Abstract:Internet of Things (IoT) has become the essential technology, which supports the safety, innovation and sustainable development of cold chain monitoring services. Since the complex technical structure and diverse data formats, there are still many challenges in current application scenarios in the cold chain monitoring services based Internet of things. From the perspective of data, the data quality problem in the monitoring process in cold chain was comprehensively analyzed and examined, in order to enhance the data awareness in the cold chain monitoring applications and its services. And thus inspire the relevant scholars to solve the data quality and optimization issues in clod chain monitoring based IoT. In light of the data quality generation mechanism, data quality assessment methods and application improvement practices, the current research status and the development trends were summarized in line with the life cycle of monitoring data in cold chain. The research and analysis indicated that the measurement and evaluation of data quality became the key to the ongoing improvement of the data quality in IoT in cold chain, which emphasized that the data quality should be handled in the process of where the data generation from the perspective of data quality. It also pointed out that the combination of assessment methods, application scenarios, and requirements differentiation was increasingly tight. And the future research should enhance the process of data retrieval through integrating data characteristics of monitoring technologies and the generation process in cold chain, and cold chain monitoring data quality should enhance the collaboration and mining of monitoring technical characteristics and their performances.

Abstract:The laser land leveling of turning radius is large and the twowheel support is easy to appear rim, which is not suitable for the accurate flat land of the small field. A multiwheel support laser land leveling hanging on tractor was designed. By analyzing the floating function of the threepoint suspension mechanism of the tractor and the multiwheel support, the working principle of the lasercontrolled flat shovel was realized. The mathematical model of the floating lifting shovel was established, and the structural parameters and working parameters of the grader were determined. Based on compaction analysis of the support wheel, the support wheel structure composing of two sets of rigid wheels was designed, which reduced the compaction and rim of the soft surface of the twowheel support. The field test of the prototype showed that the operation performance of the machine was stable. The maximum elevation difference and standard deviation of the field were reduced from 20.8cm and 4.48cm to 7.3cm and 1.72cm, respectively. The cumulative percentage of the sampling points with the absolute difference between the sampling point and the mean was less than 3cm was 9194%, which can significantly improve the smoothing of the field and meet the requirements of accurate flat land in the small field. The soil compaction degree of the grid points before and after the flat ground was compared and analyzed, which indicated that the compaction effect of the multiwheel support on the test field appeared at 0~17.5cm. However, when the depth was more than 17.5cm, the soil compaction was basically stable, and the surface soil of the whole field was compacted evenly. Moreover, the soft soil was moderately compacted after leveling, which reduced the sedimentation in the later stage of the soil and ensured the smoothness of the field. The percentage of an area that can not be leveled in the field corners of the traction leveler and hanging leveler was analyzed through the mapping method. The result showed that in the 100m×100m, 36.5m×36.5m and 25.8m×25.8m, the proportion of area that can not be leveled with traction leveler was 0.78%，5.8% and 19.4%, respectively, while the hanging leveler was only 0.09%, 0.68% and 2.25%, respectively, which showed that the hanging leveler was more suitable for small field flats.

Abstract:In the process of citrus harvesting, it is necessary to obtain information about branches and trunks of fruit trees for obstacle avoidance. In natural environment, problems such as random growth posture, different shapes and blocked branches and trunks often arise. In order to complete the acquisition of complete information of branches, the small area recognition of citrus fruit branches was completed by grid marking. The precision rate of the training model under the test set was 98.15% and the average recall rate was 81.09%, and the marker formula could still achieve better recognition results. Because the identified small areas were discrete and discontinuous, it was necessary to divide and sort the discrete areas in order to reconstruct the branches and trunks of citrus trees. At the same time, in order to solve the problems of too many background areas in Mask R-CNN model recognition frame and the recognition frame can not rotate with the growth of branches, the discrete mask obtained from Mask R-CNN model was processed with minimum external moment, and the rectangular border with minimum external moment was used to replace the recognition frame of the original model. Secondly, through the statistical analysis of the position information such as angle and distance between the centerlines of adjacent recognition frames after processing, it was found that there were constraints on the parameters such as angle and distance between centerlines. Therefore, it was proposed to use multi-parameter variable constraints to complete the division of identical recognition frames, in order to reconstruct the branches more in line with the actual growth posture of the branches and improve the ignorance. In the detection of different regions, the center point of the identical trunk recognition frame was fitted by quadratic polynomial, and the fitting error was 11.47%. Finally, the experimental results showed that the citrus tree branch reconstruction accuracy rate was 8864%. This method can provide a basis for the robot to avoid obstacles safely.

Abstract:A multidegreeoffreedom fruit and vegetable picking manipulator with a flexible arm was developed according to the bending flexible pneumatic actuators which had large bending capabilities. The static characteristic and deformation of the bending actuators were studied, and then the kinematics model of picking manipulator was established with multiple tandem joints by using homogeneous coordinate transformation and piecewise constant curvature model. At the same time, the grasp force of the picking manipulator when grasp the different objects was analyzed. In order to adapt to different grasp objectives, the grab modes were set when the robot picked the objects, and then the relationship between finger output force and air pressure was studied. Also, the picking manipulator movement track and work space were got by markers position change with air pressure. Through the simulation of the manipulator by Matlab software, it can be seen that the picking robot can complete fivefinger grasping, fourfinger grasping and twofinger grasping gestures by cooperation of flexible fingers. Subsequently, the relevant experiments were carried out to verify the theoretical model. A prototype of the picking manipulator was made and a variety of fruit and vegetable simulation picking experiments were carried out in the experimental environment. The results of harvesting experiments showed that the picking manipulator had flexible movements and high adaptability to the shape of object. It had multiple grasping modes and was easy to control, which can grasp objects of different shapes and weights stably, especially suitable for automatic picking of spherical and cylindrical fruits and vegetables.

Abstract:Aiming at the problems of low efficiency of depth measurement and lack of effective online monitoring method in rotary tiller operation, a nonlinear monitoring method of rotary tillage depth based on suspended rotary tillage attitude was developed to improve the automation level of rotary tillage quality monitoring. Firstly, the suspension attitude of rotary tiller was analyzed, and the mathematical relationship between the depth and attitude of rotary tiller was established based on the geometric relationship. After comprehensively considering the influence of the structural deformation and wheel subsidence of the suspended rotary tiller group on the measurement results, a threecalibration parameter tillage depth detection model was established. The model can be used to calculate the tillage depth in real time by fitting the relationship between the attitude angle of rotary tiller and the tillage depth. Secondly, in order to verify the measurement accuracy of the model, a rotary tillage depth monitoring system suitable for vehicle terminal was designed. The system integrated satellite positioning, realtime depth measurement, operation speed measurement, operation area calculation and stability evaluation module, and realized the display of the vehicle terminal and cloud storage. Finally, the model parameters were calibrated in the field and optimized based on Matlab. The results of the calibration test showed that the tillage depth value was decreased gradually with the increase of the horizontal inclination angle of the lower link, and the two were negatively correlated, and the tillage depth value was increased gradually with the increase of the horizontal inclination angle of the frame, and the two were positively correlated. A number of field tests were conducted on the calibrated rotary tillage depth monitoring system, and the results showed that the maximum error was 0.80cm, and the rootmeansquare error was 0.55cm. When the tillage depth was about 11cm, the measured value was closer to the real value, which happened to be within the reasonable operating depth range of rotary tillage, indicating that the rotary tillage depth monitoring system had high accuracy and good stability.

Abstract:The “separatingguiding” thought which utilize the antiblocking mechanism to guide the straw to ascend and move along the rotating wheel was proposed. Based on this thought, a cleaning mechanism on account of Archimedes spiral was designed and tested. In theoretical analysis, it was found that the Archimedes spiral could guide the straw to move up along with the outline under all the forces from mechanism and other straw at the beginning of contact, later the straw obtained speed and was thrown away because of the increased centrifugal force and decreased holding force from straw. All the straw was moved in the same way and formed straw group flow, accordingly accomplished the straw shinnying and stacking. Besides, the moving behavior of straw individual and straw group were also investigated via DEM simulation. The field experiment was also done to investigate the performance of notillage maize planter and confirm the optimal working parameter of the Archimedes spiral antiblocking mechanism. The experimental results showed that there were no blockage and exposed seeds. It can be inferred that the optimal working parameter of Archimedes spiral mechanism was 7km/h of forward speed and 600r/min of rotational speed. The mechanism designed can provide reference for the design and optimization of the antiblocking mechanism of notillage maize planter.

