干旱地区砂质土壤棉花苗床土层构建装置的研制

    Development of the soil layer construction device for the cotton seedbed in sandy soil of arid areas

    • 摘要: 针对新疆南部砂质土壤“干播湿出”棉花种植模式下,春季耕整地连续作业存在作业阻力大、苗床整不平、压不实,严重影响棉花出苗率的问题,该研究设计了一种适合砂质土壤的苗床整备装置,可一次完成碎土、平土、灭茬、镇压、耱地等作业。采用分段平土装置代替耙组进行联合整备作业,分段平土装置为两段式,首段刮土板呈“W”型对称分布,通过刮土板角度对土壤流动性、平整度和作业阻力的运动分析,确定当刮土板倾斜角为45°时碎土和平土效果最好;台架试验结果表明,镇压辊直径400 mm、碎土辊直径400 mm时综合评分最高。样机性能对比试验结果表明:较耙片式联合整地机综合工作阻力降低8.67%,作业效率提升6.6%;地表平整度标准差为11 mm;耕深稳定性变异系数为9.2%,碎土率为92.3%,表面未见秸秆残膜,分段平土装置能有效碎土、平土、灭茬;二次整备后浮动式土层构建装置能有效压实土壤构建出“上虚下实”土层结构,0~5cm播种土层平均土壤紧实度为169 kPa,适合砂质土壤精量铺膜播种作业和棉花生长,较对比机型种膜错位率下降62.5%,出苗率高于对比机型4.8%。研究结果可为砂质土壤苗床整地机研发与改进提供参考。

       

      Abstract: Cotton planting has widely used the mode of 'dry sowing and wet emergence' in the sandy soil of arid areas, particularly in southern Xinjiang, China. There are also soft and dry soil textures, as well as the residues of agricultural film. However, the continuous operation of spring tillage and soil preparation has seriously affected the emergence rate of cotton planting, such as the large working resistance, uneven seedling bed, and low pressure. In this study, a seedbed preparation machine was designed suitable for the sandy soil. The multiple operations were realized at one time, including crushing soil, leveling soil, stubble removal, pressing, and grinding. A segmented soil leveling device was also designed to replace the rake group for the joint preparation using the discrete element method (DEM). A two-stage type was then utilized to symmetrically distribute the first section of the scraper in a 'W' shape. The motion analysis was performed to explore the effect of the scraper angle on the soil fluidity, smoothness, and working resistance. Once the inclination angle of the scraper was 45°, better performance was achieved in the crushing soil and leveling soil. A bench orthogonal test was carried out to optimize the influencing factors of the diameter of the press roller, counterweight, and the diameter of the crushing roller in the machine soil layer construction device using the comprehensive scoring method. The construction of the soil layer was evaluated to compare the membership score and variance analysis of soil compactness, depth of repression, and tractive resistance membership degree. The results show that the significant influencing factors were found in the diameters of the press and crushing roller, and there was no influence of the counterweight. The optimal diameter of the press and crushing rollers was both 400 mm. The prototype test showed that the working resistance and fuel consumption were reduced by 8.67% and 5.4%, respectively, whereas, the operating efficiency increased by 6.6%. The standard deviation of surface flatness was 2.8% after two times of equipment preparation. The coefficient of variation of tillage depth stability was 9.2%, and the soil crushing rate was 92.3%, indicating no straw residual film on the surface. The segmented soil leveling device was used to effectively break the soil and stubble. The compaction degrees of 0-20, and 20-50 mm soil layer were 50-100, and 150-200 kPa, respectively. The floating soil layer construction device effectively compacted the soil to construct the soil layer structure of 'upper virtual and lower real'. The average soil compaction degree of the sowing soil layer was 169 kPa suitable for the precision sowing of film mulching and cotton growth in the sandy soil. The dislocation rate of seed film decreased by 62.5%, whereas, the emergence rate was improved by 4.8%, compared with the contrast model. The findings can provide a strong reference to develop the seedbed soil preparation for the cotton film planting in the sandy soil.

       

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