The researchers tested a new method called diffuse reflectance spectroscopy (DRS) to quickly check soil quality on small farms in India. They found that DRS can accurately measure important soil properties like pH, organic carbon, and nutrients like copper and sulfur. The results showed that DRS can predict crop yields well and give similar results to traditional soil testing methods in most cases. This means that DRS could be a faster and easier way for farmers to check their soil quality and improve their crop production.