Abstract:Representation learning is a method of representing the intrinsic information of research object as a dense lowdimensional realvalued vector. The main purpose is to find a better representation of the original data. Representation learning, with its ability to extract features automatically, shows high efficiency when dealing with a large amount of artificially limited prior data. Supervised and unsupervised representation learning models have been used in the analysis of plant phenotypic data such as text, images, and 3D point clouds. With the rapid growth of data in recent years and the rapid development of genomics research, plant phenotypic research data has features like high throughput and high accuracy. Representation learning models have gained attention in the analysis of massive highdimensional plant phenotypic data. The related concepts of representation learning were briefly introduced, supervised and unsupervised representation learning models were compared and analyzed, plant phenotypic data concepts and processing methods were briefly introduced, which was mainly focused on plant species identification, pest detection and analysis, yield prediction, gene research and morphological structure phenotypic data calculation, etc.. The significance of the research application of representation learning in plant phenotypes and its problems were also discussed. Finally, the application trends of representation learning in plant phenotypes were prospected: developing representation learning models that can be applied to the analysis of different plant phenotype data; improving the realtime and accuracy of representation learning models to enhance their practicality; designing multimodal phenotypic data representation learning models that provided consistent data views for phenotypic data analysis.

Abstract:The adequate seeding downforce and consistent sowing depth are beneficial to improve the seedling quality in the precision planting operation. To avoid the problems of undesired soil compaction and uneven germination caused by the change of soil conditions, and realize the intelligent monitoring and evaluation of the sowing quality, the design of a downforce and sowing depth monitoring and evaluation system was presented for the multi rowcrop planter. The system was mainly composed of downforce measurement device, sowing depth measurement device, electronic control unit (ECU) for data acquisition and actuator control, GNSS receiver, intelligent terminal and pneumatic driving device. The downforce and sowing depth measurement devices were applied to measure the downforce acting on the gauge wheels and the sowing depth based on the axle pin sensor and the angle sensor of limit shank respectively. The pneumatic driving device was used to provide the necessary downforce, which mainly included airspring, gas generator, electricgas proportional valve and gas tank. In order to quickly replenish the air loss caused by the rapid regulation of downforce and improve the response speed of the system, a section control method for the pneumatic driving device was adopted, and the gas generator with a double cylinder air pump was driven by a hydraulic motor. In addition, a human machine interface (HMI) of the intelligent terminal and the control program of ECU were developed based on controlled development system (CoDeSys) programming environment to realize the realtime monitoring and evaluation of seeding quality through CAN bus communication. To improve the accuracy of measurement, the static modeling tests of sowing depth and downforce were conducted on an indoor test platform and a downforce measurement model integrating sowing depth variable was established. The response characteristic test of the control system showed that the step response overshoot was less than 5.97%, and the adjustment time was positively related to the control rowunit number and the set air pressure in the range of 0.1~0.6MPa, which was not more than 2.35s for the six rowunits planter. Furthermore, in order to test the performance of the system, field performance experiments were carried out with four control modes (left section control with 600 N target downforce, right section control with 300N target downforce, mechanical adjustment with helical spring and dead weight adjustment of rowunit) and three setting sowing depths (25mm, 50mm and 75mm). The experiment of soil compaction and sowing downforce control showed that the section control method could achieve more stable soil compactness, and the right section control method could achieve the optimal downforce stability in the shallow rotary tillage filed with no less than 95.78% qualified rate. The experiment of sowing depth control effect showed that the quality of sowing depth was decreased significantly with the increase of setting sowing depth. In the depth range of 25~75mm, the minimum qualified rates of left section control, right section control, mechanical adjustment and dead weight adjustment were 91.92%, 92.53%, 70.44% and 58.72%, the corresponding maximum standard deviations (SD) were 2.22mm, 3.11mm, 3.69mm and 7.70mm, and the corresponding maximum coefficients of variation (CV) were 3.52%, 4.40%, 4.96% and 14.01%, respectively. The above results showed that the system with section control method could improve the consistency of sowing depth and accuracy of downforce, and had better performance of sowing depth and downforce control than the system with mechanical adjustment and dead weight adjustment methods.

Abstract:Aiming to the problem of pneumatic loss caused by the complex structure, dense arrangement, variable crosssectional area, bending, narrow and long characteristics of air passage on the pinholetube wheat widewidth precision uniform seeding mechanism. The fluid domain was divided into four regions according to the type of pneumatic transformation: variablearea longnarrow cylindrical zone, air pipeline curved zone, air chamber confluent zone and negative pressure port and air chamber connection zone. By analyzing the regions in the fluid domain that can lead to the pneumatic loss one by one, the principle and types of the pneumatic loss in each region were clarified. It was concluded that the diameter of the transverse air pipeline, the angle of the air pipeline and the diameter of the negative pressure port may have significant impact on the pneumatic loss. The above three parameters were taken as test factors, and the mean airflow velocity of seed hole, the minimum airflow velocity of seed hole and the standard deviation of seed hole velocity were taken as test indexes. The Fluent software was used to conduct the orthogonal simulation test of three factors and three levels. The influence degree of each parameter on the index was obtained by range analysis and variance analysis, and the best combination of parameters was determined as follows: the diameter of transverse air pipeline was 8mm, the angle of air pipeline was 105°, and the diameter of negative pressure port was 36mm. Under these parameters, the average air velocity of seed hole was 86.4m/s, the minimum air velocity of seed hole was 75.16m/s, and the standard deviation of seed hole velocity was 7.35m/s. Under the optimal parameters mentioned above, pinholetube wheat widewidth precision uniform seeding mechanism was verified, and the test result was slightly smaller than simulation result, but the trend was consistent, which proved the reliability of the numerical analysis.

Abstract:To overcome the defects like shallow plough layer and low stubble burying rate caused by the high stubble and large amount of straw after rice harvesting when the rapeseed direct seeder works in the riceoil rotation area of the middle and lower reaches of the Yangtze River, a tillage scheme that combined plowing and rotary (P&R) tillage was put forward based on the agronomic requirements of rape plants. A type of buckle device that could lift and then buckle the soil was designed for the rapeseed direct seeder to realize the orderly burying of high stubble and sticky soil. In addition, the rapeseed direct seeder integrated with plowing and rotary tillage was developed. The formation principle of buckled plow surface was expounded. The mathematical models of guiding curve, element angle and generatrix were determined. The mechanical models of the soil ridge and buckling plow were constructed. The buckling process of the plow body surface was clarified. In order to validate the function of buckle device, the test of single plow was carried out under the condition of high stubble. The results showed that the average buckling success rate of the plow was 93.41%, which achieved the desired performance. Field contrast experiments, under the condition that the stubble height were 338mm and 452mm, respectively, were carried out between the seeder with P&R tillage and the seeder with rotary tillage only. Under the two conditions, the plowing depth of the seeder with P&R tillage was increased by 137mm and 110mm, respectively, and the stubble burying rate was increased by 33.94 percentage points and 28.36 percentage points, respectively. The seedbed performance of the seeder with P&R tillage whose operation quality met the requirements of rape sowing was better than that of the seeder with rotary tillage only. The research result provided reference for the design of combined tillage machine and plow surface.

Abstract:In order to improve the practical problems of traditional rapeseed stripping technology, such as needing large rapeseed quantity to broadcast, having big variable coefficient of row spacing and existing difference of growth rate between individual rapeseed seedlings, combining the requirement of direct agronomic requirements of rapeseed, a rapeseed spoontype precision seeding and seeding device was designed, which used the spoon to carry out precision sampling. Based on the mechanical properties of rapeseed and the agronomic requirements of holeseeding agronomy, a rectangularshaped spoonshaped hole with a notch was proposed. The working process of the seeding device was described and the main parameters of scoop assembler, spoon hole, spoon number, spoon pre-tilt angle and scoop wheel rotatory speed were determined. The influencing factors of the performance of seed meter were analyzed. The bench test was carried out by using the BBD response surface optimization test design method. The effects of the pretilt angle, the length of spoonshaped hole and the rotation speed of scoop wheel on pass rate of number of cells, the missed rate and the rebroadcast rate were analyzed. The test results showed that the spoon pretilt angle was 47.5°, the length of the spoonshaped hole was 5.4mm and the rotation speed of the scoop wheel was 24.3r/min. The pass rate of the seedling number ((3±1) capsule/hole) was 91.40%. The rate of missed broadcast (0 or 1 capsule/hole) was 4.84% and the rebroadcasting rate (greater than 4 capsules/hole) was 3.76%. The field test results showed that the average pass rate of the seedling number was 88.64%, the average rate of missed broadcast was 3.52%, the density of rapeseed was 63 plants per square meter, which met the direct agronomic requirements of rapeseed. The research had novelty in the design of spoontype seeding device, which can provide reference for the design and experiment of the rapeseed spoontype precision seeding device.

