The study looked at how different factors like seedling age, sowing density, and fertilizer amount affect the quality and yield of rice plants grown for mechanical transplanting. They found that the age of the seedlings had the biggest impact on both seedling quality and grain yield. Older seedlings had better root development and sugar content, but lower grain yield due to fewer plants and panicles. The number of panicles on each plant was the most important factor influencing grain yield, followed by the number of grains per panicle. So, it's crucial to transplant rice seedlings at the right age to get the best results in terms of plant growth and yield.