Influence of levels and time of nitrogen application on yield, nutrient uptake and soil fertility status in machine transplanted rice

A field experiment was conducted at Agriculture Research Institiute (ARI), Rajendranagar, Hyderabad, Telangana on a clay loam soil during the kharif seasons of 2014 and 2015 to study the “Influence of levels and time of nitrogen application on yield, nutrient uptake and soil fertility status in machine transplanted rice (Oryza sativa L.)”. Experiment was carried out in a split plot design with three nitrogen levels viz. 120, 160 and 200 kg N ha-1in main plot treatments and three split schedules viz.2 equal splits at active tillering (AT) and panicle initiation (PI), 3 equal splits at initial tillering (IT), active tillering (AT) and panicle initiation (PI) and 4 equal splits at initial tillering (IT), active tillering (AT), tillering (T) and panicle initiation(PI) as sub plot treatments with three replications using the long duration variety BPT 5204. Application of 200 kg N ha-1 gave significantly highest grain yield (6,119 kg ha-1) over application of 120 kg N ha-1 and was at par with application of 160 kg N ha-1. Uptake of NPK was highest with application of 200 kg N ha-1 and it decreased with decreasing nitrogen levels. Three equal split applications recorded maximum grain (6,028 kg ha-1) yield and NPK uptake. Soil post-harvest pH and EC were not affected by nitrogen levels and time of application. With increasing nitrogen levels, available nitrogen increased while available phosphorus decreased and no effect on potassium.