Abstract

Investigations were carried out to study the effect of organic farming with various sources of organic manures and their combinations on nitrogen use efficiency parameters of ADT 36 rice (Oryza sativa L.). The experiments were laid out in randomized block design (RBD) with fourteen treatments, comprising twelve treatment combinations of organic manures, one treatment with recommended dose of chemical fertilizer and the other was absolute control which were replicated three times. The recommended dose of NPK fertilizer was 90: 40: 40 kg ha^-1 for Kharif and Rabi rice. The recommended dose of 90 kg N ha^-1 was substituted through organics viz., farm yard manure (FYM), Sesbaniarostrata, composted coirpith alone and in combination with neem cake and Azolla. The nitrogen use efficiency parameters such as partial factor productivity (PFP_N), agronomic efficiency (AE_N), recovery efficiency of applied nitrogen (RE_N), physiological efficiency of applied nitrogen (PE_N)­ and internal efficiency of applied nitrogen(IE_N) values were high in the treatment receiving FYM + neem cake applied at 90 kg N ha^-1 level.

Key words: Partial factor productivity, agronomic efficiency, recovery efficiency of applied nitrogen, physiological efficiency of applied nitrogen­and internal efficiency of applied nitrogen.

Abbreviation

PFPN, Partial factor productivity; PEN, physiological efficiency of applied nitrogen; AEN, agronomic efficiency; REN, recoveryefficiency of applied nitrogen; IEN, internal efficiency.