Phenophase-based nitrogen and zinc scheduling for agronomic zinc biofortification and indices of wheat (Triticum aestivum)

A field experiment was conducted during winter (rabi) season of 2012–13 at Varanasi, Uttar Pradesh, to access nitrogen and zinc management on wheat (Triticum aestivum L.) phenophase (Zadoks scale) to increase yield, grain zinc content (agronomic biofortification) and agronomic indices of wheat. The experiment was laid out in a randomized block design (factorial) with 4 nitrogen scheduling [0 kg N/ha, 50% recommended dose of nitrogen (RDN) at sowing + 50% RDN at Z₂₀, 50% RDN at sowing + 25% RDN at Z₂₀ + 25% RDN at Z₃₀ and 50% RDN at sowing + 25% RDN at Z₂₀ + 25% RDN at Z₃₇) and 4 zinc scheduling (0 kg Zn/ha, 0.5% Zn-EDTA spray at Z₄₅, 0.25% Zn-EDTA spray at Z₄₅ + 0.25% Zn-EDTA spray at Z₆₀ and 0.25% Zn-EDTA spray at Z₄₅ + 0.25% Zn-EDTA spray at Z₇₃). Nitrogen scheduling (50% RDN at sowing + 50% RDN at Z₂₀) and zinc scheduling (0.5% Zn-EDTA spray at Z₄₅) recorded significantly higher effective tillers, 1, 000-grain weight, yield, zinc uptake, partial factor productivity (PEP), agronomic efficiency (AE) and recovery efficiency (RE) over the other treatments. Nitrogen and zinc management also positively interacted and recorded higher effective tillers, grain yield, and nitrogen and zinc uptake with N₁ × Zn₁; however, the maximum grain zinc content (52.30 mg/kg) was recorded with N₃ × Zn₂ combination.