Abstract:A test stand about the pneumatic conveying system was conducted to explore the mechanism of the effect of seed tube length on the seeding performance of the pneumatic conveying system. On basis of analysis of law of average flow velocity in tubes with different lengths, computational fluid dynamics (CFD) simulation was conducted to get the map of speed flow field in tubes with different lengths. The quadratic regression general rotation combination design was used for the experiment, and the seed application rate and frequency of fans were taken as influential factors. Moreover, indexes of the test included variation coefficient of each row displacement consistency, variation coefficient of total displacement stability and the average velocity of airflow in the seed tube. A total of 24 seed transport tubes were used, with a gradient of 0.25m and a length ranges from 0.50m to 6.25m. The analysis and test results showed that when seed tube length was increased, the gas average flow velocity was decreased, the seed movement speed was decreased, and the corresponding seed quantity discharge was decreased. Therefore, seed tube length had a significant influence on the seeding quantity. When seed tube length was 2.50~6.25m, both the decrease of average flow velocity and the decline of the seed velocity were slowed down, and the seeding amount was changed smoothly. In addition, the variation coefficient of each row displacement consistency was 2.82%~3.88%, and the variation coefficient of total displacement stability was 0.39%~1.28%. Therefore, the seeding evenness was good and could meet the requirements of relevant standards.

Abstract:In order to improve the planting efficiency of planting mechanism, a high speed duckbill planting mechanism with variable catchseedling attitude for the seedling pickup mechanism was proposed. Sheep horn pepper seedlings were taken as the objects of seedling planting. The kinematics model of the mechanism was established. Its optimization goal was established, and the visual auxiliary analysis software was developed by using Visual Basic 6.0. The parameters to meet the requirements were optimized and the “water droplet” theoretical trajectory was formed. The threedimensional modeling was performed for the kinematics simulation testing which was carried out by ADAMS. The angle and speed curve of duckbill planting mechanism was analyzed to verify the rationality of the design for the seedling planting mechanism. Threedimensional printing technology was used to process some parts, and the highspeed photography bench test was carried out on the physical prototype. The correctness and feasibility of the theoretical model were verified by comparing the theoretical trajectory, simulation trajectory and actual working trajectory. The experiment showed that the average good qualified rate of planting was 99.8% and the average planting depth qualified rate was 99.2%. This verified the practicality of the mechanism and provided a theoretical basis for the cooperation between seedling planting and seedling pickup mechanism.

Abstract:Existing development for chopping and throwing components in harvester of fodder rape crop, which employs discrete element simulation, has persistent challenges that use the accurate parameters to construct the right model, highlighting a need for calibration of model parameters. Taking the rape crop stalks in the bolting stage as research object, the parameters calibration of discrete element simulation model was carried out by using the EDEM simulation software. In the first step, the diameter, density, Poissons ratio and other mechanical and physical properties of the rape crop stalk were determined. Next, a cylindrical lifting physical test of the rape crop stalk particles was implemented. Simultaneously, a series of virtual simulation experiments on the particles pileup by using the Hertz-Mindlin basic model was carried out in EDEM. The arrangement of the experiments was followed the regular twolevel factorial design, the steepest ascent design and the response surface methodology, and the basic contact parameters of the stalk particle model, such as collision recovery coefficient, static friction coefficient, and rolling friction coefficient, were determined. Subsequently, a threepoint bending failure test of the rape crop stalk was implemented and a series of virtual simulation experiments on bending stalk using the Hertz-Mindlin with bonding contact model were carried out in EDEM. The response surface methodology was applied to determine the bonding parameters such as normal stiffness, tangential stiffness, normal stress and tangential stress of feed rape stalk particle model. Finally, simulation experiments were carried out using the obtained parameters, including the stalk particles accumulation test and the bending stalk test. Compared with the physical test results, the error between the simulation and the physical test value of the angle of repose was 2.27%; the error between the simulation and the physical test value of the bending broken force was less than 4.21%. The results showed that the calibration method was correct and the calibration model was accurate. The research provided basic parameters for the discrete element simulation analysis of mechanized harvesting process of fodder rape crop in bolting stage, and provided a method for parameters calibration of discrete element simulation model for chopping stalk crops. 

Abstract:Aiming at the poor separation effect and artificial pick up potato labor intensity of the one stage lift chain potato digger, the 4U-1600 set of pile type potato digger was designed. Based on the prototype designed and selected of key operation parts, and the structure and operation parameters of ladder digging blade, two stage lifting chain soil-potato separating and conveying device and hydraulic open type potato collecting box were determined. For further study of the improved working performance of set of pile type potato digger, the Box-Behnken experimental design with three factors and three levels was performed, parameters such as forward velocity, one stage soil-potato separating and conveying device velocity and two stage soil-potato separating and conveying device velocity were selected as independent variables, which would influence the potato obvious rate and potato injury rate. The mathematical model was established, and then the effects of various parameters and their interactions were analyzed as well. The test results showed that effects orders of three parameters on the potato obvious rate from primary to secondary were as follows: two stage soil-potato separating and conveying device velocity, forward velocity and one stage soil-potato separating and conveying device velocity. And effects orders of three parameters on the potato injury rate from primary to secondary were as follows: one stage soil-potato separating and conveying device velocity, two stage soil-potato separating and conveying device velocity and forward velocity. The optimal working parameters were forward velocity of 1.50m/s, one stage soil-potato separating and conveying device velocity of 1.37m/s and two stage soil-potato separating and conveying device velocity of 0.89m/s. Confirmatory tests showed that the average value of the potato obvious rate and the potato injury rate were 95.11% and 3.36%, which were up to the relevant work quality evaluation specification requirements, and the experimental results met the design requirements of potato digger.

Abstract:In order to solve the problems of high resistance and high rate of leakage during the operation of carrot combine harvester, a kind of high efficiency drag reducing shovel was designed. The bionic drag reducing shovel tip was designed with the badger claw as the bionic prototype, and its drag reducing mechanism was analyzed. Based on the theoretical mechanics analysis, the mechanical contact model between shovel wing and soil was established. The structure parameters of the shovel wing which affected the quality of shovel were determined. Based on the EDEM discrete element simulation technology, the multi simulation model of componentsoilcrop was established. Through the single factor experiment and orthogonal rotation combined experiment, the range of its value and the law of its influence on the index were determined. The multiobjective optimization mathematical model between experiment factors and indexes was established, and the optimal parameter combination of the shovel was determined by using DesignExpert 8.0.6 software. The operation performance of the high efficiency drag reducing shovel was verified by the field performance comparison experiment. The results showed that the main structural parameters that affected the quality of scarification and shoveling operation of carrot combine harvester were the opening angle α and the inclination angle β. When the opening angle α and the inclination angle β were 120.27° and 47.37° respectively, the performance of the shovel was the best, and the forward resistance and extraction power of carrot were 1908.76N and 55.37N respectively. Compared with the chisel shovel, the resistance of the high efficiency drag reducing shovel was reduced by 5.79%, the extraction power of carrot was reduced by 2068%, and the leakage rate was reduced by 3.8 percentage points, which met the requirements of carrot harvesting. 

Abstract:In view of the problems such as low proportion of the whole harvest, low harvest efficiency, high harvest damage rate and high labor intensity during the manual auxiliary operation, a hydraulic suspension single.line yam harvester was designed based on the experience design method, the structure of the most critical component in the harvest of yam. grid vibration mining shovel was studied, and the Motion and Simulation of SolidWorks were comprehensively used. The dynamic simulation analysis and calculation of the vibrating soil breaking device were carried out with the aid of information technology, and the static and working dynamic characteristics of the component were analyzed. At the same time, combined with the agricultural requirements of yam harvest, the frequency, reciprocating vibration amplitude and related mechanical structure parameters of the vibration excavation part were studied, the optimal structure parameters were determined, and the strength analysis, calculation and verification were carried out. Finally, the field harvest experiment was carried out. Based on the theoretical and experimental research, the static and dynamic performance of the main working parts of the device can meet the mechanical property requirements of harvesting environment. The experimental results showed that the operation efficiency of the vibration excavation device was high, and it can realize the fast and efficient separation of the soil and yam. The intact rate of mechanical harvest reached 89.2%, which basically met the requirements of efficient harvest and low loss rate of farmers.

Abstract:Mechanical weeding method has obvious advantages during the ridge tillage of soybeans production in Northeast China, such as preemergence weeding can break soil consolidation and raise ground temperature to ensure orderly emergence of seedlings, the postemergence weeding can loosen the soil between plants, eliminate young grass between plants, store water and conserve moisture, and then promote the growth and development of soybean. In addition, the application rate of herbicide is effectively reduced by mechanical weeding which can alleviate the high dependence of current agricultural production on herbicide. 3ZCF-7700 multifunctional weeding machine could meet the agronomic requirements of scarifying and weeding in intrarow for corn, soybean and other crops. However, it was not suitable for weeding in the field with many crop residues and stems. Therefore, the weeding monomer mechanism was improved to solve the problems of poor adaptability, complicated structure and unadjustable lateral spacing of the front and rear combtooth drive discs. For the problems of comb teeth are easy to wind grass and clogging, weak ability to stable into the soil during the intrarow weeding, the planetary gears combtooth intrarow weeding mechanism was designed and its main parameters were determined. According to the index of weeding rate and injury seedling rate, the main factors of operation performance and the value range of each factor were obtained by single factor experiment in the selfmade indoor test bench. And then, the orthogonal test was carried out in soybean field to investigate the influence of test factors on the work performance of weeding mechanism by the combtooth angle, the deepest soil position of the comb teeth, and the deepest soil depth of the comb teeth was taken as the experimental factors. The results showed that the order of the factors affecting the weeding rate from primary to secondary was the deepest soil depth of the comb teeth, the deepest soil position of the comb teeth and combtooth angle, and that affecting the injury seeding rate was combtooth angle, the deepest soil depth of the comb teeth and the deepest soil position of the comb teeth. The optimal horizontal combination was 10° of combtooth angle, 80mm of the deepest soil position of the comb teeth, and the deepest soil depth of the comb teeth was 47.5mm. And then five field verification experiments were carried out with the optimal horizontal combination. The average result of the data was 86.3% of weeding rate and 2.66% of injury seedling rate between plants, which showed a stable work performance. The study provided guidance for the design of reliable soybean intrarow weeder.

