Using a combination of organic and chemical fertilizers can improve soil quality and crop productivity in the long term. A study in Uttarakhand found that adding organic residues along with NPK fertilizer increased soil pH, electrical conductivity, and organic carbon levels. This led to significant improvements in available sulfur and calcium content. By partially replacing nitrogen with organic materials like farmyard manure and straw, the researchers saw positive changes in soil properties. Treatments with a mix of organic and chemical fertilizers showed the best results, with specific combinations proving most effective in enhancing soil fertility and nutrient levels.