The Balance of Some Macro and Micro Fertilizers, The Effect on Nutrient Availability, Chlorophyll, Protein and Its Correlation with Yield Index of Rice in Inceptisols

Rice productivity is highly dependent on optimal soil nutrient availability. A balanced combination of macro and micro fertilizers is expected to improve soil nutrient balance and enhance plant nutrient uptake. This study aimed to determine the most effective combination balance of macro and micro nutrient, on nutrient availability, chlorophyll, protein, and its correlation with rice yield index of rice in Inceptisols. The experiment was conducted in Sroyo, Jaten, Karanganyar, using a randomized complete block design with nine treatments and three replications. The results showed that applying 75% of the recommended N,P,K dose combined with 100% microfertilizer (3 kg ha⁻¹) was the most effective treatment. This combination significantly increased soil nutrient availability, nutrient uptake, chlorophyll content, protein content, and yield index by 22.86% compared to the control group. The increase in yield index was mainly related to higher P, K, and Mn uptake, which improved photosynthetic efficiency and seed filling. Pearson's correlation analysis showed a positive relationship between nutrient uptake and yield index, while stepwise regression identified P, K, and Mn uptake as the main contributing factors. This treatment achieved high nutrient use efficiency by reducing N,P,K fertilizer input by 25% without reducing yield. Therefore, balanced macro- and micronutrient fertilization is an effective strategy for increasing rice productivity in Inceptisols.