Abstract:Coarse fodder and concentrates are separately fed by traditional feeding technology, which tends to make ruminants select feed and cause metabolic diseases. The ruminant farming gradually adopts a total mixed ration feeding technology by which coarse fodder and concentrates are mixed uniformly according to the needs of ruminant growth and production. Aiming to promote the popularization and application of the feeding technology, a paddletype ration mixer was designed, and performance tests and parameter optimization were performed by the paddletype ration mixing experimental equipment. The equipment was used to analyze the mixing process of the rations in the mixing chamber. The distribution area of the rations in the mixing chamber was divided into the accumulation area, lifting area, slipping area and slumping area. The mixing modes of each area were as follows: shear mixing and convection mixing mainly occurred in the accumulation area and lifting area, and shear mixing and diffusion mixing mainly occurred in the slipping area and slumping area; the mixing time, rotor speed and paddle installation angle were taken as experimental factors, and the coefficient of variation and net power consumption were used as evaluation indexes. The method of orthogonal rotational combination experiment of three factors and five levels was used in experiments. The influence of the main parameters of the mixer on the mixing uniformity and power consumption was obtained. The results showed that the paddletype ration mixer can meet the requirements of ration mixing; when the filling rate was 65%, the optimal parameter combination was as follows: mixing time was 5.3min, rotor speed was 8.6r/min, and installation angle was 34°. The coefficient of variation was 7.01% and the net power consumption was 51.02kJ. The research result can provide support for the indepth research and application of ration mixers. 

Abstract:The pumpturbine unit is one of the most important component of pumpedstorage power station. The axial force characteristics on pumpturbines runner is very important and may strongly influence the stability and security during the common operations. As a typical verticalaxis pumpturbine unit, some reasonable downward axial force is very necessary to load on the runner for preventing the entire pumpturbine unit from unitlifting. However, this downward axial force may be too large in magnitude especially in its pump mode. The large downward axial force will be the reason that inducing the undesirable unitsinking phenomenon. In the current investigation, a prototype pumpturbine unit was specifically studied based on the computational fluid dynamics method. The axial force was analyzed under different flow rate conditions and also different guide vane opening angle conditions. Results showed that the downward axial force met the maximum value under small flow rate condition, small guide vane opening angle condition and high head condition. The pressurebalance pipe can be applied to connect the runner upper crown leakage and the draft tube. The pressurebalance pipe can solve the problem of overloaded downward axial force. The axial force characteristics in pump mode became slightly upward without obvious change on the head and the hydraulic efficiency of pumpturbine unit. Thus, the operation stability and security of pumpturbine unit can be obviously enhanced.

Abstract:The coordinated development of land intensive use and urbanization plays an important role in promoting economic development. In order to explore the coupling and coordination relationship between land intensive use and urbanization and promote their coordinated development, the performance evaluation index system of land intensive use and urbanization was constructed respectively, and the evaluation index system of coordinated development of land intensive use and urbanization was established on the basis. The land intensive use performance evaluation index system included four subsystems: economic performance, social performance, ecological performance and management performance, and the index system of urbanization performance evaluation included four subsystems: population urbanization, economic urbanization, social urbanization and ecological urbanization. Anhui Province was taken as an example. The TOPSIS model was used to evaluate the performance levels of land intensive use and urbanization in Anhui Province from 2000 to 2017, and the performance levels of both and the variation trends of their subsystems were studied. Then, by using the coupling degree and coordination degree model and based on the value change of coupling effect coefficient, the relationship between land intensive use and coordinated development of urbanization in Anhui Province was discussed under different circumstances and the change trend. Finally, the obstacle degree model was used to diagnose the obstacle factors that affected the coordinated development of land intensive use and urbanization in Anhui Province. It was found that from 2000 to 2017, both land intensive use and urbanization in Anhui Province were increased year by year, and the trend was steady and steady. The performance level of land intensive use in Anhui Province was increased from 0.0536 in 2000 to 0.9587 in 2017, with an average annual growth rate of 18.49%, and it experienced the development process of poor performance (2000—2006), intermediate performance (2007—2010), good performance (2011—2014) and high performance (2015—2017); the urbanization level of Anhui Province was increased from 0.2715 to 0.8180, with an average annual growth rate of 6.70%, and experienced a development process from poor performance (2000-2011) to intermediate performance (2012—2017). From the perspective of each subsystem of land intensive use, the subsystem of economic performance made the largest contribution to land intensive use, while the subsystem of ecological performance made the smallest contribution to land intensive use, with weights of 0.3526 and 0.1308 respectively, and from the perspective of each subsystem of urbanization, the economic urbanization subsystem had the greatest impact on the urbanization level, while the ecological urbanization subsystem had the least impact on the urbanization level, with weights of 0.4160 and 0.1377 respectively. In the case of different values of coupling effect coefficient, the change trend of the relationship between land intensive use and coordinated development of urbanization in Anhui Province was slightly different from that in 2005 and 2012, but the trend and type of coordinated development in the other 16 years were completely the same, and the influence of coupling effect coefficient on the relationship between the two was very limited. From 2000 to 2017, the coordinated development degree of land intensive use and urbanization in Anhui Province was increased year by year, which experienced the unbalanced recession stage (2000—2001), low coordination stage (2002—2005), moderate coordination stage (2006—2012) and high coordination stage (2013—2017). From the perspective of the obstacle degree of each subsystem, the economic subsystem of land intensive use had the greatest impact on the coordinated development of land intensive use and urbanization in Anhui Province, with an average annual obstacle degree of 16.48%, the subsystem of ecological urbanization had the least impact on the coordinated development of the two, with an average annual barrier of 6.60%. From the perspective of the obstacle degree of each indicator, the obstacle factors affecting the coordinated development of the two mainly include peoples living standard, per capita fiscal income and per capita GDP in 2011 and before, and in 2012 and after, the obstacles affecting the coordinated development of the two mainly include the gap of per capita disposable income between urban and rural areas and the density of urban population. From the perspective of the first five obstacle factors in each year, according to the impact of various indicators on the coordinated development of land intensive use and urbanization, it can be divided into two stages: the first stage (2000—2013) focused on the impact of land intensive use, and the second stage (2014—2017) focused on the impact of urbanization. The research results provided new ideas and methods for studying and judging the coordinated development level and obstacle factors of land intensive use and urbanization, so as to promote the coordinated development of land intensive use and urbanization in Anhui Province and other similar provinces. 

Abstract:Aiming to apply deep learning theory and technology to model the net ecosystem exchange (NEE) of grassland ecosystems in the alpine region, based on the FLUXNET CO2 flux data of the grassland in Duolun County, Xilinguole League, Inner Mongolia Autonomous Region, from 2007 to 2008, the attentionbased encoderdecoder framework in deep learning was used to simulate NEE, and the random forest model was used to calculate the importance score of the relationship between NEE, which included the photosynthetic photon flux density (PPFD), soil temperature (Ts), air temperature (Ta), precipitation (P) 〖JP3〗and soil moisture content (SWC) and water pressure difference (VPD), and their seasonal differences in the relationship were analyzed. The result showed that the root mean square error (RMSE) of the deep learning model was 0.28μmol/(m2·s), which was declined by 0.14μmol/(m2·s) and 0.08μmol/(m2·s), respectively, compared with ANN and SVM. The coefficient of determination was 0.93, which was increased by 0.29 and 0.34, respectively. With the attention mechanism, the RMSE standard deviation predicted by 10 times training was 0.002μmol/(m2·s), which showed a reduction of 0.005μmol/(m2·s) and 0.036μmol/(m2·s) compared with Encoder-decoder network model and long short-term memory (LSTM). The attention mechanism model was more competitive in predicting stability. The importance score calculated by random forest model showed the variations of photon flux density PPFD (335) and saturated vapor pressure VPD (30.0) played a leading role in the variations of NEE from March to April. During the period from May to June after the growing season, soil water content SWC (50.5) was the main influencing factor of NEE variations. The precipitation P (3.8) showed a process of decrease in July, and the photon flux density PPFD (26.8) and the soil water content SWC (60.1) were the collaborative decision of NEE. In August, PPFD (2.8) and SWC (6.9) were relatively abundant with plentiful rainfall. The saturated vapor pressure difference VPD (41.5) and rainfall P (42.7) became the main factors affecting NEE. After September, the photon flux density PPFD and rainfall were both decreased sharply and remained stable. The temperature coefficient Q10 was increased slightly compared with the growing season and reached a maximum value of 5.96 in January, so temperature was the decisive factor affecting NEE through plant respiration in non growing season, which is 44.6 between January to March and 542 between October and December. In conclusion, radiation, temperature and moisture remarkably affected NEE in the growing season of grassland ecosystems in alpine region, temperature was the main factor in nongrowing season. Comparing with traditional machine learning algorithms such as support vector machines, deep learning theory and technology had better application prospects in the field of ecological model simulation.

