodecyl sulfatepolyacrylamide gel electrophoresis (SDS-PAGE), Fourier transform infrared spectroscopy (FITR), endogenous, exogenous fluorescence intensity and differential scanning calorimetry (DSC). The results showed that SDS-PAGE showed that the ultrasonic treatment could not change the molecular weight distribution of LP, but could change the content of subunits, infrared spectrum and endogenous and exogenous fluorescence spectra. It was showed that different ultrasonic treatment conditions had different effects on the second and third structures of LP. With the increase of ultrasonic intensity, αhelix was firstly decreased and then increased, βfold was increased first and then decreased. The endogenous and exogenous fluorescence intensity was the strongest when treated at 360W ultrasonic power for 10min, and the thermal stability and solubility of LP were improved after treatment with 360W ultrasonic power for 10min and 240W ultrasonic power for 20min. The denaturation temperature was increased by 6~7℃, the solubility was increased by 20 percentage points, and it would have a negative impact on the functional properties of LP when the ultrasonic power was too large. Combined with the test results, it was concluded that the physicochemical properties of LP were most suitable for food applications after treatment at 360W ultrasonic power for 10min.

Abstract:Sensor occluded scenes is one of the main causes of intelligent vehicle traffic accidents. In order to reduce the impact of sensor occluded scenes on active safety performance of intelligent cars, the control of intelligent car active braking system under sensor occluded scenes conditions was studied. Firstly, a database and a convolution neural network were specially established to recognize sensor occluded scenes. Secondly, different types of sensor occluded scenes were classified according to their motion characteristics. Then, a safe distance model under the condition of sensor occluded scenes was established. Finally, based on the abovementioned safe distance model, the speed of potential obstacles in sensor occluded scenes were controlled to achieve the purpose of active collision avoidance. According to simulation test and real vehicle test, the sensor occluded scenes classification proposed can better express the motion characteristics of potential obstacles in sensor occluded scenes. The active collision avoidance safety distance model under sensor occluded scenes conditions had good preventive effects on potential obstacles, and the active safety performance of intelligent vehicle in sensor occluded scenes was improved. 

Abstract:A kind of sugarcanegathering carriages of selfpropelled sugarcane transporters with scissor lifting mechanisms was designed aiming at geographic and geomorphic characteristics of hilly areas and existing problems of traditional sugarcane transporters with long wheel distances, high lifting gravity center and poor overall stability. Stabilities of traditional and scissor sugarcanegathering carriages were analyzed and studied from angles of their mass centers and discharging angles through the EDEM software based on the discrete element method. The virtual simulation analysis and experiment results showed that the lateral deviation value of the mass center of traditional sugarcanegathering carriages was 123556mm, their mass center oscillating quantity was 177008mm, the maximum change of centroid relative height was 158927mm and their discharging angle was 10493°. Both the lateral deviation value and oscillating quantity of the mass center of scissor sugarcanegathering carriageswas 70549mm, the maximum change of centroid relative height was 161982mm and their discharging angle was 2983°. Compared with traditional sugarcanegathering carriages, scissor sugarcanegathering carriages had a lateral mass center deviation value decreased by 429%, a mass center oscillating quantity decreased by 601% and a discharging angle decreased by 716%. The center of mass of the two cars was changed almost the same as the height. On the other hand, relative contact parameters needed in discrete element simulation were studied, the obtained results were validated through combination of simulation analysis tests and verification experiments in the test platform, which indicated that the theoretical results matched well with experimental ones. In other words, the sugarcanegathering carriages had a good stability. The research results provided references on stability simulation development and innovative design of sugarcanegathering carriages.

Abstract:The parallel mechanisms with analytical direct position solutions and partial motion decoupling are of great benefits to subsequent research such as error analysis, motion trajectory planning and control, dynamic performance analysis. According to the topological design theory and method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, a novel threetranslation (3T) PM was designed, which consisted of prismatic joints and revolute joints, and had the advantages of analytical direct position solutions and partial motion decoupling property and larger workspace. Firstly, the main topological characteristics such as the POC, degree of freedom and coupling degree were calculated. Due to the special constraint feature of the threetranslation, the analytical direct position solutions of the PM can be directly obtained without needing to use onedimensional search method although its coupling degree equaled to one. Furthermore, the conditions of the singular configuration of the PM, and the singularity location in the workspace were analyzed according to the inverse kinematics, as well as the velocity and acceleration of the PM were calculated and simulated. The results showed that the simulation curve was changed smoothly and continuously, and it had good dynamic performance. 

