Table 1. Stage-specific fertilization strategy for improving the yield and quality of turmeric rhizomes and tubers.

Growth stage (DAP)	Phenological phase	Primary nutrient focus	Secondary/ micro-nutrient focus	Fertilization rationale & strategy
0–69	Seedling stage	Balanced N–P–K	General supply	Promote early seedling growth. A balanced basal fertilizer is the optimal choice.
69–111	Leaf rosette and initial rhizome expansion	High N, Moderate K, P	Mg, Fe	Promote vigorous shoot development to ensure sufficient photosynthesis. Nitrogen is crucial for leaf and stem development.
111–139	Tuber expansion and secondary rhizome enlargement	High K, High P, Moderate N	High Mg, Cu, Fe	Promote initial formation and enlargement of rhizomes and tubers. Potassium and phosphorus are vital for energy transfer and starch synthesis.
139–195	Dry matter accumulation in tuber and rhizome	Very High K, Moderate P	Mg, Zn	Facilitate translocation of photosynthates to storage organs. Potassium is key during this phase. Nitrogen application should be ceased.
195–209	Maturation	Cease Fertilization	None	Nutrient uptake from soil is minimal at this stage. Further fertilization provides no benefit.