Abstract:Based on temperature and precipitation data of the whole country from 2000 to 2015, the Thornthwaite Memorial model (TW) and Zhou-Zhang (ZGS) model were used to calculate the potential net primary productivity (NPP) and the actual net primary productivity, the data of landuse change slope method was combined to analyze the farmland ecosystem, forest ecosystem, grassland ecosystem net NPP, interannual fluctuation trend and spatial variation characteristics, and the correlation between the actual productivity and potential productivity was evaluated. The results showed that the spatial pattern and change trend of national NPP simulated by the above two methods were basically the same, and the overall correlation was very high, the determination coefficient R2 can reach 0.7707. For the correlation of all land vegetation ecosystems, from most significant to least significant was as follows: forest ecosystem, farmland ecosystem, grassland ecosystem; the spatial distribution of the net primary productivity of vegetation in China presented the spatial difference of “high in the south and low in the north”, which showed a gradual decline trend from southeast to northwest; in the past 16 years, both potential and actual productivity of vegetation in China showed a slow decrease trend, if no measures were taken, decreasing trend would be maintained. The research results provided a scientific basis for China to take compulsory measures to protect the ecosystem.

Abstract:The fusion technology based on measured hyperspectral and multispectral data was used to remote sensing inversion of soil salinity to improve the multispectral model precision, and the difference for different seasons was analyzed. Yongji of Hetao Irrigation District, a typical salinization region, was chosen as the study region for establishing hyper-multispectral inversion model of spring and autumn, respectively. The optimal spectral transformation and multiple stepwise regressions were used to get the characteristic bands and spectral indices by using the measured data of the hyperspectral inversion model and Landsat-8 OLI multispectral inversion model. Additionally, the fusion model was established with measured hyperspectral and multispectral data by multiple stepwise regression based on characteristic spectral indices. The results showed that the reflectivity of hyperspectral was 36.83% higher than that of the multispectral, and the average reflectivity in spring was 23.78% higher than that in autumn. The R2 of the training set and validation set of the hyper-multispectral inversion model with characteristic spectral indices were 0.651 and 0.635 on average, the RMSE were 2.44g/kg and 2.49g/kg on average, respectively, R2 were 36.19% and 35.64% higher than those of training set and validation set of the multispectral inversion model, and the RMSE were 34.28% and 41.72% lower than that, respectively. In addition, The accuracy of multispectral, hyperspectral and fusion inversion models in spring was higher than that in autumn, the R2 of the training set was improved by 6.03%, 6.05% and 4.40% on average, and the verification set was improved by 19.07%, 12.21% and 1.75% on average. The average salinity of the spring and autumn was 6.05g/kg and 5.97g/kg which used the hyper-multispectral fusion model inversed, respectively, and the average relative errors with the measured salinity were 9.65% and 10.68%, respectively. On the whole, the soil of this region was mainly highly salinization in spring and moderate salinization in autumn. 

Abstract:Using unmanned aerial vehicle (UAV) images to inventory forest resource is a quick solution to collect high resolution data with rich imagery details. It is capable to recognize individual trees with locations and crown sizes. An intrinsic problem of high spatial resolution UAV images at centimeter levels is that the images are tended to oversegmented. In addition, UAV images captured in plant growing season can hardly observe the ground and objects beneath the canopy top, leading to infeasibility of height normalized canopy height model (CHM) based crown segmentation algorithms in forested areas with large terrain variations. To tackle these problems, a novel UAV image crown extraction approach was proposed, which was free of height normalization. Firstly, a 3D surface model was built from dense images by structure from motion technology. Initial tree locations were identified by combining height information and image contexts. An adaptive kNN neighborhood watershed algorithm was implemented to derive crown coverage of each initial tree locations. UAV images of Larch forests in Baihuashan National Nature Reserve of Beijing were used to conduct the experiment, and it was validated by visual interpretation on orthophotos and compared with a couple of images or point cloud based automatic segmentation algorithms. The results showed that the overall detection rate of individual trees was over 91%. The crown size extraction accuracy was over 81%, which outperformed the original watershed and other crown segmentation methods. It was demonstrated that the proposed method can serve to extract high accuracy tree parameters rapidly at large scales in complex terrain environment.

Abstract:Stripe rust is one of the main diseases that affects the production of winter wheat in China. The disease information was detected early in the winter wheat infection, and it is of great significance to prevent and control the disease and improve the yield and quality of winter wheat. The reflectance spectrum can reflect the change of concentration information of vegetation biochemical components, but it is greatly affected by the background noise, while the canopy solarinduced chlorophyll fluorescence (SIF) is less affected by the background noise and has certain photosynthetic physiological diagnosis capabilities. In order to study the feasibility of early detection of winter wheat stripe rust by SIF, the canopy SIF data was extracted based on two methods: 3band Fraunhofer line discrimination (3FLD) and reflectance fluorescence index. In order to explore the advantages of SIF in the early detection of wheat stripe rust, some SI sensitive to wheat stripe rust were obtained for comparison. The sensitivity of SIF and SI to wheat stripe rust early disease index (DI) was analyzed through correlation, and then the sensitive SIF and SI were used to construct the early wheat stripe rust spectrum detection model based on the partial least squares (PLS). The results showed that the fluorescence index SIF-A, ρ440/ρ690, ρ675ρ690/ρ2683, ρ690/ρ655, ρ690/ρ600, DλP/D744, D705/D722 extracted based on the radiance and reflectance method all had very significant correlation to the severity of wheat stripe rust, the correlation coefficients were -0.793, -0.523, -0.539, -0.497, 0.541, 0.446 and 0.490, respectively, which can be used as the chlorophyll fluorescence characteristic parameters for detection of winter wheat stripe rust. Based on the three sets of data, the determination coefficients of the PLS-SIF test model were 0.801, 0.772 and 0.807, respectively, and the root mean square errors were 3.3%, 3.1% and 3.2%, which were 27% at least higher than that of the SI-PLS model determination coefficients. The error was reduced by at least 24%. Therefore, canopy SIF data was more suitable for early detection of the severity of winter wheat stripe rust. The research results had important application value for timely prevention and control of winter wheat stripe rust, and provided a reference for the use of satellite fluorescence data for largearea, nondestructive detection of wheat stripe rust in the early stage.

Abstract:The largescale crop yield forecasting is of great significance to grasp the state of national grain production timely and accurately and carry out effective grain macrocontrol. To improve the timeliness of maize yield forecasting, taking central plain of Hebei Province as the study area, yield forecasting was carried out for period during 2016 to 2018. The Savitzky-Golay filtered leaf area index, closely related to maize growth and yield, was selected as the characteristic parameter. The LAI data from early July 2010 to late August 2018 were used as the modeling data, and the LAI data from early September to late September of each year from 2016 to 2018 were used as the test data. The LAI data were extracted pixel by pixel to form a onedimensional time series as the input data of the model. Based on the autoregressive integrated moving average (ARIMA) model and radial basis function (RBF) neural network, LAI data of the study area were forecasted pixel by pixel. And the average absolute error and root mean square error were used to evaluate the prediction accuracy of the two models. The results showed that the accuracy of LAI forecasting based on the ARIMA model was better than that of RBF neural network. The RMSE of step1 and step2 LAI forecasting results was 0.18m2/m2 and 0.14m2/m2 respectively, which was lower than that of RBF neural network, indicating that the ARIMA model was more suitable for forecasting summer maize yield per unit area in the central plain of Hebei Province. Based on the research correlation of weighted LAI and summer maize yield, and ARIMA LAI forecasting results, the summer maize yield forecasting models were developed at intervals of 1ten day, 2ten day, 3ten day before the harvest. The results showed that the forecasting accuracy of maize yield per unit area at 1ten day, 2ten day, 3ten day intervals was high in both the county scale and pixel scale, and the maximum relative error between the forecasting and monitoring of yield per unit area in the county (district) scale from 2016 to 2018 was only 373%. The method can be used to forecast summer maize yield at 30 days before the harvest.

