The study looked at how using a combination of chemical fertilizers, farmyard manure (FYM), and bio-fertilizers affects onion crop growth and soil health. They tested different treatments on onion fields and found that using 100% NPK with FYM and VAM significantly increased plant growth, bulb size, and yield compared to using only chemical fertilizers. This combination also improved soil fertility by increasing organic carbon, available nutrients, and sulfur levels. Overall, integrating chemical fertilizers, FYM, and bio-fertilizers resulted in better crop productivity and soil quality than using chemical fertilizers alone.