Abstract:Considering the soil in Midlower Yangtze River is sticky and its moisture content fluctuates greatly, the furrow should be ditched while rapeseed planting. Due to the lack of theoretical basis for the design of resistance reduction of plow surface, the research on soil contract surface optimization of ship type ditching system was carried out by using the method of differential geometry analysis and EDEM simulation. According to the traction resistance analysis and surface parameter analysis of the main contact surface (front plow surface, shaping surface), the main structural parameters range of the contact surface was determined. Based on the theory of differential geometry, the differential geometric expression which can quantitatively describe the spatial shape change of plow surface with straight, parabolic and exponential curves was established. The simulation results of traction resistance characteristics indicated that the parabolic type plows had better resistance reduction characteristics when the operating velocity was 0.9~1.5m/s. And its resistance were reduced by 15.09%, 16.92% and 32.59%, 31.58% respectively compared with the linear type plows and exponential type plows. The intrinsic geometric parameters E, L and M can respectively reflect the growth rate of traction resistance with speed, the magnitude of traction resistance, and the fluctuation degree of traction resistance with speed. The parameter optimization results indicated that when the operating velocity was 1.2m/s, the width of ditching plow w was 92mm and maximum element angle Φmax was 66°, the minimum traction resistance was 104252N. Field experiment indicated that the average traction resistance of the combined shiptype ditching system optimized by parameters were 956.77N, 1101.33N and 1 564.85N, and the error between the system and the simulation test results was less than 7%, and the operation effect met the agronomic requirements of rapeseed planting. The research conclusion had great theoretical value and practical significance to the resistance reduction design of plow which formed by horizontal straight line principle.

Abstract:Aiming at enhancing the mechanization level of potato microseed planting, a vibrationarranging based seeder for potato microseed was designed. The seeder consisted of seeding device, seed dropping adjustment mechanism, ditching device, and soil and ridging device, which can complete several working procedures in a single pass, such as ditching, seeding, soil covering and ridging. Based on the principle of forced vibration, potato microseeds were arranged and seeded in single row, and some seeds failed to arrange in single row were reseeded by vibration plate. The key structural and working parameters of seeding device were confirmed according to the physical characteristics of potato microseed and agronomy requirements. An adjusting plate with reciprocating motion of high frequency and low amplitude was applied to microchange the size of seeddropping mouth in dynamic conditions. By this way, the stored seeds forming arch in seed box would be avoided. Furthermore, discrete element simulation was used to clarify the reasonable vibration frequency and revolving speed of adjusting plate and driving shaft, respectively. Ditching device, soil covering and ridging device were arranged from front to back, so as to sequentially complete ditching, soil covering and ridging. Key parameters of the ditching opener and doubledisc were determined by theoretical analysis. As indicated in the field experiment, at the working speed of 5km/h, the multipleseeding index, missseeding index, qualifiedseeding index and qualifiedseeding depth rate were 4.6%, 5.6%, 89.8% and 96.5%, respectively. Results showed that performance indexes of the seeder all met the relevant work quality evaluation specification requirements. The research can provide reference for the development of mechanical planting of potato microseed.

Abstract:The increase of grain production is inseparable from fertilization. However, the side effects like energy waste, environment pollution and economic loss are largely caused by unreasonable fertilization. The characteristics of traditional fertilization machine are low operation speed, small fertilizer width and low efficiency, which also followed with unbalanced fertilization in each row, and a large amount of fertilizer is inefficiently utilized. Studies have shown that rational fertilization, especially mechanized precision proportionate fertilization can significantly improve the quality of agricultural products. In order to realize highspeed and widewidth fertilization operation, rapid quantitative transportation of granular fertilizers and proportionate fertilization in each row of the field fertilization machine, the pneumatic centralized fertilization seeder has become the main research and application machine. In order to study the movement characteristics of fertilizer particle in the pneumatic centralized fertilizer distribution device, the airsolid twophase flow characteristics in the pneumatic centralized fertilizer distribution device were numerically analyzed by the coupled simulation of discrete element method (DEM) and computational fluid dynamics (CFD). In this coupling model, solid fertilizer particles were simulated by EDEM software and the air phase was operated by Fluent software. The optimum structure parameters of the fertilizer distribution device were determined by studying the effects of the cone angle of the screwing caps and the diameter of bellows on the air pressure, air velocity and motion characteristics of fertilizer particle. Based on this structure, the distribution uniformity of the fertilizer distribution device influenced by the inlet air velocity and fertilization velocity were studied. The simulation and test results showed that the air flow and the fertilizer particle had the best fluidity and uniformity in the fertilizer distribution device with the taper angle of the screwing caps of 120° and the diameter of the bellows of 80mm. Under the conditions of 25~35m/s inlet air velocity and 0.26~0.44kg/s fertilization velocity, the coefficient of variation of fertilization amount on each row was not more than 4.9%. The distribution accuracy and uniformity of different kinds of fertilizers were also met the requirements of fertilization operation.

Abstract:In order to achieve the combination of potted rice seedling transplanting and technology of mulchfilm, a kind of walktype potted rice seedling transplanting mechanism was designed. The process of seedling picking, conveying, film perforating and cooperating transplanting was completed by a set of rotary mechanisms. According to the working principle of the transplanting mechanism, kinematic theory model was set up and digital optimization goals were set. The computer aided analysis and optimization software of the transplanting mechanism based on Visual Basic 60 was developed. A set of parameters of the transplanting mechanism which met the requirements of transplanting were obtained by optimization. The twodimensional structure of the transplanting mechanism was designed. Threedimensional model was established. The virtual prototype simulation was completed by ADAMS software. The trajectory and attitude verification tests were carried out on the prototype using the test bench and highspeed photography technology. The results of bench test, simulation analysis and theoretical analysis were almost in agreement, which verified the rationality and correctness of the institutional design. The seedling pickup test, film perforating test and transplanting test were completed on the test bench. The results showed that the success rate of seedlings pickup was 90.4%. The success rate of transplanting for films of straw fiber and plastic was 87.5% and 82.5%, respectively, the results showed that the length and width of the film holes were good, which could meet the requirements of walktype potted rice seedling transplanting mechanism on film perforating part.

Abstract:To realize the mechanized transplanting of the strawberry pot seedlings, according to the agricultural requirements of strawberry cultivation, a fullautomatic strawberry potted seedling transplanting mechanism with noncircular gear designed by using fitted Hermite curves as a the noncircular gear pitch curve was proposed, using only one mechanism to complete the four actions such as seedling picking, transporting, digging hole and transplanting. And the transplanting mechanism satisfied the requirements of the strawberry transplanting trajectory and attitude, ensuring the precise coordination of the seedling and the hole. Based on the working principle of the transplanting mechanism, the theoretical model and kinematic characteristics of the transplanting mechanism were analyzed, and the computeraided analysis and optimization software based on Visual Basic 60 was designed and used to obtain a set of parameters which met the transplanting requirements. A virtual prototype of the transplanting mechanism was established and simulated by using the ADAMS software. The physical prototype of the transplanting mechanism was developed by the 3D printing technology, and the transplanting mechanism was mounted on a strawberry transplanting test bench on which highspeed photography experiment was conducted. The results of the theoretical analysis, virtual test, and physical prototype test were essentially identical, which verified the correctness of the mechanism design. The performance test showed that the success rate of seedling picking was 92%, the success rate of planting was 85%, and the average planting distance was 1729mm, the test revealed the depth, length and width of the digging holes met the transplant requirements of strawberry potted seedling.

Abstract:In the mechanical replugging task in greenhouse, the residual matrix in plastic pan would not be beneficial for healthy seedling replugging which was caused by the endeffector removing bad seeding in previous transplanting procedure. A kind of spade endeffector was developed relatively to the needletype for the removing task. The aim was to reduce the residual matrix in the cell by increasing the contact area between the endeffector and matrix. The reasons of residual matrix in the endeffector grabbing procedure were deduced by the statics. The seedling pot would break and the matrix would collapse while the maximum cohesion in matrix was less than the total resistance which was synthesized by the gravity of seedling pot and the adhesion between the matrix and plug tray. Based on the discrete element analysis method, the seedling pot grabbing procedure by the spade endeffector was simulated by the enhanced discrete element method (EDEM). It was found that the performance of residual matrix was reduced while the cohesion of soil matrix was increased. Therefore, taking the matrix ratio and relative moisture content as the main factors and designing the experiment through the combined disc tests to measure the matrix adhesion and cohesion in the different main factors of matrix ratio and relative moisture. The aim was to find the conditions of matrix ratio and relative moisture while the cohesion was bigger than adhesion. The difference between cohesion and adhesion was the largest under the conditions of 60% of relative moisture content and 6∶3∶1 (peat∶vermiculite∶perlite) of matrix ratio. The average matrix removal rate by the spade endeffector reached 70.8%, which was superior to other conditions. Most of the matrix in the plastic hole can be removed under the conditions.

