| Corn is the main food crop in China.The black land of Northeast China is the gold producing area of corn,accounting for 1/3 of the total output of the country.With years of over-cultivation,the black land of Northeast China is facing major risks and challenges,such as thinning of black soil layer year by year,reduction of fertility year by year,reduction of microorganisms in soil,soil hardening and acidification.In order to achieve sustainable development of the black land of Northeast China,conservation tillage techniques promotion is imperative.Strip tillage technology is an important part of conservation tillage,The research on strip tillage technology and supporting devices has practical significance and practical value for the protection of the black land of Northeast China.Using theoretical analysis,discrete element and finite element simulation research methods,the characteristics of the conservation tillage technology model in Northeast China were analyzed,the structure of the main components of the strip tillage device was studied,and performance tests and field verification tests were carried out.The main research contents are as follows:(1)Summarized the main technical models of corn production in Northeast China,and analyzed the agronomic requirements of strip tillage technology.The overall structure design of the strip tillage device was carried out by using Solidworks software,and the tillage width is 26 cm,the subsoiling depth is 25 cm,and the working depth of the soil preparation disc is 10 cm.(2)The subsoiling shovel handle curve based on the function model was designed.Taking working resistance,subsoiling width stability and working depth stability as evaluation indexes,the exponential curve equation was determined as the design curve of subsoiling shovel handle through EDEM simulation test.The angle between the fertilization tube and the fertilization plate was determined.In order to optimize the operation quality of the subsoiling full-layer fertilization device,taking the working speed and working depth as the influencing factors and the uniform variation coefficient of fertilizer amount in each layer as the response index,the quadratic regression rotation combination simulation test was designed.The test optimization results are as follows: the working speed is 3.81m/s and the working depth is 25.22 cm.(3)In order to improve the trafficability of the device,a staggered split ground preparation structure was designed.Taking the disc dislocation distance,disc inclination and disc spacing as the test factors and the soil flatness and soil crushing rate as the evaluation indexes,the quadratic regression rotation combination test was designed.The optimal structure combination of the device is determined as follows: the disc spacing is21 cm,the disc included angle is 4.5 °,and the disc staggering distance is 10 cm.(4)The field experiment of strip sowing was carried out.The field growth of maize was tracked and recorded.The ground temperature,plant spacing,row spacing and sowing depth after strip sowing were measured.The field experiment show that the qualified rate of strip sowing distance is 91.7%,and the qualified rate of sowing depth is 86.1%,all of which met the requirements of the national standard GB/T20865-2017. |
