Site Specific Nutrient Management influence on nutrient use efficiency andbalance sheet of primary nutrients (Nitrogen, Phosphorous, and Potassium) in transplanted rice (Oryza sativa L.).

An experimental study was conducted during the kharif 2023 season at the Agricultural Research Station, Mugad, to assess the effects of different Site-Specific Nutrient Management (SSNM) techniques on nutrient uptake and use efficiency of primary nutrients in transplanted rice. A split-plot design was used with three replications, featuring two rice varieties, Mugad Siri (M 1 ) and Mugad Sugandha (M 2 ), as the main plots and various SSNM- based fertilizer treatments as subplots. These treatments included Soil Test Crop Response (T 2 ), Rice Crop Manager (T 3 ), Nutrient Expert (T 4 ), the Recommended Package of Practices (T 1 ) and an absolute control (T 5 ). Soil samples were collected and analysed for N, P 2 O 5 and K 2 O. The Rice Crop Manager (RCM) treatment (T 3 ) achieved the highest recovery efficiency (57.07% N, 59.74% P, 128.25% K) and agronomic efficiency (19.17 kg grain kg -1 N applied, 80.72 kg grain kg -1 P applied). STCR (T 2 ) showed the highest agronomic efficiency for K (83.85 kg grain kg -1 K applied) and physiological use efficiency for N (39.95 kg grain kg -1 N uptake) and K (69.54 kg grain kg -1 K uptake). M 2 showed more recovery efficiency (38.86%, 38.52% and 96.32%) and agronomic use efficiency (13.81kg grain kg -1 N applied, 56.54kg grain kg -1 P applied and 43.69kg grain kg -1 K applied)of N, P and K respectively. M 1 showed Physiological use efficiency (30.03kg grain kg -1 N uptake, 131.15kg grain kg -1 P uptake and 39.03kg grainkg -1 K uptake) of N, P and K respectively. No actual gain of soil N, P 2 O 5 and K 2 O was observed. an apparent gain of N (23.68 kg ha -1 ), P 2 O 5 (21.18 kg ha -1 ) and K 2 O (9.74 kg ha -1 ) was observed.