Yield performance of rainfed lowland rice as affected by nursery fertilization under conditions of intermediate deepwater (15?50 cm) and flash floods

Abstract

The effect of simulated overhead flash flooding for 10 days at an early vegetative stage of rice grown from transplanted seedlings with and without fertilizer N applied to the nursery soil, was studied under intermediate deepwater conditions at Cuttack, India. Application of 100 kg fertilizer N per ha to nursery soil at sowing or in splits improved seedling vigor measured as dry weight and N concentration of the plant tissue at transplanting. The crop raised with healthy and vigorous N-fertilized seedlings was more tolerant to ravages of flooding and showed a better stand with more profuse tillering and less mortality. The grain yield of the semi-tall cultivar Suresh was not affected by N applied to the nursery soil under partial submergence of 70±2 cm water depth. However, the semi-dwarf cultivar Gayatri planted with N-fertilized seedlings established better in the early stages and produced more panicles and a two- to five-time higher grain yield. The beneficial effect of nursery fertilization was less marked under natural flooding conditions (25–40 cm). Transplanting semi-dwarf rice with healthy and vigorous seedlings obtained by fertilizing nursery seed-bed could therefore, be a very productive low-cost technology for farmers growing rice under conditions of intermediate deepwater and flash floods.