Abstract:A type of rotary seedling pickup mechanism used in vegetable plug seedling transplanter which can realize nonuniform continuous transmission was taken as the research object. In order to improve the working stability of the seedling pickup mechanism, the counterweights method was used to improve the structure of the seedling pickup mechanism to reduce the vibration of the mechanism and improve the performance of the mechanism. The optimization design model of the counterweight was established, and the mass and centroid radius of the counterweight was determined as 0.21kg and 102mm respectively by using the exhaustive method through UG and ADAMS software. ADAMS software was applied to carry out the dynamics simulation and analysis of the seedling pickup mechanism. Counterweight was machined and assembled on the mechanism prototype to conduct dynamics tests. The simulation and test results of bearing reaction force of the seedling pickup mechanism after addition of the counterweight were compared with that before addition of the counterweight to verify the validity of the dynamics performance improvement of the seedling pickup mechanism respectively. The prototype test results showed that the maximal amplitudes of bearing reaction force of the seedling pickup mechanism in x and y directions were reduced from 409N and 77N before improvement to 369N and 69N, respectively, which were decreased by 9.8% and 10.4%. At the same time, the variances were reduced from 5126N2 and 553N2 before improvement to 3391N2 and 398N2, respectively, which were decreased by 33.8% and 28%. The dynamics performance of the seedling pickup mechanism was better and the working stability of the mechanism was also improved.

Abstract:Aiming at the problem of continuous cropping obstacles that seriously restrict the sustainable development of Panax notoginseng planting, a needle steam output device was designed. The structural parameters of the disinfection needle were optimized and verified by the soilbin test. The simulation experiments of the needle’s internal were carried out by Fluent software, the test results showed that the flow rate and pressure of the disinfection needle were increased, and no significant change in outlet temperature was found. The basic law of soil heating was verified by the soilbin test. The soil can be heated to 90℃ in 5 minutes, and the heating efficiency of the lower soil was low, and that of the upper soil was high. In order to explore the effect of different structural parameters of the disinfecting needle on the warming effect of the soil, the number, diameter and steam emission angle of the hole on one side were selected as the test factors of the soilbin test, and the time required for the soil to rise to 90℃ was selected as the test index, and orthogonal tests were carried out respectively to determine the optimal structural parameters of the disinfecting needle. When the number of single side orifices was 4, the diameter of the orifice was 2mm, and the steam exit angle was 45°, the heating time of soil by the disinfection needle structure was the shortest, for 116s. The optimal arrangement of disinfection needles was 6×6 layout, the optimal number was 36, and the spacing was 250mm by the heat transfer simulation of Fluent porous media. The changes in soil organic matter and pH value after disinfection were tested, the soil environment after disinfection met the environmental requirements for the growth of Panax notoginseng.

Abstract:〖WTHZ〗Key words: 〖WTBZ〗〖ZK(〗

Abstract:Flax is one of the important oil crops in northwest China, and Gansu Province is one of the main producing areas of flax. To enhance the mechanization level of separating and cleaning of flax threshing materials, based on the study of the flow characteristics (accumulation angle and slip angle with steel of material) and separationcleaning technological process of flax threshing materials, a separating and cleaning machine for flax threshing material was designed. Through designing and selecting of key operating components of the prototype, the important working parameters of the vibration feeding system, grain separation device, suction fan and cyclone separator were determined. The operation process of automatic discharging discarded device was analyzed and the necessary work conditions to ensure automatic discharge were obtained. For the relevant work performance test of prototype, when the electromagnetic exciter amplitude of the vibration feeding system was controlled at 14~18mm, and the conversion frequency of the suction fan of the air cleaning system was controlled at 50~60Hz, the operating machine had a strong adaptability to flax threshing material. After the operation of separating and cleaning machine for flax threshing materials, the cleaning rate of grains was 9266%, the total entrained loss rate of was 158%, there was no obvious blockage in the automatic discharging discarded device and the experimental results met the design requirements of operation machine. The research results can provide an important reference for small grain crop threshing material separating and cleaning equipment development.

Abstract:In order to investigate the effect of airflow vortex operation on the droplets size distribution of aerial spray, the XR-Teejet 110015 pressure fanshaped nozzle was used as an example, and was tested in the wind tunnel and field respectively. The wind speed in the field was simulated by the airflow velocity of the wind tunnel test, and three spray pressures were set, the droplet size were measured by the laser particle size analyzer. In the field experiment, a fourrotor unmanned aerial vehicle (UAV) was used as the platform to spray on target, then the droplet size distribution regular of each vortex shape formed by different interaction between rotor airflow and canopy were analyzed. The results showed that under the conditions of wind tunnel, each test nozzle was in a very fine atomization level, and the atomization performance was well and stable. The formation of vortex state had a significant effect on the droplets size distribution in the field test. Under the three vortex states, the comprehensive average proportion of droplet size less than 200μm was 73.52%, 74.21% and 84.20%, respectively, which was consistent with the wind tunnel test results, but the DV01, DV05 and DV09 of the droplet in the field test were significantly higher than that in the wind tunnel test. The droplets size of the obvious vortex state and small range vortex had a relatively flat distribution trend in the various layers of the crop, and the variation coefficient of volume median diameter in each layer was between 3.96% and 10.66%, but the no vortex state showed a large volatility, and the coefficient of variation was in the range of 9.49%~17.11%, which indicated that the relatively obvious vortex state was conducive to the penetration of droplets in the vertical space and achieved better application effect. The research results can provide reference and guidance for the accurate spraying operation of agricultural UAV, and have important significance for improving the utilization rate of pesticides in aerial spraying operations.

Abstract:The survey and evaluation of cultivated land quality is an important basis for the protection of the “three in one” of the quantity, quality and ecology of cultivated land, and also an important cornerstone for ensuring national food security and maintaining sustainable agricultural development. In the mountainous and hilly areas, the estimation of the attribute values of the grading factors in the survey and evaluation of cultivated land quality grades is affected by the barriers of large and mediumsized mountain bodies, resulting in the misalignment of the attribute assignment results of the grading elements. Taking the Pingan District of Qinghai Province as the research area, the method of estimating the attribute value of the grading factor based on the barrier factor was studied. The crossvalidation was performed with the inverse distance weight interpolation and the spline function interpolation method. The results showed that different interpolation methods were basically consistent with the simulation of the spatial distribution trend of three grading factors. Because of the difference between the characteristics of the original data and the interpolation principle, the interpolation method based on the barrier factors was inconsistent to different soil properties, and the most suitable interpolation method for soil organic matter and effective soil thickness was the spline function interpolation based on the barrier factor. In the soil pH value interpolation, the inverse distance weight interpolation accuracy based on the barrier factor was the highest; the interpolation accuracy of soil organic matter and effective soil thickness in the study area was higher than the average absolute error, the average relative error, the root mean square error, and the relative root mean square error of the spline function interpolation without considering the blocking factor, respectively, by 11.23%, 10.98%, 7.54%, 9.20%, and 15.08%, 11.74%, 17.41%, 9.40%. Interpolation of organic matter and effective soil layer was performed by interpolation of spline function based on barrier factors. The determination coefficients between the measured and predicted values were 0.927 and 0.901, respectively.

Abstract:Taking the Inner Mongolia Desert Oasis as a research area, the analogy analysis of complex networks and potential ecological networks was carried out to study the characteristics of ecosystem energy flow and analyze the connectivity, integrity and stability of potential ecological networks. Combined with the corresponding ecological factors, the ecological resistance surface was constructed, and 1103 potential ecological corridors and 992 ecological nodes were extracted. The potential ecological network distribution was consistent with the power law distribution, so the weighted network can be adapted to the potential ecological network for analysis. The potential ecological network connectivity in the desert oasis area was poor, the clustering characteristics were not obvious; the ecological nodes were scattered and fragmented, and the integrity was low; the energy flow inside the potential ecological network was relatively simple and not stable enough. The ecological landscape in the desert oasis area was fragmented, and the contradiction between development and ecological protection was more prominent. The overall ecological environment needed to be optimized.