Abstract:Maize is one of the most widely distributed crops in the world, ranking third only to wheat and rice. The plant height, stalk diameter and leaf area of maize are closely related to its yield, the leaf projection area and leaf stem angle have an direct effect on utilization of light energy to maize plants, the number of leaves is the indicator of the overground part biomass, the parameters such as minimum enveloping box volume of single leaf, leaf perimeter, leaf projection width, leaf projection length and so on directly affect the spatial distribution of leaves, therefore, dynamic monitoring of these traits is particularly important. However, the traditional measurement of these traits is timeconsuming, costly, subjective and destructive. To achieve the dynamic, rapid, accurate and nondestructive outdoor measurement of maize plant height, stalk diameter, leaf area, the number of leaves, leaf stem angle and so on, threedimensional (3D) models of tassel stage maize plants were reconstructed by using structure from motion (SfM) algorithm. An autonomous crawler phenotyping robot was used for acquiring multiview maize plants images along the maize crop rows outdoors. The robot could work continuously four hours at speed of 0.1m/s and would acquire about 700 stable images for a single camera. The 3D point cloud data were obtained using the multiview images in the Visual SFM software. The 3D point cloud data were preprocessed and some morphological traits such as maize plant height, minimum enveloping box volume of single plant, stalk diameter, the number of leaves, leaf perimeter, leaf area, minimum enveloping box volume of single leaf, leaf projection area, leaf projection width, leaf projection length and leaf stem angle were extracted in the Visual Studio 2013 plus PCL platform. Compared with the manual measurement, the mean absolute percentage errors (MAPE) for plant height, stalk diameter and leaf area were 3.163%, 4.760% and 19.102%, respectively. The root mean square error (RMSE) for plant height, stalk diameter and leaf area were 3.557cm, 1.540mm and 48.163cm2, respectively. The R2 for plant height, stalk diameter and leaf area were 0.970, 0.842 and 0.901, respectively. The results showed that 3D reconstruction method based on SfM algorithm was suitable for outdoor measurement. In addition, the maize plants were divided into low overground part biomass maize and high overground part biomass maize by the fresh weight of the overground part plant, meanwhile, the plant trait such as height, minimum enveloping box volume of single plant, stalk diameter and the number of leaves were extracted with segmented point cloud data to calculate the P value by single factor analysis of variance. The measured P values were 0.0003, 0.0004, 0.3170 and 0.2415, respectively, and the results proved that the traits of plant height and minimum enveloping box volume of single plant were able to distinguish the low overground part biomass maize and high overground part biomass maize evidently. The research result provided scientific researchers and crop breeders a new phenotyping method for measuring crop traits to some extent.

Abstract:Accurate detection and identification of weeds is a prerequisite for weed control. Aiming at the problem of low accuracy of weed segmentation in complex field environment, an intelligent weed detection and segmentation method based on Mask RCNN was proposed. The ResNet101 network was used to extract the feature map of weed semantic and spatial information. The characteristic map was classified by the regional suggestion network, and the preselection box regression was trained. The preselection area was screened by the nonmaximum suppression algorithm. RoIAlign was used to cancel the border position deviation caused by quantization, and the region of interest (RoI) feature map was transformed into a fixedsize feature map. The output module calculated the classification, regression and segmentation loss for each RoI, predicted the category, location and contour of the candidate area through training, and realized weed detection and contour segmentation. When IoU (intersection over union) was 0.5, the mean accuracy precision (mAP) value was 0853, which was better than that of SharpMask and DeepMask with 0.816 and 0.795, respectively. The single sample time of the three methods was 280ms, 256ms and 248ms respectively. The results showed that the method can quickly and accurately detect and segment the category, location and contour of weeds, and it can be better than SharpMask and DeepMask. When IoU was 0.5, the mAP value of the proposed method was 0.785, and the time for a single sample was 285ms, indicating that this method can realize the field operation in the complex background and meet the realtime control requirements of field pesticide variable spraying. In the field variable spraying test, the accuracy rate of identifying weeds was 91%, the accuracy rate of identifying weeds and spraying them accurately was 85%, the spray density of pesticide spray droplets was 55 per square centimetre, and the average processing time of the device was 0.98s. It can meet the control standard of pesticide variable spraying.

Abstract:In order to implement the fast and accurate recognition of tomatoes for agricultural harvesting robots under greenhouse environments, an improved multiscale YOLO detection algorithm named IMSYOLO was presented. A new backbone network structure, which was named darknet20, with one residual block was designed based on a series of the previous YOLO algorithms, and a multiscale detection structure was utilized simultaneously for the detection algorithm. Therefore, a new kind of neural network model was formed for the fast recognition of tomatoes under complex environments. Due to some features of the method such as the fewer layers required, the larger amount of information extracted, and by using the multiscale structure to return both the detection categories and the bounding boxes, the detection speed and accuracy were improved. IMSYOLO model was tested on our own tomato dataset, and the detection performance of the network before and after the improvement as well as the influence of the variation of the backbone network layers on the feature extraction capacity were analyzed respectively. The test results showed that the proposed method had ideal features with a precision of tomato image detection of 97.13%, an accuracy of 96.36%, a recall rate of 96.03%, an intersection over union (IOU) of 83.32% and a detection time of 7.719ms. Furthermore, compared with YOLO v2, YOLO v3 and some other neural networks mentioned, IMSYOLO can meet the requirements of both detection accuracy and speed. At last, the feasibility of the proposed algorithm applying to the robots was verified by the harvesting tests of the ripe tomatoes under the greenhouse environments.

Abstract:In order to solve the problem of inaccurate extraction of internal components in maize grain transmission image due to low contrast, a multichannel overlapping region segmentation method based on nonlinear transformation of color channel was proposed. The horny endosperm pixel information was obtained from the binary images of gray scale and R channel of maize; and the “farinaceous endosperm+embryo” image was transformed into Lab color space, the farinaceous endosperm image under b channel was extracted; and then the embryo pixel information was obtained from the binary images of R channel and b channel, so as to segment the components of maize grain accurately. Firstly, the transmission images of different maize varieties were collected, and the single grain was extracted. Secondly, the single maize grain images were segmented by the multichannel overlapping region method based on the nonlinear transformation of color channel, and the images of horny endosperm, farinaceous endosperm and embryo of maize grain were obtained. Finally, the recall ratio and the precision ratio were used to evaluate the segmentation effect of multichannel overlapping region method and traditional image segmentation methods on different varieties of maize seeds. The experiments showed that the recall ratio, precision ratio and comprehensive evaluation index of the multichannel overlapping region segmentation method were all over 98%. The segmentation effect was better than that of the traditional segmentation methods. It can realize the accurate segmentation of the transmission images of different varieties maize grain with transparent horny, and provide a scientific basis for the study of the threedimensional distribution of internal components and the mechanism of dry crack formation in maize grains.

Abstract:For soil moisture stress detection of maize, the physiological characteristics indicators are commonly used, but such methods can affect the growth of maize plants. To solve this problem, a maize soil moisture stress predictive model based on multiview stereo vision and support vector machine (SVM) with error correcting output code (ECOC) was proposed. Firstly, an RGB camera was used to obtain three maize images which was at -30°, 0° (maize leaf expansion plane) and 30° during the jointing stage. The obtained images were segmented in the HSV color space to extract the whole maize plant. The discrete areas were extracted and removed simultaneously by calculating the size of the connected domain and retaining the largest connected domain. Morphological dilating was used to smooth the edges of the extracted maize leaves and fill the holes of leaf, and the edge information was detected by using the Scharr filter. Then, two maize cloud models of -30°~0° and 0°~30° were established based on the stereo vision of speeded up robust features (SURF). In the process, the fast library for approximate nearest neighbors (FLANN) and random sample consensus (RANSAC) were used to reduce the error matching, and the final feature point matching accuracy was 98.95%. The iterative closest point (ICP) was used to merge the two maize cloud models data into the same coordinate system, and the registration error was less than 0.01mm. The cloud skeleton was extracted by L1median method. Finally, the parameters, including internode height, leaf length and plant height were extracted from the maize plant skeleton, and the water stress prediction model for single parameters and soil moisture stress ECOC-SVM predictive model were established. The results showed that the leaf length, the internode height and the daily growth of maize plant were significantly linearly correlated with the degree of moisture stress. In this research, the above three parameters were taken respectively as independent variables and the soil moisture content as dependent variable to establish the moisture stress predictive models. The correlation coefficients were 0.8922, 0.8928 and 0.8176, and the RMSE were 2.92%, 2.53% and 2.76%. In order to improve the prediction accuracy, a maize soil moisture stress predictive model of ECOC-SVM was established using above three maize parameters as the characterized vector. The prediction accuracy of the test set was 93.33%, showing that the accuracy of this model was very high. When the maize was at jointing stage, the predicted value of soil moisture content can be obtained from a single parameter maize water stress prediction model, and the degree of moisture stress on maize can be predicted by the multiparameter ECOC-SVM model. The research result can provide technical support for accurate access to agricultural information.

Abstract:Aiming at the problems of some chicks’ unobvious cloacal features and the influence of light on the collection of chicks’ cloacal images, a method of automatic recognition of chick sex based on convolutional neural network (CNN) and image depth features was proposed to effectively distinguish male and female chicks and enhance the benefit of raising chickens. Taking chicks’ cloacal images collected by the method of anal examination as the research object, a CNN was used to establish vector collection libraries, including the indepth features of both chicks’ cloacal images to be identified and chicks’ cloacal images. Similarity comparison was performed between the collection libraries of the indepth features of chicks’ cloacal images to be identified, and chicks’ cloacal images and the comparative results were ranked. Feature fusion was conducted for the indepth features that were ranked top n in the ranking results and were the most similar to chicks’ cloacal images to be identified and the indepth features of chicks’ cloacal images to be identified. The depth characteristics of the clonal cavity of the chick were highlighted, and then identification was carried out via CNN. The experiment results showed that the accuracy on the test dataset reached 97.04%, and in the production environment reached 96.82%. Compared with conventional CNN methods, it improved the recognition rate for identifying male and female chicks’ cloaca.

