With the sustainable development of precision agriculture and the steady progress of variable-rate fertilization technology,the centrifugal variable-rate fertilizer spreader has attracted research attention due to its...With the sustainable development of precision agriculture and the steady progress of variable-rate fertilization technology,the centrifugal variable-rate fertilizer spreader has attracted research attention due to its lower incidence of crush damage,high efficiency,and low cost.To improve fertilization accuracy and uniformity,spreading performance tests were conducted using this spreader in accordance with the test methods specified in ISO 5690 and ASAE S341.2,in which particle mass was weighed in a two-dimensional matrix of collection boxes.The effects of fertilization strategies that control the feed gate flow rate and the disc rotation speed on particle distribution,and application rate per unit area and effective swath width,were investigated.A variable-rate fertilization model was developed by analyzing the variation characteristics resulting from an increasing and decreasing application rate,and field experiments were conducted to verify its accuracy.The results indicated that when the feed gate flow rate was 300 g/s,the mean application rate was 26.47 g,the standard deviation is 2.81,and the coefficient of variation of particle distribution is at its minimum value of 14.25%.When the disc rotation speed was 600 r/min,the fertilizer was most evenly distributed with a coefficient of variation of 13.86%,and an average effective spreader swath width of 24.51 m.The proposed variable-rate fertilization model showed a high fitting degree with an S-shaped function curve for both increasing and decreasing distribution rates and the yielding coefficients of determination were more than 0.82 and 0.71,respectively.The average error between the model predictions and the test results was 9.47%,and the coefficients of determination for the increasing and decreasing distribution rates were 0.91 and 0.82,respectively,which confirmed the accuracy of the proposed variable-rate fertilization model.This investigation provided a theoretical basis for traditional empirical fertilization using centrifugal variable-rate fertilizer spreaders,and guides the selection of a multiple trajectory,variable-rate fertilization strategy.展开更多
The technology used for the storage and transportation of Artemisia selengensis is becoming increasingly important with its increasing consumption and demand;moreover,the amounts of artificial planting contribute to t...The technology used for the storage and transportation of Artemisia selengensis is becoming increasingly important with its increasing consumption and demand;moreover,the amounts of artificial planting contribute to the challenges in Artemisia selengensis harvesting.Therefore,the mechanical property parameters of the Artemisia selengensis stalks were determined and researched to reduce the mechanical damage during harvesting,transportation,processing and storage.The Artemisia selengensis stalks were taken as the test object and a physical test method was adopted to study the impact of different positions,diameters,and directions on the mechanical properties by using the TMS-Pro texture analyzer;then,the relevant changing trends of the characteristic mechanical parameters were analyzed using statistical software.In the compression test,the compression load-deformation curve was observed and the breaking force and deformation were obtained;then,the compressive strength,elastic modulus and compression energy were computed.Next,the curve-fitting of the compressive strength and compression energy was carried out.In the shear test,the shear stress-deformation curve was obtained and the shear force,deformation,shear strength,and shear work were calculated.Then,the regression fitting of the section area,peak shearing stress and shearing work was conducted.Finally,in the last bending test,the bending stress-deformation curve,bending peak force,deformation,and bending work were obtained.Then the bending forces of other plants were tested,the results were compared and analyzed with the theoretical values,and finally the regression fittings were implemented.All the analysis results showed that Artemisia selengensis stalks can be considered to be anisotropic materials.The results also showed that the compressive strength and elastic modulus decreased with the height of stalk position,while the deformation increased.In addition,with the increase in the stalk diameter,the bending strength and fracture mechanical work increased,while the deformation decreased.The research results can provide a theoretical basis and reference for the design of the harvest equipment of Artemisia selengensis while minimizing its mechanical damage.展开更多
基金The authors acknowledge the financial support provided by National Key Project of Research and Development Program(Grant No.2016YFD0200600-2016YFD0200602-4)Projects funded from special funds of the National Modern Agricultural Industry and Technology System(Grant No.CARS-14-Mechanized equipment).
文摘With the sustainable development of precision agriculture and the steady progress of variable-rate fertilization technology,the centrifugal variable-rate fertilizer spreader has attracted research attention due to its lower incidence of crush damage,high efficiency,and low cost.To improve fertilization accuracy and uniformity,spreading performance tests were conducted using this spreader in accordance with the test methods specified in ISO 5690 and ASAE S341.2,in which particle mass was weighed in a two-dimensional matrix of collection boxes.The effects of fertilization strategies that control the feed gate flow rate and the disc rotation speed on particle distribution,and application rate per unit area and effective swath width,were investigated.A variable-rate fertilization model was developed by analyzing the variation characteristics resulting from an increasing and decreasing application rate,and field experiments were conducted to verify its accuracy.The results indicated that when the feed gate flow rate was 300 g/s,the mean application rate was 26.47 g,the standard deviation is 2.81,and the coefficient of variation of particle distribution is at its minimum value of 14.25%.When the disc rotation speed was 600 r/min,the fertilizer was most evenly distributed with a coefficient of variation of 13.86%,and an average effective spreader swath width of 24.51 m.The proposed variable-rate fertilization model showed a high fitting degree with an S-shaped function curve for both increasing and decreasing distribution rates and the yielding coefficients of determination were more than 0.82 and 0.71,respectively.The average error between the model predictions and the test results was 9.47%,and the coefficients of determination for the increasing and decreasing distribution rates were 0.91 and 0.82,respectively,which confirmed the accuracy of the proposed variable-rate fertilization model.This investigation provided a theoretical basis for traditional empirical fertilization using centrifugal variable-rate fertilizer spreaders,and guides the selection of a multiple trajectory,variable-rate fertilization strategy.
基金the Jiangsu Province Agricultural Machinery SANXIN Project(Project No:NJ2014-08)Jiangsu Provincial Department of Science and Technology(BE2015334),(CX(15)1033).
文摘The technology used for the storage and transportation of Artemisia selengensis is becoming increasingly important with its increasing consumption and demand;moreover,the amounts of artificial planting contribute to the challenges in Artemisia selengensis harvesting.Therefore,the mechanical property parameters of the Artemisia selengensis stalks were determined and researched to reduce the mechanical damage during harvesting,transportation,processing and storage.The Artemisia selengensis stalks were taken as the test object and a physical test method was adopted to study the impact of different positions,diameters,and directions on the mechanical properties by using the TMS-Pro texture analyzer;then,the relevant changing trends of the characteristic mechanical parameters were analyzed using statistical software.In the compression test,the compression load-deformation curve was observed and the breaking force and deformation were obtained;then,the compressive strength,elastic modulus and compression energy were computed.Next,the curve-fitting of the compressive strength and compression energy was carried out.In the shear test,the shear stress-deformation curve was obtained and the shear force,deformation,shear strength,and shear work were calculated.Then,the regression fitting of the section area,peak shearing stress and shearing work was conducted.Finally,in the last bending test,the bending stress-deformation curve,bending peak force,deformation,and bending work were obtained.Then the bending forces of other plants were tested,the results were compared and analyzed with the theoretical values,and finally the regression fittings were implemented.All the analysis results showed that Artemisia selengensis stalks can be considered to be anisotropic materials.The results also showed that the compressive strength and elastic modulus decreased with the height of stalk position,while the deformation increased.In addition,with the increase in the stalk diameter,the bending strength and fracture mechanical work increased,while the deformation decreased.The research results can provide a theoretical basis and reference for the design of the harvest equipment of Artemisia selengensis while minimizing its mechanical damage.
