Study of the Effect of Harvest Time on Soybean Seed Quality in Ogun State

Harvest timing significantly influences soybean seed quality, with delayed harvest increasing field weathering losses and early harvest reducing seed filling, and identifying the optimal harvest window for Ogun State agroecological conditions improves farmer outcomes. This study examined the effect of four harvest times (90, 100, 110, and 120 days after planting) on seed quality parameters of soybean (Glycine max L. Merr.) at the Federal University of Agriculture, Abeokuta Teaching Farm, Ogun State, South West Nigeria. A randomised complete block design with three replications was established during the 2023 cropping season using TGX 1835-10E variety. At each harvest date, seed moisture content, germination percentage, seed vigour index (cold test), protein content, oil content, and grain yield were determined. Results showed that 100 days after planting produced the best combination of seed quality parameters: germination percentage of 91.4 percent, seed vigour index of 1,842, protein content of 38.2 percent, and oil content of 19.7 percent. Harvest at 120 days showed significantly reduced germination (72.6 percent) and increased field weathering discolouration. The 90-day harvest had incompletely filled seeds and reduced protein content. Grain yield was highest at 100 days (2.47 t ha-1). The study recommends harvesting soybean at 100 days after planting in Ogun State conditions and advocates for extension advisory tools such as visual maturity guides to assist farmers in identifying the optimal harvest stage.

Keywords: harvest time, soybean seed quality, germination, protein content, Ogun State