Effect of mulching and iron nutrition on productivity, nutrient uptake and economics of aerobic rice (Oryza sativa)

A field experiment was conducted during kharif seasons (June-October) of 2008–2009 at IARI, New Delhi, to study the agronomic evaluation of mulching and iron nutrition on productivity, nutrient uptake and economics of aerobic rice (Oryza sativa L). The treatments comprising of 4 methods of rice production viz. bare soil (no mulch), wheat straw mulch (5 t/ha), Sesbania aculeata mulch (5 t/ha on fresh weight basis) and paddy control (puddled and flooded) as main plots and 5 treatments of Fe fertilization viz. control (no FeSO₄.7H₂O), 50 kg FeSO₄.7H₂O/ha, 100 kg FeSO₄.7H₂O/ha, 50 kg FeSO₄.7H₂O/ha + 2 foliar sprays of 2% FeSO₄.7H₂O and 3 foliar sprays of 2% FeSO₄.7H₂O at maximum tillering, pre-flowering and flowering stage, as sub-plots and replicated thrice in split plot design. The highest panicles/m², panicle length, panicle weight, number of filled grains/panicle, grain weight/panicle and 1,000-grain weight and grain yield (5.36 and 5.46 t/ha during 2008 and 2009 respectively) of rice was recorded with paddy control followed by Sesbania aculeata mulch. Fe fertilization at the rate of 100 kg FeSO₄.7H₂O/ha as basal or 50 kg FeSO₄.7H₂O as basal + 2 foliar sprays of 2% FeSO₄.7H₂O recorded significantly higher panicles/m², panicle length, panicle weight, filled grains/panicle, grain weight/panicle and grain yield (4.97 or 5.07 and 5.02 or 5.10 t/ha). Paddy control (puddled and flooded) also proved its superiority over other methods of rice production in respect of total N, P, K and Fe uptake by rice. Application of 50 kg FeSO₄.7H₂O/ha as basal + 2 foliar sprays of 2% FeSO₄.7H₂O was recorded significantly higher N, P, K and Fe uptake. Significantly higher net returns (31.05x10³ and 29.35 x 10³/ha, mean of 2 years) and benefit: cost ratio (1.36 and 1.16, mean of 2 years) was recorded with Sesbania aculeata mulch and with the application of 50 kg FeSO₄.7H₂O/ha + 2 foliar spray of 2% FeSO₄.7H₂O among the iron nutrition. Thus, growing of Sesbania aculeata mulch and adequate Fe fertilization with 50 kg FeSO₄.7H₂O/ha + 2 foliar sprays of 2% FeSO₄.7H₂O to aerobic rice enhanced its productivity and improved nutritional quality.