Abstract:Aiming at the complex relationship of water-energy-food (WEF) nexus and the lack of quantitative evaluation of system security, based on the analysis of the collaborative competition mechanism of WEF nexus, the system safety evaluation index system and evaluation method were constructed, and the quantitative evaluation was carried out by taking Xinjiang as examples. The results showed that the safety level value of WEF nexus in Xinjiang showed an increasing trend over time from 1997 to 2016. The trend of WEF nexus change in each prefecture presented two stages. Except for Karamay and Urumqi, the safety level values of WEF nexus were on the rise in other prefectures from 1997 to 2009, and the safety level values were significantly different. Half of the prefectures’ safety level values showed a downward trend, and the spatial difference of safety level values were decreased from 2010 to 2016. With the change of policy orientation and the continuous improvement of technology, carbon intensity was always an important factor affecting the WEF nexus safety of Xinjiang. And the other major factors were shifted from water and energy use in agriculture to renewable energy selfsufficiency and water security. Changes in influencing factors led to the obvious difference in the spatial pattern of the WEF nexus security between the two stages. The projection value ranking of each subsystem reflected the difference of driving mechanism among different prefectures. Some effective measures combined with the main influencing factors and regional characteristics could be taken to improve the WEF nexus safety.

Abstract:The objective was to provide a scientific basis for using saline water for irrigation more effectively and reasonably. It was focused on the effects of two types of alternate irrigation regimes (alternating groundwater and saline water (GW-SW), and alternating groundwater, followed by two cycles of saline water (GW-SW-SW)) between three levels of irrigation water salinity (i.e. mineralization of 2.0g/L, 3.5g/L and 5.0g/L) and groundwater (1.1g/L) on soil moisture and saline distribution. The maize stem water uptake was investigated by detecting the stable hydrogen and oxygen isotopes of soil water and maize stem water, and the maize yield was calculated. The results showed that with the same depth of soil, soil moisture and EC were increased with the increase of irrigation water salinity, and were higher in the GW-SW-SW regime. The trend of soil moisture as depth increasing for all treatments at different periods were similar, but it was decreased at shallow depth and then increased at deep depth. The trend of soil EC as depth increasing for all treatments at the jointing and heading stage were similar to that of soil moisture; however, at the filling stage, the trend of soil EC as depth increasing for all treatments, it was increased at shallow depth, and then decreased as depth became deeper, and finally increased at deep depth. Based on the interception of curves for δ18O in soil water and maize stem water as shown, the specific soil depth values of maize stem water sources for each treatment were from 20.1cm to 26.1cm at the jointing stage, from 24.1cm to 63.0cm at the heading stage and from 11.0cm to 63.9cm at the filling stage, respectively. Except for the jointing stage, there were more than one soil depths for maize stem water sources for most treatments at the heading and filling stages. Based on the multiple linear mixed model (IsoSource), the main water absorption depths for all treatments were 0~20cm, 20~40cm and 0~20cm with the average contribution rate ranging from 33.9% to 51.0%, 27.4% to 83.0% and 32.0% to 80.6% at the jointing, heading and filling stages, respectively. The average contribution rate of the main water absorption depth in all periods was decreased with the increase of irrigation water salinity, and the average contribution rate of the GW-SW-SW regime was lower. The 2.0g/L salinity under the GW-SW regime showed the highest yield of 1.54kg/m2, which was 26.23% higher than the lowest yield in the 5.0g/L salinity under the GW-SW-SW regime. 

Abstract:The synergistic effects of biochar properties on soil properties and biota have received much less attention than their effects on soil chemical properties. To investigate how biochar properties and addition amount affecting physicochemical properties and the quantity and activity of microbial in acid red soils, acid red soils (pH value 5.40) were incubated for 50 days by adding different rates (1%~10%) of ashrich rice husk biochar (RHC) and ashlow Camellia oleifera shell biochar (COSC) pyrolyzed at 500℃. The results showed that compared with COSC (3.80% ash content, 0.22 O/C), RHC remained higher ash content (30.69%), greater O/C molar ratio (0.63) and more oxygen functional groups (C-P-O). With the addition of RHC and COSC, soil moisture contents were increased to 17.47%~28.28%, also the pH value was improved to 7.05~7.75. Additionally, 10%RHC treatment significantly increased (p<0.05) soil moisture content and the pH value by 81.98% and 43.52%, respectively. The nutrient elements of acid red soil was increased with the increase of RHC content, and with the addition of 10% RHC treatment, alkali hydrolyzed N, available P and available K in soil were increased by 84.83%, 70.47% and 595.57%, respectively. The 5% and 10% addition of COSC both had a negative correlation effect on the alkali hydrolyzed N content, which was decreased by 14.65%~29.27%, respectively. RHC and COSC both had a positive effect on the quantity of soil microbial communities, and the abundance of microbial was grown first and then dropped with the increase of amount of biochar. 5%RHC had a significant influence on the quantity of bacteria and actinomycetes, which were increased by 1040.05% and 713.59%, respectively. However, 5%COSC had a significant effect on the quantity of soil fungi, as increased by 1 265.00%. RHC and COSC treatment both had a positive influence on soil microbial biomass carbon (MBC) content and microbial activity, which were increased first and then decreased with the increment of biochar addition. Compared with the CK, 5%COSC treatment had significantly increased 11 times of MBC content, and 5%RHC treatment significantly increased the microbial activity by 60.50%. Therefore, adding ash rich rice husk biochar to amend the red soil may improve the physiochemical properties of soil and increase the quantity and activity of microbial community. The results would provide scientific basis for improving acid soil with ashrich biochar.

Abstract:Aiming to explore the aboveground biomass allocation patterns of Daxinganling and establish additive allometric biomass models for Quercus Mongolica species, a total of 78 trees were destructively sampled and collected for wood, bark, branch and leaf biomass. Of which, 31 trees were selected to excavate and collect root biomass. For each component, the share of biomass allocated to different components was assessed by calculating its ratio. The optimum biomass model for each component was decided by using the diameter, tree height, and crown width as independent variables. Seemingly unrelated regression method was applied to construct an additive system of biomass models for aboveground components. Models were validated by the leaveoneout crossvalidation method. The results showed that wood biomass occupied more than half of the aboveground biomass. With the increase of DBH, the wood biomass ratio was relatively stable, branch biomass ratio was increased, while a reverse trend was found for bark and leaf. The root/shoot ratio was decreased rapidly and then slowed down, with an average value of 036. All biomass models showed good fitting results with R2Adj in the range of 0.907~0.984. The root biomass model with the diameter as the sole independent variable showed the optimum fitting effect. The combination variable of diameter and height provided the lowest estimation errors in the regressions associated with wood and bark while using both diameter and crown width as the independent variable generated the most accurate models for branch and leaf. It was concluded that the allometric equations would provide important tools for biomass accounting of Quercus Mongolica distributed in Daxinganling mountains.

Abstract:In order to find out the effect of different water and nitrogen coupling methods on the carbon cycle of paddy fields in the black soil area of Northeast China, the field experiment was conducted in the black soil paddy field in Heilongjiang Province. Field irrigation experiments were conducted in 2018. The conventional irrigation (F) and controlled irrigation (C) were used as two irrigation methods. Four N application rates: N0 (0kg/hm2), N1 (85kg/hm2), N2 (110kg/hm2) and N3 (135kg/hm2) were set in the whole growth period. Average soil respiration, microbial respiration and root respiration rates of rice under eight different waternitrogen coupling modes were measured during the period from regreening stage to milky stage and carbon sequestration of rice organ were measured after harvesting. The results showed that the total carbon sequestration of rice plants was 446.49~716.92g/m2, of which the total carbon sequestration of CN2 treatment was the largest. At the same time, the carbon sequestration of rice organs after harvest from large to small was in the order of panicle, stem, leaf and root. The average carbon sequestration of four organs accounted for 53.69%~59.44%, 27.42%~30.12%, 7.24%~8.96% and 4.71%~8.35% of the total carbon sequestration of rice plants, respectively. Controlled irrigation mode could increase carbon sequestration of rice. Under the same nitrogen application rate, carbon sequestration of stem, leaf and root organs under controlled irrigation mode was higher than that under conventional irrigation mode. Carbon sequestration of panicles under controlled irrigation was higher than that under conventional irrigation except that of CN0 treatment, which was lower than that of FN0 treatment. The average soil respiration rate, microbial respiration rate and root respiration rate of rice were increased first and then decreased under all waternitrogen coupling modes, and reached the peak at tillering stage. Compared with nonfertilization, the average soil respiration, microbial respiration and root respiration were increased after applying fertilization, and increased with the increase of nitrogen application, except the period of seeding. The average soil respiration rate, microbial respiration rate and root respiration rate of rice under controlled irrigation mode were higher than those under conventional irrigation mode at all growth stages, except the period of seeding. The carbon sink intensity of black soil paddy field was stronger under different nitrogen application coupling modes, but the carbon sink intensity was different among different treatments, and the carbon sink intensity of CN2 treatment was the largest. The research results can provide the necessary theoretical basis for improving carbon sequestration and emission reduction potential of black soil paddy field, and provide data support for estimating regional and global carbon balance. 

