IMPACT OF NURSERY SEEDING DENSITY, NITROGEN, AND SEEDLING AGE ON YIELD AND YIELD ATTRIBUTES OF FINE RICE

摘要

Producing vigorous seedlings and transplanting them at the appropriate age are the most important factors for obtaining high yield in rice ( Oryza sativa L.) paddy production. The impact of seeding densities, N, and seedling age was evaluated in this experiment after transplanting 10, 20, 30 and 40-d old seedlings raised by using different seeding rates (high and low) and N conditions (with and without) in the 2008 and 2009 rice growing seasons. The study revealed that 10-d-old nursery seedlings, irrespective of seeding densities and fertilizer application, showed higher yields and yield attributes (productive tillers, plant height, 1000-grain weight, and straw yield), while at later stages significant interaction was observed with nursery management. Transplanting of 20-d older fertile seedlings grown with low seeding density at nursery-bed, resulted in a higher number of productive tillers m-2 (233.3, 227.3), straw yield (11.1, 10.7 t ha-1), and final yield (3.6, 3.4 t ha-1) in both years, 2008 and 2009, respectively. Yield and yield attributes were significantly reduced by transplanting older seedlings grown at high seeding density and without N application at nursery-bed. Minimum productive tillers (165.7, 133), straw yield (8.7, 8.1 t ha-1) and paddy yield (2.0, 1.8 t ha-1) were recorded with transplanting 40-d older seedlings grown at high seeding density and without N application. These findings support the use of young seedling in a system of rice intensification and illustrate that by making a minor additional investment to raise healthy and vigorous seedlings in nursery seed-bed, farmers can improve yields.