Abstract:Carrying out research on regional territory space pattern change, exploring its evolution regularity and differentiation and revealing the coupling mechanism between the quantitative structure and spatial pattern of territory space have guiding significance for promoting the orderly, appropriate and sustainable development and utilization of territory space. Taking the plateau mountainous citythe urban agglomeration in the central Yunnan as an example, and selecting the land use data in 2000, 2005, 2009 and 2015 and DEM data as the basic data source, from the aspects of quantitative structure and spatial layout to analyze the characteristics of territory space pattern change of the urban agglomeration in the central Yunnan at four time points., revealing the spatiotemporal evolution and differentiation of the territory space pattern. The results showed that the topographical features of the plateau mountainous areas affected the distribution of the territory space pattern of the urban agglomerations in central Yunnan, and the vertical differences characteristics were significant. The ecological space was the absolute main body of the territory space type in the urban agglomeration, and the production and living space were mainly distributed in the east of the central part of the study area. In the past 15 years, the spatial change of the production-living-ecological space was accelerated and the regional differences were obvious. The production and living space area were gradually increased, and the ecological space continued to be decreased, showing an overall situation of “break the pale”. The mutual transformation of ecological and production space area constituted the main type of evolution of the territory space pattern. The territory space use degree was increased year by year, and the hotspots of territory space use degree were mainly concentrated in some areas in the central and eastern parts of the study area. At four time points, the territory space pattern in the study area was generally distributed along the northeastsouthwest direction. The distribution of production and living space in the northeast was the most concentrated, and the ecological space pattern was more random. The spatial distribution characteristics of kernel density in production and living space were characterized by high density in the central, western and northeastern regions, and low in the south, southwest and northwest, and multinuclear diffusion and fragmentation. The spatial distribution characteristics of the calculated values of the kernel density of the ecological space were relatively dense in the east of the central part of the urban agglomeration, and disturbed by human activities, with severe fragmentation and uneven distribution. The development strategy of the western region and the implementation of the corresponding land policy made the territory space structure of the urban agglomerations in central Yunnan a significant change.

Abstract:Taking Baotou City of Inner Mongolia as a research area, the remote sensing images of the same month in 2006, 2010 and 2016 were selected. Combined with the land use data of Baotou City, the landscape types of Baotou City were divided into six categories, namely, forest land, grassland, water body, cultivated land, construction land and unused land. And the analysis of landscape pattern dynamics change, transfer network, landscape change spatial aggregation characteristics, center of gravity transfer, landscape pattern index change and landscape pattern evolution driving force were analyzed. The results showed that the characteristics of the urban landscape had undergone profound changes during the decade of 2006—2016. In 2006—2010, the rate of reduction of unused land was as high as 19.48%, and the growth rate of construction land for ten years was increased from 1.3% to 2.76%. In 2010—2016, totally 15.19% of the cultivated land was converted into grassland landscape, and 3.79% was converted into construction land. In the past ten years, landscape changes were distributed in Baotou City. The landscape changes were mainly distributed in the agricultural farming areas where the cultivated land was densely covered with grassland and the interlaced edges of different landscapes. In 2006—2010, in the unutilized land, the bare land in the north was ecologically treated, the area was reduced, and the center of gravity was moved 73.79km to the southeast. The landscape segmentation index, the aroma diversity, the fragrance uniformity, etc. were decreased, and the dominant landscape was not yet formed, and the landscape fragmentation was intensified. Through the analysis of landscape pattern driving force, it was found that the intensity of landscape change was related to NDVI. 

Abstract:Drought is a complex natural hazard. A remote sensingbased drought index, the integrated drought condition index (IDCI-RF) for monitoring agricultural drought, by integrating the droughtrelated information based on random forest (RF) regression technique was proposed. The optimal droughtrelated factors over different time periods were selected through correlation analyses between 17 remote sensing drought indices and the 3month standardized precipitationevapotranspiration index (SPEI-3).Based on the RF regression method, the IDCI-RF index which considered land cover data, climate classification information, digital elevation data and multisource droughtrelated factors comprehensively was established. The determination coefficients, RMSE and MAE values were calculated between the 3month SPEI and the IDCI which was derived from the RF, Cubist and Bagging model, respectively. Results showed that compared with other two ensemble methods, IDCI-RF produced higher correlation coefficient values with in situ variables and all the determination coefficients varied between 0.54 and 0.68. Additionally, regression analyses were performed between the IDCI-RF and the in situ reference data to further evaluate the capability of regional drought condition monitoring and analyses were performed in seven main provinces of the study area. Results showed that the IDCI-RF was agreed well with the SPEI-3 in different provinces, and all the determination coefficients were above 0.7. The yearly IDCI-RF variations in 21 representative meteorological sites were compared with that of the in situ drought indices to evaluate the temporal drought monitoring capability of this index. Results showed that the IDCI-RF exhibited consistent variations with the in situ reference data at the regional scales in most cases. The spatial changes in the IDCI-RF maps were also compared with the changes in the in situ reference data at the meteorological sites to assess the IDCI-RF performance in monitoring shortterm drought conditions. Results showed that the IDCI-RF maps basically showed a similar spatial pattern with the in situ reference data. The practical application of IDCI-RF demonstrated that it can provide accurate and detailed drought condition and IDCI-RF method can be effectively used for regional agricultural drought monitoring.

Abstract:In order to improve the accuracy of retrieving soil moisture content based on canopy temperature information, taking the different moisture treatment of the jointing field corn as the research object, and the UAV thermal infrared and visible light camera were used to obtain the remote sensing images of the experimental area. Different image classification methods were applied to remove the soil background and extract corn coverage and canopy temperature, then the indices such as crowntemperature difference and the ratio of crowntemperature to coverage were calculated, and the relationship between the two indices and soil moisture content was analyzed subsequently. The results showed that there were differences in corn coverage extracted by different classification methods, and there were also differences in corn canopy temperature extracted by different classification methods. The crowntemperature difference, crowntemperature difference to coverage ratio calculated by three classification methods (Grayscale segmentation, RGRI index, GBRI index) had a linear relationship with soil moisture content, and it was better to invert the soil moisture content of 0~30cm corn root depth by the two indices; the crowntemperature difference without removing the soil background held the worst effect on soil moisture content, while removing soil background by GBRI index classification enjoyed the better effect on the soil moisture content（R2 was improved from 0.255，0.360 and 0.131 to 0.425，0.538 and 0.258 at depth of 0~10cm，10~20cm and 20~30cm）; the ratio of crowntemperature difference to coverage inversion of soil moisture content performed much better than that of crowntemperature difference. At the depth of 0~10cm，10~20cm and 20~30cm, R2 was 0.488，0.600 and 0.290 in the model set, P<0.001, and R2 was 0.714，0.773 and 0.446 in the verification set, indicating that the ratio of crowntemperature difference to coverage was a new indicator for reversing the effect of deep soil moisture in the corn root zone. This study provided a new method for inversion of the soil moisture content of corn in the field by thermal infrared remote sensing.

Abstract:Forest resources have their own importance in human survival and development. Forest plot survey is used to obtain forest information and analyze the status of forest resources. With the advancement in sensor technology, remote sensing, especially LiDAR, is used to obtain point cloud data by scanning plots which can be used to extract forestbased factors. The improvement of SLAM algorithm enables the positioning without GPS signal coverage. So that, the combination of LiDAR and SLAM system can be used to get a globally consistent point cloud of a plot under the canopy which can ensure the integrity and accuracy of the extracted plot properties. However, the estimations can not be checked and the omissions or errors can not be corrected. A plot survey system based on RGB-D SLAM mobile phone was developed, which constructed the process of plot survey, the estimation of treebased properties and forestbased properties. Augmented reality technology was used to show the observer estimation results and the way of reestimation, which ensured the reliability and integrity of the acquired plot information through human intervention. The system was tested in 18 circular plots with radius of 7.5m.The average DBH estimations showed 0.36cm BIAS and 069cm RMSE; the average tree height estimations showed 006m BIAS and 063m RMSE; the volume estimations showed 8.5959m3/hm2 BIAS and 25.7358m3/hm2 RMSE; the crosssectional area estimations showed 0.9497m2/hm2 BIAS 〖JP2〗and 1.9873m2/hm2 RMSE; the stem density estimations showed -3 stems/hm2 BIAS and 13 stems/hm2 RMSE; the slope estimations showed 0.30° BIAS and 0.88° RMSE; and the aspect estimations showed -0.44° BIAS and 7.61° RMSE. The aspect estimations had a large RMSE due to the estimated pose errors of the SLAM system, but the aspect measurements were still unbiased as a whole.

