Reliable establishment of direct-seeded onion requires coordinated control of sowing geometry, nutrient supply, crop protection, and resource use. This study combined Hartley-4 optimization of a four-section, multi-row ridge seeder with a two-year randomized complete block experiment comprising ten fertilization × crop-protection treatments. Engineering tests at 5.2, 6.4, and 7.6 km h⁻¹ identified a central operating setting at 6.4 km h⁻¹ that maintained a sowing depth of 1.5–2.0 cm and depth variability below 0.5 cm. In field plots, chemical protection with vermicompost produced the highest mean total yield (25.54 t ha⁻¹), whereas chemical split NPK maximized marketable and standard yields. Biological split NPK showed the greatest two-season yield retention (0.780), although biological protection was associated with higher downy mildew severity. The biological biocomplex treatment ranked highest under the author-defined EIQ-adjusted resource-efficiency screening index, but sensitivity analysis showed that intermediate rankings depended on aggregation assumptions. The optimized design provides manufacturers with validated parameter ranges and gives users a constant-speed platform for comparing crop-management programs. Future research should test the seeder across contrasting soil textures and speeds and directly measure field capacity, fuel use, and long-term agronomic performance.

BACKGROUND: Organic fertilizers help to increase the humus content in the soil and improve its structure. The transition to local application methods allows to significantly reduce the application rates of organic fertilizers. The combined machine developed at the Research Institute of Meat and Vegetable Agriculture is designed for local application of organic fertilizers to the soil for future sowing of melons and gourds. AIMS: to ensure stable and uniform operation of the machine's dosing devices and high-quality local application of organic fertilizers. MATERIALS AND METHODS: During operation, the machine cuts two parallel furrows in the soil using disc furrow cutters, doses organic fertilizer and applies it to these furrows. Then, the installed moldboard furrow cutters additionally process the soil in the middle between the two furrows and cut an irrigation furrow. In this case, the soil removed from the irrigation furrow closes the furrows with the applied fertilizer, forming seed ridges. The combined machine is equipped with a finger-type arch destroyer-crusher. It is designed to prevent arching in the bunker and crush large fractions into smaller ones. RESULTS: The application of the experimental planning method allowed us to optimize the main parameters and operating mode of the arch destroyer-chopper: the number of arch destroyer-chopper fingers is 12 pcs, the length of the fingers is 300 mm and the rotation frequency is 12 rpm. CONCLUSION: The conducted experimental studies confirmed the increase in the efficiency of the local application of manure, the improvement of the physical and chemical characteristics of the soil and the increase in its productivity. The results of the work can be used in the design of new generation agricultural machinery and the development of precision farming technologies