ABSTRACT
The traditional method of planting soybean in Nigeria does not result in obtaining maximum yield of the crop per unit area. This is due to either incorrect number of plants per stand, interrow spacing or intra-row spacing. This research work is embarked upon to develop a four-row tractor mounted precision soybean planter in order to address these challenges. The planter was designed, fabricated (in the months of June, July, and August, 2021) and evaluated in the Department of Agricultural and Bio-Resources Engineering, Ahmadu Bello University, Zaria Nigeria, during 2021 raining season. The planter has functional units off our hoppers, four seed metering units, four press wheel, four delivery chutes, four furrow openers, and four soil covering devices. The individual planting units we rearranged on the main frame at inter-row spacing of 50 cm as recommended by the agronomic practices of planting soybeans. The developed planter was evaluated both laboratory and on the field in terms of planting speed, seedling emergence, intra-row spacing, seed delivery rate, number of seeds per hole and percentage seed damage. The laboratory calibration test of the planter shows that it can deliver one (1) single seed per hole of soybeans (TGX 1951-3F) variety and 1.4% seed damage. The developed planter was mounted at the three-point linkage of the tractor (EICHER, Model: 5660, 50 hp) rear end; soybean seeds was poured in to the hopper. The tractor was set to 7 km/h, 10 km/h and 15 km/h and at 2 cm and 4 cm depth of planting and operated. A tractor forward speed of 15 km/h at 2 cm depth of planting produced the best combination in terms of seed emergence. The intra-row spacing averages 5.7 cm, and 50 cm inter-row spacing with an estimation of 400,000 plants per hectare. The results obtained from the field showed that the seed delivery rate was 48.2kg/ha, effective field capacity of 1.14 ha/hand field efficiency of 76.6%. These results indicate that the developed planter could plant 1 seed of soybean variety (TGX 1951-3F) per hole, efficient, affordable for optimum soybean plant population per hectare.