Abstract:The automatic classification and recognition of tree image has important practical application value. Relevant research on traditional tree species recognition includes leaf recognition, flower recognition, bark texture recognition, and wood texture recognition. In order to solve the problem of recognizing the tree image with complex background in nature scenes, a tree species recognition method based on the overall tree image and ensemble of transfer learning was proposed. Four pretraining models of AlexNet, VggNet-16, Inception-V3 and ResNet-50 were firstly used on ImageNet largescale datasets to extract features. They were then transferred to the target tree dataset to train four different classifiers. An ensemble model was finally established by the relative majority voting method and the weighted average method. A new tree image dataset called TreesNet was built and experiments were designed based on the dataset, including the comparative experiments of transfer learning and conventional methods.The experimental results showed that data augmentation can effectively solve the overfitting problem and the training model had better generalization ability and higher recognition rate. The image recognition accuracy of the tree species in the complex background with the method proposed reached 99.15%, which had a better effect on overall tree image recognition compared with the conventional classification methods of Knearest neighbor (KNN), support vector machine (SVM) and back propagation neural network (BP).

Abstract:Cotton is an important agricultural crop in China, which is related to national economy and people’s life. The production, consumption and import of cotton in China always keep the front place in the world. Cotton leaves are the main organs controlling photosynthesis and transpiration, and the seedling leaves have significant influence on cotton yield and disease resistance. Therefore, accurate quantification of cotton seedling leaf traits is necessary and helpful for the cotton breeding, disease resistance research and functional gene mapping. However, the traditional method for the leaf traits investigation is generally manual measurement, which is laborintensive, subjective, and even destructive. To solve the problem, a novel method was demonstrated to extract cotton seedling leaf traits from 3D point cloud based on structured light imaging. In the study, the 3D point cloud data, including color information was acquired by the structured light scanner. Specific point cloud processing pipeline was developed to identify each leaf, by applying passthrough filtering, super voxel and conditional Euclidean clustering algorithms. Based on the segmented leaf point clouds, the leaf traits, including leaf area, leaf perimeter, leaf angle, leaf rolling degree and leaf yellow ratio were extracted accurately by using triangular patches generation, random sampling consensus, and Lab color space segmentation algorithms. To evaluate this method, 40 cotton plants treated by verticillium wilt virus were measured in seedling stage, and totally 175 leaf point clouds were obtained. Totally 75 leaves were randomly selected to be cut off for manual validation, and the leaf area and perimeter were compared with manual measurements. The results showed that the mean absolute percentage error of leaf area and perimeter was 2.59% and 2.85%, respectively, the R2 values of leaf area and perimeter was 0.9973 and 0.9822, respectively. The results proved that the automatic measurement had a high accordance with manual measurements, which proved the high accuracy of this method. In addition, the left 100 leaves were divided into infected leaves and healthy leaves by manual observation, meanwhile the leaf traits were extracted with segmented point cloud data to calculate the P value by single factor analysis of variance. The measured P values were 0.099, 0.242, 0.346, 0.531, 0.002 and 0, respectively, and the results proved that the traits of leaf rolling degree, and leaf yellow ratio were able to distinguish the infected leaves from healthy leaves evidently. In conclusion, the study demonstrated an effective novel method for accurate and nondestructive measurement of cotton seedling leaf traits, which would be helpful for the cotton breeding, disease resistance research and functional gene mapping research. 

Abstract:Leaf traits can provide important references for canopy light distribution, growth and development, and monitoring of external environment. Aiming at the problems of simplicity and abstraction in the process of processing and expressing leaf traits, a leaf traits fusion method based on morphological reconstruction was proposed. Taking the growth of cucumber leaves in greenhouse as an example, the effective accumulated temperature and growth rate were taken as characteristic parameters to establish the leaf morphogenesis model. The parametric spline curve was used to describe the geometric shape of leaf edge and vein. The dichotomy method was used to divide the leaf edge and vein curve recursively in order to realize the meshed subdivision of the blade surface. Combining with the leaf color texture information mapping model, a visual expression algorithm of leaf characteristics was introduced. The experimental verification results showed that the relative errors between the simulated and observed values of leaf traits obtained by this method were small, and the consistency was good, which demonstrated the method had certain feasibility and validity. Furthermore, in comparison with the typical statistical model and point cloud reconstruction model, the experimental results indicated that the square of correlation coefficients was above 0.95, and the root mean square deviation was no more than 0.236. Compared with traditional modeling methods, the proposed model had higher fitting degree and better reliability, by which it can effectively realize the dynamic simulation of cucumber leaf traits, which could provide a basis for realtime grasping and forecasting of plant growth and development. This method not only provided a reference for the dynamic tracking and management of greenhouse crop production, but also laid a theoretical foundation for the further study of the role of plants under various environmental factors.

Abstract:In order to solve the problem that soil moisture sensor based on standingwave ratio (SWR) principle is affected by temperature in longterm operation, a temperature compensation model based on binary regression analysis was presented. Based on the least square principle, the parameters of the compensation model were determined and the sensor was compensated. The temperature drift characteristics of SWR soil moisture sensor were analyzed from two aspects of hardware circuit and the measuring principle of soil water content. The experiment using high and low temperature alternating humid heat test box set temperature in the range of 5℃ to 45℃, the test results showed that the absolute deviation of the sensor to measure soil moisture content volume was between -2.65% and 2.22%, the maximum relative error was 29.76%, and the maximum mean square error was 2.2119%. By fusing the SWR soil moisture sensor output value with the PT100 temperature sensor output value, the temperature compensation model was obtained by binary regression analysis based on the least squares optimization calculation, and the fitting determination coefficient was 0.998. The verification of the temperature compensation model depended on the sensor experimental data at different temperatures. The results showed that the absolute deviation distribution of the measurement results of SWR soil moisture sensor after temperature compensation was ranged from -0.26% to 0.69%, and the maximum relative error did not exceed 5.23%. The mean square error was decreased by an order of magnitude and the maximum was 0.157%. The temperature compensation model established can effectively reduce the influence of temperature on SWR soil moisture sensor and improve the accuracy and reliability of its measurement results.

Abstract:The deficiencies of essential macronutrients of nitrogen (N) and potassium (K) usually affect the production of chlorophyll, cause imbalances in plant growth and drastically most importantly affect the quality and yield of agricultural products. A new N/K deficiency diagnostics method was proposed based on chlorophyll distribution features of the whole cucumber leaf. N/K deficient cucumber plants and control plants were grown under nonsoil conditions with special nutrient supply. Chlorophyll distribution maps of N deficient leaves, K deficient leaves and control leaves were determined by using hyperspectral imaging technology and genetic algorithm, and distribution features extracted from the chlorophyll distribution maps were employed to diagnose N/K deficiencies. Chlorophyll distribution features (the mean value of all pixels in leaf center region and the number of pixels with low chlorophyll content in the leaf edge region) were extracted. A diagnostic method based on these features were obtained with total diagnostics rates of 95% for N/K deficiencies. The result indicated that the extracted chlorophyll distribution features could be employed to diagnose N and K deficiencies in cucumber plants.

Abstract:Automatic recognition of newborn piglets has encountered several challenges such as small targets, ambient light variation, piglet adhesive behavior and object occlusion. A onestage DCNNs method was proposed to automatically and accurately recognize newborn piglets at high computation speed. The method merged classification and localization into one task and took the whole picture as the ROI of feature extraction, then using FPN algorithm to locate and identify piglets, which showed good generalization ability for natural multiinterference scenes. The effects of different channel number data sets and different iterations on the effectiveness of the model were compared. Support for batch image processing, and realtime detection of video and surveillance videos, with multiple storage of detection results. The recognition result of newborn piglets was output into three forms: video, picture and text file. The contents of the text included the number of piglets, the recognition confidence degree and the piglet coordinate. The combination of different output results could identify the state and behavior of piglets. The results showed that when the total amount of the data set was the same, the data set containing both night single channel and daytime three channel was close to the optimal value of the model at 20000 iterations. The precision of the model on the verification set and the test set were 95.76% and 93.84%, respectively, and the recall rates were 95.47% and 94.88%, respectively. The detection speed of the images with a resolution of 500 pixels×375 pixels was 53.19f/s. The video detection speed of 720P was 22f/s. The proposed system can meet the requirement of real time detection of piglets in a farrowing pen. 

