Response of indigenous low cost smart fertigation system on growth, physiology, root characters and yield of groundnut (Arachis hypogaea L.)

Precise application of nutrients and water in groundnut ensures optimal plant growth, enhances yield and quality and minimizes resource wastage. It promotes sustainable farming by improving nutrient use efficiency and saving water. Field experiments were conducted at two locations. This study addresses the need for efficient water and nutrient management in groundnut by evaluating the effects of automated drip irrigation and a low-cost smart drip fertigation system on its growth, physiology, root traits and yield. Location I was a farmer's field at Kanjipatti village of Kalaiyarkoil block, Sivagangai district ( rabi 2023) and Location II was the central farm, Agricultural College and Research Institute in Madurai district ( summer 2024) of Tamil Nadu. Field trials were laid out in split plot design with three replications. The main plot treatments consisted of three drip irrigation mrthods, namely; conventional drip irrigation (M 1 ), time based automated drip irrigation (M 2 ) and sensor based automated drip irrigation (M 3 ); where as five drip fertigation treatments, viz., fertigation of 75% Recommended Dose of Fertilizers (RDF) (F 1 ), fertigation of 100% RDF (F 2 ), Soil Test Crop Response (STCR) based drip fertigation (F 3 ), sensor based fertigation at 75% NPK level (F 4 ), and sensor based fertigation at 100% NPK level (F 5 ) were imposed in the sub plot. Significantly higher growth (plant height), physiological parameters (Crop Growth Rate [CGR], Leaf Area Index [LAI], Relative Water Content [RWC], Dry Matter Production [DMP], leaf temperature, Normalized Difference Vegetation Index [NDVI] and SPAD meter value), root characteristics (number of nodules, root length, volume, and dry weight) and ultimately yield (pod and haulm yield) of groundnut were recorded under sensor-based automated drip irrigation combined with sensor-based fertigation at 100% NPK level (M3F5). Sensor-based automated drip irrigation combined with sensor-based fertigation at 100% NPK level (M3F5) recorded 43.74% and 45.25% higher pod yield compared to conventional drip irrigation with fertigation at 75% RDF in both seasons, respectively. Practicing sensor-based automated drip fertigation in groundnut not only enhanced the yield but also reduced the input requirements, saving 7%−12% of water and 15%−25% of fertilizers in groundnut production.