Effect of iron fertilization on dry-matter production, yield and economics of aerobic rice (Oryza sativa)

A field experiment was conducted during the rainy (kharif) seasons of 2011 and 2012 at the research farm of the Indian Agricultural Research Institute, New Delhi, to study the effect of iron fertilization on dry-matter production, yield and economics of aerobic rice (Oryza sativa L.) varieties. The experiment was laid out in a randomized block design with 3 replications. Treatments comprised 2 rice varieties (‘PRH 10’ and ‘PS 5’) and 8 sources and modes of iron fertilization-control (no iron), iron sulphate @ 50 kg/ha + 1 foliar spray of 2.0% iron sulphate, iron sulphate @ 50 kg/ha + 1 foliar spray of 0.5% iron chelate, iron sulphate @ 100 kg/ha, 2 foliar sprays of 2.0% iron sulphate, 3 foliar sprays of 2.0% iron sulphate, 2 foliar sprays of 0.5% iron chelate and 3 foliar sprays of 0.5% iron chelate. Variety ‘PRH 10’ showed significantly higher dry-matter, yield attributing characters and yield than ‘PS 5’. Highest dry-matter accumulation and number of effective tillers/m² and grain yield were recorded with 3 foliar sprays of 2.0% iron sulphate followed by 3 foliar sprays of 0.5% iron chelate. Grain yield differed significantly among the 2 varieties of rice. Variety ‘PRH 10’ gave significantly higher grain yield than ‘PS 5’. The highest grain yield was recorded from the 3 foliar sprays of 2.0% iron sulphate followed by 3 foliar sprays of 0.5% iron chelate, 2 foliar sprays of 2.0% iron sulphate and two foliar sprays of 0.5% iron chelate, whereas the lowest grain yield was recorded in the control plot (no iron). The benefit: cost ratio was recorded the highest with 3 foliar sprays of 2.0% iron sulphate followed by 2 foliar sprays of 2.0% iron sulphate and found significantly higher over all other treatments.