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Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots, leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

Cotton stalk is an important renewable resource. China is rich in cotton stalk, if such a large amount of resources are recycled, it will produce huge economic benefits. But most of them are not recycled at present. In order to improve the mechanized recovery level of cotton stalk, study the influence of different parameters on the mechanized recovery of cotton stalk, and solve the outstanding problems such as high cotton stalk plucking rate and high cotton stalk leakage rate, this paper studied and designed a toothed disc cotton stalk harvester. The machine was consisted of suspension device, limit wheel, pull-out tooth plate, stalk discharge device, hydraulic motor, hydraulic pipeline and hydraulic control box. The key component of the machine was a toothed disc type stalk pulling device. During operation, the cotton stalk was lifted out through the toothed disc, and then the cotton stalk was discharged to the surface through the stalk discharge device. Leakage rate and plucking rate of cotton stalk were the main parameters to evaluate the performance of toothed disc cotton stalk harvester. In this paper, Box-benhnken central combination test method was used to study the working parameters of toothed disc cotton stalk harvester. Three-factor and three-level quadratic regression orthogonal test was designed. The three-dimensional model of response surface was established with the diameter of the toothed disc, the toothed disc speed ratio and the lifting height as the influencing factors. The influence of each factor on the quality of work was analyzed, and the influencing factors were optimized synthetically. The results showed that the lifting height and the toothed disc speed ratio had significant effects on the cotton stalk plucking rate (P< 0.01), while the lifting height, the diameter of the toothed disc and the toothed disc speed ratio had significant effects on the rate of cotton stalk leakage rate (P<0.01). The working parameters of the machine were deduced from the regression model optimization as follows: the lifting height was 66.2 mm, the diameter of the toothed disc was 627.59 mm, and the toothed disc speed ratio was 0.57. In November 2018, field test was carried out in the Yellow River Delta (Binzhou) National Agricultural Science and Technology Park. Test area was divided into 17 test plots (each plots is 30 m×0.76 m), leakage rate and plucking rate of cotton stalk at each test plot were calculated. The results of the Daejeon experiment showed that when the lifting height was 70 mm, diameter of the toothed disc was 630 mm and the toothed disc speed ratio was 0.57, the cotton stalk plucking rate could reach 1.5% and the cotton stalk leakage rate was low to 3.0%. The test results showed that the theoretical results were coincident with the measuring results, and the error between them was less than 4%. The research results can provide references for the structure improvement design and operation parameters optimization of toothed disc cotton stalk harvester. [ABSTRACT FROM AUTHOR]

The stem tip of vegetable sweet potato is an excellent nutritious and healthy food, which is widely used in many countries. It’s estimated that the total value of Chinese vegetable sweet potato’s market is about tens of billions of yuan, which means it has a promising future. Due to the difficulties of the long harvest period, high harvest requirement, and low mechanized level, the high cost and low efficiency in harvest is prominent. As such, it decreases the motivation of the farmers deeply. Also, the market still has a strong need for the stem tip harvester urgently. In order to fill the blanket in the mechanized harvest on stem tips of vegetable sweet potatoes in China, and to solve the current problems, in this research, we designed a stem tip harvester for vegetable sweet potatoes in combination with agronomy, which was composed of the reeling, cutting, conveying and collecting devices. It could finish cutting, conveying and collecting the stem tips for vegetable sweet potatoes every single row in one operation. In this paper, we introduced the harvester’s working theory based on analyzing the whole machine’s mechanical structure. To improve the integrity rate of stem tip, to lower the missing rate in cutting, to lower the stubble height and to improve the harvester’s working quality, we did a test on the harvester’s working parameters, using Box-Benhnken's central combination test method based on the single factor test. Three-level quadratic regression orthogonal experimental design was done through the forward speed, the reel speed and the reciprocating cutter line speed. The model of response surface was established to research and analysis the machine’s working quality due to different factors. Finally, the optimization of machine operation parameters was realized. The results showed that the prominent order in the stem tips’integrity rates was the reel speed > the reciprocating cutter line speed > the forward speed. The prominent order in the stem tips’missing rate was the forward speed > the reciprocating cutter line speed > the reel speed. The prominent order in the stem tip’s stubble height was the reel speed > the forward speed > the reciprocating cutter line speed. In 2019, the test was done in three times to verify the model’s correction in Baiba test base, Nanjing Research Institute for Agricultural Mechanization. The field test results showed the optimal working parameters were the forward speed 0.38 m/s, the reel speed 26 r/min, and the reciprocating cutter line speed 0.60 m/s. The integrity rate of stem tips was 97.10%, the missing rate was 12.11%, and the stubble height was 62.09 mm. The error was in the range of 5% compared to the theoretical optimization. Compared with the single manual picking efficiency of 0.001 hm²/h, the operating efficiency of this machine can reach 0.1 hm²/h, The operation effect of the machine was obviously improved compared with that of manual operation, better to meet the requirements of the vegetable sweet potatoes’stem tips machinery harvesting. The test research supplies a strong support and theoretical basis to the mechanical development of the harvester for vegetable sweet potatoes’stem tips. [ABSTRACT FROM AUTHOR]