IoT-Integrated drip irrigation and fertigation for improving root and physiological metrics in aerobic rice

In the kharif and rabi of 2022-2023 and 2023-2024, a field experiment was carried out at the Indian Institute of Rice Research (ICAR) in Hyderabad to analyze the effect of different IoT based irrigation and fertigation management practices on root and physiological parameters of aerobic rice. The experiment was conducted in a strip plot design with 4 horizontal plots and 3 vertical plots, all of which were randomly allocated and replicated three times. Nitrogen management practices (4) which include N₁ - Control (no nitrogen), N₂ - 100% RDN (100% inorganic), N₃ - 100% RDN (50% inorganic & 50% organic) and N₄ - 125% RDN (100% inorganic) were the Horizontal treatments. Irrigation management practices (3) which include I₁ - Saturation, I₂ - 10% DASM (Depletion of Available Soil Moisture) and I₃ - 20% DASM were Vertical treatments. Organic nutrient sources are given as soil application and the inorganic sources are applied through fertigation. Sensor based (IoT) irrigation scheduling was done. Nitrogen application, particularly N₄ (125% RDN with 100% inorganic) consistently showed the highest physiological parameters i.e., leaf area index (4.36 in kharif season and 4.29 in rabi season) and chlorophyll content (37.7 and 31.5 respectively in kharif and rabi seasons) followed by N₂ and N₃, while saturation irrigation (I₁) resulted in significantly higher leaf area index (4.23 during kharif season and 4.16 during rabi season) and chlorophyll content (36.5 in kharif; 31.5 in rabi) compared to deficit irrigation methods. N₄ consistently showed the highest root length (21.3 cm in kharif; 20.3 cm in rabi) and density (0.388 g cm^-3 in kharif; 0.325 g cm^-3 in rabi), followed by N₂ and N₃, while saturation (I₁) consistently exhibited higher root length (19.7 cm in kharif; 18.9 cm in rabi) and density (0.375 g cm^-3 in kharif; 0.322 g cm^-3 in rabi) compared to other irrigation methods. Higher dosage and recommended dosage of nitrogen fertigation were found to have statistically similar root development and physiological parameters. IoT based irrigation at 10% DASM was found to be on par with saturation for root and physiological parameters of aerobic rice.