Abstract:Water resource is one of the most important input factors in agricultural production. Despite the relative abundance of water resources, China is still considered as a water stressed country with approximately 2100m3 per capita per year. Aiming to construct the evaluation index system to comprehensively evaluate the water use efficiency and find out the problems concerning water as production input factors during the water usage process in Chinas grain production. The superefficiency DEA method was applied to evaluate the water use efficiency within Chinas grain production sector from 2009 to 2014, and to find out the proper adjustment direction and adjustment level. Eventually the countermeasures and suggestions for improving grain production’s water use efficiency in China were put forward. The results showed that there were substantial differences in grain production’s water use efficiency among China’s four major economic zones. The northeast region had performed the highest efficiency level and possessed slightly fluctuate trend simultaneously, while the central and western regions revealed the lower efficiency level and greatly fluctuate trend. Last but not the least, the eastern region with the lowest efficiency level characteristic experienced the declining trait. In addition, there were significant differences in grain production’s water use efficiency among different provinces which was attributed to unreasonable water input allocation within the grain production’s sector; the serious problem of coexistence of water input redundancy and inadequacy phenomena, which precisely reflected the failure in mutual promotion between irrigation system and effective precipitation in China’s grain production sector.

Abstract:In order to define the effect of straw returning with nitrogen application on soil properties and water use efficiency of maize in Yanghuang Irrigation Area of Ningxia, the treatment with uncovered straw and nitrogen application rate of 333kg/hm2 was taken as the control (CK), the effects of different nitrogen application rates of SR+N0 (0kg/hm2), SR+N1 (150kg/hm2), SR+N2 (300kg/hm2) and SR+N3 (450kg/hm2) on soil bulk density, water, nutrient, maize grain yield and water use efficiency were investigated. The results showed that the straw returning with nitrogen application could improve soil bulk density and total porosity in tilth soil (0~40cm), and the SR+N2 and SR+N3 treatments were the best. The mean tilth soil bulk densities with SR+N2 and SR+N3 were significantly increased by 8.0% and 8.8%, the mean total soil porosities were significantly increased by 11.4% and 12.5%, compared with CK. Straw returning with nitrogen application was useful for increasing soil organic carbon and total nitrogen at 0~40cm soil layer, and the contents of soil organic carbon, total nitrogen with SR+N2 and SR+N3 were significantly increased, compared with CK. The ration of carbon to nitrogen was decreased with the increase of application rate of nitrogen under the condition of straw returning. The enhancement of soil fertility was the highest at SR+N2, with significant increase of the contents of soil alkelineN, available P, and available K by 33.6%, 47.0% and 30.8%, respectively. The SR+N2 treatment had better soil moisture conservation effect at middle and later growing stage of maize, and it also achieved the higher maize grain yield and water use efficiency improvement. The twoyear mean maize grain yield and water use efficiency with SR+N2 were significantly increased by 33.9% and 26.2%, respectively, compared with CK. Through the twoyear results it was found that straw returning with application of nitrogen can not only effectively improve soil physical properties, but also significantly increase the soil nutrient contents, regulate the ration of carbon to nitrogen, and showed the better soil water conservation ability, therefore significantly increased crop yield and water use efficiency in Yanghuang Irrigation Area of Ningxia. The straw returning with application of pure nitrogen for 300kg/hm2was the best.

Abstract:Aiming to reveal the response of nitrogen uptake and transformation under different water and nitrogen conditions at pre and postflower, meanwhile to investigate the relationship between crop nitrogen, fertilizer nitrogen, soil nitrogen and dry matter absorption and transport. Based on the 15N isotope tracing technique, the experiment with three irrigation levels (W1:40mm, W2:60mm, W3:80mm) and four nitrogen levels (N0:0kg/hm2, N1:180kg/hm2, N2:240kg/hm2, and N3:300kg/hm2) were carried out in field conditions. The results showed that the nitrogen fertilizer recovery rate was 21.27%~44.64%, and the best value was obtained in N2W2 plot. If making a comparison of nitrogen accumulation in each organ at maturity stage, the best was in grain, then was in leaf, stem, and the last was in ear leaf. With moderate nitrogen application regime, the nitrogen accumulation in plants was the highest, however, in W1 plot, it was significantly decreased (P<0.05). The order of nitrogen transformation rate from the largest to the smallest was leaf, stem and ear leaf. The best nitrogen transformation rate was achieved with N2W2 practice which was significantly different from other treatments (P<0.05). The amount of soil nitrogen involved in transformation was greater than the amount of fertilizer nitrogen. The 15N transformation and soil nitrogen transformation of various organs of maize from the largest to the smallest was leaf, stem, and stem leaves. Totally 22.43% ~ 39.45% of nitrogen transformation in plant came from fertilizers, the moderate water and nitrogen treatment could keep higher soil nitrogen transformation. The order of contribution rate of nitrogen grain in different organs from the largest to the smallest as leaf, stem and ear leaf. Nitrogen transformation in various organ accounted for 18.29%~44.29% of the nitrogen accumulation in the grain, and the N2W2 plot had the best value. Dry matter transformation and grain contribution rate from the largest to the smallest isstem, leaf and spike leaf, and the greatest value was got in N2W2 treatment. Therefore, a clear conclusion was that the irrigation of 60mm and nitrogen application of 240kg/hm2 were the best.

Abstract:In order to find out the effects of applying biochar on soil structure, soil fertility and crop yield and its sustainability in the black soil region, the field runoff plot of 3° sloping farmland in the black soil region of Northeast China was taken as the research object, and a fouryear observation was carried out. 〖JP3〗In 2015, according to the amount of biochar applied, five treatments of C0 (0t/hm2), C25 (25t/hm2),〖JP〗 C50 (50t/hm2), C75 (75t/hm2), and C100 (100t/hm2) were set. The treatments were applied as the same amount of biochar in 2016, 2017 and 2018. The results showed that the soil bulk density was decreased gradually with the increase of biochar application and the porosity was increased gradually, and the longer the application period was, the more obvious the effect was. The generalized soil structure coefficient (GSSI) of the four consecutive years was increased first and then decreased with the increase of biochar loading, the soil threephase structure distance index (STPSD) was decreased first and then increased, and the maximum (minimum) value (98.31, 4.87) was obtained in the second year of C50 treatment. At the same time, the threephase ratio of soil was the closest to the ideal state. the contents of macroaggregates (R0.25), mean weight diameter (MWD) and geometric mean diameter (GMD) for four consecutive years were increased first and then decreased with the increase of biochar loading. The decreasing trend was the maximum in the C50 treatment in the second year. The soil available potassium and organic matter were increased gradually with the increase of biochar application for four consecutive years, and the soil available nitrogen and available phosphorus were increased first and then decreased. The highest increase of soil available nitrogen and available phosphorus in each year were C50 (46.1%, 76.6%), C50 (46.4%, 85.4%), C25 (33%, 100.7%) and C25 (23.9%, 103.2%). The application of biochar for four consecutive years can increase the yield of soybean and its components. In the second year, the C50 treatment increased the maximum yield, the yield was increased by 33.3%, and the yield was the most sustainable. The sustainability yield index (SYI) was 0.871. The research results can provide theoretical support for actual production.

Abstract:In order to study the effects of interactions of plastic film mulching and controlled/slow release fertilizer on the growth and nitrogen utilization of spring maize, field experiments were conducted at two sites in Yongshou and Changwu on the Weibei Dryland in Shaanxi Province in 2017. The experiments included two cropping patterns (e.g. full plastic film mulching, M; flat planting, F), and three types of nitrogen fertilizer (e.g. urea fertilizer, U; control release fertilizer, CU; slow release fertilizer, SU). A total of six different treatments were involved consequently. Then the influences of different interactions on the growth of spring maize were evaluated through comparisons of leaf area index (LAI), biomass accumulation, grain yield and nitrogen utilization under different treatments. The results showed that plastic film mulching could significantly increase spring maize yield by 14.0%~34.2% compared with the flat planting treatment. The plastic mulching treatment increased nitrogen content in the 0~40cm soil, reduced nitrogen leaching to deep soil layers, and increased nitrogen use efficiency by 95%~237%. Under plastics film mulching, the leaf area aging rate of ureabased treatment (U) was higher than that of the coated controlled release fertilizer treatment (CU) and the urea added DCD treatment (SU) by 42.0%~51.6% and 55.4%~66.3%, respectively. The dry matter accumulation rate of ureabased treatment (U) from flowering to maturity was lower than that of the coated controlled release fertilizer treatment (CU) and the urea added DCD treatment (SU) by 112.7%~155.2% and 30.3%~44.7%, respectively. Under plastic film mulching, nitrogen transport amount and efficiency of vegetative organs of the controlled/slow release fertilizer treatment were higher than that of the ureabased treatment (U) by 4.2%~78.1%, and the nitrogen absorption efficiency and nitrogen fertilizer utilization efficiency were higher than the urea treatment (U) by 6.6%~24.2%. Therefore, the interactions of plastic film mulching and controlled/slow release fertilizer can alleviate premature aging of spring maize, promote the growth, and increase the efficiency of nitrogen fertilizer utilization of spring maize to some extent. Thus, the combination of plastic film mulching and controlled/slow release fertilizer can be used as an effective measure to increase corn yield in the Weibei Dryland in Shaanxi Province. 

