Abstract: 【Objective】 To address the issues of poor seedling establishment and uneven population growth in direct-seeded rice in southern China, caused by rice seeds are sown on the soil surface after mechanized direct seeding and are subsequently affected by climatic and ecological conditions. 【Methods】 Based on the principle of simultaneous coverage of rice seeds with powdered organic materials, theoretical analysis of a cam-plate metering and application device was conducted. The key parameters of the cam, discharge rotor, material push plate, and discharge apparatus were determined, and a powdered organic material discharge apparatus was designed. Bench tests were carried out. A prototype rice direct seeder with simultaneous powdered organic material coverage was fabricated, and its field performance was validated through field experiments. 【Results】 The results showed that for the powdered organic materials [organic fertilizer, seedling nursery substrate, nutrient soil A, and nutrient soil B (a 2:1 mixture of nutrient soil A and organic fertilizer)], the coefficient of variation for application rate was below 7.80% at rotational speeds of 33–118 r/min, indicating good application stability. Due to the characteristics of the materials, the coverage thickness gradually decreased with increasing rotational speed, but remained stable. When applying the seedling nursery substrate, the coefficient of variation for coverage thickness fluctuated within a relatively large range of 9.41%–18.67%. When applying organic fertilizer, nutrient soil A, and nutrient soil B, the coefficient of variation for coverage thickness was below 15% in all cases, meeting the agronomic requirements for simultaneous coverage of rice seeds with powdered organic materials. Regression equations for coverage thickness were established, all with fitting degrees exceeding 0.95. Field experiment results showed that for the rice varieties Zhongjiazao 17 and Wufengyou 286, the average emergence rates under the coverage treatment increased by 19.59% and 22.65%, respectively, compared with the non-covered treatment. 【Conclusion】 This apparatus improves the mechanized level of rice cultivation and provide a reference for the design of complete rice direct seeding machines with simultaneous powdered organic material coverage.

Key words:

text-align:justify, "> powdery organic material, rice, direct seeding machine, synchronous mulching, discharge apparatus

摘要： 【目的】南方水稻机械化直播后稻种播于土壤表面，受气候和生态环境影响，直播水稻全苗难和群体生长均匀性差。【方法】基于粉状有机物料同步覆盖稻种原理，开展凸轮-顶板排施装置理论分析，确定了凸轮、排施转轮、物料推板和排施装置关键部件参数，设计了一种粉状有机物料排施装置，并开展了台架试验，试制加工了一台粉状有机物料同步覆盖水稻直播机，并通过田间试验验证了工作性能。【结果】对于粉状有机物料[有机肥、育秧基质、营养土A、营养土B(营养土A和有机肥2∶1混合)]而言，排施装置在转速33~118 r/min条件下，排量变异系数均低于7.80%，排量稳定性良好；受物料特性影响，随着转速增大，覆盖厚度会逐渐减小，但覆盖厚度稳定；排施育秧基质时，覆盖厚度变异系数波动范围较大，为9.41%~18.67%；排施有机肥、营养土A和营养土B时，覆盖厚度变异系数均小于15%，均符合粉状有机物料同步覆盖稻种的农艺要求；构建了覆盖厚度回归方程，拟合度均高于0.95。田间试验结果表明，对于中嘉早17与五丰优286而言，覆盖处理较不覆盖处理平均出苗率分别提高了19.59%和22.65%。【结论】该装置可提高水稻机械化种植水平，为粉状有机物料同步覆盖水稻机械直播整机设计提供参考。

关键词: 粉状有机物料, 水稻, 直播机, 同步覆盖, 排施装置