Fate of ¹⁵N labeled nitrogen in maize grown with nutriseed pack using tracer technique

Deep placement of fertilizers will reduce the nutrient losses to the environment and increases the nutrient use efficiency. Nutriseed pack is a small tubular assembly consisting seed with bio-inoculants on top, manure pellet in middle and fertilizer pellet at bottom. A field study has been taken to determine nitrogen recovery and to evaluate the compatibility of phosphorus fertilizer sources with nitrogen sources which suited for Nutriseed pack by estimating the recovery of applied fertilizer N added as ¹⁵N labeled urea with Nutriseed pack in maize and retention in soil using ¹⁵N tracer technique in eastern block of Tamil Nadu Agricultural University, Coimbatore. This study has revealed that the actual nitrogen recovery from fertilizer and fertilizer nitrogen retention in the soil. The highest fertilizer nitrogen recovery (¹⁵N) in leaves, stem and grain (47.95%) was found with NP(DAP)K Nutriseed pack with phosphorus as Di ammonium phosphate placement recording the highest nitrogen use efficiency of 64.91%. Relatively low recovery of nitrogen (45.25%) was observed with NP(SSP)K Nutriseed pack with phosphorus as Single super phosphate placement recording 58.67% of nitrogen use efficiency. The labeled nitrogen retention in soil is recorded low in NP(DAP)K Nutriseed pack placement and comparatively high in NP(SSP)K Nutriseed pack placement.

Actual fertilizer nitrogen use efficiency of maize from Nutriseed pack and retention in soil have been analysed through ¹⁵N tracer method in mass spectrometer.