The researchers studied the effects of long-term fertilizer use on soil properties in a rice-wheat cropping system. They found that adding chemical fertilizers increased soil electrical conductivity, while organic sources decreased it. The soil's ability to hold nutrients increased with chemical fertilizers and organic sources. Incorporating compost and crop residue reduced the amount of calcium carbonate in the soil. Overall, using a combination of chemical fertilizers and organic sources led to higher levels of nitrogen, phosphorus, potassium, and sulfur in the soil.