Abstract:Sludge residue (SLR), straw residue (STR) and vinegar residue (VR) combined with food waste and cattle manure were used as composting substance, respectively. The dynamics of enzymatic activity during composting, including dehydrogenase, urease, polyphenol oxidase and cellulase activity, and the change of humic acid composition (HA, FA) before and after composting were monitored and analyzed. The results showed that the activities of dehydrogenase and urease in the composting process of STR were increased first and then decreased with composting, and the polyphenol oxidase and cellulase activity were higher, which accelerated the decomposition and humification of organic matter. Compared with STR and VR, the dehydrogenase and urease activities of SLR remained high at the end of composting, which were 19.25μg/(g·h) and 6.22mg/(g·d), respectively, indicating that there was some unstable organic matter. After 30 days of composting, STR presented the highest degree of humification in compost, humification ratio (HR), humification index (HI), degree of polymerization (DP) and percentage of HA (PHA) was 28.89%, 19.24%, 1.99 and 66.60%, respectively. The molecular weights of humic acid were changed from 2.024Da, 3.284Da and 2.090Da before composting to 2.061Da, 3.929Da and 3.990Da after composting. Compost was used for different purposes depending on the molecular weight of humic acid. Therefore, based on multivariate parameter characterization of different residues, it provided a theoretical basis for efficient resource utilization of biogas residue and its product application.

Abstract:In order to reduce the pollution on the environment caused by waste eggshells, a method of collecting eggshell membranes and eggshells separately from eggshells mixture was explored, which acquired respective added value. Based on the Fluent-EDEM coupling simulation, the influences of cyclone structure parameters such as the diameter and height of the cleaning cylinder on the flow field characteristics, particles trajectories and particles distribution in the cyclone were studied. According to the simulation results, the structure parameters of the cyclone were determined within a reasonable range. In the eggshells and membranes collecting test, the cyclone top structure, fan rotational speed, feeding motor rotational speed and feed rate were taken as test factors, and the cleaning rate and recovery rate of eggshell membranes were taken as evaluation indexes. The simulation results showed that the flow field formed in the cleaning cylinder was that velocity was high in upward direction in the central columnar area and low in downward direction in the peripheral area, and air pressure was the lowest at the air riser, which were conducive to collecting eggshells and eggshell membranes. Increasing the diameter of cleaning cylinder would cause eggshells mixture reflux. Increasing the height of the cylinder would lead to excessive energy loss in the cylinder and low recovery rate of eggshell membranes, otherwise too small height of the cylinder would lead to small energy loss, high airflow velocity in the cylinder and low cleaning rate of eggshell membranes. The test results showed that the recovery rate of eggshell membranes adapting cone top was higher than that of flat top. If the speed of materials inlet was increased, the eggshells mixture would move against the cylinder wall due to the centrifugal force, which can not separate eggshells and eggshell membranes effectively. The experimental results showed when the feed rate was 500g/s, the fan rotational speed was 2892r/min and the feeding motor rotational speed was 918r/min, the eggshell membranes recovery rate was higher than 94%, and cleaning rate was higher than 96%. The result of verification test was close to that of optimization, and the optimization result was credible.

Abstract:Based on near infrared diffuse transmission light compensation spectrum analysis technology, a portable rice quality parameters of the instrument for nondestructive testing was developed, including spectroscopy acquisition unit, light source unit，information processing and display unit，power supply unit, and dedicated reference correction box, etc. Spectral acquisition unit light compensation and collimating lens to the focal effectively improved the signaltonoise ratio of the spectrum, the entire unit size was 207mm×90mm×148mm, which was easy to carry. Fiftytwo indica rice samples were selected and a partial leastsquares prediction model of rice amylose and protein content was established based on the portable multiquality nondestructive testing instrument. The calibration set correlation coefficients of water content, amylose content and protein content were 0.9803, 0.9770 and 0.9323, respectively. The calibration set root mean square error (RMSEc) was 0.2791%, 0.7274% and 0.2045%, respectively. The correlation coefficients of the validation set were 0.9793, 0.9571 and 0.9249, respectively. The validation set root mean square error (RMSEv) was 0.3009%, 1.1067% and 0.2127%, respectively. Based on the MFC software development tool, C/C++ language was used to write the realtime detection and control software, which realized the onekey operation of the portable rice multiquality detector and finally verified the detection accuracy and stability of the portable rice quality nondestructive tester. The maximum variation coefficient of water content, amylose content and protein content was 0.024, 0.079 and 0.034, respectively. The correlation coefficients of predicted and standard physicochemical values of water content, amylose content and protein content in rice samples were 0.9727, 0.9409 and 0.9015, respectively. and the predicted rootmeansquare error was 0.3632%, 1.3181% and 0.2430%, respectively.

Abstract:Aiming to explore the feasibility of the online nearinfrared quantitative analysis model of soybean meal from laboratory to factory transfer and application. Totally 117 soybean meal samples were collected nationwide and used, the nearinfrared quantitative analysis models of moisture and crude protein were established in the laboratory by partial least squares method, two kinds of nearinfrared online equipment installation methods were used in feed production enterprises. The laboratory models of nearinfrared quantitative analysis of soybean meal quality were transferred to feed production enterprises for online application by two different methods. The results showed that laboratory model can rapidly predict the content of moisture and crude protein in soybean meal (RSD was below 10%), R2P of moisture and crude protein were 0.83 and 0.86, RPD value of moisture and crude protein were 2.40 and 2.55, which meant that the model effect was fine; laboratory models were transferred to feed production enterprises for online analysis by different methods such as model correction and sample expansion, the deviation between the predicted value and the measured value was small and stable. The requirement for online detection can be achieved.

Abstract:In order to improve the accuracy of pork freshness identification, a method for pork freshness identification based on improved residual network and transfer learning was proposed. First of all, the pork freshness was classified into seven grades, according to the aerobic plate count, coliform bacteria and pH value of pork combined with national pork food standards（national standards）. The ResNet-50 model was trained with the PfidSet data set to have the ability of extracting image features. Then, the ResNet-50 model was improved by using model transferring and model finetuning in the following ways: firstly, replacing the full connection and classification layers of the ResNet-50 model with a 3layer adaptive network; next, initializing the improved ResNet-50 model weights by using the network parameters trained on the PfidSet; then using LReLu-Softplus as the activation function of the adaptive network; finally, transferring the knowledge gained by the improved ResNet-50 model on the image data set of the pork sample to the task of Iberico pork freshness identification. A total of 23427 images were selected to form the sample set. Then, 80% of the samples were randomly selected from the sample set to be used as the training set, and the remaining 20% for the test set. The test results showed that transfer learning could significantly improve the convergence speed and classification performance of the model, and data augmentation could increase the diversity of data, avoiding overfitting phenomena. The accuracy of classification in transfer learning and data augmentation could reach as high as 94.5%. Moreover, the test method was an efficient method for classifying pork freshness.

