Organic rice (Oryza sativa) and wheat (Triticum aestivum) production, quality and economics in irrigated agriculture.

A field experiment was conducted during 2004-07 to assess the production potential of organic rice (Oryza sativa L.). Wheat were grown in rotation on sandy loam soil with cowpea [Vigna unguiculata (L.) Walp] green manure before sowing rice and conventional organic sources (farmyard manure and rice straw phospho compost) to raise wheat (Triticum aestivum L.emend. Fiori & Paol) crop. The yield of rice varied from 4.28 tonnes/ha in control to 5.75-6.07 tonnes/ha in cowpea green manure treatments. The average yield of wheat 'PBW 343' with various organic sources varied from 2.68 to 3.02 tonnes/ha. The yield 'C 306' wheat varied from 2.89 to 2.94 tonnes/ha in different organic treatments. The relative yield of organic (green manure- farmyard manure treatment) rice, 'PBW 343' and 'C 306' wheat with reference to recommended chemical fertilizers was 86, 54 and 59% respectively. Manure treatment did not affect the nutrient content of rice grain. The inorganic fertilizer treatment increased the N content and crude protein of wheat grain over organic manure treatments significantly. Net returns over variable cost from rice were Rs 32 745 and 33 963 in cowpea green manure and chemical fertilizer treatments respectively. The benefit/Re invested was highest in chemical fertilizer treatment (Rs 12.85) compared to cowpea green manure (Rs 8.22-8.60). The net returns from wheat was highest (Rs 39 416 for 'PBW 343' and 25 136 for 'C 306') in the chemical fertilizer treatment, whereas benefit /Re invested was highest in farmyard manure treatment. Organic rice, 'PBW 343' and 'C 306' wheat need to be sold at 14, 80 and 67% premium over the sale price of chemical produce to compare the economic returns from both the systems.