Development of algorithm for variable nitrogen rate application in cotton crop by implementing tractor mounted nitrogen sensor

To produce cotton, growers must regulate nitrogen (N) during the growing season, which is one of the most essential considerations. Any new methods, techniques, or technologies that might help farmers regulate N, a crucial choice in crop productivity, will be of great use to them. In the present study, by utilizing tractor-mounted nitrogen sensor (TMNS) technology, field experiments were conducted to design an algorithm for variable nitrogen rate application for cotton crop varieties V-1 (NCS 855 BG-II) and V-2 (RCH 773 BG-II). Under node formation, fruit squaring, squaring, early, mid, peak flowering, and maturity crop growth stages, relationships between the attributes of TMNS and variable nitrogen application rate (VNAR) were also created for V-1 and V-2. The coefficient of determination between NDVI and N content (%) in leaves was 0.933 and 0.711 at the mid-flowering stage for varieties V-1 and V-2, respectively. Both varieties differ significantly in their N response, with mid-flowering (76 DAS) being a crucial growth period. So, algorithms were developed for converting sensor sufficiency index values to N application rates for V-1 and V-2 at the mid-flowering stage. For cultivars V-1 and V-2, the crucial sensor-based sufficiency index thresholds for initiating VNAR were 0.960 and 0.860, respectively. The developed mid-blooming phase algorithms were useful to predict mid-season N-application rates for cotton crops.