Abstract:The elastostatic stiffness modeling of a 2UPR-RPU parallel manipulator with 2R1T three degrees of freedom was studied based on the screw theory and strain energy, considering the compliance of the bars and joints. Firstly, the limb constraint wrenches was formulated based on the screw theory. Secondly, the strain energy of bar was formulated by material mechanics, and joint by mapping the constraint wrenches to the joint space, and concentrated limb stiffness matrix corresponding to the constraint wrenches was thus obtained by summarizing the strain energy of bars and joints in the limb, and combining with the Castigliano second theorem. Finally, the overall stiffness matrix was assembled based on the virtual work principle. The theoretical result was verified by commercial ANSYS software. The strain energy factor index was defined as the strain energy of the elastic component account for total strain energy for illustrating the influence of each elastic component on the stiffness performance of the mechanism. A fourdimensional image of slice distribution was presented, the influence of each elastic element on the stiffness performance of the 2UPR-RPU parallel mechanism was quantitatively evaluated from the perspective of strain energy. Finally, the global strain energy factor indices of the mechanism under different external wrenches were presented to find the elastic component with the maximum compliance. The proposed modeling provided a new ideas for improving the stiffness performance of the mechanism more effectively.

Abstract:In view of the high complexity of limb recognition in OpenPose, it was proposed to complete the human skeleton extraction based on TfPose, and the neural network integrated learning method was used to perform limb recognition on the robot lifting instructions to complete the intelligent lifting operation. Firstly, the D-H method was used to perform the forward kinematics analysis of the hoisting robot to determine the working space range of the hoisting mechanism, and the inverse kinematics was solved by the conformal geometric algebra method. The hoisting robot was mathematically modeled from the current position to the target position; then it was obtained based on TfPose. The human skeleton vector and RGB skeleton map were based on BP neural network and InceptionV3 network. The neural network integrated learning method was used to determine the optimal weight to complete the hoisting signal identification. Finally, the identified hoisting command limb signal was transmitted to the hoisting robot through UDP communication. The module was controlled to complete the lifting operation. The experimental results showed that the average limb recognition accuracy of the method was 0977, which solved the large cargo lifting occasions such as ports, docks and mines, and greatly improved the hoisting and loading efficiency.

Abstract:In the field of agricultural spraying, precise adjustment of electromagnetic valve flow is an important role to achieve variable spray. Due to mechanical inertia and electromagnetic inertia during the operation of solenoid valve, the response of solenoid valve is delayed. In order to improve the linear range of solenoid valve, a flow controller of solenoid valve was designed based on BOOST circuit by using the inductance characteristics of solenoid valve. Firstly, the hardware circuit of the controller was completed, including microcontroller unit, pulse width modulation (PWM) generator and solenoid valve drive circuit, and the appropriate energy storage capacitor was selected to store the output high potential of BOOST circuit. Secondly, the solenoid valve driven by double voltage did not need additional power supply voltage conversion circuit. By precisely controlling the high frequency onoff mode of the solenoid valve, it realized high voltage opening, low voltage and high frequency maintenance of conduction, and fast release of energy when closing. In the maintenance mode, fuzzy control algorithm was used to set the duty cycle of maintaining on mode, which ensured that the energy storage capacitance can provide enough power for accelerating opening mode. With the help of the spray flow acquisition platform, the flow data under different pressures (110kPa, 180kPa, 250kPa, 320kPa and 390kPa) and duty cycles (3%~97%) before and after the improvement were tested. The results showed that under the five pressures, the improved linear range of flow was increased from 10%~92%, 10%~92%, 10%~92%, 10%~92% and 8%~92% to 4%~92%, 4%~94%, 4%~94%, 4%~94% and 3%~94%, respectively. The designed solenoid valve flow controller based on BOOST circuit had wider flow liner range than the commonly traditional method.

Abstract:2D servo valve combines the pilotstage and powerstage together based on the spiral servo principle. The throttles of the pilotstage have a decisive influence on the characteristics of the 2D servo valve. The dynamic characteristics of bow and rectangular pilotstage 2D servo valves were analyzed, especially under the influence of structural parameters. Firstly, the structure and working principle of the 2D servo valve were introduced, and then the mathematical models of the bow pilotstage 2D servo valve and the rectangular pilotstage 2D servo valve were established respectively. Secondly, the step characteristics of the bow and rectangular pilotstage 2D servo valves under different structural parameters (inclined groove β, pilot stage zero opening h0, system pressure ps) were simulated by numerical method. Finally, a test rig was set up to verify the step characteristics of the bow and rectangular pilotstage 2D servo valves. As a result, the experimental curves of step characteristics of the bow and rectangular pilotstage 2D servo valves were obtained. Under the same structural parameters (inclined groove β was 82°, pilot zero opening h0 was 002mm) and system pressure ps (20MPa), the step response time of the 2D servo valve was shortened from 34ms (bow pilotstage 2D servo valve) to 14ms by adopting the rectangular pilotstage structure. Moreover, the rectangular pilotstage structure was applied to a 2D electrohydraulic servo valve which a torque motor was employed as electro〖JP3〗mechanical converter to drive the rotary motion of the spool. When the displacement of the spool was 03mm,〖JP〗 the step response time of whole system was 10ms, which showed that rectangular pilotstage electricalhydraulic 2D servo valves driven by the torque motor can demonstrate a high speed of response.