Abstract:Maillard reaction is a nonenzymatic, natural and nontoxic method to modify protein or polysaccharide. The effect of jet cavitation powers on the process of soy protein isolate-dextran Maillard reaction was studied, to improve the defect of low efficiency, long reaction time and high energy consumption on the Maillard modified soy protein isolate. The effects of jet cavitation power on the products structure and emulsifying properties were further studied, which provided theoretical support for improving the functional properties of the soy protein isolate with Maillard reaction. The results showed that the jet cavitation treatment induced the molecular structure of the soy protein isolate and exposed more reactive sites, increased the activity of protein and promoted the Maillard reaction process. When the jet cavitation pressure was 1.5MPa, the SPI and dextran Maillard reaction process was the largest, A420 was 0.55, browning was increased by 17.02%, A249 was significant increased (P<0.05). The degree of graft was increased from 32.54% to 57.89%. SDS-PAGE verified that jet cavitation promoted the Maillard reaction of the soy protein isolate-dextran. The fluorescence intensity and UV absorption intensity of SPI was increased which was treated by jet cavitation, indicating that cavitation treatment changed protein conformation and increased the surface hydrophobicity, but the fluorescence and UV absorption intensity of SPI-dextran products were decreased, indicating that dextran combined with the treated SPI surface, the hydrophilic groups were increased and hydrophobicity was decreased. The emulsifying activity and emulsification stability of SPI-dextran Maillard reaction products were increased by 40.61% and 48.46%, respectively.

Abstract:The defatted soybean meal was hydrolysised by alcalase to explore the optimal preparation parameters of calciumchelated soybean peptides, and the properties of alciumchelated soybean peptides were analyzed. The effects of mass ratio of peptide and calcium, chelating temperature, pH and chelating time on calcium binding capacity were studied, and the chelating process was optimized by Box-Benhnken experimental design and response surface methodology (RSM). The results showed that the optimum chelating conditions were as follows: ratio of peptide to calcium was 16, chelating temperature was 38℃, chelating time was 44min, and pH value was 66. Under the optimal conditions, the calcium content was the highest (7873mg/g) in calciumchelated soybean peptides. Moreover, it was concluded that the solubility of the finally obtained calciumchelated soybean peptides was 9859%. Furthermore, the molecular mass distribution of soybean peptidecalcium chelate was also determined by highperformance liquid chromatography (HPLC). The proportion of peptides with a relative molecular weight higher than 5000Da was 176%, peptides with a relative molecular weight lower than 5000Da accounted for 9824%, and peptides with molecular weight lower than 1000Da accounted for 8024%. Among them, the peptides with the relative molecular weight of 180~500Da accounted for the largest proportion. It provided a new method for the research and development of new soybean nutrition and synthesis of new calcium supplements.

Abstract:In order to improve the working conditions of drivers, a wireless network based teleoperation system for tractors was designed before, and the feasibility of the system was verified through several experiments. The system was optimized in two ways to further enhance the usability of the system. First of all, a multithreading programming, including a data reading thread and a data processing thread was used to replace single threading programming in the first generation teleoperation system under unchanged hardware conditions, because the first system based on single threading programming had relatively slow response, which cannot fully meet the realtime requirements. Then, a new user interface with a steering wheel manipulator was designed to provide operators more realistic driving experiences, because the first user interface used many buttons to manipulate, which made operation inconvenient and misoperation sometimes. Finally, tests were carried out to detect performances of the optimized system. Results showed that control commands were executed with a delay of no more than 60ms and the maximum absolute error was no more than 1053mm when the tractor was driven along a straight line at speed of 317km/h by the optimized system, with maximum RMS error of 601mm. Compared with the first generation teleoperation system, the precision of right angle turn was improved obviously for the optimized system. When the slalom test was carried out on the teleoperated tractor, there was little difference whether the driver operated in the tractor or operated remotely. Overall, the optimized system provided better remote driving experiences for operators. 

Abstract:The combustion process of internal combustion engine is greatly influenced by the swirl flow in combustion chamber, especially for diesel engines, where the diesel diffusion process in the swirl flow field is vital for combustion efficiency and the formation of pollutants, including nitric oxides and particulate matter. However, the spray diffusion process has not been lucubrated due to the difficulties of direct observation and the characterization of the internal flows in engine chamber. The diffusion characteristics of diesel spray in different intensity swirl flows were studied visualized. In this experiment, the combustion chamber of the internal combustion engine was simulated by a visualized rapid compression machine, and the diffusion characteristics of the diesel spray under three kinds of flow fields, such as tangential swirl flow field, oblique swirl flow field and straight swirl flow field, were studied. An electronically controlled injector with nozzle hole diameter of 02mm was used. The injection pulse width was 5ms, and the two injection pressures were selected to be 40MPa and 60MPa, respectively. The experimental results showed that the peak and valley values of diesel spray area and window area ratio were the highest in the tangential swirl flow field and the lowest in the straight swirl flow field under the same injection pressure and fuel injection pulse width. The process from the start to the complete mixing of the spray was the shortest in the oblique swirl flow field and the longest in the straight swirl flow field. The diffusion time of the spray oil was inversely proportional to the tangential velocity of the swirl flow and the fuel injection pressure. The results can provide reference for the design of air movement organization in diesel combustion chamber.

Abstract:Vibration energy harvesting technology is an important way to alleviate energy pressure and has broad application prospects in the field of power supply for micro devices. The giant magnetostrictive vibration energy harvesting technology has attracted attention with the excellent performance of giant magnetostrictive materials (GMM). In view of the shortcomings of the current theoretical research on giant magnetostrictive vibration energy harvesting, a columntype giant magnetostrictive energy harvesting device (GMEHD) was designed based on the material properties of GMM, and its working principle was introduced. The input and output model of the device was established and the output voltage calculation formula was derived combining with the structural characteristics of GMEHD. The response of the system under sinusoidal excitation was solved. According to the coil structure, the coil turns were optimized through circuit analysis. The finite element model of GMEHD was established by simulation software COMSOL Multiphysics and the simulation results were obtained. GMEHD was made on the basis of the above. The prototype test system was built, and the GEMHD output electromotive force time curve under different frequency sinusoidal forces was obtained, and compared with the model calculation value and simulation results. The results showed that under the sinusoidal excitation of 1Hz, 10Hz and 50Hz, the GEMHD output electromotive force amplitudes were 2mV, 15mV and 75mV, respectively, and the phase ahead the input force π/2. The model calculation and simulation value fitted well, which verified the accuracy of the model and provided a reference for the next step in the optimization design.

Abstract:The theory of degree of freedom (DOF) analysis for multiloop coupling mechanisms is not yet mature at present. Aiming at the DOF analysis of a spatial multiloop coupling hexahedron deployable mechanism, a method was presented based on the idea of selecting a hypothetical moving platform, establishing the equivalent series supporting limbs, constructing the equivalent parallel mechanism (PM), and then analyzing the DOF of the equivalent PM to obtain the original hexahedron mechanism. One of kinematic chains composed of more than one link was selected as the moving platform at first, and all kinematic equivalent series supporting limbs of the moving platform were established based on the screw theory. Then the number of links contained in the moving platform was reduced continuously, and the equivalent series limbs were reestablished. The original hexahedron mechanism was eventually equivalent to a traditional PM whose moving platform consisted of just one link. The number and properties of the DOF of the multiloop coupling hexahedron mechanism were obtained by analyzing its equivalent PM. The coupling degree of the hexahedron mechanism was reduced by the proposed method, so that the difficulty of DOF analysis of the original multiloop coupling mechanism was reduced. In addition, the simulation model of the hexahedral mechanism was built, and the kinematic characteristics of the mechanism were studied by giving different actuations. Furthermore, the folding performance of the mechanism was discussed. The research results of DOF and kinematic characteristics laid a foundation for the force analysis of the hexahedron mechanism, and the proposed method provided a way for the DOF analysis of other types of polyhedron mechanisms.

Abstract:Based on the idea of using mobile robots instead of farmers to work in the complex environment of farmland and reducing the burden on farmers, a type of reconfigurable mobile robot with wheel/track shape was proposed. Four wheel/track configurations of the same structure were adopted to reconstruct the walking unit and the vehicle body, which had two walking postures, a wheel type and a crawler type, to adapt to the complex terrain in the field. The reconfigurability of the wheel/track motion pattern was achieved by the wheel/track shape conversion device. The mathematical model of the walking unit was derived, and the relationship between angle of swinging rod of robot and height h of step and range of slope that can climb can be obtained when the walking unit robot overcame the obstacle. The virtual prototype and simulation environment of the walking unit were established in Simulink and ADAMS, and the prototype was developed. And calculated by the error formula, the simulated value and the theoretical value of the error were between 10-8 and 10-6. The driving torque error between ADAMSs simulation and theoretical values was only 126×10-5N·m, which verified the correctness of the mathematical model and obtained the driving torque required by the robot during the wheelshifting process, and provided a theoretical basis for the subsequent experimental research of this type of robot.