Nutrient uptake and nitrogen use efficiency of rice genotypes under LCC- based N application during summer

Abstract

A field experiment was undertaken at Research Farm, Department of Agronomy, OUAT Bhubaneswar to study the response of rice (Oryza sativa L.) varieties to LCC based nitrogen application under Real Time Nitrogen Management (RTNM) during summer 2015 in split plot design with three replications. Four varieties (V1- Lalat, V2- Naveen, V3- Hiranmayee and V4- Gobinda) were in main plot and sub plots were assigned with six N- management practices (N1- Control, N2- RDN@ 80 kg N ha-1 while in treatment N3 to N6, 20 kg N was applied in each split at LCC level 3 ( N3), LCC level 4( N4), LCC level 5(N5) and LCC level 6 (N6). A uniform dose of phosphorous and potassium @ 40 kg ha-1 each along with well decomposed FYM @ 5t ha-1 were applied to all the plots as basal. Nitrogen uptake was maximum (88.59 kg ha-1) in variety Naveen, whereas, the variety Gobinda had maximum agronomic efficiency (24.12 kg kg-1), recovery efficiency (37.23 kg kg-1), physiological efficiency (53.33 kg kg-1) and partial factor productivity (44.58 kg kg-1).Application of RDF resulted in maximum uptake of nitrogen (94.20 kg ha-1) and registered the highest agronomic efficiency (32.86 kg kg-1), recovery efficiency (55.40 kg ka-1)and partial factor productivity (65.61 kg ka-1). The highest physiological efficiency of 63.93 kg ha-1 and minimum N loss of 29.35 kg ha-1 was recorded forLCC 4 (N4) threshold value.