Abstract:In order to reveal the distribution of ammonium nitrogen and nitrate nitrogen in different soil layers and the distribution of soil nitrogen in plants under water and biochar management, the accumulation and distribution of NH+4N and NO-3N, fertilizer NH+415N and NO-315N in 0~60cm soil layers under different water and biochar management were studied by combining field plots with 15N tracer microarea, and the distribution of soil nitrogen in plants under different water and biochar management was calculated. The results showed that the accumulation of NH+4N in paddy soil was decreased with the increase of soil depth under dryshallowwet irrigation. The accumulation of NH+4N and NO-3N in 0~20cm soil layer was increased by applying appropriate amount of straw biochar, while the accumulation of NH+4N and NO-3N in 20~60cm soil layer was reduced. The accumulations of NH+4N, NO-3N and fertilizer NH+415N, NO-315N in 0~20cm soil layer of rice under the same straw biochar application level were higher than those of flooding irrigation. The accumulation of NO-315N in 20~40cm and 40~60cm soil layers of dryshallowwet model was significantly lower than that of conventional flooding (P<0.05) Totally 979%~1396% of the soil nitrogen accumulated in rice under dryshallowwet irrigation was distributed in plant leaves, 15.71%~20.03% was in plant stems and sheaths, and 66.00%~74.50% was in plant panicles. Considering the breakeven of soil nitrogen pool in cold and black soil area, the best water and biochar management model was dryshallowwet irrigation plus 12.5t/hm2 straw biochar.

Abstract:As a byproduct of animal slaughter, bone has highquality protein content along with comprehensive nutrients. It will cause serious environmental issues and waste of resources if handled improperly. Collagen polypeptide (CP), prepared by enzymatic hydrolysis of animal bones, is respected in the fields of material applications, such as food, films, medicines, and composites, which is principally because such materials are considered to be promising solutions to environmental impacts of synthetic polymers. However, the molecular weight distributions of CP during the extractions of waste bone proteins may affect their physicochemical properties, mainly including solubility, viscosity, gelling ability and stability, thus significantly affecting the comprehensive performances of the composites. Therefore, it is of great significance to determine the optimal molecular weight of CP and explore its underlying mechanism of action in composites. The effects of molecular weight distributions of bovine bone CP on mechanical properties, water solubility, thermal stability, compatibility and microstructures of CPcarboxymethyl cellulose (CMC) composite films were investigated by using conventional methods, such as the Fourier transform infrared (FTIR) spectroscopy, Xray diffractometry (XRD), and contact angle determination. A series of experimental composite films with a range of different molecular weight distributions of CP was fabricated by the filmcasting method. The results showed that the addition of CP would significantly improve the mechanical properties and hydrophobicity of the composite films. The microstructures of the CP-CMC composite films were smooth and compact when the molecular weight distribution of CP was 700~1000u. Meanwhile, the tensile strength, breaking strength and Youngs modulus were about 2.39, 2.55 and 10.11 times higher than those of the control group, respectively, while the elongation at break was 40% lower than that of control group, also, the hydrophobicity and thermal stability performed the best. With the increase of molecular weight distributions of CP, the water solubility of the CP-CMC composite films was increased, and the mechanical properties and thermal stability were reduced significantly, which may limit its industrial applications. The research results would provide a useful theoretical foundation and basic data to support the efficient utilization of animal bones and promote the transformation of CP into material utilization.

Abstract:Taking the rural household biogas digesters with desirable and undesirable biogas productivity in Qinghai Province as study objects, the metagenomics methods were applied to investigate the microbial community structure and the functional characteristics in the sludge samples of digesters at annual peak and nadir temperatures. Species annotation results indicated high taxon richness and biodiversity in the fermentation system. Concerning bacterial groups, Bacteroidetes, Firmicutes and Proteobacteria were the most abundant species, accounting for 72.37%~74.00% relative abundance of all floras, and they might play key roles in the fermentation. The abundance of Synergistetes (1.62%~4.73% relative abundance) in each sample was consistent with the varied biogas productivity, so the Synergistetes could be an important functional group considerably affecting biogas production. At genus level, Marinospirillum (6.75%), Clostridium (4.56%), Treponema (3.60%), and Pseudomonas (3.01%) were the dominant groups. Regarding archaeal groups, Methanogenium (25.41%~31.65% relative abundance) was the most dominant and decisive functiongroup for biogas production. Functional annotations indicated that samples from digesters with higher biogas production had more effective genes than the digesters with lower biogas production, and that the functional genes involved in methane metabolism pathways showed significantly higher abundance. The methane metabolic pathways to reduce CO2 by hydrogenotrophic methanogens were complete in all samples, and the abundance of functional enzyme genes was higher in the samples with higher biogas production. The research result indicated that H2 oxidating/CO2reducing was the major pathway for methane production in the Qinghai biogas rural fermentation system. 

Abstract:To better understand the physiological and molecular response of S. cerevisiae to hyperosmotic stress, chitin and glucan contents in the cell wall and sensitivity of the cell wall to calcofluor white (CFW) stain and cell walldegrading enzymes were assayed. Further analysis of the cell membrane integrity of S. cerevisiae was performed by staining with dual dyes (PI and Hoechst 33342). Finally, gene expression profiles of S. cerevisiae under extreme high glucose pressure were conducted by RNA sequencing (RNAseq). The alterations in membrane integrity and wall integrity in S. cerevisiae were found after high sugar stress. Hyperosmotic stresstreated cells increased sensitivity to CFW stain and cell walldegrading enzymes demonstrated that hyperosmotic stress disrupted cell wall properties. It was also found that hyperosmotic stresstreated cells increased sensitivity to PI stain, indicating that the membrane was damaged. Global transcript measurements confirmed the membrane damage observations by showing downregulation of membrane components and changes in fatty acid biosynthesis. High sugar stress did cause a compensatory response to cell wall damage through downregulation of several genes (ROM1, RLM1, PIR3, YGP1 and CWP1) involved with the cell wall integrity (CWI) signaling pathway. In addition, the previous studies were combined to discuss the CWI signaling pathway of yeast response to different stresses. The research results provided a reference for understanding hyperosmotic stress mechanism.

Abstract:Aiming to explore the effect of lactic acid-LDH-NAD system on NADH regeneration and MetMb reduction ability of yak meat mitochondria in electron transport chain (ETC). The effects of lactate on mitochondrial membrane permeability, membrane potential and the role of Lactate-LDH system in NADH regeneration and MetMb reduction in vitro were investigated. Depending on the treatment, the mitochondrial membrane permeability and mitochondrial membrane potential were decreased in the lactate treatment group, and the oxygen consumption rate and MetMb reduction in the CaL+LDH+NAD system group were the highest in all the experimental groups (P＜0.05). In the presence of antimycin A, NADH produced by CaL-LDH-NAD treatment cannot perform oxygen consumption. When Mb was only incubated with mitochondria, the Mb redox state in the system hardly changed (P＞0.05), and NADH formed by LDH couldnot restore MetMb without reductase or electron carrier. The addition of the LDH inhibitor sodium sulphate treatment group reduced the reduction of MetMb by the CaL-LDH-NAD combination (P＜0.05), but at the same time, sodium oxalate did not completely inhibit the reduction of MetMb, except for the electron transport chain mediated. In addition to nonenzymatic reduction, NADH produced by the CaL-LDH-NAD system can also be used for enzymatic MetMb reduction in mitochondria. It was indicated that mitochondrial metabolism was related to flesh color, and the oxidation process of lactate was the cause of MetMb reduction. At the same time, the reduction equivalent of mitochondria can affect oxygen consumption, MetMb reduction, and Mb redox state and beef color stability.

Abstract:Stress relaxation is the result of timedependent decay of intermolecular forces under a constant imposed strain. A stress relaxation experiment is one of the most important evaluation tools to study the viscoelastic properties of materials and it reflects indirectly the microstructure changes without disrupting them during the processing. Aiming to investigate the gelation properties of low acyl (LA) and high acyl (HA) mixed acid gellan gum gels (L/HGLG) using stress relaxation parameters. Influences of LA/HA weight ratio, gellan concentration and pH value on the gelation properties of L/HGLG were studied. The results showed that the stress relaxation behavior of L/HGLG fitted well with Pelegs empirical model. Meanwhile, LA/HA weight ratio, pH value and gellan concentration had a pronounced effect on the stress relaxation behavior of mixed acid gellan gum gels. The values of equilibrium modulus (EA) correlated well with gel hardness, indicating that EA could represent the gel strength. EA and k1 were increased firstly and then decreased with the increase of LA/HA weight ratio, reaching a maximum at around 50% high acyl gellan variant. This suggested that the biopolymers were now forming an interpenetrating network structure. The higher the gellan concentration was, the larger the EA was. In addition, high acyl gellan was less sensitive to changes in pH values, and subsequently no evidence of acid gelation was observed with high acyl gellan at higher proportion. The findings demonstrated that structuring as well as destructuring of mixed gellan acid gels can be controlled in acidic environments similar to those that were presented in the stomach after food consumption.

