Parameter design and experiment of straw inter-row collecting-mulching device in rice-wheat rotation area

<bold>Objective</bold> As one of the main planting systems in the Yangtze River Basin of China，the rice-wheat rotation system is playing an important role in ensuring national food security and sustainable agricultural development.A driving type straw inter-row collecting-mulching device was designed to address the problems of straw aerial seeds and clogging of machinery during the operation of no tillage seeders in rice-wheat rotation areas with full straw coverage.The device removes straw from the seed belt and throws it between the rows. <bold>Method</bold> Firstly，through theoretical analysis of the driving type straw-removing spring tooth and reasonable lateral displacement limitation of straw，a mathematical model was established for the spacing between straw paddles and the lateral displacement of straw.The main parameters that affect the cleaning rate and the maximum lateral displacement of straw were determined to be forward speed，rotational speed，and working angle，and the range of values for each parameter was forward speed 4-8 km/h，rotational speed 160-220 r/min，and working angle 25°-35°.Then，with forward speed，rotational speed，and working angle as experimental factors，and straw cleaning rate and maximum lateral displacement of straw as experimental indicators，a three factor three-level quadratic regression orthogonal indoor soil tank experiment was conducted. <bold>Result</bold> The results of the soil bin test showed that the primary and secondary order of influence on the straw removal rate was the rotational speed，the forward speed，and the working angle；Among them，the interaction term between the rotational speed and the working angle had a significant impact on the straw removal rate，while the interaction term between the forward speed and the rotational speed，and the forward speed and the working angle had no significant impact on the straw removal rate.The primary and secondary order of influence on the straw lateral displacement was the rotational speed，the working angle，and the forward speed；Among them，the interaction term between the forward speed and the working angle，as well as between the rotational speed and the working angle，had a significant impact on the straw removal rate，while the interaction term between the forward speed and the rotational speed had no significant impact on the straw lateral displacement.Obtained from the multi-objective optimization model，the optimal parameter combination was forward speed of 4.3 km/h，rotational speed of 220 r/min，and working angle of 26°.At this time，the straw removal rate was 84.7%，and the maximum lateral displacement of straw was 37.5 cm.Finally，field experiments were conducted on the operational performance of the cleaning device using the adjusted optimal parameter combination.The results show that the machine worked stably，with a straw removal rate of 80.6%，an average straw removal width of 25.1 cm，and a width stability coefficient of 82.2%.The operating effect met the requirements of no-tillage sowing agronomy. <bold>Conclusion</bold> The designed driving type straw inter-row collecting-mulching device has a high straw removal rate and stable straw removal width.This study can provide a reference for the study of straw inter-row collecting-mulching tools in rice wheat rotation areas with full straw returning.