Abstract:The protein was pretreated with soy protein isolate (0, 6min 200W, 6min 400W, 6min 600W, 12min 600W and 24min 600W), then heated (100℃, 20min), centrifuged and dried to prepare soluble thermal aggregate. Aggregates, using ultrasoundfree pretreatment of soluble soy protein isolate (original soy protein isolate was dissolved in phosphate buffer and prepared by centrifugation) as a control, to investigate the structural characteristics (spatial structure, particle size distribution, functional group, potential, hydrophobicity) and emulsifying properties (emulsification and effect of emulsion stability). The results showed that compared with SSPI, USTSPI reached the maximum in the ultrasonic time and ultrasonic power of 6min, 600W, and the average particle size, absolute value of potential, protein dispersity index (PDI) and turbidity were decreased by 273.50nm, 6mV, 0.33 and 288.2, respectively. The carbonyl and disulfide bonds in the functional group were reduced by 0.26nmol/mg and 0.38μmol/g, respectively, and the free amino and free sulfhydryl groups were increased by 0.16μmol/mg and 0.59μmol/g. The βturn structure was increased, the β1 folded structure content was decreased by 11.97 percentage points; the surface hydrophobicity was increased by 36478, and the emulsification and emulsion stability were increased by 123.56m2/g and 360.95min, respectively. The above results indicated that the thermal aggregates can change the protein structure to reduce the emulsification properties of the protein, while the ultrasonic pretreatment can resist the degradation of protein emulsification activity caused by thermal effects to some extent, which provided a method for solving the problem of protein emulsification degradation caused by heating.

Abstract:Path planning is one of the key technologies to realize its ability of autonomous action in complex environment. A nonsearch global path planning algorithm called MultiBug was proposed. It combined the merits of short path length of global path planning and small computation cost of the Bug algorithms, which generated better overall performance compared with traditional path planning methods. This method had great advantages in the situation of high timeliness and general path requirements. In the MultiBug algorithm, the simple pathfinding logic that followed the wall in the Bug algorithm was adopted, and bug splitting and death rules were added into the framework. The algorithm was ended when one of the bugs arrived at the target or all of the bugs met the death rules and dead, which permitted multipath parallel computation for local optimal planning solution. Grid maps, including multiple types of obstacles and various mazes, were used to testify the MultiBug algorithm. In order to ensure the reliability of operation results, each algorithm in the same grid map was run 10 times, and its operation time was averaged. Compared with DistBug algorithm, RRT* and A* algorithms, it showed much better performance stability in terms of the path length and the computational time cost. Especially when compared with the A* algorithm, which provided the shortest path length, it decreased the calculation time by more than four fifths with grid map size as 50×50 and only increased the path length by less than one fifth. In 500×500 grid map, the time was less than one tenthousandth of that of A* algorithm. By the theoretical analysis and the simulation verification, MultiBug algorithm had a time complexity as O(n), provided relatively short path, required less computational cost, and had good stability and versatility for various environments.

Abstract:The (RPa∥3R)2R+RPa mechanism is an asymmetric 3DOF translational parallel mechanism（PM）designed by the author’s team based on the POC equation of the topological structure design theory. This parallel manipulator has zero coupling degree and partial motion decoupling is also easy to be manufactured. The stiffness model and performance of the PM were studied. Firstly, the stiffness model of the limb was established by using the virtual spring method, and the static equation of the limb was given. Then the overall stiffness distribution of the PM in the working space was given, and the torsion and linear stiffness of the x, y and z axes were analyzed respectively. Furthermore, finite element analysis method was used to analyze the deformation of the PM, and the deformation results of the PM were compared with those obtained by the virtual spring method, the correctness of stiffness results was verified. Finally, the stiffness characteristics of (RPa∥3R)2R+RPa mechanism and Delta mechanism were compared with different sections, which indicated that the stiffness value of (RPa∥3R)2R+RPa PM was greater than that of the Delta PM. The research result laid a foundation for the structural design of the parallel manipulator, and also provided a systematic theoretical framework to evaluate the kinematic properties of such PMs as a basis for future dimensional optimization, prototype development and dynamics analysis.

Abstract:The multi-mode parallel mechanism could change the operation mode to meet the requirements of different functional and adaptive tasks. In order to realize the stationary transformation preferably between different modes, an operation mode transformation method of multimode parallel mechanism was proposed. Firstly, to obtain various operation modes and transformation configurations of the mechanism, the dual quaternion was used to describe the position of moving platform systematically, and the reconfigurable analysis of the multimode parallel mechanism was carried out based on the algebraic geometry, that was the polynomial constraint equations were established by using study parameters, and further prime decomposition was performed. Secondly, the reasonable actuation spaces of the operation modes and the transformation configurations of actual demand were analyzed and solved by preferring base pairs or moving pairs close to the base as the driving pairs. The actuation spaces of the mechanism were obtained by intersecting all the actuation spaces of the transformation configurations, and the optimal combination of actuators was selected according to the principles that the least actuators were used to realize the most operation modes and the mechanism had good performance. Finally, TCI (Total constraint index) was adopted to determine the approximate constraint singular space (κ<0.3), and redundancy actuation was adopted in this space to make the mechanism realize the transformation between operation modes smoothly. Taking SNU 3UPU mechanism as an example, seven operation modes and four transformation configurations were obtained, the transformation process between 3T mode and 2T1R mode was analyzed, and the correctness of the method was verified by simulation.

Abstract:Parallel mechanism with its advantages of high stiffness, high bearing capacity and high precision fills the shortcomings of the series mechanism. For a 3RRPaR parallel mechanism with redundant structure, a dynamic model was established based on Lagrange multiplier method, and then the dynamic analysis of the redundant parallel mechanism was carried out. Firstly, the structural characteristics of 3RRPaR parallel mechanism were analyzed, and the redundant structure was determined. Then the inverse kinematics model of the parallel mechanism was established by closedloop vector method, and the dynamic model of the parallel mechanism was established by Lagrange multiplier method. Finally, the dynamic equations of the parallel mechanism under noload and loading were solved by Matlab, and the dynamic response curves were drawn. The driving moment of the driving rod was calculated according to the relationship between the Lagrange multiplier and the constraint moment. The comparison between the calculation results and the ADAMS virtual simulation results verified the correctness of the dynamic modeling method. The results showed that the driving torque of the driving rod was increased with the loading of the moving platform, but the numerical variation law was basically the same as that of noload. The research laid a foundation for the dynamic control and mechanism performance research of the parallel mechanism, and also provided a method and idea for the rigid body dynamic modeling of other redundant parallel mechanisms. 

Abstract:Regarding the present situation of freight elevators among vertical farms to meet the new demand for peculiar functions, an extensible cargo drive system structure was presented with the study object of cargo lift for feedstuff, poultry and garbage transportation in vertical farms. Different from common cargo lift, after elevator door and layer door opening, cargo trolley needed to finish the task of passing in and out of elevator car through coordination running of driving motors in the elevator and outside of layer doors. The dynamic mathematical model for internal and external motors of elevator car was established according to the motor groups driving system. On the basis, trolleys were controlled when they passed in and out. And a vector control method of multimotor along the direction of rotor magnetic field was proposed based on the model identification. The cost of driving system was taken into account and the hardware structure was simplified, the method omitted torque sensor. The multiparameter linear adding weight model was created by integration of torque of three phase asynchronous motor, rotor flux, and estimation of the rotor position in order to obtain feedback quantity. In the final experiment, through the root mean square error, the identified results of torque were very close to the nonlinearity of the reference model. The feedback loop of control system was composed of torque and other multiparameter identification results. The experimental results showed that the control method was effective and advanced.

Abstract:Hydraulic transmission is widely used in aerospace, engineering machinery, agricultural machinery and other industries due to its large powertomass ratio, flexible control, and convenient speed control. Hydraulic motors are an important actuator, which determined the working capacity of the entire hydraulic system. In the existing axial piston motor, in order to realize multistage speed and torque output, energyconsuming components such as throttle valve and pressure reducing valve must be used to change the input pressure and flow rate, thereby reducing the efficiency. The new double swash plate multirow axial piston motor can utilize the special characteristics of its structure to achieve a variety of output torque. The structural characteristics and working principle of the motor were introduced. The theoretical instantaneous torque and torque nonuniformity coefficient of the motor under different working modes were derived. The effects of torque coefficient of the internal and external motor on torque nonuniformity coefficient was compared by Matlab. The experimental hydraulic system of the motor was designed and the construction of the experimental platform was completed, the principle experiment on the motor was carried out and the data was analyzed. The results showed that the motor can realize different speed and torque output under the rated pressure and rated displacement of the motor. As the torque coefficient ratio of the inner and outer motors were increased, the torque unevenness coefficient of the low speed and large torque was small, and the speed was high. The higher the low torque instability coefficient was, the better the design of the motor can achieve stable operation under different working conditions, verifying the feasibility of the new structure motor in principle, and providing an experimental basis for the improved design of the new axial piston motor. 